I'm not a carpenter and not real familiar with framing nomenclature, so bear with me. House was built in 66-67...

Crawled under the house last week to tend to the frozen pipes and had a look-see while I was under there...

I've got an issue with some of the floor joists/sill getting wet and starting to rot. I believe moisture is wicking up through the foundation. It appears that at one time there was flashing on top of the masonry to prevent that, but it has long since corroded away.

I dealt with this once before in another spot and used a bottle jack and a beam to jack everything up a hair to slide more flashing in to help alleviate the issue. Don't know if that's the correct way to fix it, but that's all I could do at the time.

Looking for advice on newer/better/more correct ways to fix this without tearing the house down to the foundation and starting over.

Mike

Pictures would be helpful.Your sure it`s not termites?

I'm in the same boat. The previous owner put on an addition and didn't allow for any air flow from the outside of the house or the main body of the house. I found out when I cut the flooring to put in a hearth for a woodstove. It has affected the integrity of the entire addition. Expensive fix.

Positive it's not termites.

Mike

I'm currently working in a house with a similar problem- rotten sill plate, with joists sinking to the foundation. The end blocking and siding is rotten too. The moisture and rot seems to be caused by the dirt being over-filled too high against the outside of the house, combined with poor grading resulting in water soaking in from the outside.
The fix is to jack up the affected joists and replace the rotten sill plate with a new pressure treated one. Rotten joists can be "sistered" to restore integrity. And obviously the dirt problem needs to be fixed come summer.

Modern codes/methods require pressure treated burial-grade lumber in contact with concrete, because the alkalinity of concrete will rot wood if there's any moisture. That's also probably why the flashing corroded away.

Pretty much what I figured...

I can't sit up under there but I have enough room to crawl comfortably and raise up on my elbows. I'd have to grade the entire property down to relieve the foundation more... Otherwise I would just be digging a depression around the house.

There's a vapor barrier over the soil in the crawl space and it does a good job of keeping it dry... But it's no help with the wicking by the masonry. So I guess the bottle jack and myself are going to get well acquainted come spring/summer.

I'm almost thinking of a system of fans to force air circulation... But if it gets humid that's just compounding the issue.

Box of matches is sounding good about now. Lol

Mike

Diagram I was looking at showed a plastic barrier on the masonry topped by a metal termite barrier with another layer of plastic barrier on top of the metal.

Mike

Plastic on top would protect the wood from the concrete, but it could also hold moisture against the wood. Meaning if water comes from any other source, the plastic might create a puddle.

Treated wood on top of concrete is what we use here, but regional construction is different. We don't have termites to worry about. Talking to a local inspector or contractor would probably give you some good ideas.

Some people with crawlspace moisture issues install a dehumidifier with a pump plumbed to a drain.



No idea how big it is, but would raising the house be an option?