Ventilation required?

[Larry D. Kage]

Originally Posted by mboyett

Now, there's an interesting angle. Owens-Corning literature states "Regardless of the deck used, the roofing installer must ensure that the attic ventilation meets or exceeds FHA Minimum Property Standards." Now, if I knew what that standard stated...

http://www.hud.gov/offices/adm/hudcl...9101c4HSGH.pdf

403 VENTILATION

403-1 CRAWL AND ATTIC SPACE

403-1.2 Attic Space

a. Cross ventilation shall be provided for each
separate space. Ventilation openings shall be
protected against the entrance of rain and
snow.
b. The ratio of the total net free ventilation
area to the area of ceiling shall be not less
than 1/150, except that the ratio may be 1/300
if:
(1) A vapor retarder having a transmission
rate not exceeding one perm is installed
on the warm side of the ceiling;
(2) Between 25 and 50 percent of the required
ventilating area is provided by vents
located in the eaves or cornices with the
balance of the required ventilation
provided by ventilators located at least
3'-0" above the vents in the eaves or
cornices; or
(3) The attic space is accessible and
suitable for future habitable rooms or
walled-off storage spaces have at least
50% of the required ventilating area
located in the upper part of the
ventilated spaces as near the high point
of the roof as practicable and above the

probable level of any future ceiling.


Other info:

http://www.hud.gov/offices/adm/hudcl...49101c4HSGH.pd

http://portal.hud.gov/portal/page?_p..._schema=PORTAL

[Kenton H. Shepard, CMI]

Originally Posted by jhaynes

From a practical standpoint it should be vented......if for no other reason because of the heat that builds up from underneath which in turn will diminish the service life of the shingles.

Amazes me why a builder would spend an extra $600.00 on architectural shingles yet save $40.00 by not adding ridge vent over the garage......what a moron.

What alarms me is where the right slope of the garage roof dumps into vertical wall over the foyer.................amazes me why architects design homes to fail...

"Where defective design work contributes more than 50% of the roofing failures, defective workmanship accounts for about 30% of the total roofing failures. Most of these errors by contractors are due to ignorence about the consequences of their actions and absence or poor supervision."

Carl G. Cash in Roofing Failures

This is good book but hard to find. Cash was a very knowledgeable roof consultant and worked closely with experts in many areas of roofing. He was involved in developing ASTM protocols for testing roofing materials.