How to calculate the amount of mortar for masonry

Brick is one of the most popular building materials. A solution is always needed for laying it. To know exactly how much cement and sand will be required to build a house, preliminary calculations are needed. We will help you conduct them, because this is an important moment in planning a construction site.

We wrote in detail about what a brick is and where it is used. But a solution for joining masonry is needed in any case. The most popular formulations are:

• Cement-sand mortar. This is a classic, cement is mixed with pre-sieved sand, usually in a 1: 3 or 1: 4 ratio, although there are other options depending on the brand of cement. The mixture is diluted with water;
• Lime. Quicklime is used instead of cement. This composition for external masonry is never used, only indoors, as it is easily washed off with water;
• Mixed. Slaked lime liquid, which is commonly called milk of lime, is added to the cement and sand. The result is a squad that has taken the best qualities of the first two options;
• With the addition of a plasticizer. It will increase the plasticity of the mixture. Often such building compounds are sold ready-made, dry and simply diluted with water, according to the instructions. Sometimes bricklayers add detergent or washing powder as a plasticizer..

Despite the fact that the composition of the mortar for masonry may be different, the requirements for its consistency are the same. Sand must be sifted, liquid lime is filtered, there should be no lumps, water is added gradually. The mixing process will significantly speed up the use of the concrete mixer.

The following factors affect the amount of solution consumption:

• Wall thickness;
• Brick quality;
• Type of brick – more mortar will be used for hollow, for obvious reasons;
• Bricklayer skill;
• Weather conditions such as humidity and temperature.

How difficult, you say. However, experts have long ago deduced average, but fairly accurate indicators of solution consumption per 1 m³ brickwork. The standard brick sizes are well known – 250 × 120 × 65 mm. The consumption will be:

Brick type	Standard solution consumption in m3 depending on wall thickness
0.5 bricks	1 brick	1.5 bricks	2 bricks
Silicate single corpulent, ceramic regular	0.221	0.234	0.24	0.245
Modular	0.205	0.216	0.222	0.227
Hollow	0.223	0.236	0.242	0.247

1 m³ masonry of about 404–405 bricks. That is, one ordinary, single brick accounts for about 0.00063 m³ solution. We translate into liters – 0.63. When laying one brick, there are approximately 100 blocks per square meter of the wall. Experts insist that the solution should be prepared with a small margin and indicate the ideal proportion – 75 liters of the mixture should be used per square meter of the wall. For a wall of one and a half bricks, the consumption will already be 115 liters.

Important! There is SNiP II-22–81, which sets requirements for the quality of brickwork. The optimum seam thickness, that is, the thickness of the mortar used, should be 10–12 mm.

All this is wonderful, thanks to the specialists with solid experience in brick construction, you can say. But cement is sold in bags of 50 kg, so additional calculations need to be made.

As you remember from the school curriculum, 1 m³ = 1000 liters. The volume of a 50 kg bag of cement will depend on the density of the material. Let’s take a standard indicator of 1300 kg / m³. 1300/1000 = 1.3 kg weighs a liter of cement.

Let’s say you are making a classic mixture of M400 or M500 cement with sand in a ratio of 1: 3. In this case, you need 333 liters of cement per cubic meter of sand, multiply by 1.3 = 432.9 kg, almost 9 bags.

As we remember from the table, 0.24 m is needed for laying a wall of one and a half silicate bricks³ solution. 432.9 * 0.24 = 103.9 kg of cement or slightly more than two standard bags per 1 m³ masonry.

Now let’s calculate how many bags of cement we need to build a one-story house 3.5 m high, 10×15 m in size and two single bricks thick with walls, that is, 51 cm. We recall the mathematics. Volume = (10 + 10 + 15 + 15) * 3.5 * 0.51 = 89.25 m³. Again we take a single sand-lime brick, which, according to our table, with a wall thickness of 51 cm, takes 0.24 m3. 89.25 * 0.24 = 21.42 m3 or 21420 l.

That is how much ready-made solution is required for building a house. We have a standard mixing ratio of 1: 3. So cement is required 21.42 / 3 = 7.14 m³ or 7140 liters, multiply by 1.3 = 9282 kg. That is 186 50-kg bags. A lot. You can save money by using M500 grade cement in a ratio of 1: 4 to sand. Then you get 116 bags.

The calculations are not too complicated if you use the standard flow rates and remember the math. Experts advise taking materials with a margin of at least 5%, because during the construction process, unforeseen difficulties may arise and the consumption will increase.