Lack of Ventilation Warps Deck Sheathing - Contractor Talk - Professional Construction and Remodeling Forum

**Ed the Roofer** · 08-03-2007, 09:23 PM

I have read some studies, especially by William Rose, which suggest that Zero Ventilation would be better than the heavily promoted 1/300 or 1/150 ventilation guidelines specified by the shingle manufacturers.

This home had ZERO ventilation, either intake or exhaust, (at least until we got done providing the solution), and the shingles were completely baked out and brittle as if they were 25-30 years old, even though the HO's best guess was around 12 years old at the time we intervened.

What factual technology documents do any of you have to prove that ventilation really is a neccessity and not a made up method for shingle manufacturers to rel;ease themselves from warranty liability.

Rose states that shingle color has much more to do with roof temperatures rather than the attic ventilation and concludes that the ventilation is of no merit.

By the way, we qwound up using the Smart Vent from DCI Products both as an intake vent and as an exhaust vent on this home. It was a minimal slope combination of different angled shed style box roofs attached to each other and had no actual ridges to vent.

I tried to upload some better more convincing photos showing the buckled decking, but the sizes were too large. How do I go about re-sizing them and submitting the better photos later on?

Ed

AaronB. · 08-04-2007, 09:26 AM

The presence of mold speaks for itself...vent the deck and reduce, if not eliminate this.

The first picture shows caved in decking, which I find to be from lack of spacing between the plywood, causing them to bind when they swell. Step on this spot, and it will be permanent, as you have found.

How are things, Ed?

**Ed the Roofer** · 08-04-2007, 10:28 AM

Much healthier Aaron.

Thank you for asking.

Finally, this week I am feeling like I am getting my energy back and do not feel like I am ready to pass out just from standing up.

How do I go about resizing photos to fit into this forums attachments. My digital camera takes the pictures in too high of a resolution and I need to reduce the size, but not make them microscopic?

Ed

MJW · 08-04-2007, 10:38 AM

Use paint to reduce the size. Open with paint, click on image and then resize/skew. If it's a 5meg or bigger camera, reduce to about 30% and it should be fine.

You're right it's a ventilation problem. If anyone can't see that they should be in a different business.

I&W shield will do the same thing as we have seen before. It just bakes the shingles when it is on the southern facing roofs or roofs with alot of wide open sun.

**Ed the Roofer** · 08-04-2007, 10:54 AM

Thanks MJW. I will try it if I can find it. Duh, I really don't know alot about computers and how to do more than the basics.

Aaron, also if I remember correctly, that job had 16" O.C. rafters, so clips should not have been required for such a minimal span.

Ed

AaronB. · 08-04-2007, 04:33 PM

I still have always attributed that to lack of space between the sheets of decking.

**Ed the Roofer** · 08-04-2007, 04:56 PM

Lack of space possibly.

Swelling would be the only reason to cause the deformations though.

Swelling is caused by moisture, ie; humidity not ventilated out.

The bottom line is that the lack of ventilation has caused the problems.

Right?

Ed

AaronB. · 08-04-2007, 06:56 PM

Surely. Proper spacing would have eliminated the binding, though, in most situations.

MJW · 08-05-2007, 07:33 PM

IMO, you are both right, but if there was not a moisture problem then the buckling would not have happened. That is the point, right?....

tinner666 · 08-05-2007, 08:22 PM

Picasa2 for pictures. Even better is a FD camera. Sony has/had a great one for web pictures. High megapixel is good for prints, but not web content, unless you like editing all your pics.

**Ed the Roofer** · 08-06-2007, 09:37 AM

What is an FD camera?

Ed