Using a calculator or ready reckoner multiply the length measurement you took in metres by the width measurement in metres.
How to measure a flat roof.
Then calculate the pitch of the roof by placing a level against it angling the level so the bubble is centered and measuring the distance between the end of the level and the roof.
Flat roofs if your roof is flat or has no more than a 3 in 12 pitch you can calculate its total square footage by simply multiplying the length by the width.
The pitch of the roof is a ratio.
Measure a flat roof.
The number of inches that the roof rises vertically for every foot of roof.
Calculate the roof pitch.
The roof area for a hip end is the same as for a gable end the intersection is equivalent to a hip slightly conservative so there is usually no need to consider triangles when measuring a roof.
Calculating the surface area.
So use a tape measure to find the height of the roof above the top wall of the building.
Steep roofs measure your house at ground level then add in the roof s overhang for greater accuracy.
The roof area is simply 114x18x2 plus 30x18x2 giving 5184 square feet which is perfectly adequate for estimating materials.
The next step is to measure the pitch also referred to as the roof slope of the roof deck.
To measure a roof start by measuring the length and width of the building s exterior walls and multiplying them to get the area.
There are a couple of ways you could tackle this calculation of surface area and membrane size.
You ll need to figure out the vertical distance also known as the rise over a 12 horizontal segment also known as the run.