DIYbanter - View Single Post

wrote:
...

So, I am told it is a bad thing to install a gable vent when you have
a ridge vent.

True, it can short circuit the air flow. However I don't generally
consider it a real problem, but also I don't consider them a real advantage.

Some suggestions I have had:
1) One contractor suggested stapling heavy aluminum foil across the
rafters to within 18" of the soffits and ridge to create a channel for
the rising air.

No channel needed unless something is blocking the ridge vents.

2) Install a solar powered roof fan near the center of the ridge (down
12-18")

Not likely to do any harm, but also not likely to move anywhere close to
enough air to make any real difference.

Is there any way to measure the draft (maybe smoke, etc)? Has anyone
had this problems?

You do want to make sure the soffit vents are clear, not just from
above. Make sure insulation is not blocking them and make sure spider webs
etc are not blocking them from below. Also remember that most soffit vents
are not all free flow. A 4X10 vent has 40 sq inches of exposure, but with
screen lovers etc may only have 20 sq inches of free opening.

Finally I don't find that 40º difference all that high. Attics are
going to get hot and unless you use some really powerful fans they are going
to get really hot on a hot day. Just think of what it would be like without
vents. Also remember that the hotter the temperature difference is the
better passive (gravity) venting works.

Any comments?
thanks, Jack

--
Joseph Meehan

Dia duit