Where Is the Water in Your Chimney Coming From?

The problem family: rain finds the weakest point

Sea-Tac's 1991-2020 normal is 40.34 inches of rain a year, and about 73 percent of it falls between October and March. A chimney stands above the roofline in all of it. Every seam, slab and seal on that structure is a possible entry point, and by the time a stain shows on the ceiling the water has usually been coming in for a while. The goal of a leak visit is to find the entry point before anyone picks up a caulk gun.

How to tell which sub-problem you have

Stain on the ceiling or wall right next to the chimney

Most often flashing, the metal that seals the joint between the chimney and the roof. Lifted counter-flashing, dried sealant, rusted step flashing or a wrong original install all let water run behind it. See chimney flashing repair when the metal is sound but the seal has failed, and chimney flashing replacement when the metal itself is corroded, lifted or undersized.

Water or rust streaks inside the firebox, worse after heavy rain

Usually the top of the chimney. On a brick chimney that means a cracked or missing crown, or no cap. On a framed (siding-clad) chimney it means a rusted-through chase cover. Rust streaks running down the siding are the giveaway. Read chimney crown repair, chimney cap replacement and chimney chase cover replacement.

Damp, white-streaked or flaking brick, no single drip

The masonry itself is soaking up water. Open mortar joints, spalled brick faces and a crown that sheds water onto the brick instead of past it all keep the chimney wet, and winter freeze-thaw makes it worse. This is a repair-then-protect job rather than a patch. Our chimney leak repair page covers the diagnosis and the order of work.

Moisture with a sour smell, or a leak that shows up in cold weather without rain

Condensation. A flue that is too big for the appliance venting into it, or an unlined flue, cools exhaust gases until they condense on the walls. The fix is a flue problem, not a roofing problem, and it starts with a chimney inspection with a camera.

What to do first

• Note when it leaks: during rain, after rain, only in wind, or in dry cold.
• Note where it shows: ceiling, wall, firebox, attic, or the exterior brick.
• Photograph any stain or rust streak from inside the house and from the ground. Do not go on the roof.

Call 206-453-2045 with those three things. We will inspect the top, the flashing, the masonry and the flue, tell you the actual entry point, and give you a free quote for that repair only. If another company quoted you a cap for a leak that is really flashing, our free second-opinion quote will say so, and we price match plus 10 to 25 percent on the work that is needed.

Why we do not sell a leak fix over the phone

The cheapest repair is the one aimed at the right spot. A new cap on a chimney with failed flashing fixes nothing and costs you a second visit. We would rather find it once, fix it once, and stand behind it: if you are not happy, we are not done.