PNW_phil
Registered User
Hi,
I'm looking into how I could retrofit my existing wall bracing to comply with "the spirit" of current code on my old house built somewhere around the 1960's. The house has a pair of windows at two corners that don't look like they comply with current wall bracing requirements. I saw figure R602.10.7 says to add 800lbs capable hold-downs in this situation and was planning to install Simpson DTT1Z at the two points in my sketch.
When I looked in the crawl space, I found existing anchor bolts in the mudsill, but there is a 4x8 beam sitting on top of the mudsill, and I can't tell how (or if) the 4x8 and mudsill are attached together. I made a sketch of my wall/foundation in this room. (The rest of the house has conventional anchor bolts visible from the main floor and does not have this 4x8 beam along the foundations inside the crawl space.)
Do you think I could shim the 4x8 with the foundation (would be approximately 2" depth difference to shim) and then add straps (maybe HRS12 or ST2122) near where the DTT1Z's will screw into the 4x8 beams? Since the 4x8 beam is continuous, I wonder if it would be better to put straps at the ends instead of near the hold-down device.
Another question: does anyone have a guess about how old shiplap used as sheathing compares to plywood/OSB sheathing? Would it be worth adding 'Let in Braces' in an 'X' pattern on the interior walls to try and strengthen the wall if I plan to keep the existing shiplap in place? If the shiplap doesn't function very well as a shear wall, then adding the hold-downs too could be altogether pointless! Somehow the house has survived ~60 years though.
I'm looking into how I could retrofit my existing wall bracing to comply with "the spirit" of current code on my old house built somewhere around the 1960's. The house has a pair of windows at two corners that don't look like they comply with current wall bracing requirements. I saw figure R602.10.7 says to add 800lbs capable hold-downs in this situation and was planning to install Simpson DTT1Z at the two points in my sketch.
When I looked in the crawl space, I found existing anchor bolts in the mudsill, but there is a 4x8 beam sitting on top of the mudsill, and I can't tell how (or if) the 4x8 and mudsill are attached together. I made a sketch of my wall/foundation in this room. (The rest of the house has conventional anchor bolts visible from the main floor and does not have this 4x8 beam along the foundations inside the crawl space.)
Do you think I could shim the 4x8 with the foundation (would be approximately 2" depth difference to shim) and then add straps (maybe HRS12 or ST2122) near where the DTT1Z's will screw into the 4x8 beams? Since the 4x8 beam is continuous, I wonder if it would be better to put straps at the ends instead of near the hold-down device.
Another question: does anyone have a guess about how old shiplap used as sheathing compares to plywood/OSB sheathing? Would it be worth adding 'Let in Braces' in an 'X' pattern on the interior walls to try and strengthen the wall if I plan to keep the existing shiplap in place? If the shiplap doesn't function very well as a shear wall, then adding the hold-downs too could be altogether pointless! Somehow the house has survived ~60 years though.