Prepare a recess in the concrete flooring where the grate will be located. The recess should be at least:
1/2 of an inch (13 mm) deep
4 inches (100 mm) wider than the outside dimensions of the frame – this allows 2 inches on all sides to maneuver the frame into position.
2. Drill anchor holes
The mat frames should be secured to the concrete floor using anchor bolts into lead anchors that are set into the floor.
Drill holes in the frames at about 2 foot intervals for the bolts. Countersink the holes.
Set the frames into the recess at the appropriate locations to position the mat(s). Mark the hole locations on the concrete. Remove the frames and drill holes in the floor for anchors. Install the anchors using an anchor setting tool.
3. Secure frames in the recess
Reinstall the frames. Secure them to the floor with 1/8" x 1-1/2" anchor bolts into the lead anchors.
NOTE: If necessary, shim under the frame sections so that the top edge of the frames is flush with the finished floor surface and the frames are level.
4. Pour concrete
Pour concrete (or grout) around the edges and in the center of the frame.
5. Level the concrete
Cut a board just slightly shorter than the width of the frame. Use the board to smooth and level the concrete.
Be very careful that the concrete is absolutely smooth and level with the inside lip of the frame. This will allow the mat to lie perfectly flat and avoid rocking.
6. Recheck all dimensions
Before the concrete sets, recheck that:
The frame sides are straight
The frame corners are at correct angles so the mat will fit properly
All inside dimensions of the frame are accurate according to drawing measurements
If the frame bows inward, use spreaders inside the frame until the concrete is thoroughly set.
IMPORTANT: The grate is made to fit snugly into the frame according to the drawing. Manufacturer or distributor cannot be responsible for problems that result from improperly installed frames.
7. Protect the frame edges
When the concrete has hardened, install plywood or other material in the recess to protect the frame edges from damage until the grate is installed.