· Michael Blair
Standing water in a crawl space is common in Middle Tennessee and rarely resolves itself. It comes from a small number of sources, and the cheap fixes come first.
Where it comes from
Surface water entering through vents or over the footing after heavy rain. Roof water discharged beside the foundation. Groundwater rising through the soil. A plumbing leak.
Which one it is determines the fix entirely, and it is usually identifiable by when the water appears.
Fix the outside first
Gutters clear, downspouts discharging well away, and grade falling away from the house resolves a large share of crawl space water at low cost.
Only when that is done does interior drainage make sense, because otherwise you are pumping water that should never have arrived.
- Clear gutters, extend downspouts six to ten feet
- Grade falling away from the foundation
- Then interior perimeter drain and sump if needed
- Vapour barrier over the ground
- Dehumidification once bulk water is controlled
Interior drainage and sumps
A perimeter drain at the footing feeding a sump pump handles groundwater that cannot be excluded. It needs a discharge point well away from the house.
A sump in Middle Tennessee should have a battery backup, because the storms that fill it are the ones that take the power out.
What the water has already done
Wet insulation must come out. Framing that has been damp needs checking for rot and fungal growth. Ductwork sitting in water is contaminated.
And the humidity that standing water produces has been rising into the house, which is why crawl space water often shows up first as a musty smell upstairs.