Step 1: Preparing the Surface
Water Resistive Barrier (WRB)
If you will be installing the stone on an exterior non-masonry surface it is recommended to apply a Breathable Building Wrap type product. First, install a flashing 4” above grade, then apply WRB starting with the bottom edge at the lip of the flashing continuing upward in a shingle-like fashion. Overlap WRB a minimum of 2” on horizontal seams and 6” on the vertical seams.
Step 2: Install RDM
Rainscreen Drainage Mat (RDM)
Next install a Rainscreen Drainage Mat to provide a minimum of 10 mm air space. This air space is necessary to provide a moisture escape mechanism eliminating the possibility of damaging moisture being trapped in the wall promoting dangerous mould growth and wall decay. Also, in freeze thaw environments, this mechanism allows the veneer to exist in a stress free condition eliminating “pop offs” . Remember to follow the manufacturers installation instructions.
Step 3: Install Substrate
Lath and Scratch Coat or Concrete Board
Directly over the Drainage Mat, or directly over the sheeting on an interior project, cover the area with wire lath or concrete board.. Needed is a 2.5 gauge expanded metal corrosion resistant lath or 3/4” concrete board.
Step 4: Applying the Stone
Mix the setting bed mortar as described in manufacturers directions. For exterior projects Brunswick Limestone recommends using a liquid bonding agent instead of water.
Layout the stone
Before you apply any of the stone, lay out a few square feet on the ground or floor in front of your project. This will give you a sense for the variety of shapes and colours you’ll be working with. Arrange the pieces so they fit and look nice next to each other, and try to avoid clumping colours together all in one area.
Install Corners First
Start at the corners and work toward the centre of the wall. Be sure to alternate long and short returns on corner pieces.
Size the stone
It’s preferable to size the pieces before application, just to be sure of proper fit and look.
Apply the stone
The back of each piece should be buttered about ¼’’ thick and firmly set using a back and forth motion until mortar squeezes out around the edges. Remove excess mortar around the stone.
There are no inside corner pieces - just meet the two pieces together.
Cutting the stone
An angle grinder with a stone cutting blade or diamond blade may be used to fit the pieces. Scoring the piece before breaking allows the cut portion to retain its natural look.
Step 5: Applying the Grout
Mix a batch of grout to manufacturers instructions.
Using Grout Bag
Fill the grout bag about half full
Gently twist the top squeezing grout in between stone filling to a level just above desired finished depth. This allows space for striking the grout.
Letting the grout dry
Let the grout dry until firm - you should be able to push on the grout without leaving fingerprints. Do not allow grout to over dry or striking will be difficult.
Striking the Grout
Using a striking tool or stick scrape along joints until the grout has a clean finished look.
Grout should crumble into sand. If it crumbles away in larger chunks its still too wet.
Sweeping the Stone
Use a medium bristled brush to remove the dust from the stone to complete your project.