I have a super-insulated house (18" thick walls, whole-house air infiltration barrier, insulated floor system, insulated foundation, conditioned crawlspace). I have a sump pit, but no pump (wasn't sure at build time whether it would be needed; it is).
I need to install a sump pump and an outlet to deal with high groundwater in spring thaw.
Most sump pumps have a 1.5" threaded outlet. Running 1.5" rigid PVC through the insulated floor system and walls will be painful; it will mean a lot of cutting, loose insulation dropping out of the floor, trying to glue a right angle inside an insulated floor system, and a large new puncture in the air infiltration barrier that helps keep the house warm.
I've been thinking of drilling a single diagonal hole (probably 24" or so) through the floor system in the crawlspace out to the exterior wall, and fishing some Pex through it. But I think this would require reducing the 1.5" sump outlet to a 1" or 3/4" Pex pipe.
A couple questions:
- I'm fairly confident that this diameter will adequately drain the water — right now a garden hose through a window is doing the job. But I don't know if there are other reasons not to reduce a sump pump. Will it wear out the motor faster? Increase the chance of outlet pipe bursting?
- Is there any reason not to extend the Pex 10-15' from the outlet outside the house, to route it far away from foundation? It's a cold climate, so freezing is possible in e.g. May; but if things are freezing, then there probably isn't as much water to pump.
- Any other advice welcome. I've never sumped before.
Best Answer
I have a sump pump that I use with a garden hose. It works great but has a slightly reduced flow capacity. If that size works for you, use it. My greatest concern would be exposure of the pipe to the cold climate. If it freezes, it will not flow water. The smaller pipe (hose) will put more "head" on the pump but should not cause any harm to your pump. As far as cutting a hole to the outside, why not hire someone or rent a drill that can "core drill" an exact size hole to the outside through almost any wall thickness. It will make for a neat and clean hole with little cleanup needed.