Your Old Roof Probably Doesn’t Have Enough Ventilation

Did you know that the air in your attic is supposed to be the same temperature as the air outside? 

Most roofs don’t have enough ventilation or properly balanced ventilation!

It’s very important for roofing systems to have enough intake ventilation and exhaust ventilation. 

Having enough intake and exhaust ventilation is what allows hot air and moisture to travel up and out of an attic. 

Without proper ventilation attics will be too hot, roofing materials will age faster, and ice dams can develop in cold climates. 

Roof Ventilation Diagram

How To Calculate How Much Ventilation Your Roof Needs – 

Most older roofs don’t have enough ventilation. Many times builders installed a few vents, but never calculated how many were needed. 

Other times intake vents get covered up by attic insulation or other building materials.

The U.S. Housing Authority recommends a minimum of at least 1 square foot of attic ventilation, evenly split between intake and exhaust, for every 300 square feet of attic floor space. 

This can be difficult to calculate without some help. Luckily, there are now roof ventilation calculators like this one from GAF

By entering the square footage of your attic space the ventilation calculator will show you how many intake and exhaust vents you will need on your roof. 

These ventilation calculators are very helpful and they are what Lime Roofing and Solar uses on every job. 

GAF Attic Ventilation Calculator

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