The Correct Way to Fix a Leaky Chimney – Expert Chimney Repair

Once it is determined that your chimney is leaking, it can be tempting to apply a quick fix to the problem to avoid a costly or lengthy repair. Perhaps you feel you can do it yourself, or maybe a repair service offers you an inexpensive “patch-it-up” option. Unfortunately, this type of “repair” may serve for a while but could be a disaster in the long run, potentially causing more costly damage to your home down the road. At McNamara Masonry Restoration, we have been diagnosing and correcting leaky chimneys for over 20 years. It is our priority to repair your chimney the right way, the first time, and we stand behind our work with a 5-year warranty on labor and materials. We work hard to ensure that your chimney is repaired properly and in a timely fashion.

In each case, the type of chimney repair we do depends upon the source of the leak and the style and age of chimney you have. After we thoroughly evaluate your chimney, we begin the process of repairing the damage quickly and accurately. Below we address the two most common types of chimney leaks and how we repair them.

Cracks in the Chimney Crown

Cracks in the chimney crown are a common problem, and there is a right and a wrong approach. The correct method is to properly restore the brick or stonework. It can be necessary to cut out all mortar joints (spaces between the bricks that are filled with mortar) using a hand held grinder. It is critical to remove the existing joints to a sound depth. An appropriate cutout is anywhere from 1/2″ to 3/4″ in depth. After the joints have been cut out and cleaned of foreign debris, we will remove and reset any loose bricks or stones. Once the prep work has been completed, it’s time to repoint. Depending on the brick and stone used, we will determine which mortar is applicable to the job. All mortar joints will receive new mortar—this is called “pointing.” We match the consistency of the original pointing as closely as possible. At McNamara Masonry, it is never a “one size fits all” approach; personalized customer service is our hallmark.

The wrong approach when addressing the pointing is called “patch” pointing. Patch pointing is when certain joints or particular areas of the chimney are repointed instead of completely repointing the whole job. Obviously, patch pointing is cheaper than a proper pointing job because it takes less time and effort. We feel this is a waste of your money. Because you can never be 100% certain of the source of water penetration, it is more thorough and effective to repoint the entire chimney. We suggest running in the opposite direction if a contractor proposes a patch pointing resolution to the leak.

leaky chimney before repair

This chimney has a cracked crown, which has led to deterioration and further problems.

If this part of the chimney is made of stucco, then we inspect the stucco to ensure that that it was installed properly and free of any cracks. On a lot of stucco chimneys, we find that stucco has been applied right over the cinder blocks. This is never a good long-term solution. A proper stucco job starts with wire lath, or backing material for the plaster. Wire lath is fastened to the blockwork first to set the foundation for the repair. Then we apply a three-part stucco system. We apply a base coat of sand, waterproof cement and lime, and then a second base coat known as the “brown coat” using the same materials. The final coat is the finish. The finish coat is available in a range of colors and textures to complement the style of your home.

Damaged Chimney Flashing

The roofing around the chimney is known as the “flashing,” and damage or wear and tear to this flashing is a common cause of leaks. This is the proper way to flash a chimney:

  • Remove all metal and shingle work around the chimney down to the wood deck
  • Install a rubberized membrane called Ice & Watershield 18″ around the chimney, returning 6″ up the chimney wall
  • Install new aluminum or copper step flashings intertwined with new roof shingles starting at the lowest point and working to the highest
  • Cut a “regret,” which is a joint 1 1/2″ deep into the masonry
  • Fabricate and install base flashing
  • Fabricate and set the counter flashing into the regret

Trust the Chimney Experts

If you are concerned that your chimney may be leaking, now is the time to address the problem. Don’t wait until more damage is done! Call (215) 887-8883 today. We will quickly evaluate your chimney and provide a professional estimate for the repair. You can rest easy knowing that our work is backed by a 5-year labor and materials guarantee.