A door’s threshold serves to help seal the interior space from the exterior, working with the door bottom to lock out drafts and moisture. Extruded aluminium thresholds come in a wide variety of contours and widths, and offer wearability and longevity far superior to wood thresholds in many applications, particularly when the project requires installation on a concrete slab floor.
Clean the threshold area of the doorway with a broom to remove any dust or debris. Dust on the concrete surface will prevent the caulking used to seal the threshold from adhering to the concrete.
Remove the rubber weatherstripping from the threshold, if applicable.
Measure the inside width of the door opening from the face of the jamb on both sides. Divide this dimension by two.
Mark the measurement determined in Step 3 on the threshold, measuring from the predrilled centre hole in the aluminium threshold. This will establish a cut line on both ends of the threshold to keep the predrilled screw holes centred in the doorway. Extend the two cut lines across the surface of the threshold with a hand square.
Use a hacksaw to cut the two end cut lines marked in Step 4.
Insert the aluminium threshold into place. Use a trim saw to cut the jamb’s door stop on both sides if necessary to position the threshold into place.
Mark the holes in the threshold on the slab surface with a pencil or marking pen.
Remove the threshold from the doorway.
Drill holes for the screw shields with an electric drill mounted with the recommended masonry bit for the screw shield diameter.
Insert a screw shield into each hole drilled in Step 9. Use a broom to clean the slab surface of any concrete dust from the drilling.
Run a 1.2 cm (1/2 inch) bead of silicone caulking along the bottom of the aluminium threshold at both edges.
Insert the threshold into place. Secure in place with screws through the predrilled holes into the screw shields installed in Step 10. Tighten until snug and the threshold is held firmly against the concrete surface.
Cut the rubber threshold insert to length and insert it into the top channel, if applicable.
Placing a dollop of silicone caulking in each screw shield will help keep the screws from loosening over time as the threshold is walked on.