We have a tri-level home in southeastern Michigan. It currently has two turbines and two gable vents. The house is 1500 sq. feet, with approximately 500 sq. ft of that being lower level (like a half-basment, so the upper level is on top of it). The gable vents and the turbines are only on the roof portion of the upper level. The middle level roof area has a small vent that lies close to the roof. We have soffit ventilation as well, but I don't know to what extent.

We are having our roof re-done, and got several estimates. Most roofers told us they would replace the turbines with ridge vents. One roofer told us that under no circumstances should we get ridge vents, and that since we had gable vents, ridge vents would pull snow into our attic. He told us about a job he had recently done where there were several inches of snow in the attic because they had both ridge vents and gable vents. He told us the turbine/gable venting system we currently had was best. We also have an attic fan, which is installed in our ceiling in the upper level. We only use it in warm weather, of course. The roofer we chose is still insisting on ridge vents and says that the story about snow in the attic is nonsense.

Any suggestions as to whom we should believe?

Thanks,
Trista

 

This is a very common problem, Having both gable vents and roof vents. The gable vent design has been improved upon in modern times and should be used only as decoration. When you have both gable vents and roof vents you are causing a short circuit of ventilation in your attic. The gable vents should be blocked off from the inside with poly or plywood and ridge vents installed. Make sure you have soffit vents installed that will balance your ventilation system. Ridge vents have 18 sq. inches of ventilation per foot and your soffit ents should have a 50/50 balance. You will need to run a ventilation calculation on your attic area to find how much you will need in the other areas of your home any roofer worth his salt will do this also for you. This web site you are in has a good ventilation calculator. A great product to use for your ridge vent is Airvent II by Certainteed because of the baffle system on the exterior of the ridge vent. We feel that ridge vents are a superior product to use on your home. The turbine / gable vents on your home now is the poorest ventilation combination you could have.