Roofer Madness
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Warning ! This Book could save you thousands of dollars and a lot of grief

Find out how to choose a roofer who will prevent your worst nightmares and make your
project a success.

9) Attic Ventilation

The Roofing Contractors Association of BC (RCABC) says “attic ventilation is not the responsibility of the roofing contractor as it is a design and building code requirement,” but the shingle manufacturers say that without proper ventilation their warranties become void.

That puts the home owner in a tough spot wondering if he has enough attic ventilation to protect his shingles, keep his warranties valid, keep his house cool in the summer and prevent mold and wood rot caused by condensation build up.

The building code says that 1 square foot of ventilation needs to be installed for every 300 sq ft of attic space. Half of this ventilation should be in the soffits and half at or near the peak.

That all sounds simple enough but unfortunately there are many complications on achieving this depending on the age of the house and type of construction. It is understandable why the RCABC didn’t want to touch this issue, as it really needs someone who is up to date on current construction practices. Someone who can look at your home as a complete system and not just one part at a time, such as just the roof only.

My advice would be to ask the potential roofing contractor some questions to see how much they know. Do they know the 1/300 ventilation ratio in the building code? Do they know the difference between the intake ventilation at the soffits and the exhaust at the ridge?

Most roofers will automatically put a couple of vents up at the ridge or suggest some other from of exhaust ventilation but not many roofers will ever consider the intake. Without a balanced system it will not work properly and can actually pull moisture into your attic.

If you have an older home that has had additional insulation blown into the attic there is a good chance that the intake ventilation from the soffits is restricted. This can be easily checked for and rectified. Attic ventilation is a complex subject especially when you get into flat roofs and vaulted ceilings but you can be sure that if the estimator doesn’t at least know about the 1/300 ventilation ratio he doesn’t know enough about ventilation to design your system.