View Full Version : Earthquake Retrofit Prep Work

12-09-2012, 04:13 PM
I am hoping that some of you may have done or have experience with earthquake retrofitting.

I have completed the home assessment checklist to figure out whether the house meets the requirements for the SEHR (Standard Earthquake Home Retrofit Plan Program). There is a possibility that the house does not meet all the requirements, but I am not quite sure. I think the house is missing the mud sill plate which is required for the SEHR. In case there is no sill plate, I will need to get a retrofit plan from an architect or an engineer in order to get a permit for the work.

Looking at the pictures, is the sill plate embedded in the foundation? Or, it is not a sill plate at all. To my understanding, a sill plate can be either embedded in foundation or installed on top of the foundation. And, it usually covers the entire foundation. The studs of the pony wall are nailed to that piece of wood embedded in foundation (see attached pictures).

What are your thoughts?

Thanks for your help,

12-09-2012, 05:30 PM
I would contact a structural engineer. The untreated wood sitting directly on the concrete would concern me alot.

12-09-2012, 07:55 PM
Are you sure that is untreated wood? I did not see any signs of rot, and the house was built in 1948.

12-10-2012, 04:19 AM
Are you sure that is untreated wood? 99.9% sure.

Windows on Washington
12-10-2012, 06:25 AM
Looks untreated to me as well.

I know that Dana knows the moisture facts backwards and forwards but if the concrete stays dry, it might be a non-issue.

How old is the concrete?

12-10-2012, 02:01 PM
Until you insulate it both the wood and the concrete are drying at a reasonable rate into the conditioned space. But if you insulate it the temps will run cooler and the moisture content of the wood will rise- it gets the same capillary draw in the foundation, but both the wood and foundation dry more slowly when running at cooler average temperatures. If there is a couple feet of above grade foundation and big roof overhangs (minimal splash-back from roof edge drips) and the foundation is well drained it could still make it though.

There's a hint of wetting history on the plank sheathing in that middle picture, but it looks like a bulk-water event, possibly even prior to the plank going up.

Nice looking stuff though- is it all doug-fir?

12-10-2012, 03:57 PM
Thank you all.

I am not 100% sure, but I think the foundation is original, so it would be 64 years old.

Dana, I will definitely finish the entire basement in the near future. I terms of foundation, 75% of foundation is about 2 feet above the ground, in other areas, the foundation is at least 1 to 1 1/2 foot above grade. The house has about 3 feet wide overhangs, and it is a single story house.

I believe the foundation is well drained since I've never had any moisture problems. The sign of wetting on one of the pictures is most likely from other reasons, mainly because the area on the other side of the wall is right at the exit door and there is a large overhang there.

I beleive it is all doug-fir. It is quite hard.

12-11-2012, 08:55 AM
When you insulate those walls don't use batts with facers, and don't use closed cell spray foam or you'll be asking for trouble (from different ends.) The foundation still needs to be able to relieve moisture toward the interior to avoid wetting the now-colder wood with ground moisture. The large overhangs are definitely a plus here, since exterior wetting events will be primarily dew rather than direct or splash-back wetting from rain, which would be putting a lot more moisture into the concrete than mere dew. Are there any signs of efflorescence on the exterior? If so, where? It would usually appear as chalky discoloring of the surface in the first foot or so above grade, but if it's within a foot of the concrete-embedded wood it could become an issue.

Filling the stud-bays with half-pound density open cell foam, and using 1.5-2" of unfaced EPS (the cheap-cooler type of insulation) between the wallboard & studs/concrete would allow the foundation to dry toward the interior without risk of wintertime load-up from interior moisture drives.

Douglas fir always turns that rich reddish brown with time and it also hardens- it's a superior building material to most coniferous species in most applications, but I'd be happier with cedar for the goods embedded in concrete due to it's better moisture resiliance.