MORTAR TYPES AND USES: A QUICK GUIDE TO HELP YOU CHOOSE WHICH YOU NEED
Choosing the right mortar can make or break your next DIY masonry project.
Walk into any home improvement or building supply store to buy mortar and you might end up more confused than ever. There are a surprising amount of options. Although all mortars have at least a few of the same basic ingredients (portland cement, lime, sand & water), not all mortars are the same.
And each type of masonry project has a preferred type of mortar that helps you get the job done right. So let’s look at a few basic types of mortars that you as a homeowner or DIYer might use.
Types of Mortar and Their Uses
When choosing mortar types, you’ll see these common properties listed that will help you choose the right one for your project.
Compressive Strength
The compressive strength of the mortar is a measure of the mortar’s ability to resist loads that try to compress it. While this can determine how strong the mortar will be, compressive strength isn’t as important for mortar as it is for structural concrete.
Workability
For masons and bricklayers, workability is one of the most important properties to consider. A mortar with good workability will spread easily, stick well to masonry surfaces, and support the weight of the masonry units.
Bond
The bond is the ability of hardened mortar to adhere to the surface it’s stuck to. Imagine two bricks stuck together with a layer of mortar. A mortar with better bonding properties will make the two bricks harder to break apart.
Common Mortar Types
These are some of the most common mortar types you’ll find at your local building supply store.
- Type M mortar
This mortar has the highest amount of portland cement and the highest compressive strength at around 2500 psi. Type M mortar is generally used for exterior walls, masonry foundations, retaining walls, and with natural stone.
An example of Type M mortar.
- Type S mortar
Type S mortar is a nice middle ground. It has a medium compressive strength of around 1800 psi. Type S mortar has high bonding properties and excellent durability. It’s commonly used above or below grade and can be found in foundations, patios, and retaining walls.
An example of type S mortar you can use for your next project.
- Type N mortar
Type N mortar is one of the most common types of brick-laying mortar used for DIY projects. It is a medium-strength mortar with a compressive strength of about 750 psi. This is the type of mortar you’ll want to use if you’re building barbeques, masonry veneers, or other non-structural applications.
Here’s some premixed type N mortar you can use for your next project.
- Type O mortar
This low compressive strength mortar is primarily used for interior non-load-bearing repairs. Because of its low strength, it’s not the best for exterior applications where it’s exposed to harsh elements.
Mortar Binding Materials
The types of mortars mentioned above are all types of gauged mortar that have different proportions of four basic ingredients – portland cement, lime, sand, and water.
But they’re not the only type of mortar. Here are some more that have other types of binding materials.
- Cement Mortar: One part portland cement and two or six parts sand. It's mainly used for basic repairs and floor leveling, among other things.
- Lime Mortar: Lime mortar has been used as a building material for centuries. It’s similar to the gauged mortar, except it doesn’t have any portland cement, just lime, sand, and water.
- Gypsum Mortar: This has plaster (binding material) and fine sand (aggregate). This finishing mortar provides a nice smooth surface on interior walls like drywall but typically has low durability in damp conditions.
- Surkhi Mortar: Surkhi mortar isn’t as common in the USA as it is in some other countries. Instead of sand, this mortar uses a fine powder made from burnt clay that gives it a distinctive red color.
- Aerated Cement Mortar: This mortar has an added air-entraining agent for increased plasticity and workability.
- Mud Mortar: Used commonly in developing countries where lime and cement are either unavailable or expensive. Mud is mixed with things like sawdust or rice husk to create a basic building material.
Special Purpose Mortars
Sometimes there are specialized projects that require mortars with very specific properties. While many of these still have a few basic ingredients, these special mortars have extra additives or binding materials not found in common mortar types.
- Fire-resistant mortar
- Packing mortar
- Sound absorbing mortar
- X-ray shielding mortar
- Chemical resistant mortar
Tips on Using the Right Type of Mortar
While choosing and working with mortar on your next DIY masonry project, here are a few things to keep in mind.
- When working with large stones and joints, add a little less water than normal to your mix so the mortar will be stiff enough to support the stones’ weight.
- For brick mortar, you can add a little more water for a smoother mix.
- For mixing just a little bit of mortar, try using a 5-gallon bucket and a heavy-duty drill with a mixing bit.
- For mixing larger amounts, it’s best to use a wheelbarrow or a mixing tub.
- Always follow the guidelines and directions for the particular brand of mortar that you’ve purchased.
- If you’ve mixed too much and it starts to get dry, don’t add more water and remix it. This will cause the mortar to lose its strength.
- Consult an expert like Alexander and Xavier Masonry in Garland, Texas, for professional help with big projects.
Whether your next masonry project is big or small, we’d love to help out! Give us a call today and get your FREE quote.
