Basement wall: Inviting frost damage?
I’m now finishing the basement of our home near Dayton, OH. Over the last few months I re-graded the dirt around the house so the water flows away, and I even dug a deep trench 2 feet outside the two walls that see the most local water and installed drains at the bottom (below the height of the footer) and another drain 1 foot from grade to intercept any surface water before it goes deeper.
Next, I’d planned to apply a penetrating silicate sealer to the inside of the block, then a coat of Thoroseal, and finally a coat of Zinnser BIN keep water vapor out. After that, 2″ EPS foam, furring strips, and drywall.
Here’s my concern: Though I’ve tried to keep water away from the outside, the house has virtually no external waterproofig on the exterior of the block. They are going to get wet. After I get done with the inside sealing/priming, they won’t be able to dry inward,so they’ll be more wet. And, with the insulation on the inside, the concrete block and mortar wil be getting a lot colder than they used to.
Am I inviting a problem with freeze-cycle damage to my foundation with this approach?
Opinions and pot-shots welcomed . . .
Replies
The walls really need some sort of waterproofing or the dampness will penetrate inside and cause all sorts of problems. Where are you? I'm in Kettering.
Dam Inspector,
Thanks for the note. Your profile wouldn't allow me to send you a personal message. I'm in Beavercreek.
Yes, waterproofing the walls is what I'm trying to do. I know working from the inside is an uphill battle, but:
1) The basement didn't get "much" liquid water even before I did anything (I've lived here five years and probably seen 1 gallon total on the floor)
2) The exterior drains are fairly extensive on the two sides of the house. While I didn't scrape the outside walls clean and apply dimpled membrane with drains at the bottom, I dug a trench parallel to the wall 2 feet away and went down to below the footer. I laid a slotted pipe in a sand bed, covered with a foot of sand, put plastic against the house side of the trench, filled with (our clay) soil for about 4 feet, the put in another slotted pipe in a sand bed to catch surface water and prevent pooling near the house. Between the house and the trench I laid Tyvek sloped into the trench (will allow the soil to dry, but won't allow liquid water to enter the space from the top). The intent of all of this was to keep liquid water away from the basement walls. I could do it myself--if I'd tried to get an excavator or backhoes close enough to dig right up against my wall I'm sure I'd have bashed through my foundation. :)
Hello neighbor! What you have done sounds to be pretty effective against water intrusion. I worked with a woman who lived in Beavercreek who had her block basement cave in. I guess tons of mud came in and wrecked the basement area, but amazingly the house itself sustained only minor damage. It took months to have the house livable again though.
I edited my profile to accept email messages.
Dayton is a very mild climate. I doubt that you have much to worry about.
And I've never heard of this sort of problem even in MN. You really only have spalling problems on masonry walls when they're sealed on the cold side, or when there's lots of moisture drive from the warm side (like in a retaining wall).
DanH,
Thanks for the info. I'll go ahead with the interior insulation. I also need to repair the many spots where the parge coat on the outside is cracked and falling off.
(And I agree that it would have made sense to waterproof the outside of the foundation while you had it exposed.)