Insulating a crawlspace prone to flooding - Page 2

benpope · 09-09-10, 10:21 AM

Per Ryland's suggestion, I have filled the inside of the cracks with polyurethane caulk. For now I am going to concentrate on the 120 sq ft. sub-basement that holds my gravity coal-to-natural-gas conversion boiler that I affectionately refer to as "The Beast". Last time the basement flooded, the burner was submerged. There are maybe two guys in town who service these ancient conversions, so having one inspect and clean out the water cost $400. Fortunately he showed me what to do if it happens again. But, I digress--the boiler deserves a thread of its own.

The next step will be to put water tight mortar on the outside of the cracks, pour cement over a 1' sq hole in the concrete with a sewage flush out valve, and paint the basement with dry-lock.

I have known for some time that the drain pipe in the floor has a 2" diameter rust hole that drains under the foundation. The soil underneath has been washed out by 30+ years of basement flooding and boiler overflow. This is obviously the source of the cracks in my foundation that is otherwise sound. I am going to have to bust it out the concrete around the drain and remove it, put in a back-flow preventer and sump, and fill in the cavity with concrete. For a temporary fix, I filled the hole with closed-cell polyurethane spray foam. According to a manufacturer that sells it for boats, it can handle intermittent contact with water. Unfortunately I was a bit overzealous in my foaming--the foam covered the pipe to the sewer. I'll go back in tonight and carve out enough space for the dehumidifier hose and a small amount of drainage.

DIYgreen2011 · 03-29-11, 01:45 PM

I think the best way to prevent future damage is to get that sump pump installed. It sounds like your crawl space is pretty accessible so the job should be easier. In your case though, you might think about actually tying the sump line into an existing line or to a place where it will not compound the flooding problem.

09-09-10, 10:21 AM	#11
benpope Helper EcoRenovator Join Date: Jan 2010 Location: Little Rock, AR Posts: 95 Thanks: 16 Thanked 13 Times in 12 Posts	Per Ryland's suggestion, I have filled the inside of the cracks with polyurethane caulk. For now I am going to concentrate on the 120 sq ft. sub-basement that holds my gravity coal-to-natural-gas conversion boiler that I affectionately refer to as "The Beast". Last time the basement flooded, the burner was submerged. There are maybe two guys in town who service these ancient conversions, so having one inspect and clean out the water cost $400. Fortunately he showed me what to do if it happens again. But, I digress--the boiler deserves a thread of its own. The next step will be to put water tight mortar on the outside of the cracks, pour cement over a 1' sq hole in the concrete with a sewage flush out valve, and paint the basement with dry-lock. I have known for some time that the drain pipe in the floor has a 2" diameter rust hole that drains under the foundation. The soil underneath has been washed out by 30+ years of basement flooding and boiler overflow. This is obviously the source of the cracks in my foundation that is otherwise sound. I am going to have to bust it out the concrete around the drain and remove it, put in a back-flow preventer and sump, and fill in the cavity with concrete. For a temporary fix, I filled the hole with closed-cell polyurethane spray foam. According to a manufacturer that sells it for boats, it can handle intermittent contact with water. Unfortunately I was a bit overzealous in my foaming--the foam covered the pipe to the sewer. I'll go back in tonight and carve out enough space for the dehumidifier hose and a small amount of drainage.

03-29-11, 01:45 PM	#12
DIYgreen2011 Lurking Renovator Join Date: Mar 2011 Location: Indiana Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	I think the best way to prevent future damage is to get that sump pump installed. It sounds like your crawl space is pretty accessible so the job should be easier. In your case though, you might think about actually tying the sump line into an existing line or to a place where it will not compound the flooding problem.