Then I have the great privilege of having a rotten beam in the summer cottage....
I have a house with a crawl space foundation. You can access half of the house from underneath and everything is fine there (bare rock beneath). I can't reach the far half of the house due to a wall in the middle and it's very cramped under that part. I opened the floor in a small room and found soil underneath. The bottom boards and about 2 cm at the bottom of the joists are rotten, but the load-bearing beams seem ok (!). The house was built in the 1940s.
Now to my question. The soil is soaking wet, even though I've drained outside. Since the house is about 75% on rock, it seems the water is getting in through a crack in the rock. My plan now is to dig out as much as possible and lay drainage pipes. Then I plan to add gravel to level it out since there are some large stones and rock protruding. On top of this, I plan to lay construction plastic and add a few more vents. I also plan to put a thin layer of gravel on the plastic so it fits tightly against the foundation wall.
Do you believe in this construction? Have I missed anything?
I will, of course, replace the joists. Should I use treated wood in the joists if moisture continues to come in?
I have a house with a crawl space foundation. You can access half of the house from underneath and everything is fine there (bare rock beneath). I can't reach the far half of the house due to a wall in the middle and it's very cramped under that part. I opened the floor in a small room and found soil underneath. The bottom boards and about 2 cm at the bottom of the joists are rotten, but the load-bearing beams seem ok (!). The house was built in the 1940s.
Now to my question. The soil is soaking wet, even though I've drained outside. Since the house is about 75% on rock, it seems the water is getting in through a crack in the rock. My plan now is to dig out as much as possible and lay drainage pipes. Then I plan to add gravel to level it out since there are some large stones and rock protruding. On top of this, I plan to lay construction plastic and add a few more vents. I also plan to put a thin layer of gravel on the plastic so it fits tightly against the foundation wall.
Do you believe in this construction? Have I missed anything?
I will, of course, replace the joists. Should I use treated wood in the joists if moisture continues to come in?
You should not use treated wood, I think, the moisture should be gone from the foundation, period. Fill with gravel so the water doesn't come up at all. A closed space, I believe, is not good from a moisture perspective.
Do not use treated wood, just as hultan says, it is not preferable. Instead, dig out so that you have 50cm free underneath after you have shoveled in about 20cm of gravel, and make holes in the wall between the left & right half and create good ventilation in general. Possibly, you can dig a deeper hole and install a sump pump that pushes away the larger excess of water. A often costly way is to expose the rock in the surroundings and seal cracks, but since water always takes the easiest path, the problem often just moves and it usually doesn't help anyone.
Avoid plastic!
Best regards, Jawen
Avoid plastic!
Best regards, Jawen
A dehumidifier is something I recommend as it will always blow out dry air and draw out moist air from the foundation. If you have soil under the house, a construction plastic should be laid on the ground, which you fixate with stones. Otherwise, you will always get moist air rising from the ground.