Cripple Wall Retrofits 1900-1945: All You Need To Know
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- čas přidán 12. 07. 2024
- A nationally recognized expert in home seismic retrofitting explains the science and practice behind every effective cripple wall retrofit.
You will also learn the importance of plywood, foundation bolts, and various floor connector work.
Then find out how these three structural components work together to create shear walls, which are the backbone of every cripple wall retrofits.
This is great information if you are planning to retrofit your own house.
It will also give you the confidence to ask seismic retrofit contractors and engineers questions that will let you know if they know what they are doing. - Jak na to + styl
Best earthquake retrofit info on CZcams!
Thank you for doing these videos. As a realtor this is great information to have. Very well explained. This allows me to have a bit more knowledge on this important subject than most agents and a good resource to send to my clients.
Thank you. This is great information for anyone doing a retrofit.
This is just such a fantastic video. As someone with no experience in this field, this was immensely helpful
Thank you for the recognition. These videos are l lot of work. Please help the channel by subscribing.
@@bayarearetrofit5814I sure have subscribed. This is really good stuff. I’ve contacted your office yesterday, hopefully we can work together.
Thank you. It was a lot of work and I am happy to see someone has benefitted.
Very interesting video! Enjoyed it very much! Keep up the good work! Thank you!
Very nice and thorough explanation. I'm a PE planning a retrofit of my house and found your presentation very complete and informative.
Thanks. As you can see it was a lot work for a self taught amateur sitting in his office in a bathrobe.
Even I understand now! This is a FANTASTIC explanation. Retrofitting is huge commitment, so I'm grateful for such thorough information.
Glad to hear that. Be sure and subscribe
Great video! Really appreciate you sharing your knowledge and experience! I’m a GC and also have worked for an engineering contractor for over 10 years. Built many engineer’s designs, and it is nice to see the actual practicality you so well present! And of course, to really understand the “why”, things are done the way they are, vs just building off from a plan.
Thank you!
You are welcome and I am happy to know I am doing something that helps people.
Awesome video! I have a house that was built in 1919 in El Granada. I have cripple walls and need to retrofit. This video helped a lot. Thank you!
By the way you mention special plywood for the shearwall? What would that be?
Ive been doing retrofits in Humboldt area since the earthquakes from 2022.. I came into it with zero experience currently we are on our sixth or seventh one... We have a house that fell 4 1/2" to the rear and 4 inches to the right.. it twisted on the cripple wall essentially... We just successfully hoisted in back in place with a series of 4 ton to 3 ton lever hoists and come alongs... Very proud of this achievement!!
I too am proud of your achievement. Did my website help?
Absolutely I learned alot from your videos! And continue to Everytime I watch. Your content is the standard we should all strive for in these earthquake prone areas! Thank you sir
You are a fantastic educator. Thank you so much for this video. I learned so much by watching it. Would you please explain what is the "reverse block method"? It was ranked as the second best method in the letter you referenced. Thank you for your time.
Go here bayarearetrofit.com/mudsill-connection-in-cripple-wall-retrofits/
Great Video, I just qualified for the Earthquake Brace and Bolt program so I'm trying to learn as much as I could in a short amount of time. This video was better than the ones on the EBB website. I do have a question:
For a post and pier foundation, with a masonry perimeter (stone & mortar), can you anchor the mud sill to the stone wall? Or will you it be best to create new cripple walls along the interior of the crawl space?
Thank you!
Look at the video on old foundations. Install new foundation segments parallel to the stone and build and brace cripple walls of the new foundations
Question: My house floor plan can be thought of as is a series of rectangles with the foundation being around the external/exposed edges of the rectangles. I.e. there is no side that is a single straight foundation. Does this (and how does this) impact the amount of shear wall I need to add (the same? more?) Do I need to be sure that each (distinct rectangle edge) has at least a portion of the overall shear wall on it? If so what is the minimum and does the length of that edge impact minimums (in some cases my edges are 4 or 5 feet)? Example: one side of the house extends 22' to the west before a perpendicular 1 1/2' to the north followed by another 23' to the west.
If it is only one floor, you only need to do the outside edges.
Right, it is only one story. The issue is I have multiple edges along each side of the house (because no side is straight -- but follows a jagged line). Do I divide up the total linear feet needs for the full side amongst these sections on a given side or does each section require a minimum number of feet even if the total along the side ends up being more than necessary? If I have a section that is problemmatic (due to plumbing, etc) will I be okay as long as the other section (edges) along that side of the house have sufficient plywood to reach the shear resistance needed for that side?
@@mfreedman1 Just treat it as one floor and do all the work on the perimeter. If pipes are in the way just put them where you can. The critical thing is to get the correct quantity along each foundation wall.
Question: An lean-to addition was added to my existing 1940s house leaving an existing portion of the foundation/cripple wall underneath the house. The lean to addition only has external foundation -- it didn't add foundation on all 4 of its edges. Do I need to add shear walls/retrofit to any of this under house cripple wall? Is any shear wall added here just part of the overall needed along that "side" of the house (i.e. the shear wall covers a minimum length needed for that side some on the exterior exposed foundation and some on the now under the house foundation.)
Explain to me better the foundation set up. Looking at the addition from the front of the house. Is there foundation under the left, right, and back sides of the addition? Or only where the addition and new house adjoin?
Are these foundations for additions?
The original foundation follows a reverse L pattern with the front of the house being longer than the side. The lean to addition filling in the L at the back left of the house making a rough square. Hence about 22 feet parallel to the front of the house (of 49 feet total) and 24 feet parallel to the side is now (of 37 total) under the house. The lean to addition foundation is poured adjacent to the back/ends of the existing foundation but not otherwise bolted/plated the existing foundation. And at least the floor joist supports (girders) aren't attached into this existing foundation under the house -- it just abuts it in the cripple wall.
@@mfreedman1 Those are tricky. You need floor to floor connectors and tension ties. These are very technical but if you type in additions in the website search box there will be some information that will get you started. These are very tricky and advising you via email will not be possible. We normally used Simpson Heavy Duty SDS screws for the floor to floor connectors and HDU2 Simpson Holdowns for the tension ties.
How do you handle floor to cripple wall connection when there is neither a rim joist at ends, or any blocking between , the floor joists sitting on top plate - perpendicular to the cripple wall? Add 2x blocking & use L90s? Or hurricane type ties at the joist/plate connection? Both?
Add blocking. First joist bay in line with the top plate and use an LTP4, the next joist push the block against the siding and use an L90 on down the line a few bays beyond the shear wall.
@@bayarearetrofit5814 Got it - thanks info, your thorough videos are stellar btw - much appreciated.
Re: add blocking - usually just toe nail (or SDS screws? ) both ends of the block? Seems like proximity to ends of both the joist & block may split the wood ? Hmm a last thought: if working left to right, suppose one could toe nail the LH side then use a longer fastener & end nail the RH side thru the RH joist from each adjacent joist bay ? May gain some strength vs toe both ends etc
You just need to hold it there enough so you can put in the hardware
@@bayarearetrofit5814 Interesting, thanks.
Makes sense to me the hardware would transfer lateral forces from joists/blocking, thru L90's block nails, thru L90's , into to top plate, and on down etc.
But.... what about vertical forces moving through same system?
Couldn't the house above shear walls also want to jump off the top plate?
Seems like the toe nailing of floor joist blocking then becomes a relatively weak point of vertical load path: if it's
top plate-->L90-->block-->joist-->1st floor/walls ?? Just trying to understand how engineers look at this, sure I am probably missing something!
The house goes up with the foundation and down with the foundation. Vertical thrust is not a consideration in the building code, even with thrust faults such as the Hayward Fault.
I am very please I could help you. Please subscribe.