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Ask This Old House mason Mark McCullough travels to Denver to help a homeowner patch a hole in a brick wall.

“The front wall of our house has some bricks that are falling apart. We have replacement bricks on hand but no clue as to how to replace them without damaging the intact ones.”
—ROBIN DOLBOW, SHOREVIEW, MN

Where to Start:

Mark McCullough repairs Brick, Summer 2022 Magazine
Mark slips a replacement brick into a spot where he has already applied a bed of mortar (left). When all the new bricks are in place, he packs and smooths each joint with his jointer tool (right).
Colleen McQuaid

TOH mason Mark McCullough: This kind of repair is fairly straightforward, but I would recommend that you rent a shrouded grinder to cut into the old mortar and a tool triggered vacuum that works with the grinder to collect the dust it generates.

The work will go faster, and you’ll be better protected against breathing in the silica in the mortar. Plug the grinder into the vacuum, and attach the vacuum hose to the grinder’s dust port. Now when you pull the trigger on the grinder, the vacuum will turn on automatically. Line up the grinder blade with one of the horizontal bed joints near the damaged bricks, and plunge it as deep as you can into the mortar.

As you cut, keep in mind where those cuts will replicate the wall’s existing brick pattern, and take care not to let the blade nick the brick. Cutting into the vertical head joints requires even more care because the blade is wide enough to cut into the bricks above and below. Just make sure not to plunge the blade in so deeply that it damages a brick you want to save. After the mortar joints are cut, use a hammer and a cold chisel to break the bricks free and

Since it’s such a small repair, it may be a challenge to get a mason to fix a small hole in a brick wall. In this guide, we share how you can tackle this project on your own with materials you can buy and tools you can rent.

Pro Tip: Brick jointer

Brick Jointer, Mark McCullough repairs Brick, Summer 2022 Magazine Dana Schiffman

Masons use this simple tool to pack fresh mortar into joints and give them a final smoothing that makes them more weather resistant. It comes in different widths and profiles to match the existing mortar.

What to Use to Fill Holes in Brick Walls?

You’ll need mortar, matching brick, and a few other tools. To fill the hole in a brick wall you use mortar. In the case of this project, we were able to find a standard gray brick mortar. For mortar, Mark used a Type N premixed mortar bag, which is manufactured by Quikrete. You’ll want to make sure you’re using the right material for the type of brick you’re trying to fix.

To find matching brick, take a picture, identify a nearby brick yard, and show someone who works there the picture. It’s likely they will recognize the brick and be able to give you the few that you need for little money. Mark went to Summit Brick Company and they were able to find what he needed.

Depending on the hole in the wall, it’s likely that surrounding bricks or mortar may need to be carefully removed. An angle grinder with a vacuum attachment can be rented from most home centers and should help keep the dust down. Mark used a 5” angle grinder with tuck pointing guard and a nine-gallon dust extractor with automatic cleaning, both manufactured by Bosch Tools.

All the other tools required for this project, including the trowel, masonry brush, and jointers, can all be found at home centers.

How to Fill Holes in Brick Steps in 13 Steps

  1. Start by identifying any bricks that have been cut for the hole. Any bricks that are no longer full-sized should be removed.
  2. To remove the smaller bricks, cut along the mortar lines closest to the brick that’s being removed using an angle grinder. To keep the dust down, use a grinder with a vacuum attachment and connect it to a HEPA vacuum. These tools can be rented from the home center if you don’t have them.
  3. Once the mortar lines have been cut, carefully hit the bricks out of place with a hammer. Watch the mortar lines near bricks that aren’t being cut out. If there’s resistance, it’s possible those bricks will end up damaged and will need to get cut out as well.
  4. Once the bricks and the mortar have been removed, wipe away any excess dust with a masonry brush.
  5. Wet the masonry brush and do a second pass on the wall.
  6. Now it’s time to put the bricks into place. Start by mixing up the mortar in the bucket with water until it’s at roughly an oatmeal consistency.
  7. Scoop some of the mortar onto the trowel and then lay it onto the brick wall.
  8. Add some mortar to one side of the replacement brick. Then, place it on top of the bed joint just laid in the previous step. Wiggle it into place and gently tap it using the back side of the trowel until it lines up with the other bricks in its row.
  9. Continue this process with the rest of the replacement bricks until the hole is filled.
  10. Use the tuck pointer to fill in all the joints as deep as possible.
  11. Slick down all the new joints using the concave jointer.
  12. Wipe off any excess mortar on the face of the bricks using the masonry brush.
  13. Once all the excess mortar has been removed, do a final slick with the concave jointer.

Expert assistance with this segment was provided by MJM Masonry.


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