Sewer p trap in crawlspace??

[Submariner]

Originally Posted by inthetrees

Our new house is built on a pier and beam foundation with a small crawlspace

I would hope this house has some type of insulated skirting to keep the cold wind from blowing through the crawlspace. Solid framed with at least one-inch of foam board on it.

Keep in mind that frost goes down to 4 foot below grade in Maine. So all plumbing, starting at the well casing, needs to be protected from freezing. If it is buried deeper than 4 foot, that meets code. If it is only 3 foot deep, then you need to add insulation on top of the buried pipe. One-inch of foam board is equal to a foot of dirt. A 3 foot trench with a pipe in it needs at least one-inch of foam on top of the pipe.

I like radiant heat systems, where you circulate heated water through PEX tubing. It is a lot easier to work with compared to copper tubing.

PEX tubing laid alongside all cold water pipes, tie-wrapped good and tight, then wrapped with foam pipe insulation, should keep the water pipes from freezing, whenever your heating system is running.

... My questions are isn't there a better way to build this? Seems like a horrible oversight putting those traps in unheated crawlspace.

One option would be the heat the crawlspace.

... Yet on the other hand ive always only heard of peoples water lines freezing, never sewer unless its backed up?

As the industry shifts to using plastic tanks for septic tanks, instead of concrete. It makes septic tanks that can float. If your soil floods often, there is a possibility that when there is standing water out there, your septic tank could pop up out of the ground, 'floating' there.

So when you first dig the hole, you have to pour concrete in the bottom and anchor chains to it, so you can chain down the plastic septic tank.

[wharton]

Check out "sealed conditioned crawl spaces" online. I build dozens of homes in the mountains of Northeastern PA, where it regularly gets to below zero overnight, and the frost go 3-4 ft deep. I built unvented concrete walled crawl spaces with concrete floors over plastic and gravel. Good drainage on the exterior, and two inches of sprayed foam on the interior means that the crawl space never gets below fifty degrees in the dead of winter, as long as the building above is heated to 50* or more. No matter what you do, I recommend that you buy a digital indoor/outdoor thermometer and locate the remote sensor up against the P-trap so you know exactly how close to freezing your drain is.

[inthetrees]

Currently the house is skirted with green zip decking and two inches of rigid foam board.

there are actually two p traps in question, both under showers, one is built low profile i think is the term and much closer to the floor, this one will be easy to seal up and seemz less likely to freeze in general, the other is built closer to the ground and seems more of a worry.

I happened to have an old remote temp/rh sensor i put down there today when i was checking it out. Unfortunately the only methods of heat here currently are a wood stove and two propane rinnai heaters. We will hopefully put in baseboard heating with an outdoor wood boiler in the next few years. Currently with the wood stove goiing it's 70 in here, and 51.8 in the crawlspace p trap. Curious what it is tomorrow morning when its 30 out

[Submariner]

Originally Posted by inthetrees

Currently the house is skirted with green zip decking and two inches of rigid foam board.

there are actually two p traps in question, both under showers, one is built low profile i think is the term and much closer to the floor, this one will be easy to seal up and seemz less likely to freeze in general, the other is built closer to the ground and seems more of a worry.

I happened to have an old remote temp/rh sensor i put down there today when i was checking it out. Unfortunately the only methods of heat here currently are a wood stove and two propane rinnai heaters. We will hopefully put in baseboard heating with an outdoor wood boiler in the next few years. Currently with the wood stove goiing it's 70 in here, and 51.8 in the crawlspace p trap. Curious what it is tomorrow morning when its 30 out

From the first of January to the end of February, there will be a bunch of nights where the temps will be -20F [no wind-chill B.S.], and the winds will be howling, and there will be 3 foot of snowbank piled up against that skirting [frozen hard into ice so no pickaxe can break it apart].

Right now is your best chance to 'fix it'. Once winter comes it will be much more difficult to get down there.

Have fun

[inthetrees]

Originally Posted by Submariner

From the first of January to the end of February, there will be a bunch of nights where the temps will be -20F [no wind-chill B.S.], and the winds will be howling, and there will be 3 foot of snowbank piled up against that skirting [frozen hard into ice so no pickaxe can break it apart].

Right now is your best chance to 'fix it'. Once winter comes it will be much more difficult to get down there.

Have fun

I think this will be our 11th winter in central maine. Granted the first one in a pier n bean house with crawlspace but i know all about winter. My plan this first winter here is to leave that crawlspace access door clear of snow for when murphy calls.

[vaughanwilliams]

Maybe put some electric space heaters wired up to a thermostat in the crawl space. Might be pricey to run but would definitely keep an insulated space above freezing.