Where 5.86 feet of joint per square foot comes from
Take one module of a running bond wall: a modular brick with a 3/8 joint occupies 8 inches by 2-5/8 inches, which is 21 square inches. Inside that module there is one bed joint running the full 8 inches, and one head joint running the 2-1/4 inch height of the brick. That is 10.25 inches of joint in 21 square inches of wall. Scale it to a square foot and you get 10.25 times 144 divided by 21, which is 70.3 inches, or 5.86 linear feet.
You can check that against the mortar volume the other way round. The joint face area in the module is 21 minus the 17.16 the brick covers, which is 3.84 square inches. Divide by the 3/8 joint width and you get 10.24 inches of joint length. The two derivations agree, which is a good sign that the model is right rather than merely plausible.
| Unit at 3/8 joints | Module | Joint per module | Linear ft of joint per sq ft |
|---|---|---|---|
| Modular brick | 8 x 2-5/8 | 10.25 in | 5.86 |
| Queen brick | 8 x 3-1/8 | 10.75 in | 5.16 |
| King brick | 10 x 3 | 12.63 in | 5.05 |
| Utility brick | 12 x 4 | 15.63 in | 3.91 |
| CMU 8x8x16 | 16 x 8 | 23.63 in | 2.22 |
Block has less than half the joint footage of brick for the same wall, which is exactly why a block wall repoints in half the time. It is also why nobody repoints block: the joints are fewer, longer and generally in better shape.
Cutting out is the job. Pointing is the easy half
Almost everybody who has not done this estimates the pointing and forgets the removal. On the default figures here, 879 feet of joint takes 14.6 hours to cut out and 9.8 hours to fill, and the cutting is the part done overhead, in dust, with a tool that will damage the brick arris if it wanders. Add setup, moving staging, masking windows and brushing down and the 150 square foot wall is the better part of a week for two people.
Production rates vary more than anything else on this page. Soft old lime mortar comes out with a hand chisel faster than a grinder can be set up. Hard portland pointing applied in some 1970s repair comes out at a third of the rate and eats wheels. There is no honest general figure, which is why the rates here are fields rather than constants. Do an hour, measure what you cut, and put the real number in.
Depth, and why the volume is so small
Repointing refills the outer part of the joint only. At a 3/4 inch cut-back on modular brick, 150 square feet of wall takes about 1.7 cubic feet of mortar net, which is under three 80 lb bags before waste. Set against a week of labour that is a rounding error, and it is why the material cost of repointing is almost irrelevant to the price of it.
The depth is a durability decision rather than a quantity one. Cut back too little and the new mortar is a skin with no key, which pops off in the first hard freeze and takes some brick face with it. What the correct depth is for a particular wall comes from the specification or from a mason who has looked at the joints, not from a general figure, and on a building with heritage protection it is usually dictated.
What decides the mix, and what this page will not decide
The single most consequential choice in repointing is what goes back in, and it is not a quantity question. A joint harder and less permeable than the masonry around it concentrates movement and moisture into the units, and soft brick responds by shedding its face. That failure is not repairable by repointing again. It is also usually invisible for several years, which is why it keeps happening.
Get the mix from the specification for the building, or from someone who has examined the existing mortar and the units. Then the mortar mix calculator turns it into portland, lime and sand or into bags, and the brick and block calculator covers any units that have to be replaced rather than repointed. For pricing a crew against a quantity rather than a rate, the crew productivity calculator takes the same inputs in a more general form.
Questions people ask
How many linear feet of mortar joint are in a brick wall?
About 5.86 linear feet per square foot of face for modular brick with 3/8 inch joints, counting one bed joint and one head joint per module. Queen brick is around 5.16, king 5.05, utility 3.91, and standard 8x8x16 block only 2.22 because the units are so much larger. Multiply by the wall area and by the share you are actually repointing; a spot repair on a failed band may be a tenth of the elevation.
How long does repointing take?
On the figures this page defaults to, 150 square feet of brick works out at roughly 30 crew hours including setup, which at seven productive hours a day is five days on the wall. The production rates you enter are treated as crew rates, so putting a second person on doubles the person-hours rather than halving the days; if your rates are per person, halve the crew size to compensate. Cutting out is half the total and nearly 60 percent of the hands-on time. Those rates are a starting point rather than a fact: soft lime joints go two or three times faster than hard portland ones, and access is the other variable that swamps everything. Time one hour of real work and rebuild the estimate from it.
How many grinding wheels will I get through?
Enough that it is worth counting. At a rough 120 linear feet per wheel, 900 feet of joint is eight wheels, and hard modern mortar can halve that figure. Diamond blades last far longer than abrasive wheels and cost accordingly. Track your own consumption on the first day and adjust; the number in the field here is a placeholder, not a specification.
Is grinding out mortar joints dangerous?
The dust is the hazard worth naming. Cutting or grinding masonry dry releases respirable crystalline silica, and the damage comes from repeated ordinary exposure over years rather than from a single day. It is a well-documented occupational lung hazard with specific control requirements and a lot of published guidance behind them. Read that guidance and set up dust control and respiratory protection before starting, and treat a painted wall on a pre-1980 building as a lead question as well.
How much mortar do I need to repoint 100 square feet?
Around 1.14 cubic feet net on modular brick with 3/8 joints cut back 3/4 of an inch, which is about 1.4 cubic feet once you add a quarter for waste, or three 80 lb bags. The volume is genuinely small. Mix it in batches you can use within the hour and expect to throw a little away every time, because a batch that has started to set cannot be brought back with water.