How to Install a Stone Archway

Assess the scope of your project. Does the fabricated arch already exist; is a standard doorway being converted into an arch; or is the framework being built from the floor up? The underlying base is important, as it will define the difficulty of the project as well as the quantity of veneer stone and other materials required to do the job. Existing interior arches made of sheet rock require cement backer board reinforcement to bare the weight of the stone. Converted or freestanding arches can be constructed with plywood, vapor barrier and diamond mesh.

Lay out the veneer stones. Even though it is a man-made product, size and shapes are often irregular to give a natural appearance. Fit the stones as if you are piecing a puzzle together, so that the alteration of shape and color is pleasing and has no gaps. For the best fit, larger stones should be placed along the flat portions of the arch, while the smaller ones reserved for the curve. Always be mindful of the keystone center. It will be a focal point of the finished project and therefore integral to the overall design.

Trowel the base with mortar parget and score with a scratch rake to establish an ideal setting surface for the veneer stones. Brush the surface with clean water with regularity, keeping it moist and free of dust and dirt while applying the veneer stones. Also, brush the back of the veneer stones prior to spreading mortar on them with the trowel and pressing them into the desired area.

Use 2-by-4 planks to support overhead stones as needed until mortar sets. The setting process can take 24 hours or longer depending on humidity conditions. Apply grout or finishing sealant only when it is completely dry and according to the stone manufacturer's specifications.