HOW MANY SQUARES OF FELT ROOF SHINGLES DO I NEED TO COVER MY ROOF?
Calculating the quantities of felt shingles required is relatively simple:
Each pack of felt shingles covers 3 square metres.
So,the first step is to calculate the area that you need to cover: Lets assume that you have a conventional shed with a duo pitched roof (an inverted 'v' shape) that measures 2.42m x 1.21m on each of the two sides.
2.42m x 1.21m = 2.93m2 x 2 = 5.86m2 total roof area.
5.86m2 / 3m2 packs of felt shingles = 1.95 packs of shingles required.
Always round up your requirements to allow for cuts and wastage, so we will say that you need at least 2 packs.
You also need to allow for the ridge: We know that the ridge is 2.42m long.
To cover the ridges you cut the shingle strips into the individual tile pieces, giving a coverage of 2.4 strips required per linear metre of ridge.
Therefore 2.42 l/m of ridge x 2.4 strips/lm = 5.8 strips needed = 6 strips required. There are 21 strips to a pack of shingles, so you will need to buy a pack to cover the ridge leaving 15 strips spare.
You may, in fact end up using most if not all of the spare shingles when laying the two sides of the roof as there was very little allowance for cuts and wastage (for which 5% is usually allowed).