How to install a window sill with scotia

To determine distant sill sits below the window reveal.

Measure to the outside of architraves plus allowance for sill overhang past the architraves plus wastage.

Cut mitre to one end of sill and square cut on the other end to the length determined in step 2.

Fix resting blocks on wall to rest the sill on while marking the corner point on sill to cut the mitre on.

Cut mitre on the other end of the sill. Mitre cuts should be on both ends of the sill ready to install.

Predrill both ends of the sill to be used for fixing with nails or screws. Apply glue to the back face of the sill and fix it into place, ensuring it is aligned with architraves at each end. Predrill the remaining sill and fix and punch nails or countersink screws.

Check for a neat fit.

Apply glue and position ends in place. Fix join with fine finishing nail and wipe away excess glue.

Remove resting blocks from underside of sill.

Align scotia to mitre cut on the underside of the sill. Determine the length of the scotia and mark the cut at the mitre join on the opposite end of the scotia.

Cut mitre on the other end of the scotia to the exact length determined in step 10.

Check ends for a neat fit. Then apply adhesive to the back faces of the scotia and fix it in place with nails. Apply glue to ends and push in place and wipe away excess glue.