How many bags of mortar do I need for 100 blocks?

For standard 8x8x16 concrete blocks, one 80lb bag of pre-mixed mortar typically lays 12 to 15 blocks. Therefore, for 100 blocks, you would need approximately 7 to 8 bags (80lb).

How many bricks does a bag of mortar lay?

One 80lb bag of pre-mixed mortar will lay approximately 35 to 40 standard modular bricks. A 60lb bag will lay about 25 to 30 bricks.

What is the ratio for Type N mortar?

The standard mix ratio for Type N mortar is 1 part Masonry Cement to 3 parts Sand. If using Portland Cement and Lime, the ratio is 1 part Portland, 1 part Lime, and 6 parts Sand. Type N is the most common for general exterior walls.

Should I use Type N or Type S mortar?

Use Type N for general exterior applications, above-grade walls, and soft stone. Use Type S for structural load-bearing walls, below-grade applications (foundations), and paving/patios where higher strength (1800 psi) is required.

How much sand do I need for 1 bag of cement?

For a standard 1:3 mix ratio, you need 3 cubic feet of sand for every 1 cubic foot (94lb bag) of cement. In weight, that's roughly 300 lbs of sand per 94lb bag of cement.

🧱 Mortar Calculator

Estimate Mortar Bags, Cement & Sand for Masonry

Material Type

Quantity of Units

Total number of bricks/blocks

Mix Type

🏗️ Mortar Coverage Rates

Estimating mortar depends heavily on the size of the masonry unit and the joint thickness (standard is 3/8"). Here are the industry standard coverage rates used by this calculator:

Standard Yields (per 80lb Bag)

Concrete Blocks (8x8x16): 12 to 15 blocks
Standard Bricks: 35 to 40 bricks
Stone Veneer: 15 to 20 sq ft (scratch coat + setting)

Bulk Mixing Ratios (Type N)

For general purpose Type N mortar, the standard mix is 1 part Masonry Cement : 3 parts Sand. If using Portland Cement, it's 1 part Portland : 1 part Lime : 6 parts Sand.

💡 From Tony Martinez, Masonry Contractor (19 years):

"Sand moisture matters! If your sand is wet (which it usually is), it will bulk up and you might accidentally add too much. Measure by volume (shovels), not weight. A standard mix is 1 bag of masonry cement to about 18-20 shovels of sand. And always mix for at least 5 minutes to activate the air-entraining agents – it makes the mortar 'fluffy' and easier to spread."

⚠️ Common Mistakes

1. Retempering too late: You can add water to stiff mortar ("retemper") within the first 1.5 - 2 hours. After 2.5 hours, the chemical set has begun, and adding water will weaken the bond significantly. Throw it out.

2. Wrong Mortar Type: Don't use Type M (High Strength) for everything. It's too brittle for general brickwork and can cause the bricks to crack instead of the mortar joint when the wall shifts. Stick to Type N for most exterior walls.

3. Not accounting for waste: Dropped mortar is inevitable. Pros figure 5-10% waste. DIYers should figure 15-20%.

Reviewed by Tony Martinez

Licensed Concrete & Masonry Contractor, 19 years experience.

🏗️ Mortar Coverage Rates

Standard Yields (per 80lb Bag)

Bulk Mixing Ratios (Type N)

⚠️ Common Mistakes

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