What Happens When the WRONG Insulation Company Gets Hired? Warning...This Gets Ugly
Vložit
- čas přidán 17. 02. 2023
- This unfortunate homeowner hired the wrong company to insulate his older Cape Cod style home. And he paid for it, twice. This video shows the methods that this other company used, why they were wrong, and how Insulwise re-insulated his home a second time so that it was permanently more comfortable and energy efficient.
- Krátké a kreslené filmy
This is exactly why I DIY as much as I’m comfortable doing as possible. Even though it takes time to learn new skills and my efficiency isn’t on par with someone who does this work for a living, no one will care as much about doing things right in my house as I will.
Either do the research and do it yourself, or hire a building-science based insulation company. And even then, you want to educate yourself as well as you can and fire as many questions at them as they can. If you find they are wary of answering questions or seem to get annoyed by it ---- walk away.
@@insulwiseenergycomfortsolu3293so I thought I saw something about the space above the room. But at the end I didn't see you. Say anything about it. So you didn't insulate the ceiling space under the room because you want heat to rise through it. But what about the space between the upstairs room and the roof?
@@davidshumway9639 Hi Dave, yes we insulate the slope ceiling areas and also the upper main attic.
We dense pack the slope ceilings with cellulose, and we air seal the upper main attic floor and then blow it with loose fill cellulose.
Andy
@@insulwiseenergycomfortsolu3293 I thought you said that but did you show it at the end. I may have gotten distracted and didn't see it. Just wondering if you forgot to cover it since the main focus was the floor bs wall areas.
Wow... thank God for people like you, sir. I am researching how to insulate a Cape style home. Thanks for the priceless knowledge transfer 👌 🙌 👍 👏
Thank you! We will be doing a more involved video where we show all of the nuances of properly insulating a Cape style home in the next few months. They are the most difficult homes to do correctly in my opinion.
Andy
After a year of research, this video shows the best option for insulating this type of home. Its also more cost effective than other spray foam optins. Yes it's labor intensive but its my home. Thank you for this!
Hi there, thank you for the compliment. We believe your assessment to also be true. You could use spray foam to spray the back sides of the knee walls, but you would still need to dense pack the slopes with a blown in material and also insulate the flat areas of the knee wall attics. We are not big fans of spray foaming the underside of roofs -- generally speaking. We find roof leaks on a WEEKLY basis in the homes that we work on, and most spray foam companies improperly spray the underside of roofs with open cell foam. To us this looks like law suit city down the road. As you've seen in the video we are also big proponents of properly ventilating attic spaces. If you do this right, you should avoid attic mold issues.
Andy
@@insulwiseenergycomfortsolu3293in the UK here banks are no longer offering mortgages or even remortgages on houses with spray foam insulation. They reckon they'll rot and don't want a property left in disrepair
4:12 Exactly the information I was looking for, thanks!
You're welcome, glad that we could help out!
Andy
I love the insight on the sealing the subflooring - one more thing I will be sure to account for when I redo the insulation in my house this spring. It's a 1954 Cape Cod style house that currently has R11 batting in the upper attic...and I have a similar knee-wall area (except it's actually a full-size door because the opposite side of the house has a dormer on the 2nd floor). I noticed similar problems with the walk-in attic: R11 batting with the kraft facing pointing out from the 2x4 studded wall frame, no weather stripping or insulation on the back of the door. So it was also nice to see how it should look when it's done, because I wasn't sure. Thank you for that. One possible issue I'm seeing with the updated insulation is that the insulation appears to go all the way into the rafters from the subfloor - and no air baffles installed. Does the house not have air vents in the soffits? Again, I potentially have a similar challenge - only 3/4s of one side of my house has soffit vents. If I understand correctly, that helps ensure that hot air in the summer can flow freely up to the ridge vent and escape. I'm also adding a radiant barrier across the bottom of the rafters (after removing existing R11 batting also in the rafters) - because my electric bill vs gas bill definitely suggests I spend a lot more on A/C in the summer than heating in the winter - even though I live in Wisconsin. I'm just not sure if I need to use a perforated radiant barrier or if I can use 1-inch foam board with radiant barrier surfacing so it's both a thermal and radiant barrier.
Thanks Tim! These spaces are difficult to properly retrofit. We bypass the slope ceiling as a ventilation pathway in these types of homes because 1) you only have 5.5" inches of space to insulate and if you use almost 2" inches of that for a baffle, you seriously degrade your R Value in a critical area 2) it's almost impossible to effectively retrofit baffles into sloped ceilings due to roof nails and no ability to staple the baffle in the middle of the slope 3) if water gets into the slope via a nail pop on the roof, it can easily dry to the upper or lower attic immediately above and below the slope and 4) we vent the lower knee walls (and upper attic if it's not already vented) using slant back vents.
We treat the upper and lower knee wall attic spaces as separate attic spaces. We've performed this solution in our area on well over a thousand homes and had good success with it. Hope this helps!
Andy
Nice work, thank you for the information.
Glad it was helpful!
Great work!
Thank you! Cheers!
Very nice job!! There’s no reason why you should have more likes and more subscribers. The home owner looked happy, especially when he offers to be your camera man.
Thank you, I agree! We did a good bit of work for this homeowner. He was in the middle of attempting to sue the previous insulation company that had done the original scope of work. Not that we don't have our bad days and miss things from time to time, but the outfit he'd originally hired was 100 miles from having a clue. But --- I see their commercials on TV and social media all the time...all that I can say is beware of the foam tube shooting shaving cream into wall bays. It's very "sexy" marketing but these companies are usually one trick ponies and have zero building science background much less interest.
Andy
I did the exact same thing in my cape in the north east. Blocking off the floor the floor joists made a HUGE difference! My crawl spaces are unseated as they should be. One thing I did that also made a huge difference was to install access doors that were solid core units set up in an exterior frame. Really worked well, and we were able to keep access to the storage areas, although they can be cold.
Nice! Yes this process works well, we've done it in probably over a thousand homes in Pittsburgh that have this configuration. The doors were a nice touch, if they're not insulated you may want to consider insulating the back side of them with a good piece of 2" inch thick foam board. The other thing you may want to consider is getting the crawl spaces ventilated, if they are not already. We've found that attic spaces of any kind that are insulated, but unventilated are good recipes for mold growth. One way or another, unplanned for water or water vapor usually finds a way in. Hope this helps and nicely done!
Andy
Great job love your videos live in texas and getting a plan together to start insulating my house
Hey there thank you, glad I can help out!
Andy
Well done, excellent videos! Thank you! This is exactly like houses from the 50s where i live in Toronto, Canada.
Questions:
1- from your comments it sounds like you installed new batts over older maybe deteriorated existing batts and then wrapped it. Do the existing batts have paper facing on either side and do your new batts have any? (Was also reading that paper facing can just be removed in recent views given its general ineffectiveness in real world scenarios)
2- my sloped ceiling spaces are the same. Lots of nails and too tight for baffles. Currently, they have older, settled rockwool batts (paper both sides) inside with a space between the roof and paper facing that allows some air flow it seems. With all things equal as your video, would it be ok to leave the air space or should the space be packed up tight?
When packed, how does the space breath or allow for moisture to escape (lets say a roof leak or rising/falling air from attic spaces)?
3- what are your thoughts on gable style vents in the kneewall spaces as an alternative. I feel like i might avoid a roof leak this way.
Thanks very much again for the great videos, let me know if you ever do any work up here, ha!
Hi Joe, thank you!
1) In this video we may have gone over top of the original R13 batts with new R19 batts to get some additional R value on the walls, but we typically remove what's there when it's in bad condition. The craft paper in all honesty is far from an effective vapor barrier. It's just paper with some tar sprayed on it -- literally. I can't remember completely, but we would have pulled the kraft paper off on the 2nd layer of batts to avoid creating a double vapor barrier (even though these things are not effective vapor barriers).
2) My guess is that those compressed rock wool batts are not giving you much for thermal performance. Put your hand on that ceiling on a sunny warm day and if it feels warm you'll have your answer. We dense pack the sloped bays every time. Typically they're only about 4-6ft long, so if there's a nail pop / small shingle leak the water doesn't have to migrate far in order to dry, either upward to the main upper attic, or downward to the lower knee wall attic space. We always vent the lower and upper attic spaces and treat them as their own isolated attics.
3) I love the gable vents in the ends / sides of the knee walls if you can get them in. In Pittsburgh we have A LOT of brick so it's far more difficult. But one in each side/ end would do just fine. They also look a little better. That said, slant back vents rarely leak. There design just really works well with shingles.
Hope this helps!
Andy
I choose to poly my slopes, but of course they added propavents before sealing the slopes. That's the best way to make kw's conditioned spaces.
This can be made to work, but the reason I prefer to not insulate the underside of the roof in knee wall spaces is because I want to get maximum air flow to the underside of the roof to help it dry during the winter months. If you have a small roof leak or mold problem, you are unlikely to see it once its been covered. In some instances when we've removed batted fiberglass or rockwool batts from the underside of roofs we have found mold growing beneath. If you have baffled and vented the roof right the odds of this happening will be diminished, but I still feel there is a higher chance of this occurring. Best of luck to you and thanks for the comment!
Andy
Hello. I’m in the process of insulating my 2-story garage - it’s basically a walk- up attic that will be conditioned space (the 1st floor of the garage will be conditioned as well). My question is specific to the 2nd story knee wall space… what I’ve heard referred to as the Devil’s Triangle. The attic within the Devil’s Triangle will be unconditioned space and I have installed wind stops in all of the roof bays, as well as baffles that extend from the soffits to the ridge vent. I’m intending to use R30 batts in the roof slope going from wind stop to just short of the ridge vent itself. I’m using R30 batts in the flat ceiling above the 1st floor space - the actual garage space - with Kraft paper facing downward towards garage space (will be covered by Sheetrock). On the backside of the knee wall itself, I intend to use 2” rigid insulation - this rigid insulation will extend into the ceiling below, for blocking - and I’m not intending to insulate under the 2nd floor conditioned space itself - I’ve read that this helps heat/cool the conditioned space above. My question is this, should I use faced or unfaced batts in the roof slope within the Devil’s Triangle? If I use faced insulation, am I creating a double barrier because I’m using rigid insulation on the knee wall and in doing so, would I be preventing any possible moisture from escaping? For full disclosure, I used R13 batt insulation (faced) on the 1st floor garage (exterior) walls. Your videos are great and I appreciate any suggestions you might have for my project. Thanks!
Hi there, sounds like quite the project! The devils triangle is the aptly named, my team and I were in one yesterday on a 94 degree day. If I'm interpreting your question right, you intend to insulate both the back sides of the knee walls and the roof slope itself? That's not something that I personally would do. I would insulate the knee wall "flats", the knee wall itself, the sloped ceiling bays, and then just the bottom flat part of the "devils triangle/ upper main attic." I would not insulate the roof deck in the knee wall space and the upper attic --- unless you would NOT be insulating the knee walls themselves and also not insulating the floor of the "devils' triangle area."
And in that case I would only insulate the underside of a roof deck with closed cell foam (if it's not going to be covered in a true vapor barrier). The kraft facing on batts is a vapor barrier in name only. Water vapor moves right through those things. With our process we leave as much of the roof deck exposed to air flow as possible to allow it to dry if moisture gets into the area. We also make sure those spaces are ventilated well. In the next week I'll releasing another video detailing how we do Cape Cods again. Hope this helps, but if you have more questions just ask. Thanks!
Andy
Thanks for your quick response Andy, I very much appreciate you taking time out of your busy schedule to share your expertise with me. This has been a big project for me but I have the benefit of it being new construction, so at least everything is open and accessible.
If I understand correctly, based on your reply and after rewatching your video dozens of times, I’m ok starting with an air baffle that protrudes into the soffit space and extends into the Devil’s Triangle and I can use a wind stop to seal from the top plate of the main floor wall to the baffle - I just need to be careful not to block the airflow through the baffle itself. This baffle will allow air to flow freely into the Devil’s Triangle. I can insulate the floor of the Devil’s Triangle (a small portion of the garage ceiling) and the backside of the knee wall itself, ensuring to put blocking under the knee wall to ensure no air moves from the soffit to under the floor of the conditioned space on the 2nd floor - and there should be no insulation under the floor of the conditioned space on the 2nd floor, thereby allowing that 2nd floor space to be residually cooled / heated by the first floor. In essence, I’ll be insulating just the “L” (or reverse “L” ) within the Devil’s Triangle (with no insulation on the roof slope itself within the triangle)?
Am I correct in understanding that I should put baffles and blocking at the top of the knee wall, and extend these baffles to the ridge vent? This in turn, allows air in the Devil’s Triangle to escape through the ridge vent? And, I can use batt insulation on the ceiling slope from the top of the knee wall to the ridge vent?
I have a flat ceiling maybe a foot or so below the ridge vent, would it be ok to put batt insulation in that flat ceiling?
Apologies for the lengthy message, but I’m anxious to get this right. Again, appreciate your guidance and expertise!
Thanks,
Craig
Wow what a cluster they screwed those folks over bad.
There are a few companies in Pittsburgh whose work we routinely redo. Like, I can't even believe people hire them. It goes to show the power of marketing I guess. The injection foam guys are uniquely bad. They tend to be one trick ponies with little if any building science chops. And that stuff is a poor product on its own IMO ( installed the stuff with two different companies when I was first getting started and saw the shrinkage first hand).
Dealt with one of thes last winter in Canada. One it got past -20C (which is basically 3-4 months long) this attic was condensating so bad it leaked through the vapor barrier and drywall and it was starting to come off the walls.
The home owner had previously had the entire knee wall spray foamed (entire roof side of bays and interior side. They spray up the sloped part of the ceiling and insulated that as well.
The upper attic had 2 huge gable vents on either side and your typical pink batt insulation between the lower bays, no spray foam up there, but it was still a sauna.
I could only recommend some temporary fixes at the time to get them thru the last month and a half of winter. I did an IR test as well as a smoke test to see where they hsd air leaks and sealed those the best i could. They were going to deal with it during summer and i wasnt involved in that so i dont know what else they tried.
But what would cause that much moisture to form
Hi there, it sounds like you made quite the find there! There are a few things that can produce large amounts of moisture in a home, moisture moving through soil and through porous block wall foundations and up through concrete floors, fish tanks, showers that are not vented out of the house with bathroom fans, but humidifiers on furnaces are usually the biggest culprits in our areas. We have seen humidifiers absolutely destroy roofs. Our solution with Cape Cods and homes with this roof configuration anticipates moisture showing up where it was not intended or expected. Venting these knee wall attic spaces with slant back vents, soffit vents, under shingle vents, etc may not be as "sexy" as using spray foam to insulate the underside of the roof --- but you are FAR less likely to have the type of catastrophic moisture situation, or even a mold problem occur.
What do you think the condition of that roof deck was beneath the foam? My guess would be not very good. Why did they not call back the insulation company that created the mess?
Andy
@@insulwiseenergycomfortsolu3293 They tried opening up the soffit vents the winter prior, and added rafter baffles though the knee walls to the upper attic.
That failed and they then brought in the spray foam company to do the entire knee wall area (minus the small upper attic) the baffles were removed and everything was sealed with foam.
The spray foam company was called back and they brought the truck out to cover some other areas I highlighted with IR pictures... this didn't solve the issue either.
I then proceeded to do the smoke test from various parts of the house to see where air is leaking to/from the knee walls attic and used my foam gun to fill in where I could, temporarily. Unfortunately with our climate there's only so much you can do when it's -30C outside as there's no way to dry out an attic at those Temps.
The roof decking in the knee wall according to the owner was fine prior to foam.
The upper attic roof sheathing, when I was there was completely covered in frost and absolutely soaked the attic from melting off.
I had removed all the batt insulation, dried the attic out the best you could and put new dry Batts down.
There is no humidifier in the house. No fish tanks or sources of moisture. The bathroom is vented to the exterior, however I don't know how long they would run the fan for after showering.
Its honestly the worst one I've come across with no obvious answer to why it's happening. They've basically rebuilt the this 2nd floor two winters in a row because of the condensation issue ruining the drywall.
Thanks. Very helpful. One question: If the bays between the ceiling and the roof deck are dense-packed, isn't there a concern about insufficient ventilation of the roof deck?
No. If water enters via a nail pop it will be able to migrate to a vented space a few feet away. The lack of ventilation where the slopes are also will not damage the shingles. Spray foam companies spray the undersides of entire roofs all the time without shingle damage (but if they're using open cell foam that could cause other damage!).
Great video, thank you. Very similar to my attic in my 1800s home, which I'm planning to use as an office space
You're welcome and thanks for the compliment! I'm glad you found this helpful. If you have any specific questions feel free to reach out, I'm always happy to help.
Andy
Thanks Andy! Do you not insulate below the roof in the knee wall? I've seen some videos where people put foam insulate in between the rafters to deflect heat hitting the roof. Also what kind of insulation do you put behind the drywall of the ceiling in the conditioned space? Did you have to remove the drywall to get that in?
@@pMurph Hey there Murph, we do not insulate the underside of the roof inside the knee wall spaces, but if you did that right (in my opinion, only using closed cell spray foam to a depth of 3-5" would be the right way to do it) you could also make that work. When insulating any structure the first thing that you need to do is define what is your air and thermal barrier, and those will nearly always be in alignment with each other. We define that barrier as the slope ceiling, knee wall, and the knee wall "flat", or flat portion of the attic floor in the knee wall space. If you air seal, insulate, and ventilate that area properly, it shouldn't really matter how hot that space gets --- that heat is not going to penetrate (or very much of it) into the living space.
We insulate the slope ceiling bay in these homes by dense packing them with cellulose insulation. The slope bay is about 5ft long normally, and we leave that space unventilated. We do this because there's virtually no way to retrofit a baffle into the space and even if there was, you'd lose valuable room for R-Value of insulation if you did. It also tends not to matter because you've got a large ventilated cavity below the slope bay (the knee wall attic space) and a ventilated cavity above it (normally anyway) in the upper main attic. These are two areas for moisture to migrate to if there is a leak in the roof and to then dry out through a roof vent.
Hope this helps!
Andy6
Thank you! @@insulwiseenergycomfortsolu3293
Great video!
Glad you enjoyed it
Thanks for the video! I’ve been trying to update my ceiling insulation and your videos have been very informative.
Covering the insulation with home wrap is interesting (at 9:23 in the video). I’ve heard of people doing that on the attic floor to prevent convective heat loss, but I’ve also seen people worried about condensation.
Have you had any issues with condensation?
Hi and thank you for the compliment! We use building / home wrap to go over the top of the fiberglass on the knee walls for two reasons. First to effectively hold it in place over the long term. We use batts fall out of or get degraded in these areas all the time. Also, we use it to act as an air barrier. It helps to keep the fiberglass from being "windwished" by air currents that may occur in the knee wall space (from roof ventilation). The prime role of the home wrap is to allow the fiberglass batt to perform its role as efficiently as possible for as long as possible.
Andy
A better method for treating the knee wall 4ft wall would have been insulating between the 2x4s with r13 so it sits flush with the studs, then on top of that use 2 inch Polly foam board rather than the house wrap. This will give a higher r value and allow you to completely air seal all the joints with spray foam or foam tape. I can’t imagine the house wrap being completely air tight.
Seeing how the inside transition was already messed up by the previous company, it would have made more sense to extend the thermal boundary to the knee wall slope and do an outside transition air seal. The soffits are not ventilated so you might as well condition this space because it has no communication to the attic.
Hi there, you're correct in that going over top of the knee walls with foam board is a better solution, but it also raises the project cost by a good bit. It's not just the foam, but all of the small triangular cuts and time that it takes on the dormer sides. We give customers this option, but hitting them with a thick layer of R-19 batts offers a massive, instant improvement over what they had.
We are not fans of insulating against roof decks, generally speaking, unless you are spraying them closed cell foam which is NOT cheap. Other solutions can allow moisture to get trapped against the underside of the roof (open cell foam, batting them with fiberglass, attempting to use foam board and trying to get all of the seams tight in difficult areas to access, etcd). We vent these spaces with slant back roof vents. This allows heat to escape in the summer, and moisture to escape in the winter. This is not only a less expensive option for the homeowner, but one that dramatically reduces the chances of a callback for a moldy roof. Thanks for the comments!
Andy
Great exactly what I need to do to my home period it's a it's a manufactured Cape and the original installation.
Was done totally wrong. I can't imagine why the people.
Who built these things everyday would get that wrong?
Thanks Matt, most of these homes were built in the late 1930's - early 1960's in the Pittsburgh area. For the most part knowledge of insulation, how to do it properly, air sealing, etc was non-existent until the 1970's. And even now we have local competitors who are "professionals" that have zero idea how to effectively deal with homes like this. Hence this homeowner paying to have it done twice within 18 months. There are multiple ways to skin a cat, but we believe our method is the most cost effective way to durably and effectively raise the energy efficiency and comfort of these homes, while providing a measure of redundancy with regard to unexpected moisture intrusion (ventilating the lower attic spaces).
Andy
Great video. You use the house wrap as to not create a double vapor barrier, almost every video on YT gets this wrong except yours! But my question is about the foam blocking. Wouldn't using those foam blocks create a double vapor barrier under your floor? I"m in a hot climate, is this something to be concerned about? Does it matter if the room is above an unconditioned garage? GREAT VIDEO!
Hi there, thanks for your comment! Do you mean the floor in the conditioned space? Or the floor in the attic space that's being used for storage? If you mean the floor in the conditioned space the answer is no because that floor itself is warm because it is a heated room. If you mean the floor in the attic space I would say that yes --- it is technically possible that that wooden floor could act like a double vapor barrier. However, the reason that it will not in practice is because the wood is loosely installed pine planking. So if we missed an air leak in the ceiling below that storage deck, and water vapor gets pushed into that space via air leakage and stack effect, it will still be able to escape through those cracks in the storage platform. At that point it can easily dry to the outside through the slant back vent that was installed in that attic space.
Hope this answered your question!
Andy
Thank you for an educational and informative video.
Is there any risk of condensation forming in the sloped ceiling bays after you dense pack them? Obviously, there's no air flow up there.
Probably a good idea to Aeroseal those old leaky ducts - they can leak up to 40% to 50% or more.
Hi Jim, great question about the sloped ceiling bays. We haven't had issues with condensation forming in the sloped ceiling bays and we've done well over a thousand homes (both 2 and 3 story) with sloped ceiling designs. We actively ventilate both the lower knee wall attics (every one, and some larger ones get multiple vents) and then the upper attic spaces also get separately ventilated. The ventilation is the main fail safe against condensation / mold issues with these types of homes.
Thanks!
Andy
@@insulwiseenergycomfortsolu3293hi did you completely fill the sloped part or did you leave a small gap for airflow?
I'm curious of the same thing. I was going to use foam board and leave a 1.5 inch air gap to allow airflow over the top plate of wall and up to the ridge vent in the upper attic.
Probably a rhetorical question, but do you do both sides of the rafter/joist bay? What kind of difference does doing one side make? I don't yet have access to the knee walls on the front of the house. The back is one large space with an access door that goes from end to end of the house, so I can easily block one side of the joist bay. You can definitely see the transition in the ceiling on my Seek Compact thermal adapter. The knee wall area that has batts laid in the joists reads warmer than the uninsulated core ceiling because of the draftiness. I would block the soffits, but they're baffled and I am going to be replacing the current one with some Hardisoffit for better flow. I currently have a bunch of 2 inch vent plugs that dont equate to much air volume.
Not sure I understand you're question, but if you mean do we seal the floor transition gaps in both the front and back of the house the answer is yes, 100%.
@@insulwiseenergycomfortsolu3293 The bay will have two sides, one on the front and other at the back of the house, so there will be two openings under the floor that stretch from soffit to soffit. I was wondering if there was any measured difference with doing just one end of the bay as I'll have to cut into the sealed knee walls that flank the dormer windows on the front of the house. I'm thinking it would stop air transfer, but I guess you really need to block both sides since the stack effect will cause pressure to move heat to cold.
Great video! What did you for the soffits when blowing in the insulation? Didn't see any of the vent barriers.
Thanks! We didn't install soffit baffles because this home did not have soffit ventilation. Instead we installed vents in the knee wall spaces to ventilate the small knee wall attics.
Andy
@@insulwiseenergycomfortsolu3293 thanks for the reply!
What did you do in the slope ceiling bays? Is there a good way to get insulation all the way up into them? Thanks!
Hi Oscar, good question. We dense pack those sloped ceiling bays with cellulose insulation. Our normal practice is create a plug at the bottom of the bay with fiberglass, and then pack them from the top down using a fill tube and the dense pack cellulose method. Using some type of blown insulation technique is the only way that I know of to effectively insulate cavities like that. For a variety of reasons we prefer cellulose insulation, but you could also use blown fiberglass or even rock wool. Hope this helped!
Andy
Great video but I face the opposite problem. Very hot and humid climate. I don't have a " knee wall" per se but my second story is more of a 1.5 story home meaning the second story is build inside of my attic. I am very leery to seal the area below the transition as you did, as I don't want to trap heat and humidity between the floors of the home. also instead of doing a home wrap as you did, I planned on adding a foam board insulation to cover my r13 bat thats currently installed. Thoughts? again FL climate.
Hi there, thanks for the comment. Any time you are insulating and air sealing a structure, the first thing that you need to do is clearly define where your air and thermal barrier are going to be. In just about every case that I can think of, these two things should be aligned with each other, meaning the same wall, floor, or ceiling plane. That's why we seal the gaps beneath the second floor walls which we call transition gaps (because that is where the home transitions from conditioned space to unconditioned space). Our summers here in Pittsburgh often get very hot and humid as well. What happens is that as air in those outer attic spaces heats up and expands, it will "expand outward" and radiate heat beneath the floor of those rooms --- IF those transition gaps are not sealed. You are relying on your home's AC system to cool and dehumidify the air between your first and second floor at that point. The space between your first and second floor, assuming they are both conditioned spaces above and below, is definitely considered to be a conditioned space.
In terms of going with foam board over top of those walls that now have R-13 batts in them, that is a terrific solution. I'd recommend using a foam board that has a silver facing on it that will also act as a radiant barrier and reflect heat back out toward the roof. That is actually a better solution than the one used in my video because the exposed faces of the studs will also be insulated. When we work in homes that already have a well installed R-13 layer in those bays we do the same thing. But we use R-19 batts when there is no existing insulation or when what is there is bad or degraded. Installing a new R-13 layer and then foam boarding over top of it becomes cost prohibitive for our customers (and having a well installed R-19 batt with an a moisture permeable home wrap over it produces a very good result on its own).
Lastly, I would encourage you to make sure that any of your attic spaces that are unconditioned are properly ventilated. You always want to leave a good way for water vapor to exit an unconditioned attic space. Doing otherwise tends to encourage mold growth.
Hope this helps!
Andy
I have the same situation in hot humid Arkansas with a 1/2 second story built into my attic. The second story walls have R13 with the paper facing out. I gather I need to turn the R13 around so the paper is against the drywall then install the silver facing foam over that? Does the foam not create a second vapor barrier? Watching the video I assumed the use of the home wrap instead of foam was that it would let moisture escape.
@@arclay10 The foam is not a vapor barrier without an actual vapor barrier on it. If you go around and air seal all the cracks and gaps then it could potentially become a vapor barrier but it's not enough of a risk to consider it a serious problem imo. Now if you were to take crawlspace vapor barrier and wrap the room that might be an issue. If you can't find foil faced foam, you can always buy radiant barrier from atticfoil and use that. That stuff is a breeze to install and helps a ton.
Would a foil type radiant barrier help as well on those exposed roof joists areas as well?
I don't have much experience with radiant barriers. When I have seen them they've always been covered in dust (attic spaces are dusty) and that seriously reduces their effectiveness. It might help, but I would be surprised if it moved the needle much.
nice job
Thanks AZ Overland!
Would you add rockwool insulation to the backside of the knee wall? There is insulation on the floor of the attic and in the roof rafters.
This is how Capes get tricky. You NEED to define what your air and thermal barrier is going to be --- either the roof slope or the back side of the knee walls. If you are committed to having the roof slope insulated, we would not recommend also insulating the knee walls. This creates in essence a "double vapor barrier" situation which is not ideal. Our preference is to insulate the knee wall, making it the air and thermal barrier, and then ventilating the knee wall space to allow for heat AND moisture dissipation. We don't believe it's a good idea to insulate an exposed roof unless you are using closed cell foam (because it has a vapor barrier at 2" thickness). But closed cell foam is quite expensive.
Andy
@@insulwiseenergycomfortsolu3293 I would like to have the insulation in the knee wall for noise.
Typical Yinzer quality. Sad to say…
I have MANY similar stories concerning “local experts” who committed to various projects (interior and exterior) after promising in depth expertise and “first rate” performance. Caveat Emptor!
Yes, and in this case the local yinzer was a "professional company" that advertises like crazy. But they're a franchise that primarily injects tri-polymer foam into exterior walls. They seem to have zero building science background or even interest. If they're not pumping foam (which we are not fans of -- see the video when it falls out of the stud bay) than they are possibly damaging your home. We have had to redo a number of their jobs...how BAD is that?
Andy
Why would you have openings into knee wall if there is no floorboard for storage.
Good question, many people actually do not. Often we need to cut in openings to perform our work then install drywall patches when we are finished. But some homeowners want to have them so that they have access to those attic spaces so they can get to them if there is a roof mold or critter issue. I personally would opt to have the access. I would want to be able to see and inspect every part of my house that I'm able to. I have seen too many small problems turn into big ones because areas were out of sight.
Andy
Ahhh i cqn totally relate as i just finished bug room that looks very similar and one side has a small knee wall we have no way of getting too right now as no access door was created. I will at some point i will add floor board, it has foil bubble backing the fiberglass batting, which is s vapor barrier also but now i want to put foam board in first then put the foil bubble up. The foamboard will as you said seal that off. Thanks for the answer.
Very informative. Did you consider making the knee wall area conditioned space? And what foam board do you use. Thanks!
Thank you, the only way to reliably make knee walls a conditioned space in my opinion is to use close cell spray foam on the underside of the roof. You need to install something against the roof that is a 100% reliable vapor barrier, otherwise you invite a mold/ roof rot situation. Closed cell foam however is very expensive, and most people do not need to use these spaces for anything but storage. Our solution is designed to economically make the original conditioned space more comfortable and energy efficient, while safeguarding the integrity of the roof by providing a way for moisture to escape to the outside. For air sealing we use 1/2" thick silver faced polyiso foam board. For insulating the knee wall access hatches we use 2" thick XPS foam board for the extra R value and durability of it.
Andy
@@insulwiseenergycomfortsolu3293 thanks!
This looks exactly like my house. Are the R-19 batts faced, towards the heated living space?
Hi John, yes the kraft paper is always toward the heated / conditioned part of the home. It's intended to function as a vapor barrier (IMO it doesn't perform this function that well, and certainly not after it's been baked in a hot attic for a years, but that's another matter). Hope this helps!
Andy
I've been trying to find the perfect video for my attic knee walls and this is it. My rafter bays were completely insulated with fiberglass all the way up to my ridge vent with no baffles. What is your suggestion to fixing this? I may of already pulled down 2 rafter bays of fiberglass to make an escape route for the extremely hot air. Edit: I have soffits and a ridge vent but no airflow
Thanks! In homes with knee walls we insulate the upper attic floor, sloped ceilings, backsides of knee walls, and the "flats" inside the knee wall attic spaces. We almost never attempt to ventilate the sloped ceiling bays, we dense pack them with cellulose insulation. We then treat the upper and lower attic spaces as individual attics and ventilate them appropriately. This has worked extremely well in the hundreds (probably over a thousand now) homes that we have done this in in the Pittsburgh area.
Andy
@@insulwiseenergycomfortsolu3293 Thanks for the reply. In terms of ventilating them as individual spaces how to you move the hot air out of the knee wall? Gable vents can be used at the very top but what about the lower space?
Hi! Thank you soooooooo much for this video. Question about the slanted walls… is it ok if there’s no air ventilation between the knee wall and upper section? I was think if moist air entered that area even from the knee wall it could create condensation and mold…
Hi and thanks for your comment! We individually vent those knee wall areas and this case did that with slant back vents. The sloped bays are too difficult to attempt to retrofit baffles into (we used to try). Also, if you were able to put in a baffle, the 2" thick baffle would reduce reduce the R value of insulation in the slope bay by ( 2" wide baffle / 5.5" wide 2x6 joist) almost 40%. When both the lower and upper attic spaces of these homes are effectively vented we do not see moisture / mold problems. And the Pittsburgh climate is a mold maker...we get tons of precipitation and lots of cool (below dew point) weather.
Also, here is a link to a fresh Cape Cod renovation video that shows the vent process more clearly.
czcams.com/video/x_z9FLeg5AA/video.html
Andy
Thank you for the reply! How do you go about dense packing the floors? Is the foam board enough to handle the pressure? @@insulwiseenergycomfortsolu3293
I'm a DIY person that has added insulation on a few newer houses. In a Cape Cod with knee walls spaces, would you want to open any soffit vents into the space?
Hi Chuck, it depends where you are choosing to make your thermal barrier. If you make the knee walls, knee wall flat, and slope ceiling like we do, than yes. You definitely want to ventilate any unconditioned attic spaces, however you can get the air flow. If you can open up soffit vents that’s great. We usually pop in slant back vents to ventilate those spaces.
Andy, Owner
Hi Chuck,
Sorry I thought that I responded to you already. Where, if, and how you ventilate depends on WHERE you choose to define the thermal barrier. We almost always choose to define the thermal barrier as the knee wall flat, knee wall itself, and then the slope ceiling. In that case yes, you want to bring air flow into those knee wall spaces any way that you can. If you can do it effectively with soffit vents that's great. We usually just pop a slant back vent, box vent, roof louver etc, into each individual knee wall space. Doing this helps the knee wall spaces to exhaust heat in the summer, but more importantly allow moisture to escape to the outside during the winter (if any finds its way in) which will prevent mold growth. Hope this helped!
Andy
Would a Cape Cod style knee wall be an appropriate place to use rafter baffles, to connect ventilation to the central attic?
Hi John, technically speaking yes that would be an ideal place to install ventilation baffles, but there are a few issues to note here.
1) These bays often already have some type of degraded insulation in them, and there are always nails coming down from the roof, so it's often difficult to impossible to effectively install baffles. You're also going to need to double up a 4ft baffle to get it to extend down into the lower knee wall attic AND have it extend above the insulation in your upper "main" attic space.
2) You still need to have your lower knee wall attic spaces vented somehow, either with soffit vents, slant back vents, or under shingle intake vents to bring in outside air to "feed" the vents in your upper attic.
3) Most of the roof rafters that we see in these homes are 2x6's, which in reality is actually 5.5" inches wide. So you're already seriously constrained for space in terms of adding additional R-Value for insulation. If you install a baffle that takes up another 1.5" of space, so now you're down to 4" for your insulation layer.
That said, if there is no drywall in place and things are totally exposed, we will baffle the sloped bays and install a R-19 or R-13 batt of fiberglass. A proper ventilation channel is always nice, but for we rarely see homes where there is no ceiling in place. The way that we insulate Cape Cod and Three Story homes has been delivering significantly improved thermal / energy efficiency performance for us for years, with mold free attics to boot.
Thanks!
Andy
@@insulwiseenergycomfortsolu3293 awesome, thank you for your insight. It'll help me get my house sorted out.
Is blocking the ceiling joists necessary if its insulated under the decking of the top floor? Getting ready to finish our cape cop and under the upstairs decking is insulated so is the blocking necessary? Thanks!
Yes, it is necessary. The reason is because insulation itself does not stop air flow and air leakage. When we encounter floors in these spaces we cut a 12" wide gap in them, seal the "transition gaps", and then put the floor back in. It is certainly more work, but it will improve the comfort and energy efficiency of the home for doing it.
Andy
How can I find a company like yours in my area (New Jersey)? Excellent job, I would love to locate a company like yours to seal up my cape code. What would a job like this typically cost?
Hi there, unfortunately I don't know that area well, but I would recommend looking at insulation company websites and try to find companies that emphasize a building science based approach or at a minimum mention air sealing extensively on their web site. Far too many companies are "Jim Bob's" with a truck performing this work as if it was still 1972. Lastly, if they insulate knee wall spaces the way that we do (isolating them), they really should be individually ventilated one way or another, otherwise the risk of downstream moisture / mold issues goes up significantly.
Good luck!
Andy
Excellent video, but you didn’t show how you insulted the slant wall or the top space.
Correct, that's an omission. I am going to create a proper video that shows how we insulate these types of homes that shows all of the details. In these case we dense packed the slopes with cellulose insulation. The slope itself is unventilated, as it's nearly impossible to get a baffle into place. But if there is a nail pop or some water intrusion through the roof, the moisture does not have to migrate far before it hits either the ventilated attic above or below.
Andy
Should there be insulation under the floor of the living space if an unconditioned garage is directly below the room?
Great question -- the answer is yes. We dense pack garage ceilings with cellulose insulation here on a weekly basis. Almost all garage ceilings, even on houses built recently are ineffectively insulated. The older houses often have no insulation. Fiberglass batts are almost always ineffective. You NEED a solution that 1) blocks air infiltration coming in at the exterior wall rim joists and 2) stays in constant and continuous contact with the floor above.
Andy
@@insulwiseenergycomfortsolu3293 thank you Andy! I have a completely unfinished room above my garage. It is only studded with zero insulation. I’m trying to understand what the proper way to do things are before I DIY or hire someone. I am in a fortunate position to where I can be sure it is done properly the first time. Good to know fiberglass batts are ineffective in this application. That was going to be my initial plan of action.
I have a cape cod house in South Carolina my knee walls are not insulated. So I need to use unfaced insulation and what kind of plastic wrap around the insulation? When I go in my crawl space and look towards the outside wall I can see daylight
If you're just doing the knee wall spaces, you want to 1) air seal the electric outlets and floor joist openings beneath the knee walls 2) insulate the back side of the knee walls with at least R-19 kraft faced batts (kraft facing goes against the interior walls) 3) cover the batts with a home wrap such as tyvek paper or a store brand equivalent. Or you can go over the fiberglass with foam board for extra R value. That would be my suggestion.
Andy
@@insulwiseenergycomfortsolu3293 wouldn't the home wrap act as a second vapor? I have a similar knee wall but larger in a split level house and am considering doing similar
(great video btw, thank you!)
Question. Before you put the insulation boards in and foam around them, do u push insulation in under the floor first? Does it matter, or make it worse. Great video. My entire house is like this and house never gets warm.
Good question. We do not put insulation in between the two conditioned floors. You would typically not insulate in between conditioned floors or rooms, unless the intent is to insulate against sound transfer. In this case we want the heat from the first floor to rise upward and warm the floor of the second floor. Blocking the "transition gaps" with foam board and foam sealant ensures that the warm air rising from the first floor cannot escape into the knee wall spaces. Hope this helps!
Andy
@insulwiseenergycomfortsolu3293
How is the space between floors ventilated, now that it has been sealed from the unconditioned air?
@@insulwiseenergycomfortsolu3293so one area is conditioned to conditioned and I have insulation in the normal locations so I will add the panels so the outside air does not go through the floor. However my second to third floor is conditioned to a completely open third floor with zero insulation. We never finished it so it’s just storage. The 2nd floor ceiling has no insulation and I think all my heat is getting lost there. So I should pack the third floor with insulation and put panels in as well correct.
If the hot spot ( or cold in winter) is now above the sub floor, why bother insulating the gable ends?
We would not insulate the gable ends inside the knee walls in an attic like this.
What did you do in the slope ceiling bays?
Hi Walt, when we deal with homes that have upper floor structures like a cape cod style home, our standard practice is to dense pack the sloped ceiling bays with cellulose insulation. We block the bottoms of the bays with plugs of fiberglass insulation, and then dense pack them by fill tubing down the bays from the upper main attic space. The lower knee wall attic spaces and upper main attic space are then treated as two separate attic spaces, and ventilated accordingly.
Thanks!
Andy
So you blocked/plugged the soffit and up the sloped ceiling bays? My attic is a cape cod style but my soffit aren't blocked and I have insulation up my sloped ceiling bays just like you showed earlier in the video, and I have a ridge vent. I tried to create some sort of air flow by stuffing baffles on my sloped ceiling ontop of my sloped insulation. So that air flow can come from my soffits, through the sloped ceiling baffles and out the ridge vent. I feel like your video is the opposite of what I just did.
@@leekyciabrown3769 Hi there, this house did not have any soffit vents, many of the older homes in this area do not have them. We installed slant back vents to get air flow into the lower knee wall attic spaces. We dense packed the sloped ceiling bays full. The upper main attic and lower knee wall attic spaces are treated as individual attic spaces with this method. We dense pack the slope sections to maximize R-Value for the homeowner, and also because attempting to slide baffles up from below or down from above is often impossible, depending on 1) the thickness of the existing insulation in the slopes and 2) the length of the nails used by the roofers to attach the shingles. As long as these individual attic sections are decently ventilated, and they have been air sealed (this is a huge part of our process for limiting moisture build up in these areas), than there should not be an issue with mold growth.
Hope this answered your question!
Andy
So why you not insulated part of oblique roof?? I mean this part where you put ventilation. Just what I need to do is a floor and other side of iside walls?? Thanks
Sorry for the late response, we chose not to insulate the area where we installed the vents because you don't want to insulate the underside of a roof unless you have a vapor barrier present. If you just put fiberglass batts into the bays water vapor from inside the home can migrate through and around the fiberglass and become trapped against a colder roof deck (in the winter) and then condense and cause mold growth. We often encounter batts that are installed against the underside of roofs in knee wall attic spaces, and when we remove them often find that mold has been growing on the underside of the roof. Hope this helps!
Andy
Does that home have soffits?
This home does not have soffits. We installed slant back vents in every knee wall in order to get them ventilated.
Andy
Did you use baffles or are they not necessary for this type of job? Thanks
This house did not have any soffits or lower intake ventilation, so we did not install them. We ventilated these spaces by installing slant back vents in the roofs of the knee wall spaces.
Do da man thank you@@insulwiseenergycomfortsolu3293
Great video. Is the house wrap meant as a vapor barrier? I’m guessing not as it has some gaps along the bottom. Is it only meant to air seal? In either case, are the gaps okay?
Thanks! For homes in heating zones (where there are cold winters) the vapor barrier should be on the inner side of the thermal / air barrier of the home. In most cases that the walls with several layers of paint on them (not perfect, but still pretty effective).
The house wrap in this case serves two primary purposes. One is to protect the fiberglass and hold it in place over time. The second is to protect it from air flows inside the knee wall spaces which can act as a "wind washing" process which wicks heat from the fiberglass batts.
Before we install the batts, we use foam to seal all of the penetrations on the back side of the knee walls such as electric outlet boxes, switch boxes, etc.
Hope this helps!
Andy
Man. Need a respirator with. Microphone. Someone patent that. Youre welcome.
Haha...I agree!