How to Look

at a House

A blog with answers
to your questions about

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

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

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

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

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

  8. What is roof pitch?

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

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

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

  12. What is a “cool roof”?

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

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

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

  16. What is the difference between plywood and OSB?

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

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

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 a TPO roof?

  16. When is a railing required for the edge of a deck or porch?

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

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.

   But both materials have pros and cons, and galvanized is still the predominant choice for applications other than roofing, such as agricultural and livestock structures:



  1. Coating more resistant to damage during bending or cutting

  2. Less expensive

  3. Has distinct spangle pattern and bright metal color when new, like in the close-up photo above.

  4. Better paint adhesion


  1. Lasts only a little more than half as long as galvalume

  2. Less resistant to corrosion due to rain and coastal salt air



  1. Lasts almost twice as long

  2. More resistant to corrosion due to rain and coastal salt air


  1. Coating more easily damaged during bending or cutting

  2. More expensive

  3. Muted spangle pattern and softer, gray metal color when new, like in the photo at the top of the page

  4. Not as good paint adhesion

    Because any installation work that disturbs the rust-resistant coating will open up an area for early corrosion, it is always better to cut metal roofing with shears rather than a saw, which tears away the coating near the saw cut. Also, screws have replaced nailing as a method to secure the panels to the roof deck. A screw holds the panel snug and a neoprene washer under the screw head covers and seals the small area of coating damage at the screw penetration. Nails had the annoying tendency to loosen and gradually pop up over the years, making numerous tiny openings in the roof, like in the photo below.

    The next two photos show rust at galvanized metal roofing at the bottom panels due to damage of coating when cutting panel, and corrosion behind chimney due to acidity of wet leaves accumulated behind chimney deteriorating the coating.

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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