The supporting mortar joints have fretted

Fretting mortar and how to fix it

Fretting mortar is a common problem for brick and stone homes, especially in homes built up until the late seventies. Essentially it’s where the mortar between brickwork begins to ‘fret’ or fall away. If you spot it early there’s a good chance you can escape any major structural damage and a potentially large repair bill.

What causes it?

Fretting mortar is caused when cement joints become damp or where a badly mixed batch of mortar was used during construction. This can happen in a number of ways including:

  • exposure to the elements,
  • reticulation or pool water spraying on the brickwork,
  • incorrect mixing of mortar at the time of the build.

Mortar has fretted out from between bricks

How to spot it

Fretting mortar is pretty easy to spot. When you’re inspecting your external brickwork have a look at the cement joints. If you see any crumbling or powdery mortar it’s a good indication that your brickwork is fretting. In its advanced stages the mortar will be almost completely missing. At that point the rows of bricks may begin to collapse onto the bricks below. Be prepared for an expensive repair job if it gets to that stage.

Wait any longer and this fretting mortar will cause major structural damage

How to fix it

There’s only one way to fix the problem and that’s to replace the mortar (also called re-pointing). Re-pointing is the best way to ensure the structural integrity of your home and to make sure fretting mortar isn’t an ongoing problem. Re-pointing is done by cutting or vacuuming out the fretted joints and replacing them with a correctly mixed mortar. It’s usually a simple, straight forward job that can be completed by a competent bricky.

While there may be just one way to fix fretting mortar there are a few ways you can stop it from becoming an issue in the first place.

–  Perform regular checks and maintenance of brickwork.

–  Apply a sealer. If you know an area of brickwork will be exposed to the elements or damp conditions, apply a sealer from the outset. Brick sealers provide a waterproofing layer which inhibits erosion and damage.

Next time you’re outside have a look at your external brickwork and check for signs of fretting mortar. A simple once over now could save you some money in the long run.