With summer wrapping up and fall fast approaching, many homeowners may find themselves saying “…we need to get this roof replaced before winter.” If that’s you, we want to provide a short session of roofing school for common roofing terms that can help you ask a roofing contractor good questions, understand the answers, and make smart roofing choices.
A Short Roofing Vocabulary Lesson
Square is the basic unit of measurement used by all roofers. One square of roofing is equal to 100 square feet of roof surface area. Think of it as a 10’ by 10’ area on your roof. Example: 3,000 square feet = 30 squares.
Generally, a contractor’s estimate will allow for extra material that will be lost due to cutting in the installation process. A roof that has 2,700 sq. ft. of area could easily and correctly, be estimated at 30 squares or more, depending on the configuration.
Ask your roofing contractor how many squares are needed to cover your roof and make note of the figure.
Pitch is the slope angle of your roof, usually expressed as a ratio against 12. For example, a 3:12 pitch would be a roof that rises 3 feet vertically for every 12 feet of horizontal run.
Roofs that are 7 or 8:12 pitch can be challenging to walk on, and generally 9:12 and steeper is considered non-walkable. Steep pitches mean that a contractor will have extra time and equipment needed to work safely on your roof, so a steep roof will generally price out higher per-square than a walkable roof.
On the low-slope side, once a roof pitch falls below 3:12 it is generally not suitable for shingle-style roofing, whether metal shingles or even asphalt! There are specialized products needed for low-slope roofs less than 3:12.
We can help you determine what roof pitch or pitches you have, and if they present any challenges. If there is a pitch change or pitch transition on your roof, ask how they will handle that area.
Flashing is the general term for a roofing accessory or trim piece designed to keep water out of a joint, intersection, or penetration. Roof flashings are generally made of metal and sometimes made on-site to fit the situation, although many flashings can be factory-made parts. Chimney flashings, plumbing vent flashings, wall flashings, and skylight flashings are all examples of this principle.
Flashings improve any roof’s long-term durability as they help keep water out of these areas instead of relying on caulking, tar, or goop of some kind. Although sealants can be used in association with flashings, it is generally the flashing itself doing the bulk of the protection, with the sealant as a backup.
Flashings can be made from one piece of metal or from many small pieces of metal overlapped, called “step flashings.” Continuous or one-piece flashings have fewer seams than step flashings.
Ask your roofing contractor how they will flash (the verb form of the same term) each of these areas on your roof.
Underlayment is a material placed under the visible surface of the roof. With asphalt shingles the most common underlayment used is felt paper, a paper-based roll of material saturated with asphalt. Felt paper of a heavy grade is an acceptable underlayment under asphalt shingles, although it is considered temporary and made to be replaced often as the shingles.
Under more permanent roofing like metal, most contractors today use synthetic underlayment that is lighter and stronger than felt paper, and designed to last longer.
The general purpose of underlayment is to serve as a final moisture barrier beneath the roofing material. Underlayment can also provide a smooth working surface when roofing over old shingles, and is a preferred practice when roofing over asphalt shingles with metal.
There are also some types of specialty underlayment, used in limited and specific situations to achieve a particular goal. Radiant barriers, fire protection, ice, and water barriers are some examples of specialty underlayment.
It’s important to note that underlayment should never be used as a substitute for actual roofing and should never be counted on to overplay its role, such as to prevent a roofing product from leaking at a roof pitch lower than its design specs indicate.
There you have it; a short roofing vocabulary lesson.
Do you have more questions about buying a new roof?
We can help. We’re your local, professional roofing contractor, American Metal Roofs of Northern Wisconsin, specializing in making certain that you get exactly the right roof for your home. You can contact us for a no-obligation conversation about your roofing quandary, or questions.