stucco on builders foam

[grazhina]

Not really stucco, but I was wondering how well dry wall compound and similar products adhere to builders foam. I've been playing around turning a section of foam into a stone wall using small amounts of paper clay to build up some stones' texture higher here and there. I completed a small practice section and it looks pretty good, but would a bit of dry wall compound be easier and faster to work with, rather than dabbing glue on some individually carved stones so the paper clay will stay stuck?  

[KathieB]

10 minutes ago, grazhina said:

Not really stucco, but I was wondering how well dry wall compound and similar products adhere to builders foam. I've been playing around turning a section of foam into a stone wall using small amounts of paper clay to build up some stones' texture higher here and there. I completed a small practice section and it looks pretty good, but would a bit of dry wall compound be easier and faster to work with, rather than dabbing glue on some individually carved stones so the paper clay will stay stuck?  

You could try some of the drywall compound on the builder's foam. If it doesn't stick well to the plastic surface, maybe mix in some white glue? Or put a thin coat of gesso over the plastic surface? Gesso sticks to nearly everything (as I'm reminded when I have to scrape it off of my hands).The drywall compound should stick to that very well.

[Dalesq]

I agree with KathieB. My experience is that acrylic paint will stick to the builder's foam so gesso should work fine and will give you a surface for small things to adhere. Acrylics are what I used to paint the base and rock on the Chanticleer. But in order to get the builders foam to stay affixed to the plywood base I had to use Gorilla Glue. White glue didn’t work. Gorilla Glue is kind of awful stuff because it expands and is water activated, but for adhering strength it’s super aggressive. 

 

[Mid-life madness]

I have seen this stuff at hobby lobby, and it looks interesting. Have you see ii?

[KathieB]

11 minutes ago, Mid-life madness said:

I have seen this stuff at hobby lobby, and it looks interesting. Have you see ii?

This is for smoothing the bumpy surface of styrofoam. It looks like it would work well for that purpose. Builders foam/insulation, however, has a thin skin of smooth plastic on it, so no smoothing would necessary. The trick is to get the applied product to adhere to the plastic skin.

[grazhina]

Well, it looks like I'll try gesso and the drywall compound next. I recently got some sandable gesso, it's thicker. I'd post a picture of what I wound up with today, but the photo sort of flattened it out and it didn't look as good as it did in RL. I was pretty pleased with the results so far.

[Khadi]

I would apply a very thin coat if you use drywall compound.  I tried drywall joint compound on builder's foam, and the compound cracked when it dried.  I'm think that the moisture in the compound caused the foam to expand when it was wet and then contract as it dried leading to the crack.  My favorite for stucco and grout is paint mixed with craft sand.  It is a lot less messy.  I learned that from someone on this site, although I must apologize because I forget who originally suggested it so I can't give them credit.

[grazhina]

18 minutes ago, Khadi said:

My favorite for stucco and grout is paint mixed with craft sand.  It is a lot less messy.  I learned that from someone on this site, although I must apologize because I forget who originally suggested it so I can't give them credit.

Yes, I know a few of us do. I did that on my first scratch built house. I was also concerned about the drywall compound eventually cracking on the builders foam, so that was good to know, thanks.

[grazhina]

I just thought maybe I should let you all know how I'm going about my "stoning". I used a pencil to press in lines that form the outline of each stone, sort of like drawing but pressing hard. Then I used several different kinds of chains and dropped them in clumps, pressing them into the foam to make indentations and roughen up the stones. After that I used several different things to incise around some of the stones making some of the spacing deeper or wider. I used a tiny flathead screwdriver, a metal skewer and a small chisel to do this. I painted the whole thing with a greyish tan color, then I decided to apply something to make some of the stones a little bulkier. This is where the glue and paper clay came in, I used it on a few of the stones here and there to add a bit more texture, then I started painting stones with mixtures of paint. I was planning on having the front of the house be whitewashed stone and the sides left natural color. That's a pretty traditional old look, but now I'm not so sure. if I really, really like the stonework I might leave it natural. On the other hand, I might get gawdawful sick of carving and painting stone and say heck with it, where's the whitewash?

[WestPaces]

29 minutes ago, grazhina said:

I just thought maybe I should let you all know how I'm going about my "stoning". I used a pencil to press in lines that form the outline of each stone, sort of like drawing but pressing hard. Then I used several different kinds of chains and dropped them in clumps, pressing them into the foam to make indentations and roughen up the stones. After that I used several different things to incise around some of the stones making some of the spacing deeper or wider. I used a tiny flathead screwdriver, a metal skewer and a small chisel to do this. I painted the whole thing with a greyish tan color, then I decided to apply something to make some of the stones a little bulkier. This is where the glue and paper clay came in, I used it on a few of the stones here and there to add a bit more texture, then I started painting stones with mixtures of paint. I was planning on having the front of the house be whitewashed stone and the sides left natural color. That's a pretty traditional old look, but now I'm not so sure. if I really, really like the stonework I might leave it natural. On the other hand, I might get gawdawful sick of carving and painting stone and say heck with it, where's the whitewash?

I'd like to see how it turns out Grazhina. What do you use for whitewash? Watered down white paint? Something else? I wanted to do 'painted' brickwork on my Beacon Hill so any tips would be welcome.

[grazhina]

Janet, I do use watered down paint for whitewash, generally applying 2 coats or more depending on the look and how thin the paint is.

[grazhina]

I just thought of something since we're on the subject of whitewash and stone. Here's a fireplace I did that's another old timey look, plastered over and whitewashed stone. In this case I made egg carton stones, applied a thin layer of drywall compound, then I whitewashed the chimney. If you zoom into the picture you can see the outline of the stones under the plaster and whitewash.