Old Concrete Basement Wall Waterproofing
My Dad has an approximately 90 old home here in Harrisonburg, Virginia that has an old concrete basement foundation. The home is used as a professional office and they use the basement for storage. During heavy rain he seems to be getting more water on the floor on the East side of the house. Since access is good on this East side we have decided to excavate this side to expose foundation, waterproof, provide foundation drains, repair underground roof drains, backfill with crushed stone, slightly regrade to provide some positive drainage away from foundation, and repave the area we excavated.
On the inside there is a couple layers of paint and probably some kind of waterproofing paint or coating that seems to have trapped moisture in the wall and caused some areas to spall. These small areas where the surface has come off and exposed small(6″ x 6″ x 1-2″ deep)soft and wet areas of the concrete.
Thought this might be a good forum for advice. Also, we have an excavator lined up but I am concerned that the exterior of the wall may require some preparation (besides cleaning) that out local waterproofer is not used to performing.
Replies
Greetings dt,
This post, in response to your question, will bump the thread through the 'recent discussion' listing again.
Perhaps it will catch someone's attention that can help you with advice.
Cheers
when in doubt add garlic
Thanks rez,
Hopefully someone will see this.
dt
Hello neighbor,
I figured somebody more knowledgeable than me would tackle this. That's what bumps do, bring a would-be thread back into the stream.
You say your concrete wall is soft? Sounds like you might want to address that before you worry about waterproofing. And "waterproofing" around Albemarle county is usually spraying on tar. Which doesn't waterproof. There are several good choices for waterproofing. I prefer bentonite, which is the same expansive clay our Health Dept. prefers for water well grout.
Grading so surface water flows away from the building is obviously an important step. If your site is sloped enough you might consider what I do with our underground houses. We use 6 mil poly to shed ground water, ideally out 20' from the perimeter. If you have dry dirt on the outside of your foundation, you don't need any waterproofing. We don't. If your site isn't well-drained, you need more.
The last house, the client insisted on a standard footing drain. Never saw a drop come out of it. Site was on the side of a hill. Surface water flows around the house. Just like our place. PAHS Designer/Builder- Bury it!