My house was built in the '80s (British Columbia) when they were allowed to put the water shutoff in or adjacent to an outside wall....stupid, I know.

I've had a minor freeze once, when there was a cold snap and a section where the former irrigation system was removed, without being re-insulated.

I'm just fixing that area up now we have a water meter installed - I'm using Isoboard for most of it because I want the highest R-value in the narrowest space (below grade adjacent to the concrete wall the water meter comes as close as 1" to the concrete.)

The shutoff etc is enclosed in a triangular area in a corner, so I'm making sure that the insulated area is now the outer wall - it was not well done originally.

I'm wondering about this little section of concrete floor - should I insulate it or not?

I'm concerned if I do, and there's a leak, it'll conceal it. I have also fitted a Floodstop just downstream of the shutoff in the same enclosure:

http://www.aartech.ca/fs1-2-npt-floodstop-automatic-water-shut-off-sys tem.html

http://www.smarthome.com/7115H2C/Water-Heater-Leak-Detection-FS3-4C/p. aspx?green=1bbf8c00-6f14-9a53ca-81f9-f6afccca37e9

If you note the sensor, it's basically a printed circuit board which will activate the alarm and shutoff valve if it detects moisture, and I'll connect it to my alarm system as well (They make water detectors without a shutoff, but why not shut the water off AS the leak's detected?)

If I use Isoboard, a slow leak might just end up underneath the foam. Fibreglass insulation might be better but again, it'd have to be really wet for the detector to notice it.

Since it's such a small area I'm inclined to leave the concrete floor bare, it's less than a square foot and should be well within the conditioned area. I'm also putting in a heat tape because of the outside taps, so I figure it's well covered already.

Thoughts?

My former house was built on a concrete slab. The hot and cold water supply pipes ran through the concrete. There was never a problem of freezing.