One of the most important steps to properly executing masonry repairs is matching the mortar of the pre-existing structure. The following are four things that should be noted and factored into the mortar matching process to find the appropriate mortar:
The three major types of mortar are known as Type N, Type S, and Type M mortar.
The first consideration that should be taken into account is whether the original mortar was Type N, Type S, or Type M mortar.
If the exact type of the original mortar is unknown, it's possible to choose a mortar according to the demands of the application.
If the masonry wall that is being restored is non-load bearing, Type N is likely the type of mortar that should be used. On the other hand, Type S mortar is typically used for load-bearing walls. Type M mortar is a type of mortar that cures harder than all the other types, making it ideal for either retaining walls or brick pavers.
Mismatched mortar can cause shrinking or expansion that could rapidly lead to the development of new cracks after restoration.
Certain types of mortar may shrink or expand as they dry. This can cause a masonry wall that is being repaired to develop more cracks after restoration. Choosing a type of mortar that is specially formulated for restoration will minimize the chances that a mortar will shrink or expand excessively and cause further damage to a masonry wall.
Mortar must not only match the existing structure aesthetically, but also structurally.
One of the major concerns in mortar matching is finding a mortar that is structurally compatible with the pre-existing structure. It's important that the mortar that is chosen is durable enough to support the structure. Also, a mortar that will resist moisture once dry is important. This is especially true if the wall is situated in a location where it will be exposed to precipitation often.
Closely matching mortar may require some experimentation.
Mortar will look different once it is dry than it looks initially when it is being mixed. This means that it's typically necessary to dry a sample of the masonry to match it exactly with the pre-existing structure.
It's important to note that the sand used to mix mortar will have the most significant impact on the end appearance of the mortar. This means that you might want to look first at the possibility of changing the sand you're using if you're having trouble matching mortar appearance.
For more information and assistance, talk with masonry restoration professionals or visit websites like http://www.mararestoration.com.