The short answer
Inspect the Chimney First
Before you seal anything, look at the chimney from all sides. Check the flashing where the chimney meets the roof, the metal cap or crown on top, and the mortar joints between bricks. Rain usually gets in through cracked flashing, a crumbling crown, or porous brick.
Use a flashlight inside the attic or around the fireplace to spot stains or damp spots. If you see water marks, that tells you where the leak is. A simple inspection can save you time and help you decide whether you can handle the fix yourself or need to call a pro.
Repair the Crown and Mortar
The chimney crown is the concrete or mortar cap on top. Cracks in the crown let water run down inside the brick. You can fill small cracks with a masonry repair caulk, but larger damage may need a new crown poured by a mason.
Mortar joints that are missing or crumbling should be repointed. That means scraping out the old mortar and packing in fresh mortar. This is a job you can do for small areas, but a mason is better for tall chimneys or extensive damage.
- Use a wire brush to clean loose mortar
- Wear gloves and safety glasses
- Match the new mortar to the old color
- Let each layer dry before adding more
- Seal the crown with a masonry sealer
Apply a Water Repellent
A breathable water repellent for masonry can help keep rain out while letting moisture escape. These products soak into the brick and create a barrier without trapping water inside. They work well on clean, dry brick.
Clean the chimney with a stiff brush or a pressure washer on a low setting, then let it dry for a few days. Apply the repellent with a brush or sprayer, and follow the product instructions. You may need two coats for good coverage.
Check Flashing and Roof Seals
Flashing is the metal strip that seals the gap between the chimney and the roof. If it is loose, rusted, or pulled away, rain can run behind it. You can reseal the edges with roofing caulk, but if the flashing itself is damaged, a roofer should replace it.
Also check the step flashing and counter-flashing, which are the overlapping pieces that direct water away. A roofer can re-bed and re-point the flashing into the mortar joints. This is not a job for a homeowner if the roof is steep or high.
When to Call the Pros
If rain has already leaked into your walls, ceiling, or attic, the wood and drywall may be wet. Wet materials can lead to mold and rot. The pros can inspect the extent of the moisture, dry the structure, and repair the damaged areas.
They use moisture meters and drying equipment to get everything fully dry. If you have a leak that keeps coming back, or if you notice sagging drywall or peeling paint, it is time to call in help. Acting quickly reduces the chance of long-term damage.
Water damage does not wait
Call (801) 383-0232 any time, day or night, and describe what happened.
Call Now (801) 383-0232Frequently asked questions
Can I seal my chimney myself?
Yes, for small cracks and minor mortar issues you can apply caulk or a water repellent. But for flashing problems or a damaged crown, a roofer or mason is safer. If water has already caused damage inside, the pros should handle the cleanup.
How do I know if my chimney is leaking?
Look for water stains on the ceiling or walls near the chimney, damp spots in the attic, or a musty smell. During heavy rain, check the fireplace interior for drips. If you see any signs, trace the source before sealing.
Will sealing my chimney stop all rain leaks?
Sealing the brick and repairing the crown can stop many leaks, but flashing and roof issues need separate attention. If the leak comes from the roof junction, sealing the brick alone will not help. A thorough inspection of all parts is the right approach.