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I’m currently assisting some friends who found a bunch of dry rot in their new (to them) home. The rot started due to the post and pier foundation (I like to call it a straw and pier, ’cause the old creosote posts were just like a bunch of big straws stuck in the ground :), and had spread through the girders, into the subfloor and up the wall in some places.
The old owner had actually replaced all the girders and rotten posts (with more straws????, another project is gradually replacing all the posts with a monolithic sonotube/pad pour with a bracket up to the girder), but he simply finish nailed (this guy does everything with his finish nailer….builds forms, frames, everything) scraps up to cover the rest of the dry rot. We’ve ripped out the bulk of the old rot, the ground contact issue will be taken care of over the next couple of years (it’s a dry area so that should be soon enough), new and improved drainage has already happened.
My question is how important is it to get every last bit of rot torn out? If the bulk of it (over 95%) is gone, and the ground contact is gone, will the rot continue to spread, or isolated will it just be a soft spot. Thopugh getting it all out is preferable, we’re running into some diminishing returns with what rot is left…..we could spend as much time as we already hjave into it just to get the last 5% of rot, which is in small (less than a square foot) patches in unimportant (non structural) locations.
On another note……I noticed the thread about improving this board. Though a ten+ year subscriber to FHB, this is my first visit to this web site. But, if you want to see a well designed and easily navigated message board go to http://boatertalk.com It’s a whitewater kayaking site, but the structure of the board is incredibly easy and instinctual, something this site isn’t I’m afraid. I’m sure Eric Princen (Boatertalk designer and owner) would love to sell you his code too :))
~matt hudgens
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This is a tough call. Dry rot does stop completely if it's absolutely dry. But it only takes a tiny amount of water to bring it back to life. I recently tore out an old bathroom wall where the bottoms of the studs were very dry, but dry rotted so that they crumbled away from the nails. Even though this stuff was 76 years old, the nails within the dry rotted studs were shiny, not rusted. Perhaps a good exterminator will know if there's a way to actually kill the dry rot organism.
-- J.S.
*On questionnable areas after rehab, and wooden members that have been wet, I let dry or force dry, then liberally soak all with Clear Wood Preservative (not sealer). It combats bacteria, mold, mildew and other small critters. Is not as good as pressure treating, of course. Product will repel water when dry but obviously must address moisture/water issue that caused the "dry" rot. Odor is very strong so if in bath wall or basement is important to have plenty of ventilation. Some thoughts. Randy
*There isn't a practical way to kill the spores. I can't find the link but the recommendation is to remove all timber a minimum of 18" past the rot and treat the remainder with a fungicide. Dry rot needs moist timber to grow, but once grown it sends out small tubes and pumps the water to fresh areas of dry timber. These tubes pump by capillary attraction and can move water over 30' from the source so as well as keeping the area dry a good through ventilation helps to stop the rot spreading.Personally I wouldn't take chances with dry rot -- given ideal conditions it can travel from foundations to ridge in less than 6 months.
*If you can't ( or don't want to ) remove all the wood, you can encapsulate dry rot in mildly dry rotted areas by using various epoxy compounds. Penetrating epoxy is very viscous and will soak into less than sound wood. Epoxy filler along with fiberglass cloth or other reinforcing materials can build back to a higher strength than the original wood. Just finished a repair of a dry rotted 2"x8" subfloor under a leaking toilet. This has been covered in past posts. The penetrating epoxy may be difficult to find locally. I ordered some from a web source called "Rot Doctor" and also bought some from a large lumber yard which was made by Smith and Company of Richmond, CA. The Smith product was more fluid than the Rot Doctor stuff and soaked in deeper, but didn't seem as strong. It also used more solvents and I found an organic respirator to be essential. West System Epoxy has a good reputation for epoxy products, but I don't know if they have a very fluid penetrating epoxy. There were a couple of other brand names listed in the past posts. Rot Doctor has some good information on their web site even if you don't buy from them. http://www.rotdoctor.com/11qa.html
*In addition to the above, I think that the TimBor product containing boron combats the spread of rot. It renderes the area it penetrates inhospitable to fungii and bacterium. Another thing not mentioned is insects which are killed by this product. Carpenter ants and powderpost beetles crawling through the wood carry the spores with them.