Chimney and fireplace symptoms
There is water in the bottom of my fireplace after it rains
Water on the firebox floor after a Portland rain often means the flue has no cap, with a cracked crown or leaking flashing next. Hold off on fires until the firebox and smoke shelf are dry and the source is found.
Updated
What to do right now
Soak up the water with old towels and leave the damper where it is; closing it on a wet smoke shelf traps water against the plate. Note whether the puddle is black or clear, and whether it arrived during the storm or the next morning. Hold off on a fire until the firebox is dry; we want to see the water pattern before it is burned off.
Likely causes, most common first
Four ways rain ends up on the floor of a fireplace, most common first.
- Most common
An uncapped flue taking rain straight in
The sign: Water arrives while it is still raining, the puddle is black with soot, and from the yard the chimney top shows bare clay tile rather than a metal hood.
The fix: A stainless cap with a screen goes on the flue tile, and rain no longer falls straight down it. Chimney Cap Installation, from $299
- Common
The crown is cracked and running water down inside
The sign: The water shows up hours after the rain, the brick inside the firebox is wet in streaks, and the top course looks dark or white-streaked from the ground.
The fix: The crown is coated when the cracks are fine, or poured new with an overhang when pieces are missing. Chimney Crown Repair, from $349
- Common
Flashing is sending roof water onto the smoke shelf
The sign: Water comes with a ceiling or wall stain near the chimney upstairs, and the shelf behind the damper is a wet, sooty pool.
The fix: New step and counter flashing at the roof joint, with a cricket where a wide chimney needs one, cuts the path off. Chimney Flashing and Leak Repair, from $399
- Less common
The flue is sweating from the inside
The sign: Dampness in the firebox in cold weather with no storm, a water heater venting into a chimney the furnace left behind, and a sour smell.
The fix: A camera run shows whether the flue is wet and flaking from condensation, and the finding decides between a liner and a cap. Chimney Inspection, from $129
Two minutes of safe checks
Five checks from the hearth and the yard that usually narrow it to one cause.
- From across the street, look at the top of the chimney: a metal hood on legs is a cap, a bare tile sticking up means rain has a straight shot.
- Note the timing: water during the storm came down the flue, water the next morning worked its way through the crown or the brick.
- Look at the color: black water carried soot off the flue walls, rusty water came off the damper, clear water ran down the firebox brick.
- Shine a light past the open damper at the smoke shelf without reaching in; a dark pool or a tide line of dried soot says the shelf is catching water you never see.
- If there is an ash dump, check the cleanout door in the basement or at the base outside; wet ash under a dry firebox means water is running down behind the hearth.
The smoke shelf: the puddle you never see
Behind and above the damper sits a flat ledge called the smoke shelf, and much of the rain that comes down a flue lands there first. The firebox puddle is only the overflow.
The shelf was built to turn downdrafts back up the flue, and it does the same to water: it catches it, holds it against the back of the smoke chamber and lets it soak into brick and soot. A shelf can stay wet for weeks after the firebox has dried.
That standing water is why an uncapped chimney smells musty, why the damper plate rusts in the open position, and why the mortar behind the firebox softens over the years. Clearing the shelf is part of every sweep for exactly this reason.
Why an open flue in Portland is a funnel
A flue tile is an open pipe to the sky, and the airport normals average about 37 inches of rain a year. Over a winter that is a surprising amount of water going straight to the smoke shelf.
The cap also keeps out what the rain brings with it: fir needles, leaves and the birds and squirrels that treat a warm flue as a den. Caps fail too; a screen matted with creosote holds water in the tile, an undersized cap sits crooked and shelters half the opening, and one that blew off in a windstorm leaves the flue wide open.
When water in the firebox is more than a cap job
Have the chimney inspected rather than capped when any of these shows up with the water.
- Chunks of clay tile, flakes of brick or sandy grit on the firebox floor; a flue shedding pieces has a cracked liner, and a camera run finds how far the damage goes.
- A ceiling or wall stain near the chimney at the same time; the flashing or the crown is involved and a cap alone will not stop it.
- The firebox stays wet for days and the mortar between the firebrick crumbles at a touch; the firebox needs repair before another fire, and the fireplace stays cold until then.
What stopping water in the firebox involves
The order is simple and obvious first, with the camera held back for the cases that need it.
Confirm the path
We look at the smoke shelf, damper and firebox walls, then the top of the chimney: cap, crown, tile and the flashing at the base. Water often leaves a trail of soot streaks pointing to the opening.
Cap the flue
A stainless cap sized to the tile is fastened with its screen clear of the opening, or a multi-flue cap covers a stack with several tiles. Wet soot on the smoke shelf is cleaned out the same visit.
Repair above the cap
When the trail runs down the inside of the brick rather than the tile, the crown gets a flexible coat or a new pour, and failed flashing at the roofline is replaced.
Check the liner
If the water carried tile fragments or the flue serves a furnace or water heater, a camera run looks at every joint before you light a fire, and you see the footage with the posted price.
Water in the firebox: common questions
Why is there water in my fireplace after rain when the chimney has a cap?
A cap covers the flue opening, not the crown or the brick around it. Rain landing on a cracked crown runs down between tile and brick and comes out on the smoke shelf; rain soaking the stack does the same more slowly. An undersized or crooked cap also lets water in on the windward side.
How much water in the firebox after a storm is normal?
None. A chimney with a sound cap, crown and flashing stays dry inside, and even a damp smoke shelf means something above it is open. A few drops after a sideways downpour on an uncapped flue is an open pipe behaving like one; a puddle every storm is a repair getting more expensive while it waits.
Is it safe to light a fire with water in the fireplace?
Wait until the firebox and the smoke shelf are dry. A wet flue draws poorly and smells, steam off wet masonry carries soot into the room, and if the water brought tile fragments down with it the liner may be cracked, which needs a camera look before any fire. Dry it out and find the source first.
Why is the water in my firebox black?
Because it came down the flue. On the way it washed through the soot and creosote on the flue walls and the smoke shelf, which turns it dark and sour and stains the firebrick and hearth. Clear water often ran down inside the brick or through the firebox walls, and points to the crown or the flashing.
Will a chimney sweep fix water in my fireplace?
Not by itself. A sweep clears the wet soot off the smoke shelf, which ends the smell, and the look-over that comes with it often finds the opening. The water itself stops when that opening is closed: a cap, a crown repair or new flashing. A cap is a short job once the tile has been measured.
Related pages
Areas we cover for this
Calls about water in the firebox come in from Cully, Hawthorne and Sunnyside, Lents and every other part of the metro we serve.
Ready to book a sweep?
Call with what the fireplace is doing, or text a photo of the opening and one of the chimney top, and we will name the service and its posted price before we come out.