How to repair crumbling mortar between bricks

Brick homes and chimneys are durable and built to last thanks to mortar joints that take the brunt of damage caused by wall movement, foundation settlement and exposure to elements.

A buffer between the bricks, mortar joints are designed to crack and deteriorate before the brick when faced with movement and other stressful pressure.

So, it’s important to repair and seal mortar joint cracks as soon as you discover them to prevent water from entering and causing further damage. Otherwise, a small problem today could become a major headache — and expense — in the future.

Before you begin this project, remember: • Mortar joint sealant is temperature sensitive; don’t apply in temperatures under 50 degrees Fahrenheit.

• Work in a ventilated area, and wear safety glasses and waterproof gloves.

• Quikrete Advanced Polymer Mortar Joint Sealant • Chisel • Hammer • Caulk Gun • Trowel • Utility Knife • Waterproof Gloves

• Safety Glasses

Now, let’s begin!

1. Prep the Surface

Widen the crack to ¼ inch with a chisel and hammer and remove any damaged concrete. Make sure the crack’s edges look like an inverted V and remove any loose material with a brush.

2. Apply Sealant

Cut the nozzle tip of Quikrete Advanced Polymer Mortar Joint Sealant at an angle. Make sure the opening matches the width of the crack.

Load the sealant in a standard caulk gun and slowly force a bead of sealant deep into the crack. Mortar joint sealant is flexible and can stretch up to 700 percent, so it can withstand wall movement and temperature changes that cause homes to expand and contract.

Drag a trowel over the mortar joint immediately after placement to remove excess material and match the surrounding surface.

4. Let Dry

It doesn’t take much time for the surface to dry. The area should be tack-free in about two hours, depending on temperature, humidity and joint depth.

For wider, deeper and longer cracks, you should consider making the repairs with traditional mortar. Mixing the material is critical in the success of this repair.

And you can enjoy a more attractive, and durable, brick surface.

If a mortar mix is old and weathered, or has been applied incorrectly in the first place, perhaps using too little water, it can crumble and ultimately affect the stability of the wall. you can check the mortar between your bricks to see if it is dusty or cracking, then try and stick a screwdriver into the mortar, if it holds, you need to repoint the brickwork. Repointing is not too difficult for a DIY enthusiast, but it is a labour intensive process.

Wind, rain and frost all damage the mortar so re-pointing the mortar is crucial to stop the wall wearing away and to prevent water ingress into the building. If you feel the job is too difficult or time consuming, simply use the quick online form to collect 3 quotes from local builders in your area. To do the job yourself you will need safety goggles, dust sheets or old newspaper, chisel and/or large screwdriver, hammer, cement, sand, wooden board for mixing cement, putty knife, trowel, plus a vacuum cleaner or stiff brush.

For those who have the time and inclination to carry out repointing as a DIY job, the first thing you need to do is cover your work area with a dust sheet or old newspaper, then, wearing safety goggles, knock or scrape out any crumbling mortar using a chisel and hammer. Then, if possible, vacuum the hole to remove any loose or crumbling mortar and dust. Next, make up the mortar mixture, remembering that cement mortar comes in different colours, so mix a little up and first on a piece of scrap paper and let it dry to check the colour is in keeping with the rest of the buildings brickwork.

This takes extra time but you then avoid having an area of mortar with obvious repairs. It is best to complete an area of around 1 square metre at a time, doing the verticals first, then the horizontals to keep track of where you’re up to. begin by spraying a bit of water into the hole to dampen it, then apply mortar mixture into the hole using a trowel to make sure you've filled the hole up with mortar.

When the mortar is still moist but not completely dry, flatten the surface with a putty knife and smooth with fine grade sandpaper when fully dried. Note that if you have a pre-1930s house with a sandy kind of mortar, it could be lime mortar. You must avoid using a cement mortar on top of lime mortar as this can do more harm than good. If in doubt consult a bricklayer or builder before carrying out any repointing work.