Building Shear Walls - 8 Essential Tips
ฝัง
- เผยแพร่เมื่อ 22 ส.ค. 2024
- From bayarearetrofi.... A retrofit shear wall is created when a cripple wall is converted into an earthquake-resisting shear wall. Many people believe this is simply a matter of putting in foundation bolts and plywood. It is actual much more complicated than that.
First you will learn how to convert cripple walls into shear walls using tested and code compliant methods rarely understood in the trades. This video answers questions such as "How many bolts will I need?" "Which kind of bolts resist the most earthquake force?" "What type of plywood should I use?" "How thick should it be, and how should it be nailed?"
Another important consideration is how the wall framing behind the shear wall should constructed. It is also important to figure out if Simpson Strongtie holdowns are necessary. There is a book 180 pages long that discusses how all these things are combined to create earthquake resisting shear walls which are the most important part of any seismic retrofit
Geeez, I did not know it was so long. Happy you enjoyed it.
Thank you. Engineers always make things Waaaaay more complicated than they need to. If you study the videos and website carefully you will know more than 99% of the engineers out there.
There are so many factors that determine shear wall failures, though in the end for retrofit applications it always leads back to the nails and quality and thickness of the plywood. However, tests have shown once you go beyond 15/32" structural 1 you don't get much if any benefit.
Once you have the right plywood you need to keep nail failures from happening.
Nail diameter is a big one because the larger the nail the greater the resistance to pull-out, nail penetration is another factor for the same reason; though you never need to go more than 2 5/8 into the framing per extensive testing. With 10d nails, you can't use the 3 1/4" commons 2" o.c. because the wood will split. It might even be 3" o.c. I can't remember. That's why they make 10d shorts.
We have no problems with 10d nails 1" apart in old-growth redwood.
Nailhead diameter also makes a difference as you speculated.
Staples also work well because you can put them 1/2 inch or less.
Look up APA research report 154 to see the original testing.
One side. Inside is cheaper
I remember calling Simpson StrongTie and them telling me to use longer nails but I recommend you call them for confirmation. Personally, I think General Note "m" found at the beginning of their catalog covers it and you don't need longer nails.
I’m a newbie planning to enclose a carport with 2 overhead garage doors. I found your video just what I need before approaching a structural engineer to review my permit application construction drawings. Thank you! Jane😊
Sir, you are a generous GENIOUS! 80)
I retired from San Rafael, where even Loma Prieta didn't bother us, to Salem Oregon where this Cascadia Subduction Zone dwarfs Hayward & San Andreas...
I can't afford a full-blown retrofit downstairs, but I want to fix whatever glaring oversights the building code still had in 2000 when it was built. You have given me SUCH a greater understanding of the cripple-wall improvements that my only remaining question is whether plywood or OSB is superior...
Thanx again!
I am very pleased I could help you.
This video is excellent, very informative and helpful! Thanks for sharing... 😁👍👍👍👍👍
Make sure you get an engineer who does woodframe construction. Engineers are all licensed to do this work but you need someone who primarily works on houses or is a historic building preservation engineer, the latter are very rare.
Absolutely wonderful information! Thank you so much for all of your time and effort to share in a professional manner.
Thanks for letting me know. Comments like yours make it worth it.
Loved your video. You made the concepts perfectly accessible for non-engineers.
Thank you!
Cross stitching the two top plates intuitively makes sense since you're preventing splitting on the cap plate when high density nailing as well as unifying the two plates; I'd also run 10d through both plates on that joist clip.
I am sorry, I don't quite know what you mean. Can you exp;lain a little further? Is the cap plate the same as a upper top late? What is cross stitching? You mean mean nailing them together? How will that prevent splitting? You mean nail into the upper and lower top plate? Which joist clip? What minute will I find it?
@@bayarearetrofit5814 Yes, cap plate = upper plate. The typical tendency in excessive nailing is fear of a build up becoming "nail weak" due to splitting/cleaving. Consequently, "cross stitching," a zig zag pattern between the two top plates, is the "intuitive" carpenter's solution, i don't why it is spec'd by the engineers in the code literature you showed. 3" of wood behind vertical seams between panels is primarily done why? splitting? edge turnover? Like wise 3" of wood via compression blocking nailed between studs and face nailed into mudsill/bottom plate would seem to help prevent panel turn over and nail tear out. More timber more nails and more options for distributed nail patterns and less split up wood which can resist nail tear out.
Ok, I understand now.
WOW. This video is packed with useful knowledge about how to build shear walls. Thank you for mentioning items you recommend changing versus the ABAG Standard plan A of 2008. Thank you - thank you for making it!
Great video!! I live in Southern California so it’s very important to me. I’m in the process of doing a kitchen ( and a little more remodel) so I’m sure I will have questions.
Glad to help. Please be sure and subscribe.
Read the part of the webpage that discussed perit. It is under "Before Hiring"
Excellent video
Thanks, it was a lot of work.
Awesome video. Thanks.
I wish there was some sort spacing and dimensions of those shear walls.
This is a fantastic video--best I've seent to understand framing and shear walls. thank you.
Glad it helped you. That is the whole point and I really appreciate the comment. If you find other videos that are helpful please be sure and let me know.
@@bayarearetrofit5814 Awesome. Of course I wish I would have seen this a month or so ago before finishing my walls- I followed the standard the plywood mfr said, which was nails every 6" on edge, 12" in field". Since I don't want to tear off the siding I just painted, should I improve my shear walls by nailing plywood on the interior before adding drywall? Or I realized putting up the fibercement siding I've actually added a nail every 7" in addition. Does that help, or do you think I should add plywood to interior? thanks for your help...
@@GregoryDibb I think if you you include the fibercement nailing you have a nail about every 3 1/2 inches and should be OK.
@@bayarearetrofit5814 I figured that should help. that chart you showed about how impactful nailing frequency is was amazing. i guess my siding nails are only 2" nails though--hopefully that still helps. it wouldn't be too much trouble to add plywood on the inside... Either way I will focus on doing what you showed with the hold-downs--that was a helpful explanation.
The same chart says you need 11/2 inches penetration into the framing, which apparently you have, or at least are close enough.
It is normally a function of the nails, not of the metal. Check the load ratings under the F1 direction. That tells you how much capacity the hardware has.
So I have this wall that has a groove cut diagonally top to bottom through the 2x4s and it has a thin metal bracket placed in that groove; one nail in each 2x4. It does not have any plywood on the wall but only sheet rock. Does this metal brace constitute a shear wall?
No
Happy to help. If you make a video of your own I will be happy to post it on my channel.
I wasn’t always clear in the video whether the retrofit added a plywood/osb panel on the inside or outside of the wall. Would welcome that clarity in a reply if you’re able. I came to the conclusion that generally you depicted interior panels, not exterior. In my case I’m residing a house, so I plan to install on the outside if decide to add.
It does not matter.
Yes, that should be fine
Hi Howard - I feel pretty good about the construction portion (nuts and bolts so to speak) of the shear walls thanks to your examples, but less sure about specifying some other details. I'm wondering if you could answer a few questions for me. I'm trying to dig out the info, but a little confused. 1. Should shear walls always be done in match pairs when possible (opposing walls)? It seems like that's what you are saying. Intuitively that makes sense to me in that you would want the walls on opposite sides to provide the same resistance so that they would react in a similar way to external forces (although sometimes this isn't possible).
2. Is it better to split up a shear wall, half on one corner and half on another or is it ok to just have one long one in the middle? Some corners just have too much stuff in the way to put anything in the corner. Is this a case of do the best you can, i.e., "don't let the perfect be the enemy of the good"?
3. In terms of reinforcement schedule (determining linear feet of shear wall), Standard Plan A has a table, is that a fair way to go, or is it ok for a single-story to have a minimum of 50% of the length but maybe add some, go a little longer than shorter just to be conservative? It's not much extra work-wise or material-wise for me, assuming extra length doesn't cause a problem. I really appreciate you sharing your knowledge and experience. Thanks for any suggestions/tips that you can offer!
Throw Standard Plan A out the window. You need to calculate it based on house weight. Email me direct to info@bayarearetrofit.com and I will show you how. Sorry I am so late your email got buried.
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. Give me a call 510-418-1676
Thank you,,,,, very informatingal
Hello again. Since I left my thank-you comment 10 days ago I have re-watched this video twice. I was very happy in a couple places to find that when I paused the video & said "that doesn't make sense", you then said the same thing when I started playing it again! Ha-ha. (Also, lining up the vent holes with the foundation bolts is brilliant.)
I hope I'm not imposing too much, but I am left with just 2 very basic questions:
1. You've said nothing about OSB, which makes me think that those who extol its virtues may be full of... something;
2. From the 1st diagram @ 2:00 to the one at 22:00, the geometry-center in my brain is wondering if horizontal or vertical orientation of the plywood is significant? My gut says that a horizontal sheet nailed to more studs may be more stable for horizontal shaking.
e.g., for simplicity's sake, let's say @ 2:00 there is a vertical 4x8 next to a vertical 3x8... Would 2 horizontal 4x7's be better, worse or indifferent?
Many thanks again,
Mark
Orientation of the plywood does not matter. OSB is rated the same as plywood.
@@bayarearetrofit5814 Sorry, I was probably overthinking the geometry... As for the latter, the lumber yard explained the confusing Structural I plywood, with Roman numeral not 1, is the way to go for strength over beauty, but they didn't say OSB had the same thing. Many thanks once again!
Thanks for the video, and the information.
Thanks, be sure and subscribe.
Great video, and extremely informative, please keep them coming. I was wondering will it be a good idea to shear wall on a pony wall in the area that above it needs to be supported with a shear wall?
Yes, absolutely!
Great video. Thanks.
Would nails + wood glue for plywood attachment be a good idea? I noticed aircraft skin are gradually now being ‘bonded’ instead of riveted to the frames. Nice information sir thanks.
Good question! A friend of mine says he is going to use Liquid Nail behind his cripple wall plywood/OSB...
Thank you for this video. Noticing that the failure is usually at the point of the nail head and the plywood sheeting, would it not help to make a special ribbed nail with a larger diameter head? I would suppose cost is a factor. Thus add more nails to share the forces. Would 3/4 ply have stronger pull out strength at the nail head? Our area is not known to have major quakes. My first exterior and interior walls (for my home)I decided to use 1/2 and 3/4 plywood with liquid nail, screws to pull it down first, then 8 and 10D. I learned a great deal from your video. - Thank you!
Very informative. Thank you. How about using Simpson SD 10 x 2 1/2 joist hanger screws instead of nails to attach plywood? Tight space, I'm laying on my side and no longer have a nail gun.
This is not a tested system.
Yes. Be sure and subscribe
The sheer transfer tie, model A35 by Simpson, hardly seems stout enough to perform under a seismic event. There is however a 16 gauge angle made by MiTek 2"x2"x6" model USP ML26-TZ that would make more sense as it is twice as thick as that simpon model that you can bend by hand. Your thoughts appreciated.
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. We have A35s. L90s are better.
Around minute 9:30 of the video, the diagram shows an hvac duct going through the sole plate of the shear wall in a raised foundation construction. Is such a large notch in the sole plate of a shear wall (for the rectangular duct) allowed? How would it be reinforced? I was thinking a metal brace horizontally across the notch might suffice for a one-sided shear wall, but it would not be possible to drive nails in that section of the sole plate for a double-sided shear wall.
I doubt it is legal but in retrofitting we must work we must work with what we find. If we have large breaks in top plates or bottom plates we use 2 x 4s as straps because they will work in tension and compression. A 2 x 4 is as strong as the strongest Simpson strap.
Sr i just subscribed to your channel and found very important information, I am building an adu by myself, and currently working on the shear walls sheathing, the plans ask for structural II PLYWOOD, osb, or cdx, but I can’t find it at any store ( Home Depot, lowes) they just have structural I, I wonder if the inspectors are really strict on that aspect, I can’t just find any information on internet,please can you give me some orientation, thanks in advance for sharing your knowledgment
Strutural II is a very old term for rated sheathing. You cannot find it anymore. Your designer must be old as dirt and out of touch with the modern world. I would be suspicious of everything else in his design.
@@bayarearetrofit5814 thanks a lot,.
My house was built in 1986. Are the studs in that house considered old growth lumber? Wondering if I need to use 3” spacing for my edge nails on my shear wall.
No, they are not old growth.
I'm confused! At 5:24 you say 2.25" long nail - but isn't 10d a 3" nail (the red arrow is on the 10d line)? On the one hand, I understand a shorter nail with "Minimum Nail Penetration in Framing" of 1-5/8" but why 10d then?
It is a 2.25 10d "short" just for shear walls.
Shear walls are typically designed to extend from a sole plate to a top plate of a wall. But, in a raised foundation, is it permissible (or even better) to extend the sheathing from the sill plate, over the cripple wall, and into the shear wall above? Or does doing so reduce the efficacy of the shear wall?
Does the spacing between the blockings matter in the design of the shear wall? Say I have 3 rows of 4' x 8' OSB, does it matter that I have 4' - 4' - 2' going up or 4' - 2' - 4' ? I have a feeling that it does.
Do you mean does it matter if the plywood is vertical or horizontal?
Simple question, does shearwall start at the bottom on top of the concrete slab or overlap on the side of it.
I don't quite know what you mean. The plywood is nailed to the bottom and the bottom of the wood framing.
@@infocook4854 plywood can’t sit on slab because it potentially could sit in water. Bottom plate to edge of slab so shear panel overlaps stem wall or slab.
Thanks I found what I needed
Is there a minimum length for the shear wall section? Using your example, if I use 10d@2" OC and a 24" wall will it support a 1740lb seismic load?
The closer you get to 26.5" the weaker the shear wall. After 26.5 if equals zero.
So general question, based off of your qualms with some of the nailing to the top plates, is the upper top plate not secured to the lower top plate with significant enough resistance values to shear so as account for their design? If that were not so, I would assume the need for a double top plate to be dependent solely on alignment of your studs with upper assemblies and to counteract weak wall connections during erection.
There is not way to know but if you want to nail the two top plates together and make it one piece it won't hurt.
Hi Howard, Excellent video. Is an expansion gap required between the plywood sheets, or should they butt-up against each other?
The American Plywood Association wants a 1/8" gap but it is B.S. It does not matter from what I have seen.
The American Plywood Associations says the must be a 1/8" gap, the Ph.D research scientists at the University of Washington wood science department say you need a 1/8" gap but I have never seen it as a problem and I live in San Francisco where there is a lot of moisture. I trust my eyeballs more than a guy in a white coat sitting in an office. Engineers usually trust the guy in the white coat. You pick. Please subscribe to the channel.
@@bayarearetrofit5814 Stucco fellas have complained that the absence of the gap is the unpreventable cause of the cracking of stucco from wall buckling or deflection when moisture caused swelling occurs.
What a great video! So many topics described along with very practical advises, thank you. Does it matter whether plywood is installed long or short side horizontally?
This is discussed in Research Report 154. bayarearetrofit.com/retrofit-contractors-engineers/american-plywood-association-research-report-154/
I see I did not answer your question. Sorry, I misunderstood. Orientation of plywood does not matter.
great video - thanks
Great video. Would be nice to have some sheeting top clips information sometimes you come across odd ceiling framing. Thanks
What is a top clip?
Simpson LTP4 is one style of tie clips. Thanks
yes, we use those.
So if I understand this correct 1/2 compared to a 3/4 plywood has no gains? I had an inspector make me change one out to a 3/4
Your inspector was an idiot. Next time show him APA Research Report 154 Table 1 bayarearetrofit.com/retrofit-contractors-engineers/american-plywood-association-research-report-154/
Be sure and subscribe
It is not old growth redwood. You probably have plywood siding which means you don't need to do anything.
Howard. Just to be clear, plywood grain direction does not matter as long as the fasteners are installed as recommended? Overall great video.
That is correct. Look at APA Research Report 154 available on the site for downloading. Please give me a like and subscribe.
awesome video, thanks!
You are welcome! Thanks for appreciating all the hard work I put into it.
Thank you for this video.
STUCCO and adding a blocking cripple stud (a sister cripple wall stud to allow nailing the edge of the plywood to): The back side of stucco intrudes slightly into the space where the new stud will go (the space facing into the crawlspace). That causes the edge of the stud (the edge to nail to) to protrude out from the existing stud. I expect it will be OK to cut a thin strip from the new stud, so that the face to nail to will sit flush with the top plate and mudsill. Does that sound reasonable?
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. Yes, that is OK. Watch the video on stucco. You were in pretty good shape as is.
Hi,
Great informative video. I am currently retrofitting my property using the LADBS standard detail plan set One. I have cripple walls not tall enough for bolts to go straight down from above so I am using URFP plates instead. Do I still need ventilation holes?
No
Hi, I'm going to have a shear wall installed on my house. Would there be an advantage to using wood screws rather than nails for attaching the sheathing?
Is there any value to running a glue bead on the frame before applying and nailing the sheathing?
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. No. Glue does not have the ductility of nails.
For plywood shear wall nails, what do you think of a 30 degree nailer that uses full round head but offset nails, like a paslode CF325XP ? (I don't remember you discussing this.)Thanks again for your videos and info Howard. Really appreciated.
Always use full round head. That is important.
Great video Howard. Can you comment on Foundation Plates? Are they equivalent to hold downs?
They have completely different functions. Plates are for lateral, hold downs are for tension. Type in "Overturning" in the search box and watch the video and read the material
Are all shear walls need to be connected to concrete wall ?
If you mean the foundation, then yes.
Hi Howard,
Your videos and reference material have been quite helpful to me. I certainly have a better understanding of some of the key seismic risks and I have been able to review the contractor proposals with a much more critical eye…which has generated several questions that I hope you can help me with.
Here are my questions:
1. My house has cripple walls with plank and beam construction, so that 2” thick subfloor planks are directly supported by 4x6 beams (no rim joists). The ends of the beams butt against the top plates and are toenailed into the top plates, two nails on each side of the beam. So, it would seem to me that the Floor to Cripple Wall shear transfer ties aren’t needed. (2” subfloor is directly nailed to the top of the cripple walls and floor support beams). Do I understand this correctly?
2. Also, the ends of the floor beams are supported vertically by 2x4 jack studs at the end of the beam, with the jack studs toenailed into the foundation sill plate. So, the jack stud as currently installed would interfere with obtaining more than a 44” continuous span of plywood sheathing. A contractor proposed removing the 2x4 jack stud and installing 4x8 lumber board within the cripple wall behind the girder beam end centered, allowing equidistance of the board on either side of the girder beam end for plywood sheathing attachment. My question is, how have you previously dealt with this plank and beam end of beam support issue? I would appreciate your feedback on the contractor’s proposed solution as well. I’m also wondering if it wouldn’t be sufficient to just move the jack stud outward to below the top plates on the inner side of the to-be installed plywood sheathing. Then the beam could be supported by either a header hanger or gusset attached to the relocated jack stud.
3. Finally, I’m trying to understand if the floor support beams would be exposed to significant lateral or transverse seismic forces. Isn’t the floor beams’ only function to provide vertical support? I also see in the AWC plank and beam publication that straps are installed across adjoining floor beams…Is this necessary? Am I missing something?
Many thanks in advance, Dave
Can you send me photographs? I am having trouble visualizing this. Please subscribe. More videos are coming.
@@bayarearetrofit5814 Will do
Dave Wegmann
1 day ago
Hi Howard,
Your videos and reference material have been quite helpful to me. I certainly have a better understanding of some of the key seismic risks and I have been able to review the contractor proposals with a much more critical eye…which has generated several questions that I hope you can help me with.
Here are my questions:
1. My house has cripple walls with plank and beam construction, so that 2” thick subfloor planks are directly supported by 4x6 beams (no rim joists). The ends of the beams butt against the top plates and are toenailed into the top plates, two nails on each side of the beam. So, it would seem to me that the Floor to Cripple Wall shear transfer ties aren’t needed. (2” subfloor is directly nailed to the top of the cripple walls and floor support beams). Do I understand this correctly?
YES
2. Also, the ends of the floor beams are supported vertically by 2x4 jack studs at the end of the beam, with the jack studs toenailed into the foundation sill plate. So, the jack stud as currently installed would interfere with obtaining more than a 44” continuous span of plywood sheathing. A contractor proposed removing the 2x4 jack stud and installing 4x8 lumber board within the cripple wall behind the girder beam end centered, allowing equidistance of the board on either side of the girder beam end for plywood sheathing attachment. My question is, how have you previously dealt with this plank and beam end of beam support issue? I would appreciate your feedback on the contractor’s proposed solution as well. I’m also wondering if it wouldn’t be sufficient to just move the jack stud outward to below the top plates on the inner side of the to-be installed plywood sheathing. Then the beam could be supported by either a header hanger or gusset attached to the relocated jack stud
I THINK YOUR IDEA IS A GOOD ONE.
.
3. Finally, I’m trying to understand if the floor support beams would be exposed to significant lateral or transverse seismic forces. Isn’t the floor beams’ only function to provide vertical support? I also see in the AWC plank and beam publication that straps are installed across adjoining floor beams…Is this necessary? Am I missing something?
Many thanks in advance, Dave
FORGET ABOUT THE POSTS AND BEAMS. THEY ARE ONLY FOR VERTICAL SUPPORT.
@@bayarearetrofit5814 Great. Many Thanks!
How does OSB compare to Structural 1 plywood for using on shearwall sections?
Identical
Can i put a 14" W x 43 " tall X 575" deep electrical panel board? into a shear wall?
Yes, but block around it and make the corners with a radius.
@@bayarearetrofit5814 thanks for your reply. Area there are standard details I could download ?
When installing H10A's, and the shear wall plywood goes all the way from the foundation to the floor above, should the H10A be put on top of the plywood rather than underneath it? Same question regarding mending plates.
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. Under is better but Simpson allows over. I think there is a 25% reduction.
Thank you so much for all of this information. I do plan to reference everything you’ve provided for my retrofit project. One note regarding the extra nails on the lower top plate; engineering for construction is one view, but having had to tear apart a lot of structures such as these I can tell you that those extra nails will make it much more difficult to demolish. Granted, earthquakes may go about things differently than us monkeys with pry-bars but I’ve had to curse a lot more when undoing all those extra nails ;-)
RECONNX makes a tool that drives nails through the plywood. A real life saver.
Thanks for the information. I am currently working in Sparks, Nevada and they seem to have different codes compared to city of Reno and the county.
My role is drywaller including all phases of the trade. Framing thru texture and grid so I do not have any actual role in the shearing unless you count Sheetrock. My question is about plywood shearing.
In your video, you supply tables showing minimum nail penetration but I see no mention of maximum nail penetration. I ask because I see in other municipalities that shear nailing heads of nail do not penetrate the surface but in Sparks, NV they allow deep penetration. This bothers me because during the stresses from a quake it would seem that the 3/8" plywood used will easily rip out from nailing. I also noticed flooring in all municipalities has nail heads exposed over the surface and I thought it is for the same reason as to not rip through nailing. Can you explain maximum penetration please?
By the way, the exposed nail heads on flooring are a nuisance when scraping taping mud from the floors.
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. If the studs don't split at time of installation they won't split when loaded.
What about sheathing around doors and windows in a shear wall? Should you cut the openings out of the 4x8 sheet or use separate pieces that are all square or rectangular?
It does not really matter so long as all the edges are blocked and all the framing is stitch nailed. Personally, I would do as little stitch nailing as possible and use the biggest sheets I could.
@@bayarearetrofit5814 Thanks, this is helpful, and it checks out with my structural engineer.
Happy to hear that. Please be sure and subscribe.
great video thanks. i was wondering if there are any rules as to the minimum width of the plywood panel. As an example if you had to cover 9 linear feet, would it be ok to use a 4ft panel, butted to a 1 ft panel, butted to a 4 ft panel where at each butt there were double studs?
So long as you have everything blocked and sistered together at the seams you should be fine.
What do i do when the floor edge joist are doubled and flush with the cripple wall. I cant use the L70 because it is flush. Do i take plywood all the way up or need special metal strap?
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. Yes
Very informative. Do you mind walking through a Seismic lateral analysis Design example ? May be do another video
Videos take a ton of time I just don't have.
I already did but people kept using it on their own homes and I was facing the liability.
Yeah, I understand that. May be you can share the example with me. I am a trying to learn and get my foot into the door. Let me know I can connect with you privately. thank a bunch in advance.
email me at info@bayarearetrofit.com and I can send you a link
If blocking. Should we use khil dry or green “wet” Doug fir to avoid splitting and max strenghth
Read about green lumber in the pdf library.
www.bayarearetrofit.com//PDFs/APA%20Green%20lumber%20effect%20on%20shearwalls.pdf
Green lumber is best. The kiln dried splits. Looks like you found the APA bulletin.
I spoke to the American Plywood Association about table B-1 in Research Report 138 www.bayarearetrofit.com//wp-content/uploads/2013/05/APA-Research-Report-138-1.pdf and based on that table using a plywood strip rather than sheet metal and the research scientist I spoke to at the time had no problem with it so I think that is another option if you don't want to take the plywood down.
I think I have a somewhat typical style of construction, a cripple wall, with a double 2x4 top plate on top, then 4x6 joists with 2x6 blocking in between the joists, and finally 1-1/8" plywood tongue & groove subfloor on top of that.
The problem is where the kitchen sink water and drain come in. In that location, they cut out the 2x6 blocking between the joists and the double 2x4 top plate and the mudsill at the bottom of the cripple wall. About a 3-1/2" gap, all to accommodate the water and drain pipe.
My idea to mitigate this is:
1. blocking: I don't know what to do about the 2x6 blocking with the water pipes and drain, except to maybe try to build it out to make the blocking continuous as much as possible.
2. top plate: for the double 2x4 top plate, they scabbed on a 2x4 on the side, so I thought maybe just change that out for a longer 2x4 that bridges the gap with a lot of nails and shear transfer ties.
3. mudsill: for the mudsill, they left a gap but they didn't use it so I thought I'd take out about 4' of mudsill and replace with a longer piece so that it's continuous and then bolt it all to the foundation.
Seems like this might be a somewhat common problem. Any suggestions appreciated!
It is a common problem. Bridge the gap with a 2 x 6 or 2 x 8, nail the existing top plates together on each side of the break and put about 20 nails through the 2x into both the upper and lower top plates
The new soon-to-be-published ICC guidelines are even worse.
Greetings!
What is another brand of hand driven nails that can be used for this work that has 2 1/2” nails?
I know that simpson brand is one, but they don’t seem to make 2 1/2” long nails that are hands driven.
Or is it ok to use 3” long?
Any info, from anyone would be appreciated.
Thanks.
Any builder's supply store will have a good selection. Not sure why you don't want to use a nail gun.
Does the APA Research Report 154 ever specify the number of plies the plywood sheathing should contain in Table 1? I ended up using 4-ply Rated CD plywood (didn’t realize until after 300 nails were driven in) instead of 5-ply Rated (or better Structural 1). Can I trust the values in Table 1 if using 4-ply or should a reduction factor be used? I saw that 3-ply is a major no-no and basically cosmetic so I’m hoping 4-ply has some reasonable middle ground. The good news is my shear wall is 24 feet long - likely twice as long it needed to be - so hopefully over engineering it makes up for any inadequacy using 4-ply Rated.
What you have is fine.
Bay Area Retrofit thanks. Given the effort I’ve put in, I wish I had done it “right”, but glad to know what I did is sufficient.
You did it right, you used "Rated" instead of Structural 1, very little difference in capacity according to the chart.
Bay Area Retrofit I understand. I wish I had paid a little more attention though and gotten 5-ply Structural 1! Oh well :)
The nails must be flush with the surface. Earthquakes cause nail pull thru and when the nails penetrate the plywood the damage is the exact same thing that happens in nail pull thru. In other words, you cause earthquake damage before the earthquake does it. Please be sure and subscribe.
What kind of staple gun do you use for the sheet metal approach? I have a cheap pneumatic stapler that isn't pushing the staples through the sheet metal. Would a non-pneumatic stapler work better, or do I need a more expensive pneumatic stapler?
I only found one stapler that shot the gauge and length needed and it is made by Paslode. What are you trying to accomplish? We hardly ever use sheet metal anymore because there are other options.
@@bayarearetrofit5814 I put up a shear wall that is a few inches over 8 feet, so I had to split it into 2 pieces. I planned on using the sheet metal approach to attach the two together and didn't put any blocking behind the plywood. It sounds like I might have to remove one of the pieces of plywood and add some blocking.
They also make plywood in 10 foot lengths.
My wall is covered up with 3/4 ship lap old growth Douglas fir is it strong enough whole interior of basment walls is covered with it its built 1910 all the pony walls like and a sheer wall across
Horizontal siding of any type is only worth 100 pounds per linear foot. If the nails ever rusted from lack of painting, even less.
@@bayarearetrofit5814 its double horizontal only single is on chart would you just double it to 200 or is 100 the value regardless
Double
hi Howard - Can you tell me which is the most recent "Standard Plan A"? I see the one on your web site says 2008. Is that the latest? Is there an "official" copy somewhere?
Also, I have the situation that you described where the access hole is too small so I would need to butt plywood panels to achieve the full height of the cripple wall. I don't see anything about the methods you described to accomplish that in the standard plan A. If I wanted to get a permit do you think they would accept one of those methods? I'm curious if you've had experience with that situation.
2008 is the most recent one. Why do you want to use it?
Use blocking at the plywood edges, 3by is the best or flat 2by with 15ga staples.
Do whatever you want. The building department does not care what you do.
@@bayarearetrofit5814 I don't "want" to use the plan, but I thought since I'm doing the retrofit that it might be worth it to get the permit if I could save money on insurance.
I don't know if it's worth it to get the permit but if I do, I don't want them to not reject the horizontal butt joints.
You didn't mention the 26 gauge by 5" sheet metal. That sounds like the easiest! Is the sheet metal hard to find? (Thanks again Howard! :-)
The CEA does not care if you follow a standard. They just want a contractor to sign a form. A handyman with a license can do that for you. Do it right and for Standard Plan A. Sheet metal is expensive, blocks will work much better for you.
Great video. I see you make your own walls. Simpson makes steel strong walls. Is it worth the extra money to purchase from Simpson? .
They make Strongwalls for garage door openings. Other than that we always build our own.
@@howardcook6432 I am placing them on my garage, the walls on the garage door side are only 8" long with very little support. The garage is old built in the 20's and is leaning to one side, my thought is to place a 2' shear wall on each side which would shrink the garage door. But the question is should I purchase the shear walls or make them my self?
Thanks for addressing horizontal seams. I think I will use the sheet metal and staple approach. Out of curiosity, how are the horizontal blocking 4x4's supposed to be attached to the studs?
Unless you have the tools, blocking will be easier. Just nail it.
Ok - the blocking I need to install ends up being directly under the top plates. I would use 4x4s for the blocking. So I'm thinking I can just increase the length of the lag bolts to not only install the blocking but also take care of the shear transfer ties :)
3 1/2" + 1 1/2" + 1 1/2" = 6 1/2".
8" SDS screws will be great since I don't need 2" penetration in to rim\ends joists (my home doesn't have them). I don't know exactly how thick my sub-floor is but I assume I'll get a little bit of penetration in to my first story wall framing.I really appreciate all the help and guidance you've provided. Thanks!
Why 4x4 instead of 2x4?
Howard describes when\why to use a 4x4 in the video (the part about horizontal seams). Essentially, 4x4 allows for nails without worry of splitting. Otherwise, I'd have to look into staples or worry about splitting a 2x4 when I nail it.
@@chrisc7465 got it, Thanks ..what about SDS screws in 2x4 shouldn't that take care of the splitting problem?
No. Wood screws have not been tested.
Hi Great video.
So will OSB 15/32 work as sheer?
Sorry I am so late in my reply. I do not know TH-cam did not notify me about your comment. Yes
Once a shear wall is that narrow it becomes a post and is rated at zero.
I don't know what you mean by offset
I'm referring to 30 degree nailer that has a full round head but the head is offset to one side with respect to the body of the nail so that when the nails are in the nail clip they can rest against each other, sort of like a clipped top nail, but instead of being clipped they just offset the head.
Now I understand. I don't see a problem so long as the nails are flush with the top layer of plywood.
How can a person access an area sealed off by a shear wall? Large areas of my attic are behind shear walls, and I want to install ceiling fans and lights.
You need be create an access and use screws instead of nails. Screws are not an approved shear wall system but in some cases you have no choice. Do not use drywall screws, they are brittle and snap.
I'm sorry to hear of your lack of respect for our government; I have my reservations too but I certainly appreciate government enforced building codes--after all, theyre the bare minimum requirements.
I also appreciate government enforced building codes, assuming they bother to write a building code and provide education on how to use it. The government has not done either of these things for seismic retrofitting.
@@howardcook6432 I live in Sacramento county. On their website they state that the earthquake codes are set by the california building code (cbc) and that they must resist those motions as set by the ASCE/SEI 7 Standards. I don't know if that he's you where you are but you can always look at the 2016 codes.
I know all about the CBC and am dismally disappointed.
@@bayarearetrofit5814 so, it'd been a few days and I've been patient; were you planning on explaining way you're not impressed since you're the professional installer regarding this matter or are you just going to bitch like the first guy--thid is a serious questiom
Please go to the website and search for "Standard Plan A" and "Appendix Chapter A3". Appendix Chapter A3 is part of the2019 CBC. The chair of the Appendix Chapter A3 committee was also the chair of the Standard Plan A committee and he started this new effort because A3 had so many problems. I never finished my critique of Appendix Chapter A3, but did finish my critique of Standard Plan A. Watch the videos and if you think this improvement to A3 is a fine work of engineering and practice please write me back and tell me why you believe that and I will post it on the page about Standard Plan A and call it "Another point of view". I am always delighted to see someone take time to defend a position I may not agree with. In other words it is now your turn to explain. I hope to hear from you soon.
Hi Howard - I feel pretty good about the construction portion (nuts and bolts so to speak) of the shear walls thanks to your examples, but less sure about specifying some other details. I'm wondering if you could answer a few questions for me. I'm trying to dig out the info, but a little confused.
1. Should shear walls always be done in match pairs when possible (opposing walls)? It seems like that's what you are saying. Intuitively that makes sense to me in that you would want the walls on opposite sides to provide the same resistance so that they would react in a similar way to external forces (although sometimes this isn't possible).
2. Is it better to split up a shear wall, half on one corner and half on another or is it ok to just have one long one in the middle? Some corners just have too much stuff in the way to put anything in the corner. Is this a case of do the best you can, i.e., "don't let the perfect be the enemy of the good"?
3. In terms of reinforcement schedule (determining linear feet of shear wall), Standard Plan A has a table, is that a fair way to go, or is it ok for a single-story to have a minimum of 50% of the length but maybe add some, go a little longer than shorter just to be conservative? It's not much extra work-wise or material-wise for me, assuming extra length doesn't cause a problem.
I really appreciate you sharing your knowledge and experience. Thanks for any suggestions/tips that you can offer!
Nice video! Very helpful!