Painting Styrofoam

[Pike]

Styrofoam? No, it isn't woodworking, but it is a workshop question.

Our garage is completely dedicated as a workshop. When the recent cold snap was forecasted, I realized that it was going to be difficult to keep it above freezing in there.

As it happens, the garage panels have convenient slots that allowed me to insert approx 1.5" of styrofoam insulation into them. That would be 1" of the white stuff and .5" of the blue stuff.

It worked great - with the outside temperature at 5 degrees F it was no effort to keep the shop at 55F with a very small electric heater.

Now having done all of that, I don't like the big blue checkerboard effect. There are 16 panels approx 19"x46". I would like to paint them white but have not tried painting styrofoam before.

On test pieces I have tried latex primer and Krylon spray primer with latex over it. As I expected, the latex primer scrapes off easily. The Krylon spray primer adhered very well, but I don't enjoy the thoughts of spray painting that huge of an expanse...

Ideas?

~Pike~

[Edwin Pawlowski]

Garage panels? Is this a metal building?

The blue stuff is Styrofoam. That is Dow Chemcial's register trade name for extruded polystyrene foam. The white stuff is expandable polystyrene board that could have been made by anyone.

I assume you are painting only the blue and not the white. Any latex or acrylic paint should work. You don't plan to scrape the walls do you? Avoid anything with ketones as it will dissolve the styrene. The best method is to cover it with a non-flammable plastic vapor barrier (it is white) and then sheetrock. It will stay cleaner, meets fire code, and looks finished.

Alternatively, you can take out the blue, put in Georgia Pacific stuff that is yellow ;)

[Wood Butcher]

The answer seems so obvious that I probably don't understand the problem correctly.

Put the blue stuff behind the white stuff.

Art

[Pike]

My apologies... I didn't have my glasses on and left out the word "door". Garage door panels.

Yup.

Nope. But swinging boards around, etc.

Yeah but I left out the data point that it is an overhead door, so sheetrock doesn't quite work out for me. I have been trying to visualize using sheetmetal as a flame barrier but haven't got it worked out yet.

Almost did that to begin with but didn't feel it would stay in place the first time the door was opened.

~Pike~

[Pike]

I guess I left out too many details. :)

To get the cut to size panels of insulation into the door panels I had to flex them mightily. I put the white stuff in first because it was thicker and more brittle. I then put the blue stuff in after that as was easier to flex.

If you looked at the door panels from the end they would look like:

[___________]

(turned horizontal, exterior facing down, interior facing up)

There is probably a standard method for insulating garage doors - I just don't know what it is. :)

~Pike~

[doordoc]

Most insulation kits from the factories have a thin light weight vinyl backer glued to the insulation to give it a clean look. Some commercial doors have a thin (30 or 24 ga) steel interior cover panel but something like that would probably add enough weight that you would probably need to change the springs to compesate. On the residential kits they also use plastic angles to dress up the gap between the insulation & the vertical hinge stiles where the insulation can't go under them.

Doordoc

[Edwin Pawlowski]

You could always contact the door maker and they may have the proper sized panels that they normally use on the doors. I'm sure that is an expensive option though.

You can buy aluminum that is pre-painted white. It comes in rolls and is easily cut by scoring and breaking. Any place that carries siding supplies should have it. You could buy a roll of flashing material too if you don't mind the natural look of aluminum.

[Wood Butcher]

Ah, yes. I understand now. I had a similar problem when I lived in Tucson. The summer sun striking the uninsulated door caused it to hit 160+° and radiate into the garage like an infrared heater.

My solution was to trim the styrofoam inserts so they would go into the pockets with just a bit of bending. They fit somewhat loosely when they were in place but never fell out and performed just fine even though there was a small uninsulated space at the top edge of each panel. I thought about using white duct tape to seal up the edges but never got around to it.

Art

[Jay Pique]

It's a pain in the ass, I'll tell you that. We've installed a bunch of styrofoam crown moulding recently, and it's shit. The joints don't mesh and it won't take paint. It's passable from the floor, but it just feels chintsy to me.

JP

************* Putty and paint.

[Leon]

Always test first. I have some spray paints melt Styrofoam.

[Pike]

Indeed, almost any solvent will. I used some scraps for my original test. I get by without the spray primer melting the insulation for two reasons. a: the blue insulation has a very thin plastic skin adhered to it that is a little more resistant to solvents. b: I am spraying a very light coat that dries instantly.

~Pike~

[Pike]

I went the Krylon spray sandable primer route (about 30 minutes ago). I'm still a bit dizzy from the fumes... I need another can to finish it up. A couple of days after that I will roller latex primer over it.

~Pike~