There's a few bricks around my house about 40cm up from ground level where the vertical mortar between the bricks has completely fallen out / eroded away.

In a few spots, there's insects going into it and making a home.

I think I should fill it in, but I'm not sure of the best way to do it.

Mix up some mortar? Just use caulking?

I'm in SWO, Canada, so whatever I do has to be weather resilient.

  • As noted, if they are weep holes, you likely don't want to fill them in. Otherwise, what you are wanting to do is called 'tuck pointing' and there are several ways to do it. Googling it should turn up some tutorials/videos for you.
    – DA01
    Aug 1, 2012 at 17:22
  • You can get pointing compound in a tube like caulk. Much easier to use. Aug 1, 2012 at 17:30

2 Answers 2


Is it the bottom row of bricks, and are they regularly spaced? (I guess that's only possible if your foundation comes up 40cm.) Because if that's the case, they're weep holes, and shouldn't be filled in. Otherwise, I'd go with @Tester101's answer.

  • Sure sounds like weep holes. If so, don't fill them! If you are worried about insects, get an insecticide or use a pest control specialist. Aug 11, 2010 at 18:50
  • you can also stuff the weep hole with a bit of steel wool. That way it still vents but makes it tougher for bugs to get in.
    – DA01
    Aug 1, 2012 at 17:22
  • what is the difference between weep holes and cracks? If the point of weep holes to let moisture escape, don't cracks accomplish the same goal? Therefore can you just leave certain cracks without ill effect? Or should you fill all cracks as part of upkeep?
    – Budric
    Sep 29, 2015 at 0:25
  • @Budric Weep holes are planned vertical spaces without any mortar between two bricks. They're generally only one brick high. A crack in mortar will not have the same amount of open surface area, so moisture will not escape as readily. Also, cracks in mortar usually propagate to wider and longer cracks, while weep holes do not.
    – Doresoom
    Oct 9, 2015 at 19:59
  • Make sure you clean the joint very well (with a stiff bristle brush) making sure you remove all dust and debris from the crack.
  • Mix up some mortar and put it in something similar to a pastry bag (the thing bakers use to decorate with). A large Zip-Lock bag with a nipped corner should work.
  • Squeeze the bag so the mortar fills the gap making sure the mortar goes as deep as possible.
  • Wipe off any excess mortar.
  • Wait for the mortar to dry slightly and then tool the joint to match existing joints.

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