Tough ventilation, moisture problem
We are working on a house built on a fairly steep slope. The house is built on poles with the upper wall sitting on rocks right above ledge rock. Over the years this wall has sunk into accumulated dirt. We are pinning a footer to the ledge, building a two foot high block wall and replacing the floor framing with treated lumber. We will be forming a gutter with concrete to guide surface water away from the house and will put in weep holes to let water on the ledge through the house.
In two areas a slab has been poured in a past attempt at fixing the problem. The slabs are in good condition but both are damp from the weeping of the ledge rock. I will cover these slabs with treated sleepers but am uncomfortable with the wetness. Is there a way to ventilate this space or do I seal it off the best that I can?
Replies
In sealing your slabs, you might be interested in a product we recently had to use, called Xypex. It is mixed into a slurry and scrubbed into the damp concrete surface with a brush. It then soaks into the capillaries of the concrete and crystallizes, preventing water from wicking through the concrete to the point that it is considered 'waterproof.'
We had an elevator shaft in which an incorrect weeping tile installation caused the shaft to constantly collect water (the absence of a drain is a story in itself). Unsure of the most efficient solution for this problem, we did some research. The Xypex testimonials are remarkable- Defence Department bunkers, traffic tunnels, university buildings, government infrastructure projects- many of which are apparently continuing to perform as promised after more than twenty years.
It cost a couple of hundred dollars (Canadian), the rep showed up and applied it in an afternoon (no unusual equipment, no noise, no fumes), within a week it was dry as a bone, and has been dry ever since.
I have always been wary of water proofings applied to the surface opposite the pressure source in spite of what the product literature may say. I was pleasantly surprised by this product, and would recommend that you consider it.
couple hundred dollars Canadian. Whats that, about a buck ninety eight U.S.?
The joys of building an obstruction in the natural flow of water.
As discussed by the frugal architect, you can seal the concrete to prevent dampness but it might not address the effects of the infiltration of the water.
I think I'd want to have a closer look at your construction. Any chance you could post a picture or two?
Gabe
"I think I'd want to have a closer look at your construction. Any chance you could post a picture or two? "
Another reason to get myself a digital camera. Unfortunately I can't post a picture of the problem now.
One of the biggest problems I face is that much of the previous work is not too readily accessible and there are fissures in the ledge that could not possibly be sealed especially within the budget of this project.
What is the best way for me to seal the joint between the ledge and any further concrete that I pour? Waterstop? Leave a gap and caulk?
Thanks for your help.
Sometimes you have to sit back and look at your problem from another angle.
Without doing any other work, how can you "divert" the water away? Can you give the water a better way around your area of work?
Can you insert a drain pipe or fill with a more porous material like crushed stone? Can you line the outside with drainage lining?
I you can minimize the water presence or even pressure against your work you have half the battle won.
When I have a serious problem at work I get a bunch of my co-workers together and talk out the problem in a very informal think tank session. I've got 35 years of construction experience to bring to the table but a lot of times my 35 years hasn't experienced everything and I take advantage of the other guy's esperiences around me.
But you have to do it in a relaxed atmosphere. A problem will frustrate you if you try to solve it in fustration.
Gabe