More blog posts about roofing:

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

  2. What are the right words for talking about a roof?

  3. Why are most house roofs slanted instead of flat?

  4. How can I make my roof last longer?

  5. Should I buy a house that needs a new roof?

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

  7. What is the minimum pitch of an asphalt shingle roof?

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

  9. What’s the difference between a gable roof and a hip roof?

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

  11. What is roof pitch?

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

  13. What are the most common problems with older houses?

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

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

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

  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 an H-clip?

  23. If my roof is not leaking, why does it need to be replaced?

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

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

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

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

  28. What can I do to prevent roof leaks?

  29. Why is there no attic access hatch in the house?

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

  31. What is an SPF roof?


More blog posts on related subjects:

  1. How can I tell if a house has insulation?

  2. What are the warning signs of a dangerous deck?

  3. Does it make sense to buy an older mobile home and remodel it?

  4. How do you determine when the house was built?

  5. Should I buy a fixer-upper?

  6. How do I remove cigarette odor in a house?

  7. The house has asbestos siding. What should I do?

  8. How do I get insurance if my home can’t pass a 4-point inspection?

  9. There’s an old fuel oil tank underground in the yard. Is it a problem?

  10. What is “knob and tube” wiring?

  11. Why do the floors slope in this old house?

  12. The garage has been converted to a family room. Is that alright?

  13. What is the minimum pitch for a metal roof?

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

  15. What is the difference between plywood and OSB roof sheathing?

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

  17. What are the different roof deck attachment discount categories for a wind mitigation inspection?

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

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

  20. What is a roofing boot?

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

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

  23. What are roofing purlins and battens?

  24. What is a “square” of roofing?

How to Look

at a House


A blog with answers
to your questions about
HOME INSPECTION
and HOME MAINTENANCE

Welcome to our blog!
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.

   The 20 to 30 year average lifespan estimate is based on “average” conditions. Many factors contribute to a longer or shorter life of the roof; so a particular modified bit roof’s life can vary—sometimes significantly—from the average. Here’s a list of conditions that affect roof longevity:

Color of roof - A dark roof absorbs more heat, which shortens the lifespan.

  1. Angle of roof slope - Higher pitch roofs tend to last longer.

  2. Orientation of roof surface - A roof slope facing south will get more sunlight, and have a shorter life.

  3. Attic ventilation - An unventilated or poorly ventilated attic reduces roof lifespan.

  4. Quality of roof material - “Economy” roof materials have a shorter life.

  5. Installation - Sloppy or improper installation shortens roof life. Manufacturers typically blame the roofing contractor for a roof that has a short life, and they are sometimes correct.

  6. Accumulation of leaf debris on roof - Because this type of roof is often nearly flat, rain does not fully wash away pine needles and leaves, and they tend to build up over time if not removed regularly. Their decomposition creates acidic areas that speed up the aging of the roof. In the photo below, the roof surface is buried under decomposing leaves.

  7. Trees near roof - Tree branches rubbing on a roof or the acidity from the accumulation of leaf debris on a roof shortens its life.

  8. Ponding - When there is an area of a roof that has a puddle of water that does not drain after a rainfall, it is called “ponding.” Although a gravel roof is watertight when correctly installed, ponding tends to deteriorate the roof in the ponding area over time. Even a “flat” roof is designed with a slight slope for drainage, and ponding is always the result of settlement or sagging of the roof framing, or poor installation of the roofing.

  9. Harsh climate - Severe weather, both harsh winters and hot summers, along with big temperature swings within a 24-hour period, also shorten lifespan because of the expansion and contraction of roof materials.

   As a gravel roof reaches the end of its lifespan, it looks like the picture below, with areas of missing gravel and exposed roofing felt.

   To learn more about how to recognize when it’s time to replace your roof, go to our blog: “How can I tell if the house needs a new roof?”

   If you want to understand the difference between an “architectural” and a regular shingle roof, see our blog: “What's the difference between an "architectural" and a regular shingle roof?”

   To figure out why your roof is leaking, go to our blog: “Why is my roof leaking?”

  To understand the basis, potential use, and limitations of lifespan ratings, see our blog post “How accurate are the average lifespan ratings of home components? Are they actually useful?”


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.
©2015 - McGarry and Madsen Inspection.

 

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