Gutters protect your foundation only if the water leaves the house: keep gutters and downspouts flowing, extend every downspout at least three to five feet from the foundation, make sure soil slopes away from the house, and check underground drain lines each fall. Overflowing gutters and short downspouts are among the most common causes of wet crawlspaces in the Pacific Northwest.
How roof water reaches your crawlspace
A typical roof sheds a large volume of water in a single winter storm. When a gutter overflows or a downspout empties right against the wall, that water saturates the soil along the foundation and finds its way through vents, cracks and the gap between the foundation and framing.
Fixes in order of cost
- Clean gutters and flush every downspout before winter.
- Add downspout extensions or splash blocks so water lands three to five feet away.
- Regrade soil and bark so it slopes away from the house for the first several feet.
- Fix overflow points by adding downspouts or upsizing gutters.
- Test and clear underground drain lines, or replace them with above-ground extensions.
- For persistent water, consult a drainage contractor about curtain drains or crawlspace drainage.
Signs of a drainage problem
- Standing water or damp soil in the crawlspace
- Musty smell inside the house
- Efflorescence (white mineral deposits) on foundation walls
- Erosion channels in beds below the roofline
- Mold or rot on rim joists
Frequently asked questions
How far should downspouts extend from the house?
At least three to five feet, onto ground that slopes away from the foundation.
Will gutters alone keep my crawlspace dry?
Gutters are the first line of defense, but grading, extensions and sometimes crawlspace drainage are also needed.
Are underground downspout lines a good idea?
They work when maintained, but they clog and collapse over time. Test them every fall by running a hose into each one.
Need a hand?
- Downspout Cleaning & Repair: Clogged, crushed or disconnected downspouts cleared and rerouted so water leaves your foundation.
- Gutter Cleaning: Hand-cleaned gutters, flushed downspouts, roof edge cleared and everything bagged and hauled away.
- Seamless Gutter Installation: Seamless aluminum gutters formed on-site to the exact length of your roofline, in your color.