How to Install Cultured Stone on Interior Arches

Use a stud finder if necessary to determine the locations of the studs surrounding the doorway. Mark the wood in the area where the veneers will be installed as clearly as possible to give the best possible knowledge of the wood system in the wall. Use sandpaper to sand all surfaces that are to be covered with stone veneers.

Cut out sections of lath and stretch them tight against the wall. Drill them in place using 3-inch wood screws and plastic washers. Space the 3-inch screws every 12 inches along the studs and the doorframe. Decrease the spacing to 6 inches along the outside edges of the lath. Keep stretching the lath tightly and overlap it by 4 inches at least when pieces touch.

Spread out mortar on the lathed area. Allow all the mortar to work its way under the lath and apply it until it forms a layer 1/4-inch thick. Scratch up the mortar as it starts to dry using a rake. Let the mortar dry for two days.

Begin applying veneer stones to the arch, starting with the capstone at the top and working your way down. Slap 1/4 inch of mortar on the rear surface of each veneer, and then press it against the mortar for 30 seconds. Apply the largest stones first and use the smaller ones later to fill in the gaps, cutting stones as needed using a saw. Finish the application of the final sections of veneers by cutting thin stones in half and securing them to the floor around the archway with their cut surfaces against the floor but only the rear surface mortared. Choose stones that are thin so they do not pose a tripping hazard.

Remove excess mortar and allow to dry for 24 hours. Apply grout in between the stones if that is the look you want for your archway. Use at least a small amount of grout between the stones to make them more secure and connected.