TwinWillows said:
It sounds like your builder did not install any closure(s) under the cap?
FWIW..Under the ridge cap on our barn I installed alternating 3ft lengths of pieces of foam closure with a vented closure strip (looks like industrial brillo pad like material). Nothing blows in/under the ridge cap w/this stuff.
It looks more and more like the builder's shortcut will be an ongoing problem for the owner. The ridge vent just was not done well, irrespective of any comments about how he may have done a hundred of them that worked, this one doesn't.
If satisfaction cannot be had from the builder redoing it and getting it right and something like turbine vents are selected as a fix, then the ridge vent needs to be permanently sealed. Turbine vents work very well and will draw out a large volume of air when the wind blows and a decent amount through convection when there is solar heating of the roof, even with no wind blowing.
The reason the ridge venting needs to be sealed off with turbines is that the partial vacuum pulled by the turbines will suck in air through all openings, including the ridge vent. Sucking air in through the ridge is NOT A GOOD THING and will ruin the performance of the venting system.
The best performance is when incoming air enters as low in the attic as possible, typically from one of two sources. IF the space below the attic is conditioned then the attic vent air needs to come in around the eves. If the space below the attic is not conditioned and it is desired to get some ventilation through it then ceiling openings will let the hottest (ceiling height) air be pulled up into the attic and exhausted at the turbines. Both air inlet sources will allow the turbines to sweep out the hot air from the attic, assisted by natural convection.
If ventilating the spaces below the attic is desired then provision for airflow from out doors, low in the outer walls is best and will reduce stored (stagnant) air.
Pat