figuring squares per roof footage

Old 04-08-02, 08:22 AM
chris crews
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figuring squares per roof footage

im in need of help in how to figure how many squares of shingles to buy to repair my roof i need to remove all old shingles and apply new ones could anyone help me the dimensions of my roof are 18ft by 41ft any help is welcomed with open arms
Old 04-08-02, 09:51 AM
Mike Swearingen's Avatar
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A square is 10'X10' = 100 Sq. Ft.
Normal 3-tab shingles are three bundles to the square. Some roofing has five bundles per square, like mine.
I assume that you must have a ranch-style house and each side of your roof 18"X41' with no dormers, etc. , or is that the total?
Either way: 18 X 41 = 738 Sq. Ft. = 8 squares (or 2 X 738 = 1476 = 15 squares). Get at least two extra squares +/- for doubled up starter courses, ridge cap, waste and trim, and planned color-matching left-overs for future storm damage repairs.
After the tear-off, install new drip edge along the bottom of the roof under the roofing felt and over the roofing felt on the edges.
Get new boots for any vent pipes sticking through the roof.
I'm not a pro, but there are some good ones in here, so I'm sure that they'll be chiming in.
Good Luck!
Old 04-08-02, 10:12 AM
HappyWoofer :-)
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You'll have to go on roof for an accurate measurement and add 5-10% for overage(offcuts,waste,etc) waste is greater with valleys and hip roofs.

Try this link
It's a matter of dividing your roof into squares or triangles and multiplying width x length(for the measurement from the eaves to ridge add an extra 6" for starter course) You'll also have to measure your caps(1'=1 square foot) The standard is 3 bundles per 100 sq.ft. unless you are buying specialty shingles.Other materials you will need:
-1"(minimum) or 1 1/4" gal roofing nails (dependant on your nailing experience)
-tarpaper and/or ice and water shield
-metal steps and flashing(if installing new-advised)
-valley(metal or asphalt)if asphalt should be double layer
-fasteners for attaching metal to brick,if applicable(concrete nails,tapcons,etc)
-hook(roofer's)blades for cutting
-metal drip edge(optional)
-have tarps on hand just in case
-stripping shovel(if on plywood it can generally be "peeled" off)

Woof :-)

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