How do I stop my chimney from leaking?

Asked By: Lance Werckmeister | Last Updated: 21st June, 2020
Category: home and garden home appliances
4.9/5 (71 Views . 38 Votes)
How to Waterproof Your Chimney and Prevent Chimney Leaks
  1. Step 1 – Measure the Surface Area of Your Chimney. The first step to waterproofing your chimney is to determine how much material is needed.
  2. Step 2 – Clean the chimney.
  3. Step 3 – Protect Non-Target Areas.
  4. Step 4 – Minor Chimney Repairs.
  5. Step 5 – Choose a Water Repellent.
  6. Step 6 – Apply the Water Repellent.
  7. Step 7 – Cleanup.

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Similarly one may ask, how do you fix a leaking chimney?

To repair loose roof chimney flashing:

  1. Clean any leaves or other debris out of the gap between the flashing and chimney.
  2. Use a chisel to remove any hardened roofing cement.
  3. Apply a generous amount of roofing cement behind the flashing.
  4. Use masonry nails or screws to reattach the flashing tight against the chimney.

Also, is it normal for rain to come down chimney? If you've been hearing a dripping sound coming from your chimney after a heavy rain or noticed moisture and stains on the wall near your fireplace, you likely have an issue that must be fixed by a professional. Rainwater trickling into your fireplace is not normal.

Also asked, what would cause a chimney to leak?

Generally, there are three areas that could be the source of the chimney leak and they are: Cracked or Loose Mortar. Crack in Chimney Flashing. Damaged Roof Shingles.

How do you fix a leaking brick chimney?

Step #3: If Your Leak is in Brick of Mortar You can do this by prying apart the pieces with a crowbar or screwdriver. Use the caulking gun to apply mortar and replace any bricks that were removed. Finally, coat the entire outside of your brick chimney with waterproofing to help prevent future leaks.

18 Related Question Answers Found

Does water come down chimney?

Unless a chimney has a cowling, rain often comes down its relatively small aperture. But all chimneys have a bend built into them to prevent any downdraught. Any normal rain will be absorbed by the insides of the chimney and prevented from going all the way down by this ledge.

Can water leak through chimney?

Water can infiltrate your chimney system through its flashing, cracks in the mortar or siding, straight from the top, or from the chimney crown. If you notice water in your fireplace after a storm, call a professional repair team. Chimney leaks can worsen over time without proper repair.

How much does it cost to seal a chimney?

Average Prices of Chimney Repair Work
According to 2017 averages across the country, homeowners may spend anywhere from $85 to $1,600 on fireplace repair work of all kinds. Water leak repairs along the roofline and chimney crown repair can cost anywhere from $150 to $350 on average.

How do you seal a chimney stack?


Apply a bead of butyl rubber caulk around three sides of the chimney at the top, and set the cut piece of metal on the chimney so the edges line up with the caulk bead. Press the metal into the caulk. The goal of this metal cap is to prevent rain from coming in, but it shouldn't be an airtight seal.

How do I find a leak in my chimney?

Time to find the leak!
  1. Start by wrapping the chimney with the plastic wrap about a 1/2 inch above where the chimney meets the roof.
  2. With one person on the roof and the second in the house (either in the attic or watching the ceiling), turn on the hose and let the water run down the lowest side of the chimney.

How much does it cost to flash a chimney?

Chimney flashing ($200-$350): Metal is installed where the chimney and roof meet as added protection against water infiltration. If it doesn't need replacing, repairing flashing costs anywhere from $20-$120.

How does rain not come down the chimney?

In the absence of one, water -will- come down the chimney. Assuming it doesn't have any sort of cap, remember that individual rain drops are small, and so is the opening of the chimney. It's a relatively small target, so while some rain falls down, likely not enough to be noticeable if it's anything short of a monsoon.

Do all chimneys need a cap?

A chimney cap prevents water from entering the chimney. Moisture can enter the flue anytime it rains, without a chimney cap. This can cause water to get inside the attic or house as it runs down the brickwork. It is best to choose a chimney cap with the mesh siding to prevent critter from entering your chimney.

How much does it cost to waterproof a chimney?


Average cost $150 – $250. Why Do You Need Chimney Waterproofing? Chimneys are often times one of the most overlooked systems in our homes.

How do you seal an old brick chimney?

Seal the chimney bricks
Start at the bottom of the chimney and spray the brick until the excess repellent runs down about 8 in. below the spray line. Work your way up to the top. Apply a second coat within five minutes using the same technique.

Does a brick chimney need to be sealed?

As a result, chimney masonry should be protected from exposure to water. That's why many chimney professionals recommend homeowners apply a waterproof sealer to protect the chimney from water damage.

Do chimneys need liners?

However, if you're not using your fireplace and your chimney acts solely as a vent for your furnace or water heater, you may not need to have a liner installed. Homeowners with gas or electric inserts most likely do not need a new liner because those types of fuel don't produce enough heat to damage a masonry chimney.