wrote:
Hello,

Appologies in advance - I am a total clueless newbie. I did try a
google search of the archieve, but no luck.

Last year, I bought a cottage in the Muskokas in Central Ontario. The
cottage was built in 1993, is well insulated and is lived in all year
round by the previous owners until I bought it. The primary heating
source is an efficient wood stove, but there are base-board electric
heaters. The cottage has post and beam construction, and there is 5-6
feet under the cottage, with a dirt floor (what I call the crawlspace).
The walls of the crawlspace are cinderblock, but are insulated. The
"roof" of the crawlspace (which is also the floor of the cottage) is
not insulated - it is bare wood covered in carpet upstairs. The
cottage has heated lines bringing the water from the lake, and the
pipes run in the crawlspace (with the water heater etc.)

Last year, my first year with the cottage, I left the heaters on at
about 15 degrees C when I wasn't there, but the pipes froze on me when
the weather hit - 20 or 30. The previous owner never had a problem
with the pipes freezing, but then living there year round, the place
was always warm (and presumably some heat went through the floor and
kept the crawlspeace warm) and the water was being used. The copper
pipes are insulated with that grey foam stuff.

My initial thought was to use something like this
http://www.heatline.com/palprod.htm , but I was advised that if the
power went out (which it does from time to time), the heat would
dissipate quickly and things would freeze. So I might be better to
insulate the ceiling of the crawlspace and put a heat source down
there.

I am looking for any suggestions overall, but if the advice to heat the
crawlspace is right, what type of heating can/should I use, given that
it is going to be on a dirt floor (or maybe a sheet of metal or
something on a dirt floor) and will be left alone for a few weeks at a
time.

Is there a heater with a themostat that I can use in this application?
If so, presumably I would then insulate the ceiling of the crawlspace.

Sorry for the long question.

Regards,

Gideon


First thing you do is cover that dirt floor with 6
mil plastic. If you are going to be down there,
then throw some board on top of the plastic where
you wall.

Second, make sure the water supply pipe is buried
below the freeze line and that it is well
insulated where it comes into the crawlspace. If
it comes out of the ground, then construct a 2
square foot box (no bottom or top around the pipe
and fill to a 1 foot depth of insulation.

That said, if you kept the set at 15 C it should
never have frozen. You say the cinder block is
well insulated? how? You should have at least 3"
of insulation and it should run from the floor
above to the bottom of the wall. Note that a lot
of people insulate to the top of the concrete wall
and then fail to insulate the wood space from the
top of the concrete to the sub floor above. (you
con lose a lot of heat if that 8" or 10" space is
not insulated.

The best way to insulate in your case is to
insulate just the walls and not insulate the
bottom of the floor. At some temperature probably
-5 C or so you need some heat in the crawl space.
and let that heat filter up to protect the pipes
above the crawlspace.

Ransley suggests draining, which is a good option.
You have lots of space in the crawl space, so
make sure the plumbing has slanted runs and put
drains in at the low spots and put containers
(plastic garbage cans) in to hold the drain water.
The biggest problem is the water heater so
attach a hose to the heater drain valve and leave
it coiled there or install a permanent pipe to
drain outside. Although the water heater could
take more than an hour to drain (don't forget to
pull the breaker on the water heater) the rest
shouldn't take more than 15 minutes to open the
drains and then open upstairs taps. That is, it
should only take an hour or so to get the water
system ready for use or drained.