Why Roof Warranty Problems Start in the Attic

I have been tearing off roofs since 1986, and I can tell you that winter exposes and exacerbates any weakness your system might have. Over the years, most of the issues I have faced as a contractor come down to two things. Moisture and heat.

The shingle almost never fails first. The attic does. And when it does, the customer blames the roof, the manufacturer blames the install, and nobody names what actually went wrong. So let's name it. Your attic space is an essential part of your roofing system, and modern homes have made ventilating it harder than it used to be.

Modern homes do not breathe like they used to

Not that many years ago, homes were much more porous. Now, as houses have become more energy efficient, they have also become more sealed off. Every year we work on tighter envelopes, better insulation, foam here, tape there. That is a win for utility bills and a real problem for the space above the ceiling.

Your modern home is designed to breathe through one system. Fresh air in at the eaves, bad air out at the top of the roof. In the summer that means hot air out. In the winter that means moist air out.

The problem is the winter. Without a strong temperature difference to drive convection, the system stalls. Hot air from the living space hits the cold roof decking and condenses just like a can of pop. I have literally seen water dripping from the interior boards in winter conditions, and most of the warranty issues I have dealt with over the years trace back to it. Condensation drips onto insulation, insulation loses its R-value, moisture travels through to become interior stains, then mold. Non-vented moist air also leads to wood rot, warped decking, and expensive change orders on the next tear off.

The homeowner never sees any of it. You do. Six years later, when you are pulling the shingles off.

Where the CFM race went wrong

Solar attic ventilation was a great idea. Free power from the sun to help move air out of the attic, working with the roof's design instead of adding another electrical run. Manufacturers seized on it immediately. Then they got in a horsepower race. Bigger panels, bigger fans, louder marketing. Most of them tried to squeeze the highest horse power out of a solar panel to power the largest fan possible.

Large solar fans do not take into consideration roof design. Roofs are designed to passively pull air in from the intake vents at the eaves and exhaust it uniformly from the highest point, either through multiple can-type vents or a ridge. The keywords are uniform and multiple.

Drop one high volume fan on top of that system and you break it. Large, high-CFM solar fans have to get their air from somewhere, and due to their power, they rob it from the nearest ridge vent or can-type vent instead of pulling from the eaves. That defeats the uniform air movement concept the roof was designed around. You get hot spots in every part of the attic the big fan cannot reach, and in the winter you get moisture pockets exactly where the fan is not touching. Hot spots and moisture pockets, over and over.

Even if you only needed one super-duper high-CFM fan to cycle the attic air, what happens on a cloudy day? Can you tell me your large solar attic fan works on cloudy days? I didn't think so. On cloudy days that whole roof reverts to a passive system that the big fan already sabotaged.

Uniformity and balance beat volume every time

The only proper way to work within the design of a modern roof is to scrub and move air in a uniform manner across the entire attic. That is not a marketing line, that is code, that is manufacturer spec, that is convection. So the fix is not to fight the design. The fix is to enhance it.

The future of solar attic ventilation, and the reason we built Solar Blaster in the first place, is multiple smaller fans placed uniformly along the roof instead of one big one planted in a single spot.

The physics is the whole reason it works. A small fan is not powerful enough to rob from the surrounding vents, but it is strong enough to solar activate the passive vents to exhaust the air already searching for a high point. It does not overpower the passive system. It wakes it up. And that is the difference between a fan that fights the roof and a fan that helps it.

What that looks like on the jobsite

The patented Solar RidgeBlaster was the first true solar powered ridge vent in the country. It drops into the ridge cut you are already making, and it uses a 10-watt panel to power three small fans. As soon as the panel captures enough energy, the first fan runs, even on most cloudy days. On full sun, all three run. Passive vents work like they are supposed to under thick cloud conditions, and when the sun comes out, the air starts moving through the system you already installed.

The same principle runs across our entire product line. Shipping container vents that mount on a single raised rib. Shed vents. Warehouse vents. Solar assisted tubular skylights. Same principle every time. Small, distributed, uniform.

Solar Blaster products were designed by a roofer for roofers. Everything installs from the rooftop. There is no attic access, no rerouting, no adding a new visible fan on the front slope of somebody's house. It works in conjunction with what you are already installing, and it conforms to local and national code because it is not replacing the passive system, it is boosting it.

Why this matters for us

Warranty issues are problems for both the contractor and the homeowner. Our job is to hand a customer a roof that lasts its promised life expectancy with zero problems, and a warranty problem is a stressed out homeowner and a trip back out to the house we would rather not make.

A properly vented attic protects everything the roofer just built. It protects the decking from condensation. It protects the insulation from losing its R-value, since a percent and a half of moisture in insulation cuts the effective R-value by 33%. It protects the framing from rot and the interior from stains and mold. It protects the promise we made when we handed the customer the warranty card.

Proper venting is cheap insurance. Small, uniform, balanced, solar assisted ventilation is the right way, and it is the future of roof ventilation.

Move the air. Protect the roof.

References

Roofing Contractor, "Solar-Powered Ridge Attic Fan," March 28, 2012