In a building construction project, there are different types of masonry works. Such as brickwork, plasterwork, tiles work, pointing work, and patchwork, etc.
Different type of masonry construction demands different mortar mix ratio.
Using the same mortar mix ratio for all types of masonry work will hamper the quality of the construction.
Then which proportion should you use for a particular type of masonry construction?
I’ll discuss the matter all through in this post.
Before that, let’s have some lights on…
What Is The Mortar Mix Ratio?
As you know mortar is a mixture of cement, sand, water, and sometimes lime.
There are also some other ingredients that can be added to the mix. Such as plasticizer, waterproofers, frost proofers, accelerators, and color additives, etc.
I want to discuss a little bit about these ingredients. So that you can better understand the mortar mix ratio.
Cement: As you are a construction professional you already know about this. It is a bonding material.
Sand: It’s a fine aggregate that is mixed with cement and water to prepare mortar.
There are various types of sand used in construction depending on the type of masonry works.
Such as soft sand, sharp sand, plaster sand, etc.
Soft sand contains fine grains of sand and mostly used for brickwork, pointing, and where thin layers of mortar are required.
Sharp sand is more coarse than soft sand.
This sand is normally mixed with other sand to prepare the mortar and it helps to prevent cracks during the drying process.
This type of sand is used in the situation where thick layers of mortar are required. Such as bedding roof tiles and garden projects.
The grains of plaster sand is not as fine as soft sand but not as coarse as sharp sand. This type of sand should be washed before use to remove clay and salts.
Lime: It can be used in conjunction with cement. It’s also can be used as an alternative to cement in some mixes. It’s commonly used with soft, permeable bricks that would likely crack if cement is used.
Plasticizer: To make the mortar sticky and easier to point over, the plasticizer is added to the mix. It’s a liquid.
Waterproofer: Its name says about it. Mostly used in outer plastering.
Frost proofer: It protects mortar from freezing conditions. But I have doubts about its function. Use it at your own risk.
Accelerators: It accelerates the dry time of mortar. If you add this to the mortar mix, you’ll have a little time to work with the mortar. Because it’ll start to set too early. So use it when you absolutely need it.
Color Additives: The name says it all. If you want to add color in a mortar you can add this. But avoid excessive amounts.
Some Considering Points During The Proportioning Of Mortar
- Take special care during measuring sands.
Because of the moisture present in the sand, it’ll cause the bulking of the sand. That means wet sand will have more volume compared with dry sand.
- The presence of moisture content in the sand may affect the strength and bond quality of the mortar. So you need to be careful mixing water to the mix.
- Masonry units absorb some amount of water from the mortar and thus reduces the water-cement ratio of the mortar.
So, you need to be careful while adding water to the mortar mix. This is the reason we soak masonry units in water before using it.
A wrong mix ratio or careless measuring of mortar’s ingredients can make the mortar weak.
What Happens If You Make The Mix Too Weak
- The mortar will fail to bind sufficiently.
- It can be washed away after minimal weathering.
- It may crumble after a short amount of time.
Sometimes we think that adding more cement to the mix will make the mortar strong.
But strong mortar can also hamper the quality of the job.
What Happens If You Make The Mortar Too Strong
Strong mortar dries too quickly and shrink. As a result, It produces cracks.
So the mortar mix ratio should be in such a way that ensures the mortar is wet enough till the job is done.
What Is The Best Mortar Mix Ratio?
It depends on the type and location of the job you’re going to execute.
Before discussing this, let’s see the mix ratio for different types of mortar guided by ASTM 270,
- M-Type mortar requires 1 part of Portland cement, ¼ part of lime, and 3½ part of sand.
- S-Type mortar requires 1 part of Portland cement, ¼ part of lime, and 4½ part of sand.
- N-Type mortar requires 1 part of Portland cement, 1 part of lime, and 6 part of sand.
- O-Type mortar requires 1 part of Portland cement, 2 part of lime, and 9 part of sand.
- K-Type mortar requires 1 part of Portland cement, 3 part of lime, and 12 part of sand.
As you now know the mix ratio of different types of mortar, now let’s see…
How To Choose The Right Mortar Mix Type For Different Masonry Work?
Type M Mortar Mix
It has the highest amount of portland cement and is used in heavy loads and below-grade construction. Such as foundations, retaining walls, and driveways.
The compressive strength of this type of mortar is at least 2500 psi. But it has relatively poor adhesion and sealing properties. That’s why it’s not recommended to use in exposed locations.
Type S Mortar Mix
The S-type mortar has high tensile-bond strength and provides at 1800 psi of compressive strength.
This mortar is suitable for below-grade applications. Such as masonry foundations, retaining walls, and sewers.
This mortar is also suitable for at-grade applications like walkways and brick patios.
Type N Mortar Mix
This mortar provides a medium compressive strength of 750 psi.
It’s a general-purpose mix and is recommended for exterior and above-grade walls that are exposed to high heat and severe weather.
It’s also useful for interior load-bearing walls.
Type O Mortar Mix
This mortar is useful for the above-grade, interior, and non-load-bearing walls.
Due to its low structural capacity, it isn’t recommended to use in exterior applications.
It shouldn’t also be used in areas subjected to high winds.
But due to consistency and easy application, it’s ideal for repointing and similar repair works on existing buildings.
The O type mortar provides relatively low compressive strength, at only about 350 psi.
Type K Mortar Mix
This mortar provides a very low compressive strength of only about 75 psi.
Normally, it isn’t used in new constructions. It is primarily used for restoring the masonry on ancient buildings.
You now know about the different types of mortar and their uses.
Now let’s see the…
Mortar Mix Ratio For Different Types Of Masonry Works
Mortar Mix Ratio For Bricklaying
The mortar mix ratio for bricklaying mostly depends on the size and location of the brick wall and the type of bricks.
For buildings, we use the following mixes –
- The mortar mix ratio for most of the 5 inches thick wall in a residential building is done with 1 part cement and 4 parts soft sand mortar mix ratio.
- For 10 inches thick brick wall above the plinth level you can use 1:5 or 1:6 mortar mix ratio depending on the brick quality.
- For retaining walls which may be in regular contact with water, use 1 part cement and 3 parts soft sand. It’s sometimes recommended to use 1 part lime with the mix depending on the type of brick.
- For brickwork below the plinth level, 1 part cement, 1 part lime and 4.5 parts soft sand or 1 part cement and 4 parts soft sand can be used for the mortar mix.
Mortar Mix Ratio For Block Wall
Concrete blocks or cement blocks are different than bricks. The basic mix ratio for most of the block wall is 1 part cement and 4 part soft sand or 1 part cement and 5 part soft sand.
Mortar Mix Ratio For Plastering
Use 1 part cement 2 parts plaster sand, 2 parts sharp sand, and half part lime for most of the plastering work.
Mortar Mix Ratio Of Tiles Work
Use 1 part cement and 4 parts sharp sand for most of the tiles work.
Depending on the types of tiles you can use anything from 3-6 parts sharp sand with 1 part cement for preparing the mortar.
The mortar mix ratio for tiles mostly depends on the thickness of the bedding mortar. If thickness increases you can increase the sand quantity into the mix.
The mortar mix ratio actually depends on various things. Such as the location of applications, type of masonry works, quality of masonry blocks and ingredients of mortar, etc.
So it’s best to consult with your local engineers or visit the construction projects in your area and ask help from them to know the best mortar mix ratio for your particular job.
Now Your Turn:
I hope this post will help you to choose the best mortar mix ratio for different types of masonry works.
Now please share which mortar mix ratio you use in your area for bricklaying, plaster, tiles, and pointing work.
Please make comments below along with the name of your city and country….