DIY Repointing Chimney Mortar

Some years back, I looked up one day and saw that my chimney seams were beginning to crumble. This was in the days before the internet, so I raced right off to the library to find out how I was supposed to fix that chimney cement. After reading about repointing chimney mortar, I went home to get out the ladder to go take a look. I learned something right away, I don’t like being on a roof attached to a two-story house. Then, I examined the chimney and realized how easy repointing the chimney mortar would be. I decided to try fixing the chimney cement with tools that I had around the house instead of buying the fancy bricklaying tools that the book suggested and my repointing chimney mortar project came out just fine.

Girls? When you crawl up onto your roof for the first time, understand that all neighbors for miles around are going to be watching every move you make while you are repointing the chimney mortar. Don’t wear anything that can be looked up, tie your hair back, and be ready for a helpful crowd of onlookers to form at your feet. Just hold your ground; remember that you like your old cheap tools much better than buying new ones.

How to fix the chimney cement:

The hardest part about fixing the chimney cement is when you climb up and down the ladder a few trips to deliver all of your tools and mortar onto the roof. As far as the actual job of repointing chimney mortar goes, you are simply getting rid of anything crumbling out of the chimney seams and filling in those cracks with new chimney cement or mortar.

Remove crumbling mortar: Starting at the bottom of your chimney, examine all of the seams between bricks to see if any mortar is loose or crumbling. Poke, prod, scrape, and dig into those holes with a strong metal tool until all of the loose mortar falls out. Clean up your chunks with a broom quickly so that you do not kick them down upon your friends who are giving helpful suggestions and cat-calls on the ground.

Mix new mortar: Mix your powdered mortar on the ground in little batches by following the package directions. Try not to touch it with your hands because it dries them out fast and makes the skin crack open. With gloves on, take your bucket of mortar back up to the roof so that you can start your repointing chimney mortar project.

Put mortar in seams: Starting at the bottom of the chimney, scoop a little bit of mortar out of your bucket onto a wide scraper. Using a second skinny scraper, scrape the mortar into the chimney seam. Pack this in there tight with an old butter knife. When the seam is a little bit overfull, smooth over the top to remove the excess wet chimney cement.

Let chimney dry overnight: You need to let the repointing chimney mortar project dry overnight and preferably until the next weekend. Once the new chimney cement is dry, go back up onto the roof with a pile of old blue jean pieces or an old paint brush and clean your bricks back to pretty.

What not to do: If your chimney is leaning over, has bricks missing, or otherwise looks structurally unsound – call an expert, and do not try to fix this yourself.

While you’re up there: As long as you are standing on the roof, you may want to make sure that your flashing around the bottom of the chimney isn’t leaking by adding a little more approved sealer, and drop a chimney cleaning chain down the hole to knock some of the buildup out.