Anyone here insulated their basement floor?

[dave11]

I have a walk out basement, and the concrete slab that nears grade level is extremely cold in the winter. I plan to insulate it with 1" XPS and plywood.

The hot water tank sits about ten feet from the exterior wall and door leading outside. I was planning to insulate the floor past it, but was unsure whether raising the tank and placing it on the insulated floor is the right way to go, or to install the floor insulation around the tank.

Raising the tank would require reconfiguring the plumbing, as well as the power vent stack used by the HWT. A fair amount of work, but could be done.

Raise the tank, or insulate around it? Is there a preferred way? Or a drawback to one way or the other?

Thanks.

 

[ironpony]

when I built ours I installed a thermal break of 2 inch foam between the foundation and slab. Onto your question, look into cork it might give you the same result without the thickness. Definitely raise the heater off the floor, concrete sucks the heat out of everything.

 

[semipro]

I'd consider foaming around the tank with plans to add foam when the tank needs service or replacement.
Since its gas fired you're probably not losing much heat from the tank through the concrete floor like you wood if it were a electric-resistance HWH.

I plan to insulate our floor. I'm thinking I'll skip the plywood though and place laminate over the XPS. We've done that elsewhere in the house with great success.

 

[drewosbaldo]

Same is the issue which I am facing but here I really got some great tips which is really helpful will definitely go with semipro technique.

 

[velvetfoot]

I plan to insulate our floor. I'm thinking I'll skip the plywood though and place laminate over the XPS. We've done that elsewhere in the house with great success.

I didn't know that would work. I've been thinking about that for a while. Can you describe a little more in detail? Is everything floating, including the xps, or is glue involved somehow? 1" thick xps? etc? Not that I care, but does the laminate suffice as a fire retardant like the printing on the foam board states? Again, not that I care and I would do the same as well. I'm just not into tapconning a bunch of holes into the basement slab.

On the original post, does the gas fired heater have any fire related requirements? I imagine they're designed to be installed on wooden above grade floors, but the heater manual might say something about it.

Not that it helps, but when I installed an electric tank I put a 2" piece of xps underneath. I did use those flexible connectors though-maybe you could use them for the plumbing at least?

 

[semipro]

I didn't know that would work. I've been thinking about that for a while. Can you describe a little more in detail? Is everything floating, including the xps, or is glue involved somehow? 1" thick xps? etc? Not that I care, but does the laminate suffice as a fire retardant like the printing on the foam board states? Again, not that I care and I would do the same as well. I'm just not into tapconning a bunch of holes into the basement slab.

We installed laminate in a 10x8 room that originally had wood subfloors with padding and carpet. Since floors adjacent to the room were wood there was quite a difference in height. We installed 1" XPS, taped the seams, then installed the laminate directly on top. Everything is "floating". No glue was used. We've had no problems and big dogs and heavy filing cabinets have not caused problems.
We thought we'd try the same in our basement which has concrete floors. I've tested for water coming through the slab and its not an issue. I suspect that poly sheet was installed under the slab.
I'm not sure the fire rating of the laminate floors but don't see why they couldn't be used in the basement if they can be used in bedrooms, etc.
We were going to go with the waterproof Allure laminate but our basement is very dry so we may go with a less expensive standard laminate. The Allure was also made in China which I want to avoid. There are many American made laminates available.

 

[velvetfoot]

Thanks! That's awesome that it works.
I was talking about the fire talk printed on the foam. It says something like must be covered with 1/2" of gypsum board or similar.