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We want you to be an informed homebuyer, and each blog post is a question that we have answered for our friends and customers over the years. Hope they help you make a good choice for your next home.

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Shed - Roof with a single slope.

Flat - Just as the name implies, except that it must have a slight slope to avoid standing water.

A-Frame - A gable with a steep slope, the living space under the roof, triangular front and rear walls, and the roof reaching nearly to the ground.

Butterfly - An upside-down gable roof.

Gambrel - Similar to a gable roof, but has two slopes on each side.

Mansard - Similar to a hip roof, but has two slopes on all sides.

Roof Parts and Terminology

Batten - Strips of wood spaced apart, upon which roofing is attached. This is often used for metal roofing. Also called purlins.

Boot - A sleeve that fits over the plumbing vent pipe penetration of the roof to waterproof it. Also called a pipe boot or collar, it is traditionally made of lead, but newer types use other materials.

Cricket - A saddle-type structure at the upper side of a chimney to prevent water or snow from accumulating behind it. It is essentially a small gable roof perpendicular to the main roof slope.

Counter-Flashing - The vertical, top piece of a two-part flashing, usually found around vertical surfaces that penetrate the roof, such as a chimney.

Dormer - A framed structure with a window that penetrates a roof.

Drip Edge - A metal flashing installed at the edge of a roof with a bottom edge that angles outward so that any water going over the edge drips off clear of the underlying fascia.

Fascia - A wood board or other material covering the vertical face of rafters or a roof overhang.

Felt - An asphalt-impregnated sheet that is installed between the deck and roofing, which acts as a secondary layer of water resistance. Also called tar paper or underlayment. The newer “synthetic” felts utilize plastic instead of asphalt.

Field - The center area of a roof slope, which is also the least likely place for a leak.

Flashing - Pieces of special trim, usually metal, installed to prevent leakage at the intersection of roofs slopes and at any roof penetrations, such chimneys, skylights, and adjoining walls.

Gable End - The upper portion of the side wall under a gable that forms a triangular point.

Kick-Out Flashing -  A flashing that diverts water away from the end of at the adjacent wall penetration of a roof. Also called a diverter flashing.

Pitch - The term used to describe the slope of a roof, usually expressed as the inches of vertical “rise” per 12-inches of horizontal “run.” A 4/12 pitch roof climbs 4-inches for every 12-inches measured under it horizontally.

Rake - The sloped edge of a roof, such as at the ends of a gable roof. Also called rake end.

Reroof - Installing a new roof after removal of the existing roof.

Roof-Over - Installing a new roof over an existing roof without removing it. A maximum of two layers of roof is allowed in most jurisdictions.

Ridge - The upper horizontal line where two roof slopes meet and slope downward in both directions. A trim piece that covers the ridge is called a ridge cap.

Soffit - The finished underside of a roof overhang.

Sheathing - The boards that are used to create the roof deck, usually plywood or OSB (Oriented Strand Board).

Square - A roofer’s term for 100 square feet of roof surface. Because it is a rounded-off number, a roof that is “23 squares” would be approximately 2300 square feet,

Transition - The lower horizontal line where roof slopes meet. Transitions require a flashing.

Valley - The line formed by the intersection of two sloping roof planes. Flashing here is called valley flashing.

Roof Materials

Asphalt Fiberglass Shingle - A type of shingle that uses asphalt for water proofing and has fiberglass reinforcement. A granule topping provides protection for UV sunlight deterioration. It is the most popular roofing material in America. The two basic types are three-tab, which has a relatively flat surface, and dimensional (also called architectural) shingles, that are heavier and more three-dimensional.

Built-Up - Multiple layers of roofing felts (usually 4-ply) cemented together with asphalt between each layer

Built-Up and Gravel - A built-up roof with a heavy top coat (flood coat) of asphalt embedded with gravel.

Metal - Metal roofing is usually steel with a rust-resistant coating, either galvanized or galvalume, although some types are copper or aluminum. It is defined by the “profile” the metal sheet is shaped into, such as 5V-crimp, PBR, or standing seam.

Modified Bitumen - An update of asphalt roofing that eliminates the requirement for hot tar, and is an alternative to built-up for low slope roofs.

Tile - Defined both by shape, such as barrel, flat or S-tile, and material, such as terra cotta and concrete.

Other - Wood shingle, wood shake, and slate are examples of roof materials rarely used in our area.

Blog Posts About Typical Roof Defects

  1. I’m buying a ‘50s house with a “gravel” roof. Is the roof going to be a problem.

  2. What does “lack of tab adhesion” in an asphalt shingle roof mean?

  3. What causes a lump or dip in the roof?

  4. Why is my roof leaking?

  5. Should I buy a house with an old roof?

  6. What is the difference between roll roofing and modified bitumen?

  7. What is a roofing boot?

While we hope you find this series of articles about home inspection helpful, they should not be considered an alternative to an actual home inspection by a local inspector. Also, construction standards vary in different parts of the country and it is possible that important issues related to your area may not be covered here.
© McGarry and Madsen Inspection


Kick-Out Flashing

3-Tab Shingles

Dimensional Shingles

More Blogs on Similar Subjects:

  1. Are roof trusses better than roof rafters (stick framing)?

  2. How can I be sure my roofing contractor got a permit?

  3. How can I make my roof last longer?

  4. What is the cost difference between asphalt shingle and metal roofing?

  5. What’s the difference between a roof inspection and a roofing estimate?

  6. What is roof pitch?

  7. What’s the difference between “composite” and regular wood siding?

  8. Should I buy a fixer-upper?

  9. What are “shiners” and why did they make me lose my insurance discount?

  10. What do you look for when you inspect a roof?

  11. Why does my insurance company want a roof letter?

  12. I saw some staining on the ceiling. Do you think the roof is okay?

  13. How do I find out the age of a roof?

  14. What is a TPO roof?

  15. What is a “cool roof”?

  16. What are the roof sheathing requirements for a roof replacement in Florida?

  17. Can metal roofing be used on a slow slope/pitch roof?

  18. How many layers of roofing are allowed on a home?

  19. What is the average lifespan of a house?

  20. What is the difference between galvanized and galvalume metal roofing?

  21. Does it cost more to roof a hip roof than a gable roof?

  22. What is fiber reinforced concrete?

  23. What is the difference between a clip, single wrap, and double wrap for the wind mitigation form?

  24. What is a “continuous load path”?

  25. Is a ridge board/beam required for a roof framed with rafters?

  26. What are the most common problems with wood roof trusses?

  27. What is the difference between roofing felt and synthetic underlayment?

  28. Why is a popped nail in a shingle roof a problem? How do I fix it?

  29. Why is it a mistake to replace and roof not replace its flashings?

  30. What are the hazards to avoid when going into an attic?

  31. What are roofing purlins and battens?

  32. What is a “square” of roofing?

  33. How can I tell if a roof has more than one layer of shingles?

  34. What is an SPF roof?