Do-It-Yourself Guide to Determining Roof Cost
Creating a Roofing Material List for Budget Control Before the Job
Jul 13, 2009
Before tackling a roof tear-off, the do-it-yourselfer can accurately determine roof cost by following these simple steps for measuring a roof.
Roof tear-offs can be tricky and frustrating jobs even for professionals. For the handy do-it-yourselfer, it is wise to do a little research and get an accurate measurement for the whole job. Having a full roofing material list in hand makes it easier to decide whether to do a tearoff and reroof, and keeps the roof cost in line once the project begins.
Materials Needed for Roofing a House
- Roof sheathing if rot is present.
- Drip edge.
- Ice and water shield.
- 30# felt paper.
- Roofing nails at least 1 1/2" long.
- T-50 staples.
- Mortar nails or wall anchors as needed for brick flashing.
- Shingles, including starter shingles and hip and ridge shingles.
- Pipe boots.
- Roof vents.
- Flash cards and flashing material.
- Caulk.
How to Measure a Roof for New Shingles
- Draw a diagram of eace face of the roof, labeling all eaves, gables, ridges, valleys, and walls, as well as noting any chimneys, stack pipes, antennas, etc.
- Measure each dimension as labeled on the diagram and round up to the next foot. Get a numerical count for pipe boots needed, and lineal footage of flashing material required.
- For drip edge material, add up measurements for all eaves and gable edges, add ten percent for waste, and divide by ten feet, the length of a single stick of drip edge.
- For ice and water shield, add up the length of all eaves and multiply by two for six feet of eave coverage. To this number, add the lineal footage of all valleys and any other areas particularly vulnerable to leaks. Take the total lineal feet number and divide by 66, the number of feet in a roll of ice and water shield. Be sure to add for waste and overlaps.
- For felt paper, determine the total square footage of the roof and subtract off the amount of ice and water shield needed. Add for waste and overlap. Normally the amount of ice and water shield and felt will be around two square more than the dimensions of the roof. 30# felt paper comes in 66 foot rolls just like ice and water shield.
- Roofing nail needs can be determined by suppliers based on the total square footage of the roof. A few small boxes of staples are usually enough to secure the felt paper to the sheathing prior to shingling.
- Pipe boot counts can be taken from the existing roof.
- If using box vents, count the number existing (and reuse if at all possible to save money). If using ridge vents, work off lineal footages for all ridges on the house.
- Flash cards are needed when a wall intersects a roof edge. One card is needed for each course of shingles butting against a wall. Flash cards come in packs of 100.
- Flashing materials (brick wall counterflashing and apron flashing) come in lengths of 10 feet. Alternately, they can be bent up using trim coil stock and a portable brake.
- For starter shingles, find the total lineal footage of the eaves and divide by the coverage per bundle. There are many options for starter shingles, including roll-out products, but using 3-tab shingles and simply turning them upside down works well. They are more rigid than most starter shingle products, and easy to use in following chalk lines to keep the first course of shingle straight.
- For shingling the main roof, find the total square footage, add for waste and divide by 100 to get the number of square needed. Suppliers can help determine how much waste to figue in based on roof style and type of shingle selected.
- For hip and ridge shingles, take the total lineal footage of all hips and rigdes and divide by coverage per bundle. 3-tab shingles can be used in place of hip and ridge shingles, and are much more cost effective. Each 3-tab shingle will give close to a foot and a half of coverage.
- Gather an organized, comprehensive list of necessary roofing materials, noting how much of each item is needed.
- Present the list to several suppliers, making sure to check out different shingle brands and styles to get the best price.
- Remember to include dumpster rental in the overall job cost.
The copyright of the article Do-It-Yourself Guide to Determining Roof Cost in Home Exteriors is owned by Jim Whitton. Permission to republish Do-It-Yourself Guide to Determining Roof Cost in print or online must be granted by the author in writing.
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