Guide to Repointing Chimney Mortar

When the mortar that holds the bricks together, starts to crumble, all the loose pieces should be removed, and the gaps filled in with new mortar. The procedure for doing this is called ‘repointing.’ While you are looking the chimney over to see just how much mortar needs to be repaired; take the opportunity to check the bricks for any cracks or breaks. This would be a good time to replace them. It would be like killing two birds with one stone. Repointing your chimney mortar is not hard work, but it is time consuming. Of course it all depends on the amount of repair work that needs to be done; but with proper planning, you should be able to get it done in a day.

You can use vinyl cement to repoint if you choose to, and some people prefer to do so. It is a lot less work, and it can be applied with a caulking gun. The down side to this is the patching is visible. My husband and I repaired a chimney on one of our rentals this way. We really didn’t care for the way it looked; so we ended up taking some white paint and small brushes, and painting the mortar. It took us a lot longer, than if we would have used mortar in the first place.

If you don’t mind messy, mortar is the way to go. And when you are finished; the patchwork should be hardly visible.

Take the garden hose and spray off the chimney. Then, take a wire brush and brush off all the crumbling and loose mortar.

If you are working up on the roof of the house, make sure you use a life-line. Many people have been severely injured because they did not make sure they were tied off for safety. Since my husband and I do remodeling, we have safety harnesses; but you might be able to rent one from a business that rents equipment.

After you have cleaned off all of the crumbling and loose mortar; mix your mortar according to the directions. Scoop some mortar onto the hawk; a square palate with a handle on the bottom. Scoop some mortar onto the pointing trowel. Using the tip of the trowel, apply mortar to the joints of the bricks and pack it in as much as possible. Scrape away excess mortar with the side of the trowel. When the mortar is firm, but not dry; press a jointer along the joints. This is what gives the mortar a smooth look. You have to keep the mortar stirred or it becomes stiff. Stir it occasionally to keep it workable and easy to work with.

Every day for the next four or five days, finely spray down the area or areas that you repaired. If it is just one relatively small area, you can cover it with a wet burlap bag. This process keeps the mortar from drying too quickly, and possibly cracking.

If you are doing the repair job up on the roof, you might consider making it a two person job. My husband usually does the work higher up, and I do the going back and forth. After a few trips up and down the ladder, the body tends to get a bit tired.

One thing to consider when repointed the mortar on your chimney, and that is the time of year that you do it. In hot, dry weather the mortar will dry and turn hard much faster, so you will want to mix smaller amounts of mortar at a time.

Repointed your mortar is not a hard job, but it is a little tedious; just remember – safety first.