waterproofing around the soil line
Guys, I’ve got a problem. I’ve built a 3 story house, slab on grade, and have
back filled all around the lower floor (basement) and extended it outward about
30ft all around (I’m in a flood zone. Hey, the land was free and I’m sitting in the
middle of pecan orchard). It’s a basic rectangular house that looks like something
you’d find in the countryside of the UK or Ireland. It’s built of icf’s with a stucco
(Permacrete) finish. The basement is wrapped with a dimpled waterproof
membrane. The stucco stops right at the membrane (soil line). I need to cover
that joint to waterproof it. In retrospect, I should’ve had the stucco guys run
it down another foot or so. Oh, well. I’ve thought about running metal lath
around the perimeter with a coat or two of stucco. I’m not settled on that
though. Whatever the solution, I would like for it to have an old look about it.
I’d appreciate some creative solutions, guys. I’m about brain-dead.
Replies
If you're in a flood zone, your problem water will be coming up the basement wall from under ground, instead of down from the sky as rain--is that your situation? Or are you talking surface flooding with no essential ground saturation? Depending on the situation, you set up your flashings to shed water the way it will be arriving....
If your problem is going to be deep, standing flood water, then I'm not sure what to suggest.
I can't think of any good way to really seal that joint against standing or running (as in river overflow) water in a flood situation. The basic premise of waterproofing is that you can't stop water, you can only convince it to go somewhere else by giving it an easier path...
If you are going to have your house sitting in what is essentially a swimming pool for extended periods of time, you probably should have built the entire foundation inside a huge, seamless, butyl-rubber bag that ran up the walls far enough to get the top edge above the 100-year flood line.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
Hey thanks for responding, Dinosaur. I'm not concerned with flooding. I've got
so much backfill around my house I'm like an island out here. And, besides, my
finished floor is 5ft above the hundred year flood (which gives me a nice 9ft
ceiling in my basement). No, my main concern is rain running down the walls
behind the water proof membrane and trickling into my basement (I thought
icf's were water tite!). So, any thoughts?
Flash it.
Tuck some heavy-gauge galvanized flashing up inside the stucco, then down outside the membrane. Glue it in place with roofing pitch. Make sure you have the shop that fabricates it create a fold-back 'crush' on the down edge (the fold-back must go to the inside), and it should be bent outward just a tad so drips off it will fall clear to the ground and can't roll back uphill to the inside by capillary action.
The flashing should go at least 6" up under the stucco (12" is better if you can manage it), and drop below the top edge of your membrane by at least 6" as well.
If you're concerned about æsthetics you can paint it; remember to use a primer for galvanized metal first.
Dinosaur
'Y-a-tu de la justice dans ce maudit monde?
There are different kinds of flood zones. What is the reason yours is likely to be flooded? The Feds have rules for how to deal with this,
Frankly I am confused because one of those rules prevents you from having any living space finished floor less than one foot above the max flood elevation. The other thing that confuses me is the idea of a basement with a slab on grade. Basements are built below grade. Maybe you could clarify your use of terms ...
Excellence is its own reward!
Thanks for responding, piffin. As for the flood situation, my finished floor is
5ft above hundred flood. And, besides, I've got so much backfill around my
house that I look like an island out here. So, I'm not concerned about flooding.
(I do keep my canoe tie up nearby...). My concern is rain running down the walls
behind the waterproof membrane and trickling into the basement. Oh, by the
way, the slab is on grade giving me a nice basement with a 9ft ceiling. Back to
leaking. What's a good way to treat the joint between stucco and the membrane?
I still don't see the concern. The idea of the membrane is to provide water a place to run instead of being held up against the wall by soil until it leaks in.
You provide the water a place to go other than into the house.
So the drainage material leads water to the perimeter drain which ( Normally leads to daylight) in your case must lead to a sump pump.
You do have a perimeter drain leading to a sump, right?.
Excellence is its own reward!