How To Repair Concrete Block Mortar Joints

Fifty-fifty the most beautiful brickwork is just so much rubble without a bed of mortar to seal and hold it together.

What Is Mortar Repointing?

When mortar starts cracking, receding, and falling out of the joints, it'due south time to chisel out the erstwhile stuff and trowel in the new, a procedure called repointing. This is a simple task, merely it has to be done with care, using the right tools and the correct materials to avoid damaging the brick and permanently compromising the integrity and appearance of the wall. For me, that means using paw tools and lime mortars similar to the ones masons employed 100 years ago.

Tin Yous Mortar Over Old Mortar?

If your brick is 50 years old or less, you tin can probably repoint it safely with modern, portland cement–based mortar (although the guy doing the adjacent repointing, who'll accept to grind it out, may curse your determination). Merely if your business firm was congenital before World State of war II, the mortar is probable a mix of lime putty and sand, and you should try to lucifer it. Otherwise, over time, equally the soft former brick swells and shrinks against the rock-hard mortar, the bond between them will pause, moisture will get trapped in the wall, and the brick faces will start popping off. Traditional lime mortar acts like a cushion, flexing with the brick's movement while allowing moisture to migrate easily out of the wall.

A restoration bricklayer tin analyze sometime mortar and make a compatible mix, or you can send mortar samples to companies such as U.Due south. Heritage and get a custom alloy with the same colour and characteristics. You tin choose betwixt hydraulic lime, which comes in bags and hardens when it reacts with water, much like portland cement, and lime putty mortar, which comes in buckets and slowly hardens by reacting with carbon dioxide in the air.

How to Mortar Bricks in vi Steps

Step 1

Rake Out the Bed Joints

Scrape out the horizontal joints to a depth of at to the lowest degree ¾ inch. (Joints wider than ½ inch have to be deeper: 2½ times the joint's width.) A carbide-tipped grout saw works well on these ¼-inch-wide "butter joints." (On wider joints, utilise a cold chisel and an engineer's hammer.) Avert electric bending grinders. Unless you lot're trained to use them, they're nigh guaranteed to cut into and disfigure the brick.

Step 2

Clean Out the Head Joints

After removing three or iv courses of bed-joint mortar, dig out the vertical joints. Be careful non to striking the edges of the bricks above or below. Here, the erstwhile mortar is beingness chiseled out by tapping a 5-in-1 painter'southward tool with a hammer.

Step 3

Launder Down the Wall

Person washing brick wall to prepare apply mortar.

Whisk away all the crumbly debris with a stiff-bristled brush, and so check that the blade of your constrict-pointing trowel will fit into the joint. If the blade is too wide, grind it down with an abrasive bicycle. Mist the wall with water until the brick is thoroughly clammy and starts to drip; this is a critical pace because dry materials volition suck the wet out of the new mortar and forestall information technology from curing properly. Wait until the next 24-hour interval before filling the joints.

Step 4

Mix the Mortar

Mist the brick once more. Then, following the directions on the bag, stir water into the dry mix until information technology reaches the consistency of peanut butter and clings to an upended trowel. Wait until a film of water forms on the mix, near 15 minutes. Stir the water dorsum in. The mortar is at present set to use and remains workable for viii hours. If it gets likewise dry in that time, you lot tin "retemper" it occasionally by calculation water.

Stride 5

Make full the Joints

Scoop a dollop of mortar onto a brick trowel or hawk, agree it upwardly fifty-fifty with a bed joint, and push the mortar against the back of the articulation with the tuck-pointing trowel. Eliminate voids with a few slicing passes of the trowel'due south edge, and then add together more mortar until the joint is filled. Once you've finished three or four courses of bed joints, go back and fill the caput joints. Finally, shine and compact all the mortar with the trowel's flat face and scrape the backlog mortar off the brick.

Step 6

Castor the Wall

Person brushing brick wall with stiff bristle brush.

When the mortar is firm to the bear upon, brush diagonally beyond information technology to remove any dry mortar crumbs. (Brushing in line with the joints can pull out the fresh mortar.) Then carefully sponge mortar residual off the brick faces. For the adjacent three days, use a tarp to protect the soft joints from the sun, air current, or hard rain, and give the wall a daily misting to keep the brick and mortar moist.

Tools You lot'll Demand

Source: https://www.thisoldhouse.com/masonry/21016676/how-to-repair-mortar-in-a-brick-wall