How to Repair an Outdoor Limestone Wall

What You'll Need
Stone repair kit
Putty knife
Clean paintbrush

A limestone wall can be an ideal way to enclose a garden, providing a strong and solid barrier at the perimeter. However, with it being in an exposed position, you may find that it can sustain damage from wear and tear. Being aware of the correct process for repairing the limestone will ensure that you can keep it in good condition.

Step 1 – Inspection

Start by examining the full extent of the limestone wall to make yourself aware of every point where repair is required. This will help you to determine the quantity of material required to undertake the repair. In addition to the number of holes and defects, consider the severity of them. Be aware of the color to ensure you get a repair kit that matches.

Step 2 – Prepare

Ensure that you undertake the repair procedure in clear conditions, to ensure that you achieve the best result without being hindered by inclement weather. Start the preparation for repairing the outdoor limestone wall by cleaning the surface of the sites that you intend to repair. Remove any loose particles and debris with a stiff-bristled paintbrush, gently brushing out the recesses prior to undertaking the repair. Many stone repair kits will require you to mix components together to get the compound that you need; this should be undertaken as part of the repair process. This will usually involve adding a liquid hardener to a paste and thoroughly mixing it, which must be done in accordance with the instructions.

Step 3 – Application

Ensure that the repair compound is thoroughly combined before use. Gather some of the compound onto the tip of a putty knife and apply it to the defect in the limestone wall. In the event that the recess is large enough to make it impossible to fill it with one swipe of the putty knife, it will need to be filled gradually. Carefully apply the repair compound in a smooth manner, ensuring that there are no air pockets. Continue until the paste completely fills the recess to the surface level. You will then be in a position to draw a scraper across the surface to level it out and create a smooth finish, making sure that any excess paste is removed. Complete this entire process for one defect before starting on the next so that there is no risk of it drying out before you can finish it properly.  

Step 4 – Finish

Protect the limestone wall while the paste is being left to dry to avoid it being disturbed. It should be left to dry in accordance with the instructions but for, at least, 12 hours. The stone repair compound will dry to an extremely hard state and can be treated to ensure it matches the limestone that surrounds it. If the surrounding limestone is as smooth as the repair site, there will be nothing more that needs to be done. Alternatively, use some sandpaper to make the surface look rough.