What is this stuff on my foundation?

[DaveS]

I have a "new construction" house that has foam insulation sheets covering the block foundation - the insulation is on the outside of the wall.

The foam is covered with some sort of gray coating.

I've gotten out of control with the weed whacker a few times, and there are a few places where it is cracked, or flaking off.

What is this stuff? I need to get some to do some repairs.

If I didn't know better, I'd say it was some sort of roofing material (but it isn't shiny like the silver roof stuff). It seems pretty thick (i.e. it isn't paint), and is fairly brittle (i.e. not some sort of rubber coating).

Anyone have a clue?

[siliconbauhaus]

Sounds like rigid foam insulation to me mate but it shouldnt be exposed anyways imho.

[LarryG]

It sounds like EIFS ... Exterior Insulation and Finish System ... often referred to by the Kleenex-like trade name "Dryvit."

Odd that it'd only be used as a foundation covering, though. What's the main exterior finish of the house?

[steve-norrell]

I have a "new construction" house that has foam insulation sheets covering the block foundation - the insulation is on the outside of the wall.

The foam is covered with some sort of gray coating.

It seems pretty thick (i.e. it isn't paint), and is fairly brittle (i.e. not some sort of rubber coating).

Anyone have a clue?

They used that stuff on some "new construction" that we had done. I asked about it when it was installed and the contractor said that it is better than hot tar painting, but probably not as good as using a rubber membrane. It is stiff, grainy and almost like a thin coat of sprayed-on concrete. It was inspected and approved by the code police.

In my case it was applied directly to the outer surfaces of the concrete blocks and allowed to dry before back fill.

It has been in place two years, with no sign of any seepage. Since it does appear stiff and brittle, I wonder about its use on a relatively soft surface like foam panels. Are the foam panels "closed cell" insulation?


Regards, Steve.

[DaveS]

Ok, I see I caused a little confusion.

We have a "walk out" basement (where half of the basement isn't actually under ground), and this rigid foam insulation is only on the block that is above the dirt (I think).

The gray stuff is something that was either sprayed, or rolled on over the (closed cell, I believe) foam panels. It almost looks like some kind of fine grained painted on stucco.

The rest of exterior of the house is vinyl siding.

I believe they put up the foam as a cheaper way to insulate the exposed foundation wall (required by code) without doing it on the inside of the basement.

I have since finished the basement, and insulated the inside very well - so, I would just tear off the foam (with the gray stuff) and just leave the exposed block (paint it with dryloc maybe), but the vinyl siding sticks out 2" to compensate for the foam.... oh well.

[DaveS]

ok, after further research...

It is not brittle at all - just the one little piece was. It comes off in big flexible sheets, and is like really thick paint, with some sort of sand texture.

It was clearly applied with a big thick bristled brush.

I've taken it to a few home stores, and a called a bunch of insulation and block guys - no one knows what it is.

So... assuming that I can't **fix** it - If I take it all off (which shouldn't be too hard),

What can I replace it with?

[DaveS]

One more thing I just discovered - under the flexible layer, is a layer of white brittle stuff, almost looks like crumbly plaster.

I didn't notice it at first because it is gone in most of the places where the stuff is coming off.

[Jbridge337]

Sounds like stucco. Usually done in a couple of layers with only the top layer having the colorant in it. That would explain the grey on top of white. Hard to say without seeing it in person. If that is what it is, the BORG has a material in the paint section that is a premixed stucco patch that dries light beige. Wouldn't match what you are patching, but you'll have a hard time matching colors with anything you use.

Jim

[siliconbauhaus]

can you take a photo of it mate....might make things easier here all around?

[68KANE]

A word of caution here bud; in Georgia builders were putting blue foam board below ground level extending up to and behind the siding or stucco. In either case, they'd cover it with material resembling stucco/cement and call it good. Well, it turns out that it's a perfect medium for termites/carpenter ants to travel up and attack either the studs or siding. When we went to renew our termite bond on our last house, I had to remove all this stuff before they would renew us.

I got a shovel and dug down a couple inches around the house to get as much of it out as I could. To break up the cement/stucco material covering it, use a soft mallet to loosen it up. As you remove it, inspect it for signs of termites/ants and mark any areas that need to be treated. You'll be able to tell as the foam will have channels in it if you had an infestation. This is of course, if you decide to; if not get a home inspector to look at it. Good luck.

[DaveS]

thanks for all the help guys... I really appreciate it.

Anyway - I finally got in touch with our builder, who put me in touch with the company that did the waterproofing on the foundation.

They told me that the product on my house is "RetroFlex" foundation coating... which they can't get anymore, and they don't use anymore because it falls off.

The white stuff is plain old plaster - used to smooth out the joints and divots in the foam.

I went over the whole foundation, and it looks like, even though there are only a few rips and holes, the coating in general appears to be failing, and is loose from the wall. So, I think it has to go.

They are coming out to give me a quote for repairing/replacing the coating - hopefully they will look at the shoddy work they did the first time and give me a better rate.

On second thought, I'm not sure I'll give them the work...