Skylights fall into two general categories as far as flashing is concerned: those that protrude above the surface of the roof, and those that do not. The ones that protrude above the roof should be flashed in a manner similar to a chimney the sides should be step flashed either with one-piece step flashing or step and counter flashings, the bottom should have an apron flashing; the top should have the largest piece of flashing which extends well up under the slate (at least I 2"); and all four corners should be folded (or soldered) to prevent leaking.

Some of the standard commercial skylights come with pre-formed flashings which may need to be modified by roofing Toronto to fit your particular situation. Flashings are easy to make, so it may be advisable to make your own rather than buying expensive, generically pre-formed skylight flashing. Remember this rule when making step flashings: the bottom of the step flashing should line up with the bottom of the slate above, and the top of the step flashing should line up with the top of the slate behind it, if the step flashing must be fastened (nailed) to the roof, then allow an inch or two of flashing to extend above the top of the slate below it for nailing. If it fastens to the skylight, that won’t be necessary.