Plan on about three 80 lb bags of pre-mixed mortar for 100 standard bricks. QUIKRETE Mortar Mix lists 37 bricks per 80 lb bag, so 100 bricks take 2.7 bags; with the 15% extra the Brick Industry Association suggests for mortar waste, that is 3.1, so buy 4 bags. For 8 × 8 × 16 in concrete blocks, one 80 lb bag lays about 12 blocks.
The mortar calculator turns any number of bricks or blocks into bags for each bag size.
Bricks and blocks per bag
| Bag size | QUIKRETE Mortar Mix: bricks | QUIKRETE: 8 × 8 × 16 in blocks | SAKRETE Type N: bricks | SAKRETE: blocks |
|---|---|---|---|---|
| 80 lb | 37 | 12 | 40 | 15 |
| 60 lb | 28 | 9 | 30 | 11 |
| 40 lb | 19 | 6 | 20 | 8 |
The two brands differ by about 10%, which is why it pays to read the bag. Both figures assume ordinary joints; thick joints, cored or rough bricks and mortar dropped on the ground all use more.
Bags for common jobs (80 lb bags, 15% extra)
| Job | Units | QUIKRETE | SAKRETE |
|---|---|---|---|
| 100 bricks | 100 | 4 bags | 3 bags |
| 500 bricks | 500 | 16 bags | 15 bags |
| 1,000 bricks | 1,000 | 32 bags | 29 bags |
| 100 blocks | 100 | 10 bags | 8 bags |
Checking it against mortar volume
The Brick Industry Association gives mortar by volume: about 8.1 cu ft per 1,000 modular bricks with ⅜ in joints, before waste. That is 0.81 cu ft for 100 bricks. If you mix your own mortar from cement, lime and sand, start from that volume; with pre-mixed bags, the bricks-per-bag figure on the bag is the simpler guide.
Which mortar type?
- Type N: general-purpose mortar for above-grade walls, garden walls and brick veneer. Both mixes above are Type N.
- Type S: stronger; used below grade and for retaining walls and paving.
- For repointing an old wall, match the existing mortar rather than using a stronger type.
Worked example
A garden wall needs 709 modular bricks (see how many bricks per square foot). With QUIKRETE 80 lb bags: 709 ÷ 37 = 19.2 bags; with 15% extra, 22.0, so 23 bags. With 60 lb bags: 709 ÷ 28 × 1.15 = 29.1, so 30 bags.
Smaller bags
| Bricks | 60 lb bags (28 bricks each) | 40 lb bags (19 bricks each) |
|---|---|---|
| 100 | 5 | 7 |
| 250 | 11 | 16 |
| 500 | 21 | 31 |
| 1000 | 42 | 61 |
Smaller bags cost more per pound but are easier to carry and mix by hand, and less is wasted if mortar stiffens before you use it. For larger jobs most people mix 80 lb bags in a wheelbarrow or a small mixer.
Frequently asked questions
Can I use concrete mix to lay bricks?
No. Concrete mix contains gravel and is made for slabs and posts. Use a masonry mortar mix rated for laying brick and block.
How much water does a bag need?
Follow the bag; mortar is mixed to a workable consistency that holds its shape on the trowel. Add water gradually rather than all at once.
Does a block wall use more mortar per unit?
Yes, each 8 × 8 × 16 in block takes about three times as much mortar as a brick, which is why one 80 lb bag lays about 12 blocks but about 37 bricks.
Sources
- QUIKRETE Mortar Mix (No. 1102) data sheet (bricks and blocks laid per bag, Type N)
- SAKRETE Type N Mortar Mix data sheet (bricks and blocks per bag)
- Brick Industry Association, Technical Note 10: Dimensioning and Estimating Brick Masonry (brick and mortar per 100 sq ft, waste allowances)
