How can I fix a leaking masonry chimney?

Virginia Fuller
by Virginia Fuller

I have a masonry chimney that doubt g hard rains it leaks in the fireplace. We have replaced the flashing and updated the cover with stainless steel cover. The house is 50 years old. Think the concrete probably has washed and the rain is coming through. What can I do to seal these “cracks” and washed masonry?? The chimney looks good and is sturdy. Just needs a sealer of some sort. We live in Alabama so many rain storms and wind. Many thanks !!! Save my chimney!!!

  4 answers
  • Seth Seth on Jun 15, 2019

    Virginia,

    You may need more than just a sealer. Wind driven rain can still leak into your cover. (I am assuming you still use the fireplace and have not completely sealed off the chimney.) At the top of he chimney is the crown wash. It is the angled concrete that sheds water. Your cover sits on top of it. If it is cracked, it will leak. The mortar joints between the bricks/stones probably need to be repointed. They also will leak if compromised over time. A mason or chimney repair company would be the ones to consult with before undertaking a repair.

  • William William on Jun 15, 2019

    I agree with Virginia. Heavy rain driven by rain can still bypass the chimney cap. The top of the chimney should be sloped away from the opening to divert rain. No cracks, loose, flaking mortar joints. There are no sealers that will seal chimney bricks 100%.

  • Sharon Sharon on Jun 16, 2019

    Agree with all said above, having had a 70 yr old chimney myself, the bricks may also need to be repointed also. If your handy working on a ladder. https://www.youtube.com/watch?v=jPcp0iLoJtM I got a certified chimney sweep in town to redo the concrete chimney cap and then a sheet metal cap that we had to remove and caulk to make it waterproof.

    After all that it still leaked, and was discovered the metal roof was installed improperly where it hit the chimney.... it should have had a triangular wedge installed at the back of the chimney to direct the water away and down the sides to the gutter;.... https://www.youtube.com/watch?v=1Abr7hbTXqk https://www.youtube.com/watch?v=JCYzGMBI3JU

  • J Brown J Brown on Jun 17, 2019

    We had an ongoing intermittent leak around our brick chimney. After multiple roof repairs even after replacing the roof and chimney cap that old leak would return in heaving driving Florida rains. We sprayed the chimney bricks with Seal Crete and the leak stopped. Don't be afraid to really "hose" it down the Seal Crete goes on milky but dries clear. AND remember to retreat every couple years.

    Good Luck