5 Tips for Mixing Chimney Mortar

chimney on a house
What You'll Need

Mortar is a combination of cement and sand that is used to hold together construction blocks. When water is added to this mix, it turns into a paste. This paste becomes hard when it dries. Mixing the chimney mortar can be a tricky task. There is absolutely no doubt that doing the mixing on site ensures greater strength and flexibility. However, the measuring and the mortar consistency need to be accurate.

When working with concrete, bricks, and stones, it is important to ensure that the mortar that holds these materials together is correct. In fact, the right consistency of mortar would predict the success of the chimney. If the mortar is weak and not right, the chimney could become unstable. The correct mortar mix would ensure the stability of the chimney as well as spread easily, making it easy to work with.

1. The Different Types of Mortar

stacking bricks using mortar

The first tip to remember when mixing chimney mortar is the four different types of mortar that are commonly used in building projects. These types are Type O, Type S, Type M, and Type N. The basic mortar ingredients remain the same. Portland cement to bond, water to turn it into a paste, sand, and hydrated lime to strengthen the mix are added to the product. However, the types are differentiated due to the different proportion of ingredients added.

Type O is the least strong of all the mortar types and is suitable for lightweight jobs and tiny chimneys. Type S is relatively stronger and is used for heavy outdoor projects. Type N ensures medium strength and can be used for both outdoor and indoor projects. Finally, Type M is a high strength mortar that is used for heavy-duty buildings like walls. The most commonly used mortar for chimneys is also Type M.

2. Mix Correctly

Mortar ingredients can be bought separately or together. Various pre-mixed mortar of different types are available in home improvement and do-it-yourself stores. All that needs to be done to the pre-mixed mortar is add water in the right quantity. To know the right quantity, read the instructions at the back of the packet. When buying ingredients separately and mixing them, ensure you have a good and well-tested recipe. Measure all ingredients accurately and carefully mix them together.

3. Don't Make Too Much

The next tip to remember when mixing the mortar is to first decide how much mortar needs to be mixed at one time. If you are working on a large chimney, it is a good idea to use an electric mixer as it could save you a lot of time and effort when mixing bulk quantities. However, if you are working on a small chimney, do so in a wheelbarrow using a shovel or a hoe.

4. Consistency

wheelbarrow holding mortar and a shovel

While mixing the mortar, keep checking the consistency. Add water slowly and keep checking the consistency. If too much water is added to the mix, and it becomes wet, it may easily spread all over the materials, making it difficult to work. However, when adding water, ensure the mix is wet enough so that it is not crumbly.

5. Let it Sit

Fifthly, remember it takes at least thirty days for the mortar to dry completely. Do not forget to apply a coating of a waterproofing product on it.