Hey Mike, I've seen the flash and batt method used successfully. 1. Start with 2x6 walls. 2. spray 2 inches of closed cell for a good vapor barrier. All rim joists and soffits are filled only with foam. 3. R-21 batts are applied next. If a stud bay has been overfilled just compress the batts because you already have enough insulation in that spot from the foam, the reduced insulation value from compressed batts aren't an issue. 4. Moving the dew point in the wall isn't an issue with this method. By the way, I love the content you put out. Don't stop!
Watching all your videos, deeply appreciate the information, turned to your channel after Marshall Remodel mishap, your doing a great service to the home building community! Im on the framing process of my barndominium build already researching best insulation practices, howdy from Texas 🤠
Very good video! I have talked about this before but I got a garage added to my house when I purchased it in 2012. Amongst a few issues where corners were cut I felt shorted by only having 2x4 walls and 2x4 trusses. So I built out the inner walls to allow the install of more insulation. I originally got a quote for 1inch foam and the rest in a net and blow system. After doing some further research I found that filling out the rest of the cavity with open cell was a better idea. In all the outer wall has much closer to 2 inches of foam with the rest open cell. While not ideal the system works very well especially for sound. Now, when I remodeled my son's room in the existing house I made a point to fill the entire outer cavity with closed cell spray foam. The foam was trimmed flush and I installed a second 2x4 inner wall for wiring. I then placed rockwool batts in those walls. That was more for sound but had the added benefit of insulation. Long story short I only did that because I was confident in both systems on the outer side and the inner side. His room also has rockwool on the inside walls so not to hear me watching videos like these in the spare bedroom on the other side. I really like that system much better and he and his brother, the cat, like sitting in the window sills and only loosing 3.5 inches on the outer walls. The second reason I took this approach is because I also had the entire house resided when I purchased it. The siding contractors ripped off the wood siding in a day and I came home to find the entire house wrapped in house wrap. What I didnt find out until years later was the reason they worked so quickly. After adamantly recommending I get the entire wood siding removed they neglected to think about what was under it. I simply had 1/4 inch polyiso with thousands of nail holes in it for the siding. Instead of putting up OSB they quickly covered the walls with house wrap so I wouldnt notice. Adding that second inner wall firmed up the system. If I ever get the house resided I will get 1/2 inch OSB bolted to the studs and rigid foam on the outside. In the meantime I have to fix the issue one room at a time when I remodel. The closed cell foam in the entire cavity does a good job of making the structure rigid.
@@SprayJones Stories like this guy's need to be told. I saw this in the late 90's when I was an apprentice, you could walk up, cut a hole with a utility knife next to the door ,reach in and unlock. Spray foam would be a good fit to add wall strenght and air seal during an interior reno.
I have been developing a wall system that can handle the 50°C to -50°C temperature variation we can get here in Saskatchewan. Your videos have been invaluable.
I can’t tell you how many times I’ve tried to educate building inspectors on Foam. And argued with them when they wanted to put a vapor barrier in the bathroom on top of the spray foam. Also mostly arguments stemmed from achieving a proper R-value that’s all they seem to care about lots of times we are forced into a flash and fill scenario just saw the house with pass inspection. Even had the inspectors push back on engineered drawings. We both amazed and terrified me thinking these guys were so arrogant that they knew better than engineer.
I'm approaching the deadline of making a final decision on insulation in zone 3/4 depending on what map you look at. One of the local contractors who's known to blow 0.1- 0.15 ACH uses Closed cell spray foam on the top and bottom plates, banboards, and any seam with the OSB board and they also use 3" of CC on roof decks at a minimum. Here's the twist they fill a 2x6 cavity with R-22 of dense cellulose for sound dampening and insulation if I subtract the cellulose and add 2" of closed cell it raises the price on my home 10,000% which was the entire budget in 2019 during planning, haha. I like the idea of sound dampening due to being out in the country. We have quads, dirt bikes, cattle, loud trucks, etc and anything to keep the interior space quieter is a plus and being 10,000 cheaper makes it difficult to see the ROI. I do like the added strength close cell provides especially since my wife designed a 2-story home with a 12/12 pitch room and added two loft bedrooms. I also noticed a lot of the well known channels aren't using the pink stuff it's either Rockwool or Cellulose. One of the older Build show uploads had closed cell with a layer of dense cellulose. I can't recall the reasoning behind that combo outside of bypassing one of your listed problems of the insulation getting in the way of drywalls.
I am in the middle of a gut-reno of an old balloon framed block house zone 4A. We framed new exterior walls 5" off the block (required by engineer for structural reasons), and the current plan is to spray 2 inches of ccSF continuously along the masonry walls, then add mineral wool batts to each stud bay. My question is, mineral wool is 3.5". Should it be pressed against the foam, leaving a 3" gap between it and the drywall? Or is it better to leave a gap between the foam and mineral wool? Why mineral wool and not more closed cell? Sound attenuation. Urban location. Thanks for any help!
I am a retired mechanical engineer and always only heard the horror stories about spray foam. Thank you for this channel. If I buy another house, I will spray foam the attic.
The main issue is having the right sized studs cause in some areas you have to have a certain amount of spray foam before you can even do flash and batt per code. Usually min 2-3 inches to be a vapor barrier and thats just walls. Usually you have to have more in the roof cause of temp differences. I also feel it depends on the experience of the contractor doing this and being able to do a good job
My next house I am thinking do spray foam on all exterior walls and attic. On the interior walls I want to use a BIBS system for sound proofing/bonus R value.
Hi! At 12:24 you circle the spot where the wall meets the truss, what point are you trying to make? We’re currently building and my husband wants to spray foam in that exact area to get an air seal, while the roof is an open vented roof.
I am planning to CC SPF my detached garage workshop. After discussing plans with two spray foam contractors in my area, both had no problems with spraying 2” of CC on the walls (R14) to leave room for R15 rockwool. The reason I want the rockwool is to provide additional sound deadening for my neighbors. They said the additional foam would not be as beneficial as the rockwool would be to the sound deadening and the R14 of foam is a great air sealing and I shouldn’t have any condensation problems. I live on Long Island (Southern New York) Do you see any issues with this plan? The walls are 2x6 The roof will be getting 4” of closed cell as well.
I did the same. It seems to work well. Quietest room in the house. However, like you I made sure I had enough foam to do the job by itself before adding anything else. In my case it was 3.5inch closed cell foam with a separate 2x4 inner wall which is not structural, has all the wiring, and contains 3.5inch mineral wool. My son loves his thicker window boxes and so does his cat. It has the added benefit of being Quiet. Now I just need to at least put rockwool over the room or finish the entire attic with more spray foam.
Thank you for your extraordinarily thorough videos. We are building a new house in Ohio. The upshot I have from your multiple videos is: 2" spray foam walls and 4" spray foam vaulted ceilings and attic roofs, and DO NOT use hybrids by adding other insulation. Is it reasonable to expect that new wiring can be run through walls years later (say adding an outlet) without having to remove the drywall? Assume 2 x 4 studs.
@@SprayJones So, if 2" CSF is used, then adding wiring or re-wiring electric years later is no more problematic than if the walls were batted? This is an argument the contractor is using against 2" CSF between 2x4s.
@@SprayJones Yep, got it! Your spray foam and electrical wiring video nailed it. As usual, that video was extremely thorough and completely squelched my contractor's concern. Thanks.
When the chart is talking about outboard insulation, isn't it referring to exterior insulation, so Ridgid continuous insulation in the outside of the house. That way the air barrier is on the outside of the house and the dewpoint would be in the exterior foam rather than in the wall. I may be wrong, please correct me if I am.
You are on the right track. In board to out can be just that or it can be the location of where the vapor barrier is placed in open fibrous insulations.
@@SprayJones I live in valley stream, NY marine 4... My plan so far is to have r10xps on the exterior of the home and to airseal the cavity and install Rockwool. This way the house can dry to the interior if any water were to somehow either get into the cavity or to get onto the exterior sheathing. Another option I was thinking of was to flash the inside of the cavity with 1" of closed cell and then install Rockwool batt in front of that. This way approximately 1/3 of the total insulation is still on the outside of the house. I already have the r10 XPS on the outside, would it be overkill to install 1" of Closed cell on the inside? No matter what I do not want to use open cell since it's more like a sponge and would take for ever to release the moisture it absorbs. Also a site I use often is, it's an amazing tool to help calculate total r value of the wall, especially since it takes into account framing. From my understanding it wouldn't make sense to do all spray foam in a 2x4 wall with no exterior insulation because the cavity would have r21ish but the studs would only be r4 max. But r10 on the exterior plus r15 Rockwool in the cavity equates to r25 in the cavity and r13 at every stud. Much better overall r value, plus the Rockwool is fireproof when compared to closed cell, also Rockwool is vapor permeable but moisture resistant as it is made from either rock or steel. For my roof since it was a new shingled roof by previous contractor, I will be using 4" of closed cell plus r23 rockwool in the attic. Total r51. Next time I do the roof over I'll install exterior foam there as well. I will have a return and supply in the conditioned attic as well to control humidity at the ridge. Does this sound like a well thought out plan? www.ekotrope.com/r-value-calculator I will have an erv and minisplits in the home. Any suggestions or modifications you recommend? My vapor barrier is installed on the outside of the sheathing. From outside to inside: Vinyl siding>taped r10 XPS>tyvek house wrap>1/2" plywood> Option a: caulk air seal, 1" flash and batt cc and Rockwool Option b: caulk air seal and then Rockwool 2*4 walls will use r15 Rockwool, if Rockwool we're to be compressed the r-value actually goes up slightly.
What about the millions of homes that have batts in the walls with no foam. How come these homes are not getting water damage due to vapor forming inside the walls? I mean the walls are enclosed (bottom plate, top plate, fire break. OSB, Tyvek, and sheetrock and paint on the interior. So some air leakage would cause the vapor on the fiberglass? Wouldn't an inch or two of foam only help prevent or slow the air leakage?
Even with really thick walls like 6-10', it still seems better to spray foam as thick as you can afford. I don't know the difference in cost but i'm guessing 1" of spray foam with fiberglass fill is probably similar to a straight 3" spray foam (or even 4"). The extra cost would be worth it anyway for the reasons you point out.
I have a new flash and batt video I will be making where we will look seriously at how much the batt even adds to the equation. I think fans of this system will be SHOCKED!
I have a 1.5 story with 2 bedrooms up. The roof is a ballon type on platform. I'm thinking about putting in 2" closed cell in the crawl space and a full 6" in the cathedral portion and up to the ridge beam. Can I put 4-6" open cell over the 2" to increase the r-value while lowering the cost? Is there any downside to this?
What about in a basement? 1 inch on the exterior wall (sprayed before framing, bottom plates 2 inches from the wall), then a basic moisture barrier, 3.5 inch mineral wool and then a poly vapor barrier.
@@SprayJones sound deadening from mineral wool, and there would still need to be a dimpled membrane on the floor for moisture, since the house is 70 years old and isn't insulated from the outside. I watch a lot of your videos, but don't really like the 'type writer' vs 'smart phone' strawman fallacy, mineral wool has sound deadening benefits that sprayfoam doesn't have, the cavities in the wall with sprayfoam can actually act as an amplifier for sounds.
I have a question .I built a deer hunting hut/shack 6x6 i insulated it with rock wool it does not have a vapor barrier on it and i want to finish off the inside so i am not breathing in the fibers.What do i use as a vapor barrier?
If you went with cellulose though you could use that mesh system and blow it into the remaining space not taken by the foam. Then at least the irregular foam surface wouldn't matter. I wouldn't do less than 2in of foam though to make sure the dew point is not at the foam surface. There shouldn't be a second vapor barrier in this method or it could trap moisture. And it is impossible to truly seal them. Also the studs have to be foamed on both sides all the way to inside wall (tapered off so you don't have to trim it), otherwise the thermal bridge they provide will put the dew point on their surface. Smaller cavities just filled (nearly) completely with foam. Thoughts?
@@SprayJones $$$ Unless you tell us real world examples. Like $3,000 for 2 inch closed cell and $3,000 for 3.5 inch open cell in 2x6 Versus $7,000 for 5.5 inch of closed cell since you don't have to change machine setup.
Great video, thank you for posting. I'm about to get my barndominium spray foamed 2# 3" to the roof and 2# 2" to the walls. It will be applied directly to the metal wall between the purlings as there is no framing put up yet. When i frame it will be 2x6 studs and we were going to insulate between the studs with traditional fiberglass batts. not necessarily for the insulation properties but more for sound deadening properties. Im wondering if that will cause a problem down the road?
So you’re saying if you have a hole in your siding and sheathing, spray in closed cell which acts as a vapor barrier, moisture is getting through and will get to the batt? Kinda puts a large negative on closed cell spray foam and the techs not doing a good job closing up the cavity no?
No. I am saying all the seams in the siding where there is no SPF. Air leakage that has to be sealed with caulking or membranes. If you have air coming into the cavity via this method. I will be having a video in 1 week launch that is dedicated to vapor barrier and air leakage.
@@SprayJones but if you’re spraying from inside out, the foam should fill any gap. Regardless I think most use zip panels now and the seams get tapped so that should block any true moisture from getting into the cavity behind the spray foam.
@@neckofthewoods24 You are correct, all of it. It is not a failure of the SPF which is properly applied, I have seen guys get next to nothing in a crack or corner, even left some plywood bear, so that will get wet and start to ignite issues. Will be doing another better quality flash and batt 2.0 video soon where a more thorough explanation will be given.
This is interesting but... -- QUESTION -- Why do you think that Matt Risinger used only Rockwool bat insulation on his personal home. No spray foam (except for a six foot spot in a garage). I don't get it... He should know better. He did use some exterior foam sheets under his metal roofing. But basically he did an entire home in Rockwool. What gives?
Mike- after watching your videos, I'm convinced and have what I think is a good spray foam company set to work on my new build house. They bid for 2-3 inches on the walls throughout the house. Great. They the bid for blown in cellulose in the attic of my vented roof. Why cover the biggest area in the house house with cellulose? Is it because to get the right 'R' value for code I would have to spend a LOT of cash (R-49)? Any insight appreciated.
I am going to get my basement sill plate and rim joist spray foamed should I use open or closed I get mixed articles about closed will trap the moisture in the wood and open will let the rim joist breath
Found your video randomly. Really enjoyed it. Watched it all and when you talked about dew point I was wondering is there a sealer you could spray onto of the foam? Would it be worth it?
@sprayjones watched the video and read all the comments....what I'm not understanding is if you have 2x6 studs and spray 3" in CCF what do you do with the other 3" of air gap before adding your drywall??
@@SprayJones Local spray foam installer is claiming that it HAS to be filled with fiberglass insulation to keep cold air from gathering in there, which did not add up to your videos. Thanks SO much for the input!
@@SprayJones see my inner wall and outer wall post. I wanted some extra R value to get to the passive house standard one day but was unwilling to sacrifice either system. 3.5 inches of spray foam on the outer wall and an inner wall on top with 3.5 inches of mineral wool. Might seem a little weird but I didnt want to use half of one wall system and then half of another. I treated it as two different systems. The side with the mineral wool is the service cavity.
Building a house right now that has 2x4 framing and the insulation would be 1” spray foam with wet sprayed cellulose that is trimmed flush to the studs. The wet cellulose im not a huge fan of, considering its it wet and cellulose. Im assuming from this vid you would not approve of that, adding another 1” is like an additional $4k
What is this reluctance to spending money to do it right? Would you buy cheap china wire because you saved 2k? Envelope is the most important expense after structure.
Hey Mike, thanks for the video. I'm still just a little bit confused. I just bought an old house with wooden siding (then covered by aluminum) and so I'm sure there is nothing on the outside of the house stopping air movement or even insulating value. So my thought was to just use a little bit of closed-cell spray foam (something like Great Stuff) to just do the inside edges of the 2x4 frame to 'stop the airflow' somewhat and then using Rockwool with no other vapor barrier to give me the R-value. What are you thoughts on this?
I was wondering, what would be your opinion on mixing expanded polystyrene with spray foam, as doing 2 inch of polystyrene glued to the sheating between the studs, with a gap on each side, and then adding 2 inch of sprayfoam everywhere, and 4 inch on in the gaps
OK, one last swing at this. What are your thoughts on a 2 x 6 exterior stud wall, plywood sheathing, Delta Vent SA WRB, 3 inches of Rock Wool Comfort Board 80 (R-12) on the outside of the wall on top of the Delta Vent SA (to block thermal bridging from the studs). Inside the 2 x 6 exterior stud wall, 2 inches of CCSF, and Rock Wool R-15 behind the foam, vapor retarder membrane, followed up with 5/8 inch dry wall? This build is in the deep south USA. As an alternative in leu of spray foam, Zip-R (R-9/2 inches of polyiso Zip shealthing) could be used in place of the plywood and Delta Vent SA.
Zip r, then spray foam inside, netted blown in insulation, then drywall. That eliminates thermal bridging, and issues with thickness variations in the bays
Hi Mike- My insulator is pushing this system in 2x6 walls with 2" of foam and 3.5" of R-15 batt (rockwool?). They have done a lot of houses in the area this way, and I assume no issues. One issue he points out with just foam is that foam will not have any sound deadening effect. Not sure if this is true? I assume I would have to caulk the wall cavity first before any foam job? They typically put up no vapor barrier with this system. The foam only option would require 4 or more inches of foam. Thoughts?
@@SprayJones great. I have one contractor who wants to do 2” of spray foam then blown cellulose in wall. The other is 3” spray and leave the rest open. Trying to decide
I literally just finished buttoning up a great room where I did 1" of xps foam board sealed with canned foam and then r15 Roxul over top of the foam board before covering with sheet rock. I am in climate zone 5. Am I doomed???
Cannot say, I am here to provide science info not do building inspections of your work. Next Friday the Flash and Batt II video will launch. Check it out...
I have this exAt issue, my customer a builder Himself builds his own house and he build a 2x4 wall he want me to wrap the wall with 2” over the studs and build a second wall out of 2x4 and put another r12 fiberglass infront of it ... I guess i would Just do 3” and forget about the fiber but he wants it. It seem with this video it says hybrid=junk as major risk . But I wonder if we do it this way we have 2” continues so we will be prob fine. Ceiling is gonna be 3” roofline it’s not meeting code but it seems he’ll get away with it (Manitoba). What’s ur thoughts run away or spray 2” wall and let him do his batt think 3.5” ? Thanks
Why are you only assuming fiberglass? What about flash and batt with mineral wool (Rockwool)? What about warmer climates like Texas (where I am)? The insulation needs are really different and often open cell is adequate (looks like you are only using closed cell).
Sure. Hang around long enough and I'll cover it all. Open cell can be used but no matter where you are it is not as good of a product as closed cell is. When I do something it is with the best.
@@zackdreamcast Simple: don't believe in any of it. Don't mix oil and water. Clay cannot be mixed with steel. Only reason someone messes with this is being cheap. Pick foam, pony up the cash and move forward.
Spray Jones given your experience on this subject I imagine you’re the best person to ask. Let’s say a 2000sq ft home , what is the price difference between full foam and a flash‘n’fill? Just curious what sort of change in price we are actually talking about.
@@zackdreamcast Too broad of variables to give an outcome. "I want to buy a car to drive to work and have some fun on weekends. How much?" Not trying to be difficult. Just that thorough.
Hey Mike, I've seen the flash and batt method used successfully.
1. Start with 2x6 walls.
2. spray 2 inches of closed cell for a good vapor barrier. All rim joists and soffits are filled only with foam.
3. R-21 batts are applied next. If a stud bay has been overfilled just compress the batts because you already have enough insulation in that spot from the foam, the reduced insulation value from compressed batts aren't an issue.
4. Moving the dew point in the wall isn't an issue with this method.
By the way, I love the content you put out. Don't stop!
I would think mineral wool would be a good replacement for the batting. More expensive than fiberglass but not the same problems with water/mold.
did you even listen to what he said?
@@sladeoriginal what about rockwool instead of fiberglass?
Mike Jones
Thank you again for your expertise and common sense approach to this area.
Appreciate that Giocondo. Stay tuned there will be much more interesting things coming soon.
That’s why i used 2 inch, 4x8 sheets of closed cell insulation to do my basement. No problem putting batts in after and saved a bundle.
Watching all your videos, deeply appreciate the information, turned to your channel after Marshall Remodel mishap, your doing a great service to the home building community! Im on the framing process of my barndominium build already researching best insulation practices, howdy from Texas 🤠
Awesome, thank you!
Very good video! I have talked about this before but I got a garage added to my house when I purchased it in 2012. Amongst a few issues where corners were cut I felt shorted by only having 2x4 walls and 2x4 trusses. So I built out the inner walls to allow the install of more insulation. I originally got a quote for 1inch foam and the rest in a net and blow system. After doing some further research I found that filling out the rest of the cavity with open cell was a better idea. In all the outer wall has much closer to 2 inches of foam with the rest open cell. While not ideal the system works very well especially for sound. Now, when I remodeled my son's room in the existing house I made a point to fill the entire outer cavity with closed cell spray foam. The foam was trimmed flush and I installed a second 2x4 inner wall for wiring. I then placed rockwool batts in those walls. That was more for sound but had the added benefit of insulation. Long story short I only did that because I was confident in both systems on the outer side and the inner side. His room also has rockwool on the inside walls so not to hear me watching videos like these in the spare bedroom on the other side. I really like that system much better and he and his brother, the cat, like sitting in the window sills and only loosing 3.5 inches on the outer walls. The second reason I took this approach is because I also had the entire house resided when I purchased it. The siding contractors ripped off the wood siding in a day and I came home to find the entire house wrapped in house wrap. What I didnt find out until years later was the reason they worked so quickly. After adamantly recommending I get the entire wood siding removed they neglected to think about what was under it. I simply had 1/4 inch polyiso with thousands of nail holes in it for the siding. Instead of putting up OSB they quickly covered the walls with house wrap so I wouldnt notice. Adding that second inner wall firmed up the system. If I ever get the house resided I will get 1/2 inch OSB bolted to the studs and rigid foam on the outside. In the meantime I have to fix the issue one room at a time when I remodel. The closed cell foam in the entire cavity does a good job of making the structure rigid.
Ok.
@@SprayJones
Stories like this guy's need to be told. I saw this in the late 90's when I was an apprentice, you could walk up, cut a hole with a utility knife next to the door ,reach in and unlock.
Spray foam would be a good fit to add wall strenght and air seal during an interior reno.
I have been developing a wall system that can handle the 50°C to -50°C temperature variation we can get here in Saskatchewan.
Your videos have been invaluable.
I can’t tell you how many times I’ve tried to educate building inspectors on Foam. And argued with them when they wanted to put a vapor barrier in the bathroom on top of the spray foam. Also mostly arguments stemmed from achieving a proper R-value that’s all they seem to care about lots of times we are forced into a flash and fill scenario just saw the house with pass inspection. Even had the inspectors push back on engineered drawings. We both amazed and terrified me thinking these guys were so arrogant that they knew better than engineer.
We are working on a solution that will help these inspectors get better educated.
I am one of the people that asked for this video, and it was a great explanation!
Appreciate your viewing Jack. Stay tuned because I am going to have big big stuff ahead.
I will stay tuned. And I sincerely appreciate the fact that you never do clickbait titles.
I'm approaching the deadline of making a final decision on insulation in zone 3/4 depending on what map you look at. One of the local contractors who's known to blow 0.1- 0.15 ACH uses Closed cell spray foam on the top and bottom plates, banboards, and any seam with the OSB board and they also use 3" of CC on roof decks at a minimum. Here's the twist they fill a 2x6 cavity with R-22 of dense cellulose for sound dampening and insulation if I subtract the cellulose and add 2" of closed cell it raises the price on my home 10,000% which was the entire budget in 2019 during planning, haha. I like the idea of sound dampening due to being out in the country. We have quads, dirt bikes, cattle, loud trucks, etc and anything to keep the interior space quieter is a plus and being 10,000 cheaper makes it difficult to see the ROI. I do like the added strength close cell provides especially since my wife designed a 2-story home with a 12/12 pitch room and added two loft bedrooms.
I also noticed a lot of the well known channels aren't using the pink stuff it's either Rockwool or Cellulose. One of the older Build show uploads had closed cell with a layer of dense cellulose. I can't recall the reasoning behind that combo outside of bypassing one of your listed problems of the insulation getting in the way of drywalls.
I don't understand what your question is.
I am in the middle of a gut-reno of an old balloon framed block house zone 4A. We framed new exterior walls 5" off the block (required by engineer for structural reasons), and the current plan is to spray 2 inches of ccSF continuously along the masonry walls, then add mineral wool batts to each stud bay. My question is, mineral wool is 3.5". Should it be pressed against the foam, leaving a 3" gap between it and the drywall? Or is it better to leave a gap between the foam and mineral wool? Why mineral wool and not more closed cell? Sound attenuation. Urban location. Thanks for any help!
I am a retired mechanical engineer and always only heard the horror stories about spray foam. Thank you for this channel. If I buy another house, I will spray foam the attic.
Thank you!
The main issue is having the right sized studs cause in some areas you have to have a certain amount of spray foam before you can even do flash and batt per code. Usually min 2-3 inches to be a vapor barrier and thats just walls. Usually you have to have more in the roof cause of temp differences. I also feel it depends on the experience of the contractor doing this and being able to do a good job
My next house I am thinking do spray foam on all exterior walls and attic. On the interior walls I want to use a BIBS system for sound proofing/bonus R value.
Hi! At 12:24 you circle the spot where the wall meets the truss, what point are you trying to make?
We’re currently building and my husband wants to spray foam in that exact area to get an air seal, while the roof is an open vented roof.
I am planning to CC SPF my detached garage workshop. After discussing plans with two spray foam contractors in my area, both had no problems with spraying 2” of CC on the walls (R14) to leave room for R15 rockwool. The reason I want the rockwool is to provide additional sound deadening for my neighbors.
They said the additional foam would not be as beneficial as the rockwool would be to the sound deadening and the R14 of foam is a great air sealing and I shouldn’t have any condensation problems.
I live on Long Island (Southern New York)
Do you see any issues with this plan?
The walls are 2x6
The roof will be getting 4” of closed cell as well.
I have stated my views on this system. You have enough foam to perform functionally.
I did the same. It seems to work well. Quietest room in the house. However, like you I made sure I had enough foam to do the job by itself before adding anything else. In my case it was 3.5inch closed cell foam with a separate 2x4 inner wall which is not structural, has all the wiring, and contains 3.5inch mineral wool. My son loves his thicker window boxes and so does his cat. It has the added benefit of being Quiet. Now I just need to at least put rockwool over the room or finish the entire attic with more spray foam.
I did spray foam CC 2 inches thick with 31/2 inches of Rockwool in 2X6 exterior walls no problem with Drywall also Zip sheathing on exterior
Thank you for your extraordinarily thorough videos. We are building a new house in Ohio. The upshot I have from your multiple videos is: 2" spray foam walls and 4" spray foam vaulted ceilings and attic roofs, and DO NOT use hybrids by adding other insulation. Is it reasonable to expect that new wiring can be run through walls years later (say adding an outlet) without having to remove the drywall? Assume 2 x 4 studs.
Correct. Ensure your thicknesses will line up with your local code.
Thanks for watching.
@@SprayJones So, if 2" CSF is used, then adding wiring or re-wiring electric years later is no more problematic than if the walls were batted? This is an argument the contractor is using against 2" CSF between 2x4s.
@@markarnold570 Correct that is rubbish. You can wire. What are the odds you would have to? 100:1 500:1??
Watch the wiring and SPF video
@@SprayJones Yep, got it! Your spray foam and electrical wiring video nailed it. As usual, that video was extremely thorough and completely squelched my contractor's concern. Thanks.
Does Spray Jones do Blower Door Test before and after each job they do to show the home owner one benefit of spray foam?
No
When the chart is talking about outboard insulation, isn't it referring to exterior insulation, so Ridgid continuous insulation in the outside of the house. That way the air barrier is on the outside of the house and the dewpoint would be in the exterior foam rather than in the wall. I may be wrong, please correct me if I am.
You are on the right track. In board to out can be just that or it can be the location of where the vapor barrier is placed in open fibrous insulations.
@@SprayJones I live in valley stream, NY marine 4... My plan so far is to have r10xps on the exterior of the home and to airseal the cavity and install Rockwool. This way the house can dry to the interior if any water were to somehow either get into the cavity or to get onto the exterior sheathing. Another option I was thinking of was to flash the inside of the cavity with 1" of closed cell and then install Rockwool batt in front of that. This way approximately 1/3 of the total insulation is still on the outside of the house. I already have the r10 XPS on the outside, would it be overkill to install 1" of Closed cell on the inside? No matter what I do not want to use open cell since it's more like a sponge and would take for ever to release the moisture it absorbs. Also a site I use often is, it's an amazing tool to help calculate total r value of the wall, especially since it takes into account framing. From my understanding it wouldn't make sense to do all spray foam in a 2x4 wall with no exterior insulation because the cavity would have r21ish but the studs would only be r4 max. But r10 on the exterior plus r15 Rockwool in the cavity equates to r25 in the cavity and r13 at every stud. Much better overall r value, plus the Rockwool is fireproof when compared to closed cell, also Rockwool is vapor permeable but moisture resistant as it is made from either rock or steel. For my roof since it was a new shingled roof by previous contractor, I will be using 4" of closed cell plus r23 rockwool in the attic. Total r51. Next time I do the roof over I'll install exterior foam there as well. I will have a return and supply in the conditioned attic as well to control humidity at the ridge. Does this sound like a well thought out plan? www.ekotrope.com/r-value-calculator
I will have an erv and minisplits in the home. Any suggestions or modifications you recommend? My vapor barrier is installed on the outside of the sheathing.
From outside to inside:
Vinyl siding>taped r10 XPS>tyvek house wrap>1/2" plywood>
Option a: caulk air seal, 1" flash and batt cc and Rockwool
Option b: caulk air seal and then Rockwool
2*4 walls will use r15 Rockwool, if Rockwool we're to be compressed the r-value actually goes up slightly.
What about the millions of homes that have batts in the walls with no foam. How come these homes are not getting water damage due to vapor forming inside the walls?
I mean the walls are enclosed (bottom plate, top plate, fire break. OSB, Tyvek, and sheetrock and paint on the interior. So some air leakage would cause the vapor on the fiberglass?
Wouldn't an inch or two of foam only help prevent or slow the air leakage?
Even with really thick walls like 6-10', it still seems better to spray foam as thick as you can afford. I don't know the difference in cost but i'm guessing 1" of spray foam with fiberglass fill is probably similar to a straight 3" spray foam (or even 4"). The extra cost would be worth it anyway for the reasons you point out.
I have a new flash and batt video I will be making where we will look seriously at how much the batt even adds to the equation. I think fans of this system will be SHOCKED!
I have a 1.5 story with 2 bedrooms up. The roof is a ballon type on platform. I'm thinking about putting in 2" closed cell in the crawl space and a full 6" in the cathedral portion and up to the ridge beam. Can I put 4-6" open cell over the 2" to increase the r-value while lowering the cost? Is there any downside to this?
What about in a basement? 1 inch on the exterior wall (sprayed before framing, bottom plates 2 inches from the wall), then a basic moisture barrier, 3.5 inch mineral wool and then a poly vapor barrier.
No way. Why mess with this? Do you carry a type writer to use while on your smart phone?
@@SprayJones sound deadening from mineral wool, and there would still need to be a dimpled membrane on the floor for moisture, since the house is 70 years old and isn't insulated from the outside.
I watch a lot of your videos, but don't really like the 'type writer' vs 'smart phone' strawman fallacy, mineral wool has sound deadening benefits that sprayfoam doesn't have, the cavities in the wall with sprayfoam can actually act as an amplifier for sounds.
I have a question .I built a deer hunting hut/shack 6x6 i insulated it with rock wool it does not have a vapor barrier on it and i want to finish off the inside so i am not breathing in the fibers.What do i use as a vapor barrier?
what about 2 inches of closed cell followed by filling the cavity with open cell that is then trimmed?
I am not a fan of that. Pick one and stick with it. What are you really saving??
If you went with cellulose though you could use that mesh system and blow it into the remaining space not taken by the foam. Then at least the irregular foam surface wouldn't matter. I wouldn't do less than 2in of foam though to make sure the dew point is not at the foam surface. There shouldn't be a second vapor barrier in this method or it could trap moisture. And it is impossible to truly seal them.
Also the studs have to be foamed on both sides all the way to inside wall (tapered off so you don't have to trim it), otherwise the thermal bridge they provide will put the dew point on their surface. Smaller cavities just filled (nearly) completely with foam.
Thoughts?
@@SprayJones $$$
Unless you tell us real world examples.
Like $3,000 for 2 inch closed cell and $3,000 for 3.5 inch open cell in 2x6
Versus
$7,000 for 5.5 inch of closed cell since you don't have to change machine setup.
learn lots from this channel,
Thanks Ken. Stay tuned Big stuff ahead this year!
Great video, thank you for posting. I'm about to get my barndominium spray foamed 2# 3" to the roof and 2# 2" to the walls. It will be applied directly to the metal wall between the purlings as there is no framing put up yet. When i frame it will be 2x6 studs and we were going to insulate between the studs with traditional fiberglass batts. not necessarily for the insulation properties but more for sound deadening properties. Im wondering if that will cause a problem down the road?
Watch the pole building video that we did. It goes over all of that.
Be interested in your thoughts on combination system with spray foam and rockwool!
It's no good. Pick one and go 100% with it.
Do we need vapor barier for open cell insulatio?
95% of the time yes.
So you’re saying if you have a hole in your siding and sheathing, spray in closed cell which acts as a vapor barrier, moisture is getting through and will get to the batt? Kinda puts a large negative on closed cell spray foam and the techs not doing a good job closing up the cavity no?
No. I am saying all the seams in the siding where there is no SPF. Air leakage that has to be sealed with caulking or membranes. If you have air coming into the cavity via this method.
I will be having a video in 1 week launch that is dedicated to vapor barrier and air leakage.
@@SprayJones but if you’re spraying from inside out, the foam should fill any gap. Regardless I think most use zip panels now and the seams get tapped so that should block any true moisture from getting into the cavity behind the spray foam.
@@neckofthewoods24 You are correct, all of it. It is not a failure of the SPF which is properly applied, I have seen guys get next to nothing in a crack or corner, even left some plywood bear, so that will get wet and start to ignite issues.
Will be doing another better quality flash and batt 2.0 video soon where a more thorough explanation will be given.
@@SprayJones that’s makes sense. Now why does it happen when some spray foam pulls away from a stud? How do you avoid it?
@@neckofthewoods24 Wet, improper technique. Please watch "5 failures and why". The delamination is the 2nd question answered.
This is interesting but... -- QUESTION -- Why do you think that Matt Risinger used only Rockwool bat insulation on his personal home. No spray foam (except for a six foot spot in a garage). I don't get it... He should know better. He did use some exterior foam sheets under his metal roofing. But basically he did an entire home in Rockwool. What gives?
I don't know...
Free Roxul?
@@SprayJones ... hmmm. maybe
Mike- after watching your videos, I'm convinced and have what I think is a good spray foam company set to work on my new build house. They bid for 2-3 inches on the walls throughout the house. Great. They the bid for blown in cellulose in the attic of my vented roof. Why cover the biggest area in the house house with cellulose? Is it because to get the right 'R' value for code I would have to spend a LOT of cash (R-49)? Any insight appreciated.
Ask them...
I am going to get my basement sill plate and rim joist spray foamed should I use open or closed I get mixed articles about closed will trap the moisture in the wood and open will let the rim joist breath
Closed. Trapped moisture is someone who does not understand building science talking.
Found your video randomly. Really enjoyed it. Watched it all and when you talked about dew point I was wondering is there a sealer you could spray onto of the foam? Would it be worth it?
No. Don't mix oil and water. You'll wish your father never met your mother if you start going down that road. Go all rigid or all fibrous
@sprayjones watched the video and read all the comments....what I'm not understanding is if you have 2x6 studs and spray 3" in CCF what do you do with the other 3" of air gap before adding your drywall??
Nothing. Enjoy modern technology.
@@SprayJones Local spray foam installer is claiming that it HAS to be filled with fiberglass insulation to keep cold air from gathering in there, which did not add up to your videos. Thanks SO much for the input!
What if you used mineral wool instead of fiberglass batts?
Same
@@SprayJones see my inner wall and outer wall post. I wanted some extra R value to get to the passive house standard one day but was unwilling to sacrifice either system. 3.5 inches of spray foam on the outer wall and an inner wall on top with 3.5 inches of mineral wool. Might seem a little weird but I didnt want to use half of one wall system and then half of another. I treated it as two different systems. The side with the mineral wool is the service cavity.
Building a house right now that has 2x4 framing and the insulation would be 1” spray foam with wet sprayed cellulose that is trimmed flush to the studs. The wet cellulose im not a huge fan of, considering its it wet and cellulose. Im assuming from this vid you would not approve of that, adding another 1” is like an additional $4k
What is this reluctance to spending money to do it right? Would you buy cheap china wire because you saved 2k?
Envelope is the most important expense after structure.
What about flash of 2 or 3" then Rockwool in a 2x8 stud?
With 1 inch of rigid foam board on the outside*
Hey Mike, thanks for the video. I'm still just a little bit confused.
I just bought an old house with wooden siding (then covered by aluminum) and so I'm sure there is nothing on the outside of the house stopping air movement or even insulating value. So my thought was to just use a little bit of closed-cell spray foam (something like Great Stuff) to just do the inside edges of the 2x4 frame to 'stop the airflow' somewhat and then using Rockwool with no other vapor barrier to give me the R-value.
What are you thoughts on this?
Waste of time. Line the stud bays with DOW sytrofoam and caulk the seams. Of just get a spray foamer....
Is there a product. Not spray. But thin hard foam boards you can lay under tile for a remodel?
Don't know
I was wondering, what would be your opinion on mixing expanded polystyrene with spray foam, as doing 2 inch of polystyrene glued to the sheating between the studs, with a gap on each side, and then adding 2 inch of sprayfoam everywhere, and 4 inch on in the gaps
Just go full SPF and don't mess around. There is no advantage and many issues you could create doing that.
I did that with a Do it Your Self foam kit and my wife was very pleased with the results, so was I, wink.
OK, one last swing at this. What are your thoughts on a 2 x 6 exterior stud wall, plywood sheathing, Delta Vent SA WRB, 3 inches of Rock Wool Comfort Board 80 (R-12) on the outside of the wall on top of the Delta Vent SA (to block thermal bridging from the studs). Inside the 2 x 6 exterior stud wall, 2 inches of CCSF, and Rock Wool R-15 behind the foam, vapor retarder membrane, followed up with 5/8 inch dry wall? This build is in the deep south USA. As an alternative in leu of spray foam, Zip-R (R-9/2 inches of polyiso Zip shealthing) could be used in place of the plywood and Delta Vent SA.
No mixing of products...
KIS: Keep it simple
Please watch this: czcams.com/video/NBTKyCqA4c0/video.html
Go rigid as much as possible.
Zip r, then spray foam inside, netted blown in insulation, then drywall. That eliminates thermal bridging, and issues with thickness variations in the bays
Hi Mike- My insulator is pushing this system in 2x6 walls with 2" of foam and 3.5" of R-15 batt (rockwool?). They have done a lot of houses in the area this way, and I assume no issues. One issue he points out with just foam is that foam will not have any sound deadening effect. Not sure if this is true? I assume I would have to caulk the wall cavity first before any foam job? They typically put up no vapor barrier with this system. The foam only option would require 4 or more inches of foam. Thoughts?
You are mixing oil and water. My thoughts are in the video already. In 16 years of installing SPF for people we never do a mixed cavity of insulation.
@@SprayJones So, by code, I need at least R-20 (or greater - Climate zone 5), which would mean 3+ inches of foam or two spray sessions?
@@Mogman150 3 inches of closed cell, correct, applied in 2 passes.
How do you feel about 3 inches of closed cell in a 2x6 wall? Just leave the extra space open? I was told I don’t need any more
Do that all the time. Have a video on what to do with the space. In the walls section playlist.
@@SprayJones great. I have one contractor who wants to do 2” of spray foam then blown cellulose in wall. The other is 3” spray and leave the rest open. Trying to decide
@@guydrivescar4549 3" foam only.
I literally just finished buttoning up a great room where I did 1" of xps foam board sealed with canned foam and then r15 Roxul over top of the foam board before covering with sheet rock. I am in climate zone 5. Am I doomed???
Cannot say, I am here to provide science info not do building inspections of your work.
Next Friday the Flash and Batt II video will launch. Check it out...
What about Rockwool ?
All the same.
I have this exAt issue, my customer a builder Himself builds his own house and he build a 2x4 wall he want me to wrap the wall with 2” over the studs and build a second wall out of 2x4 and put another r12 fiberglass infront of it ... I guess i would Just do 3” and forget about the fiber but he wants it. It seem with this video it says hybrid=junk as major risk . But I wonder if we do it this way we have 2” continues so we will be prob fine. Ceiling is gonna be 3” roofline it’s not meeting code but it seems he’ll get away with it (Manitoba). What’s ur thoughts run away or spray 2” wall and let him do his batt think 3.5” ? Thanks
Thanks for watching.
What about a BIBS over top of foam?
What the R value is a myth video.... that is my thought.
Spray jones what options do we have when sound proofing a vault ceiling after 2lbs foam is applied?
Do you provide consultation for a fee?
No
Why are you only assuming fiberglass? What about flash and batt with mineral wool (Rockwool)? What about warmer climates like Texas (where I am)? The insulation needs are really different and often open cell is adequate (looks like you are only using closed cell).
Sure. Hang around long enough and I'll cover it all. Open cell can be used but no matter where you are it is not as good of a product as closed cell is. When I do something it is with the best.
@@SprayJones i would still like your thoughts on using flash and batt with Rockwool given that product qualities vs fiberglass.
@@zackdreamcast Simple: don't believe in any of it. Don't mix oil and water. Clay cannot be mixed with steel. Only reason someone messes with this is being cheap. Pick foam, pony up the cash and move forward.
Spray Jones given your experience on this subject I imagine you’re the best person to ask. Let’s say a 2000sq ft home , what is the price difference between full foam and a flash‘n’fill? Just curious what sort of change in price we are actually talking about.
@@zackdreamcast Too broad of variables to give an outcome. "I want to buy a car to drive to work and have some fun on weekends. How much?" Not trying to be difficult. Just that thorough.
What were the batts around the 14:00 mark being used for?
Sound dampening in between certain floor and wall sections
I would rather do all close cell as appose to doing a mixed insulation to get R values up.
Yup.
I'd rather have millions of dollars instead of thousands. What can you do?
RV are all insulated with fiberglass . Why ? Spray foam seems better ...
It is.... Cost. You get what you pay for.
@@SprayJones merci
Use mineral wool insulation and problem solved.
Damn that cheesy music is annoying
Go watch the new flash and batt II video.
I will re-do this in time.