Damp Under Window Sill Patched

Once the leak is stopped, the damp patch won’t dry on its own. You must remove the damage:

But before you call an expensive contractor, let’s diagnose the problem. In 90% of cases, the fix is simpler (and cheaper) than you fear.

Protect your investment. If you see signs of damp, act fast. damp under window sill

We see this all the time: damp patches appearing directly under the window sill.

It usually starts with failed external weather sealing. Rainwater penetrates the masonry, saturates the sill, and tracks inward. Left untreated, this leads to: ❌ Dry rot in the timber. ❌ Blown plaster and bubbling paint. ❌ Toxic black mould growth. Once the leak is stopped, the damp patch

Every spring, walk around your house with a caulk gun and a flashlight. Check under every window sill. If you see a hairline crack, seal it that day . Clean weep holes. Trim back any plants touching the sill.

We tackled this [this week/today] by: ✅ Raking out the old, failed pointing. ✅ Applying a flexible, weather-proof sealant. ✅ Treating the internal stain with a damp-blocking primer. Protect your investment

Ignoring damp under window sills can lead to a range of problems, including:

If you’ve done all the above and the damp returns within a month, or you see a white, fluffy salt deposit (efflorescence) on the sill, your problem is structural. Likely causes:

Call a reputable damp surveyor (not a free quote from a chemical injection company). Expect to pay for a diagnosis – it will save you thousands.