We have an unconditioned crawl space (yes I know I need to seal it up and will soon). So we have been worried about frozen pipes in this very cold weather. We have done everything to prevent pipes freezing and so far it has worked. The sink cabinet doors are open, water is dripping through the night, and our fingers are crossed. So not really everything, which I will explain now.
If your pipes do freeze, hopefully they will not burst from the expansion of the ice. If this happens, get a plumber in to repair the pipes, but that only fixes the symptoms of the real problem. The real problem being that the pipes are in an unconditioned crawl space. Why did we ever think it was a good idea to leave our crawl spaces unconditioned, then we also thought it would be a good idea to install water pipes in that space. This seems absolutely crazy to us today in new construction, but it is very common in existing houses. So if your pipes froze this winter or if you don’t want to have to worry next year, seal up your crawl space and insulate the space.
An insulated crawl space will have a duct supply and return (slightly undersized) so that there is positive pressure, but temperature controlled. It will have a heavy plastic liner across the floor and up the walls. It will also have insulation on the exterior walls and open cell spray foam in the rim board to complete the system. This complete system brings the crawl space into your thermal envelope, so no insulation in the floor above is needed.
We have many issues in our old house that over time slowly I am addressing. Frozen pipes, drafts, and high energy bills are all symptoms that need a holistic solution to address. Don’t continue to treat the symptoms without addressing the problem.