Finding the sill angle of your homes window allows Spencerworks to custom mill the lower sash rail of your new window for a perfect match.
Step 1. Place a carpenters square against the side blind stop,with its base resting on the sill (figure 5).
Step 2. Measure the distance (rise) at point A, of the sill from the two inch mark.
Step 3. Use the chart below to find your sill angle.