Handyman Contractor in Acworth, Kennesaw, Woodstock, Canton, & Marietta
Handyman Contractor in Acworth, Kennesaw, Woodstock, Canton, & Marietta

Roofing Ventilation 101

Roof Ventilation 101

One of the biggest problems shingle manufacturers have;


In fact, when completing a shingle warranty, shingle manufacturers’ want pictures of

your homes intake (soffit-vents, gable-vents, and eaves-vents) and

exhaust (ridge-vents, whirly birds, and roof louvers).

Why should you care about roof ventilation?

Improperly ventilated attics increase the temperature in the summer and the moisture during the winter.


A lot of builders in the south have run AC lines through the attic or through unconditioned spaces (it’s cheaper).

The standard insulation wrap for AC runs doesn’t work well in the summertime if your attic doesn’t breathe right, and the temperature soars.

Most homeowners are going to notice the hot attic.  Most people we talk to think all attics are hot, and that’s just the way it is.

That’s not right, and there is something you can do about it!

Have you ever wondered why nails back out of shingles and cause leaks?  Well now you know the leading cause!

(pic from This Old House)

The correct way to ventilate your roof

The proper balance is an even (50/50) intake to exhaust.  Since getting 50/50 rarely happens the rule is – MORE INTAKE than exhaust.

Most roofing companies are trained on this (if they have had manufacturer training).  But, because it doesn’t relate to the longevity

of their workmanship warranty, they don’t care to explain it or implement a successful ventilation setup.

If you’ve made it this far, you can probably tell we know what we’re talking about, and


And, you’re right.

But, like we tell everyone, don’t just take our word for it!  Do your due diligence!

A very good resource is Lomancos’ ventilation calculator.

A bit of advice though.  These work on minimum building codes.

And, when has the minimum ever been good enough (except for paying taxes)?

When you measure the footprint of your home, go ahead and say its around 400-500+ square feet

more for the calculator.  You’ll circulate / exchange more air and that’s not a bad thing.

Final Thoughts

We recently measured a homeowners attic at 149+/- degrees.  That’s insane!

After installing gutters on his home, this homeowner took our advice and used the Lomanco calculator to fix his intake.

His roof had been replaced by someone else and the exhaust ventilation was changed to ridge-vent.  Which is great ! ! ! if it’s balanced.

Unfortunately, the previous roofer did not know (or care) and it was WAY OFF!

Having already installed a new Lenox 14 seer AC unit to cool the house, which didn’t solve the problem, he figured he’d take our advice.

The homeowner had to add 20 extra soffit vents (for a total of 30) to make up for how much ridge-vent was installed.

He called us 3 weeks after the gutters and told us he completed the work.

End Result

After adding the vents, he said he noticed the difference that day.

His AC unit could finally keep up, and every part of his house was cool.

In fact, he noticed it now only runs half the time it used to!

He said he, his wife, and his wallet thanked us!

If you’d like help because your attic isn’t roughly the same temperature as it is outside year-round . . .

Give us a call!