Spray Foam for leveling?

[Lorne]

When I started to suggest this idea I figured people would think I was nuts, but maybe I'm not as nuts as I thought.


[url www.thisoldhouse.com/toh/article/0,,1574553,00.html
some interesting uses for this stuff.

Only half of my shower floor is unlevel , so I thought of laying down one or two sheets of 3/4" plywood, checking the level and then spraying some foam under the low end and waiting until it hardens.
When dry it is hard to compress and 100% waterproof.

[Yanita]

Hi,

This is more informational than repair...I am going to move to the Off Topic forum.

Yanita

[Greg]

It may work, but you have to take into consideration that foam does expand before hardening, the trick will be to figure out how much. I have used it on tub enclosures to stiffen up the soap shelves that feel flimsly. Greg

[Dean3]

It would have to be some very dense foam to support any real amount of weight,especially when there would be a person moving around while showering,or,if it was a tub/shower stall with the tub full of water.. I'd study careful the current uses of the exact foam product before going ahead with it.

If it is a heavy duty shower pan I would forget foam altogether and do it the tried-n-true way. Most pans like that then get nice tile above and it would really su%k to have the foam compress and the tile grout come apart.

Dean

[Jim from Canada]

It is fairly common to foam under tubs, but they must be filled befor doing so. They need the weight in them for it to work right. If you could put a few hundred pounds in the shower base while it is level, I can't see foam being a problem. There are different ratings of foam, you would have to look up which is the right one to use. They are rated in "pound densities" most, for around windows and doors, are light, 1/2 lb rating or so, for fully insulating a wall (like walltight) they are a 2 lb. density. Something else to consider is that when any type of foam burns in a house fire, they give off toxic fumes.

Jim

[Dean3]

Way cool Jim,I only knew that the can type foam had different densities.

If I ever was going to foam under a tub I might consider keeping the foam away from the drain area so if there ever was a problem I still had eassy access,,,maybe the drain could be "formed" around,,You know,,kinda like a concrete form only it would keep the product out of the drain area instead of contained within like a concrete form.

Dean

[Lorne]

I ended up just using shims and little blocks under the 3/4" plywood. It is now level and firm.
Thanks for the "Foam" info.