If you are planning to repair your home’s mortar and this just happens to be your first time attempting a repointing project, you probably have a lot of questions about how different parts of the project should be done. After all, since it is such a large undertaking, you’ll want to do it right on your first attempt. One of the most common questions for people, who have never repaired their home’s crumbling mortar, is how much mortar should be removed before replacing it.
A good rule of thumb is to remove all of the damaged mortar in the joints to a depth that is equal in size to the width of the joint itself. Areas containing sound mortar do not need to be removed, but there is no reason these areas can’t also be removed if that is what you choose to do. The choice for whether or not you wish to remove all of the mortar will probably depend on the amount of mortar that is currently damaged or missing.
If most of the mortar appears to be damaged or has completely eroded away, then it is probably easiest to just remove all of the remaining mortar in one shot. This will prevent you from having to make several smaller repairs as the older mortar continues to crumble and fall away. On the other hand, if only small areas of the mortar are in need of repair, then it is probably more efficient to replace only the areas that are missing, weak, or damaged.
To determine which areas are damaged and should be repaired, use a screwdriver or nail and press it firmly against the mortar. By poking and scraping at the mortar, you should be able to identify the areas that are chipping away or have a sand-like or brittle feel to them. These areas, along with any places where the mortar has eroded, should be prepped for reporting.
By learning all that you can before starting your repointing project, you will have a much better chance of your mortar repairs going off without a hitch. Knowing information like how deep you should remove damaged mortar, will greatly help you during the repointing process. Though not all mortaring jobs are alike, a good rule of thumb is to remove any weak or damaged mortar to a depth equal to the width of the joint itself when preparing for a repointing project.