How to apply stone cladding

Fernhill Stone have produced a step by step guide on the careful and proper installation of stone cladding.

Tools and materials required

Health and safety

The following personal protective equipment must be worn at all times.

Surface Preparation

Once there is a structurally sound wall surface in place, surface preparation can begin.

• Apply two layers of water resistant barriers from the button up smoothly, to ensure upper layer laps lower at least four inches. The typical water resistant barriers are usually number 15 felt or grade D building paper.
• Apply the corrosion resistant metal lath horizontally using galvanised fasteners, ensuring that they penetrate through the shieving and into the studs at least one inch. Be sure to hit each stud every 6 inches on centre vertically.
• Install lath with minimum one inch overlap. The surface should feel rough, allowing the mortar to catch when applying the motor scratch coat

Installation/Application

Multiply the height by the width of the area that is to be covered, subtracting openings such as doors and windows. This is the total surface area for which you will need stone.

• To measure corner stones, measure the linear meterage of the external corners to be covered including any doorways and windows that have corners.
• The quantity of mortar required will be one bag per square metre of flat stone. Multiply the linear meterage of corners by 0.3 to give you additional bags required for corner stones.

Additional mortar may be required depending on the stone type and quantity – Fernhill Stone can provide advice on this.

Grouting the Joints

• Once the stone cladding has been applied, fill a grout bag with mortar and fill in the joints. Ensure all broken or cut edges are covered with mortar.
• Once the mortar joints have dried, a strike tool can be used to push the mortar into any cavities or voids to create a seal around each stone.
• Clean the edges with a tuck pointer, preventing water or pests from settling in the spaces.

Finishing the process and cleaning

Clean the wall with detergent and water using a bristle brush, before cleaning with fresh water.

Do not!

• Use acid or acid based products – this will damage the stone.
• Use a wire brush – this will damage the stone face.
• Use a high pressure power washer.
• Let loose mortar dry overnight.
• Use a wet brush – this may leave permanent staining.
• Sandblast.
• Use corner or flat stones in exterior horizontal planes or to cap walls in high freeze thaw areas.
• Use stone below water level, i.e. swimming pools.
• Use chlorine and other chemicals as they may discolour products and other masonry materials.