How to determine if basement slab is insulated?
jdt141
| Posted in Energy, Heating & Insulation on
Is there an easy (read: non-invasive) way to tell or inspect if my basement slab has rigid foam insulation beneath it? The home is newer (built in 2001), so I would assume it is possible, but not likely.
I ask because I would like to finish the basement. From what I have read there are many different ways to insulate the floor (not at all, VB+ double layer ply, XPS+double layer plywood, VB+XPS+single layer ply or double layer ply), and I thought the first step would be to determine if insulation was already present under the slab. If my thinking or understanding is off here, I’d appreciate a course correction 🙂
Replies
I suppose you could measure the temperature of the slab and compare it to the air temperature. No insulation would show a greater difference than an insulated slab.
jdt
Mildly invasive-drill a hole, ground up foam should be brought up with the concrete powder. If unsure after that-drop a probe of bent (90 deg.) stiff wire down the hole-rotate-to dislodge some foam-vacuum out hole and look for pcs. of foam.
Yeah, probably drilling a hole is the best way. Two or three might be needed to be sure. Just stay away from the areas where drain pipes might be running.
Use an Ir thermometer to measure your average slab temp then do the same on an older home in the neighborhood. if that doens't work you'll have to drill a small hole.
Is there a rough in for a bathroom? I have one in my basement which is boxed off for the tub/shower that wasn't poured (allows me to move the rough in 8"-10" inches in any direction. All I would have to do is go pull the 2x box out and look. Its a pretty common practice in our area to leave this boxed in section unpoured.
What would you do differently if there was or wasn't foam under the slab?