Masonry repair is essential to the overall upkeep of your home. Cracks in the mortar allow water and pests to enter your home and can lower the value of the home or even prevent a sale. However, not just any repair will do. If the mortar used to repair the cracks does not match, it can cause more damage to the wall and still have the same effect on the value or sale of the house. This is why it becomes so important to get the right mortar for the repair.
The right mortar for repairing cracks in masonry and grouting is different for every house. This is due to inconsistencies in the mortar mix, the use of different types of mortar and/or different aging and staining of the mortar. Even if you match the composition of the mortar and the compressive strength of the mortar, the repair can look bad and stand out if the color of the mortar and the gradation of the sand do not match.
Most professional masonry repair specialists assume they can match mortar simply by color matching the mortar with pigments or stains, and some try to match sand. While this may work most of the time for them, it only works because the client doesn’t know it went wrong and neither party understands the problems this method can cause. This problem most often occurs in right-to-work states that do not require a license for masonry repair and city codes do not impose a repair standard related to this problem.
That said, the only correct way to identify your mortar and find a suitable repair mortar is through mortar analysis.
There are different types of mortar analysis available. The most commonly used is acid digestion, which has limited accuracy. In fact, all of the official individual test methods have wide error ranges. It is only through a combination of different mortar testing procedures that accurate results can be obtained. By gathering more information about the mortar, its compressive strength, acid digestion, chemical reactions, weight loss, and comparing these results along with a calculation of the specific gravity of the binding materials and sand, the composition of the mortar can be identified. more accurately.
Only after identifying the composition of the mortar, the color can begin to match correctly. This is because many base shades of mortar color are a direct result of the mortar’s composition. For example, a white sand with gray and black particles in a white mortar will give a bright white mortar with a slight gray cast in the light, but a blonde sand with red particles will appear beige to pink in a white mortar.
Once the base formula is determined, the color can be matched by making minor adjustments to different colors of the base materials as long as the ratio and formula remain constant. Final adjustments can then be made with pigments or dyes as needed.
With a proper repair mortar, masonry repairs will bond better and last longer without damaging the wall.
And if you have a mortar that contains historic lime, you can still get the analysis from one of these websites, but using the provided mortar formula, you can order the historic lime mortar from Virginia Lime Works.
