Does Your Home Need Roof Ventilation?

Roof Ventilation

Does Your Home Need Roof Ventilation?


Yes. Your attic is jam-packed with trusses and insulation. The vents are located near the peaks of your roof. Vents only work with good soffits. Both are important.



What do roof vents do?


Proper vents and soffits let your attic breathe. In winter your attic should be freezing and in summer as warm as outside.


Vents and soffits allow air in and air out. Equalizing the temperature in your attic with the outside keeping your home comfortable year-round.


Air gets in through the tiny perforations on the underside of your soffit, circulates in your attic, picking up humidity and excess heat and exits out the vents.  


So what can go wrong?


Not enough vents especially on older homes. About one vent per 450 sf is adequate. Not enough vents causes an air traffic jam trying to get out too few vents and results in attic overheating in summer and icing in winter.


Plugged soffits is a common serious problem. It can happen in brand new homes and older alike. It is the result of poor and incompetent insulation installation.


Styrofoam barriers (soffit dams) should separate the attic insulation from the soffits. No soffit dams = plugged soffits = no ventilation = stagnant air.


Blocked soffits in summer will cause attic overheating and can cause premature shingle failure. Humidity buildup can cause black mold on the trusses and plywood sheathing.


Blocked soffits in winter will cause icing on attic structural members. Your attic will resemble an ice cave in deep winter. When the ice melts in thaw it causes rot in wood structural members and soaks the attic insulation – neither is good.

Fixing Vent Problems


Adding vents: Divide your main floor area by 450 and that gives you the minimum vents you need.


Installing New Vents: Ideally add vents on your next roof replacement and save money. If you have the problems described above you can have new vents installed before your new roof is due.


Unplugging Soffits: Hire a professional. This is not a handyman job. The dust and environment in your attic is a health and safety hazard. Soffits will be cleared and soffit dams installed. Cost – $500 to $1000.

ROOFMAX Calgary Services 403-560-8015
Call us for a Free Estimate or Inspection at 403-560-8015 – We’re here to help

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