The Attic

Attic Ventilation: Signs of inadequate ventilation are rusting nails, wet or rotted roof sheathing, and excessive heat buildup. Adequate attic ventilation can be measured by calculating the ratio of the free area of all vents to the floor area. The free area of vents is defined as their clear, open area. If a vent has an insect screen, its free area is reduced by half. The free vent area-to-floor area ratio should be 1 to 150. If the calculated ratio is less, consider adding ventilation, especially if you’re in a hot and humid climate.

​If the attic also contains an occupied space, check that the ventilation from the unconditioned, unoccupied areas at the eaves is continuous to the gable or ridge vents. Also check that the free area of eave vents is approximately equal to the free area of ridge or gable vents. If ventilation appears to be inadequate and additional vents cannot be added economically, consider adding mechanical ventilation.

Plumbing Stacks and Exhaust Ducts: All plumbing stacks should continue through the roof and should not terminate in the attic. The stack pipes should not be loose, broken or damaged.

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