Heating Cottage Crawlspace - Pipes Freezing

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
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Any heatsource or power needed can fail, even a new set up, and freeze the pipes when you leave, Safest is to drain them , put antifreeze in traps and have no worry. Im set up so its a 1 minute job, turn off main, open line drain, open faucets, pour in antifreeze. Then I also dont have the cost of wasted heat.
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m Ransley wrote:

Thanks. I do know that, but if my power goes out, it doesn't (usually) go out for all that long, and my thought was that if the power is out for few hours at minus 30, then if the pipes alone are heated in a freezing crawlspace, it will not take long to freeze, but if the whole crawlspace was, say, 15 C, then it would take a lot longer to cool off, by which time the power would be back up.

I agree that this is the safest way to go, but I was hoping to avoid having to go through that every week or two. I was hoping that there is a solution that works that would avoid it.
Thanks again,
Gideon
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Might be able to use just a 100 watt light bulb! May want to experiment to see what is needed so you only use the minimum amount of heat required and save on the heating cost. They make wireless indoor/outdoor thermometers which have a wireless remote sensor, might want to stick the remote in the crawlspace with one lightbulb, two lightbulbs, or additional heating if that does not work. (Place temp sensor away from bulb of course.)

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I grew up in Iowa on a farm that when the water line in the ground was put in was not deep enough in spots. On the coldest nights Dad would leave the water tap on just a crack so that the pump would come on a few times a night. Seemed to solve the issues on the really cold nights.
If your going to use electric heat tape. Make sure you insulate over the tape and pipe. It might help the run time on the electric.
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Which would only work if something was pumping the water along. Should power go out you're still stuck.
If it's going to remain unheated and unoccupied then the only sensible thing to do is drain the lines.
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SQLit wrote:

I have adopted that as a stop gap at the moment.

Thanks.
Gideon
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issues as using heat tape (ie. lose power, things cool off). I've done this. I installed a drain at the lowest point of my system. When I leave, I turn off the main, open the drain, and fill all my sinks/toilet/drains with RV antifreeze. I have heat tape/insulation on all the lines under the cabin for when we are up there but I haven't had an issue yet. The added benefit to just shutting the water off is you eliminate the potential for a burst line or leak (I've got a washer/dryer) when I'm not there. HTH Cheers, cc
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James "Cubby" Culbertson wrote:

Whatever works the best! My girlfriend's father suggested propane, but I have visions of an unattended propane heater blowing up my cottage. Is this a realistic concern?

I was thinking of electric, hoping that the larger area wouldn't cool off fast enough for the pipes to freeze if the power went out for a few hours. My intitial post was sort of seeking input on whether there is a heater (preferably with a thermostat) that I could safely leave on when I'm not there.

The cottage was built so that the water can be drained, but there is a hot water heater and (excuse the clueless term) large tank with water and air that is part of the pumping system. I would hate to have to drain and refill everything every week or two. OTOH, maybe there's no realistic alternative.
Thanks, cc.
Gideon
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I had a wall hung unit at my cabin that burned propane. Used to leave it on all the time during the winter and never had any issues. It was one of those ventless ones though and it stunk like hell. I wouldn't want to run it under the house. I have since retired the wall hung unit and installed a forced air furnace under the house which as a bonus, keeps the crawl space pretty warm.

At the end of the day, any time you leave something "on" there is a level of risk, particularly if you're not there to react quickly if need be. I leave my furnace on up there on the lowest setting and hope I don't get back up there and find a pile of ashes. One reason I drain my lines is so I don't get up there and find a swimming pool in the place.

So you're on a well/pump. The expansion tank is there to buffer the pump from running all the time. Honestly, that tank, I'm guessing, doesn't hold all that much water. On my water heater, I drain about 1/2 of it out...plenty of room for expansion should the water freeze. I don't know, a few gallons of water vs. frozen/burst pipes and a real mess to deal with....I'd probably go the drain route (actually, I already have). I'm sure there are other alternatives that I'm not aware of but draining seems like the less risky of the ones I know. Cheers, cc
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So power outages dont last where you are, well get a major ice storm and 5 days can happen. best is drain, but at least turn off the main 5 gpm can ruin a house fast, its your house.
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Not sure why this comment? I do drain my lines as I mentioned in earlier posts. I basically shut off and drain my lines any time I'm not there (summer included). Cheers, cc
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snipped-for-privacy@rogers.com wrote:

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.
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George E. Cawthon wrote:

I will look next time I'm up.

Well, I kept the "upstairs" at 15 C. I am not sure how well the heater travels down to the crawlspace (hence my thought of heating the crawlspace).

It is insulated with the rigid foam insulation. I haven't measured it, but I may do that. There is an access door (from outside), that wasn't sealed properly last year when I had freezing problem. I believe I have it insulated now (with the rigid foam and some Fiberglass pink).

Another thing I will check when I get back up there!

That's what I was thinking (still need an answer whether there is a heater I can leave down there unattended). As the outside temperature will likely get to minus 20 or 30 C (as it did last year), I was looking for help.

As I said to the other helpful posters, I am trying to avoid that, if I can.
Regards (and thanks),
Gideon
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snipped-for-privacy@rogers.com wrote:

just need to make sure you don't have any air leaks. The plastic over the dirt will improve temperature control. As one other person suggested, a light bulb can be used for a heater.
Years ago, I constructed a play house for my son; it was 9'x9' with two 7' high stories. The bottom story is used for storage. We try to keep the temperature in the bottom from falling below 40 F (about 8 C) because we store canned goods and potatoes there. We heat the lower level with a 75 light bulb when the temperature drops below 32 F (0 C.) by turning the bulb on for a few hours each day. When temperatures drop below 0 F (about-16 C), we run a 750 W heater for a few hours each day. You could probably keep your crawlspace above freezing with two 100W bulbs operating all the time and a small heater with the thermostat set to go on at 30-35 degrees.
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George E. Cawthon wrote:

Any recommendations for a heater like this that would be the least dangerous to leave unnattended?
Thanks,
Gideon
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You can probably buy a complete rig designed for wellhouses, but I still don't understand why you want to heat the whole crawlspace when the only thing you need to keep warm is the pipes.
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