Form Ties, Snap Ties, Tie Rods
Adventures in Home Construction
Form ties, snap ties, tie rods are all names for the same thing, pictured above. Little metal rectangles, usually close to the form seams. Sometimes they stick out 1-2", because the contractor didn't snap them off. Sometimes they are totally hidden by the original concrete pour, or covered over with a patch. They were put there to hold the forms the correct width apart during the original pour. They do not indicate that there is structural reinforcement in the foundation. And they can leak! Water present on the outside finds a little gap down these babies, and flows into the basement and runs down the wall, often leaving a rust stain.
I once discovered a very strange form tie. I was at a house in Alstead, NH, where there was a wall full of leaks. At first I thought the water was coming through these 2 very small and short cracks, but that could not explain the flooding, and there was little staining coming from them. But there was staining below a whole row of form tie holes. Upon closer inspection, I found that there was dirt and ants coming out of them. They were virtually emptty, except for the dirt. As I pulled out the dirt, I discovered cork. The builder had used cork for the form ties, which broke down over time and ended up creating 1/2" channels for water, dirt and ants to flow into the house.
A couple of months later I was at my SEON Building Science Group and a fellow from the same area northeast of Keene mentioned these. Apparently, a builder in the 70's and 80's in the Alstead area had used cork on 20 some odd houses.
Last year I ran across them again at a condo in Keene, NH.
I can stop water coming through and around form ties with urethane injection. It creates a complete block of the hole or wraps the tie in hydrophobic urethane foam, stopping the water permanently.
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