hail damage or manuf defect?

[Brian A. MacNeish]

Originally Posted by dvalley

I don't have case studies, this is my actual experience with inspecting thousands of Massachusetts & New Hampshire roofs with venting issues.

I've seen many roofs under 10 years old (with improper venting) that need to be re-roofed immediately. Simply climbing into thousands of hot 140+ degree attics in the summer months can tell you a lot about attic ventilation. Simply put excessive heat to tar and see what happens....It melts.

Read this study done for the NRCA:

http://www.professionalroofing.net/a...2/feature2.asp

[Brian A. MacNeish]

More on roof venting from Fine Homebuilding:
http://www.greenbuildingadvisor.com/...and-insulation

Martin Halladay used to be the the editor of "Energy Design Update", a pricey periodical (US $385/year) that keeps you ahead of the curve. It is not as good technically as it used to be when it cost me $550 Canadian.....remember when: $.70US = $1CDN.

A few years back, Martin, myself and a few others had a fight on against the P2000 insulation company in a huge scam in which the company should have been prosecuted for fraudulent claims......1" of regular expanded foam insulation with foil on one side was claimed to be R27!!!!!!!!!!!!!!!! Wisconsin, by law, limited their claims to R5....I'd like to shake someone's hand there.

[ROBERT V. YOUNG]

Mr.Russell
Thank you for your reply Mr.Russell and I do know you had no intent upon being harsh or judgemental.
I see you share you knowadge freely and open and was trying to matbe aid david in his findings.
You possess the wording and skill to addres the subject at had with documentation and thats a plus.
Please excause my spelling.

[Brian A. MacNeish]

Originally Posted by dvalley

Brian,

The venting requirements have changed over the years due to today's tighter homes.

The venting requirements have changed over the years because shingle manufacturers did not have properly trained building scientists on staff. They are trying to deal with 2 problems, attic moisture and premature shingle failure with claims that attic venting takes care of both of these problems.

The moisture seen in the attics in colder weather was moving upwards from the home due to heated air leakage. Instead of really studying the problem, they simply shot first (in their minds venting was needed) and asked questions later (hey, now we know if we airseal the attic and have good interior exhaust fan ventilation/moisture control for the house interior, the attic moisture problems are seriously reduced or go away with adding attic ventilation.

I consulted on the 4th house in my career this past summer where adding attic ventilation actually caused more problems:
SCENARIO: Small 100-125+ year old, 1+1/2 storey home with outer attics; a single older women occupant
-house was retrofitted for energy conservation in summer 2008
-winter 2008-9, a bit of water dripping/running from upper ceilings
-summer 2009, lady consulted with roofer and municipal building inspector....both recommended more attic venting (without checking for moisture sources in the house....how much moisture can a retired single older lady produce?)
-winter 2009-10, moisture problem is worst and house is colder (even though it is a milder than average winter here (I was working outdoors with a short sleeved T-shirt in March)
-Summer 2010, I recommended drying up the unfinished stone basement moisture problems (this area was a huge 24 hour humidifier with an infinite source of water called the earth's water table). I visited her house once later during the most humid part of the summer....she had her dehumidifier turned off and was commenting on how dry the basement now was.....in previous years the dehumidifier ran fulltime.
I also recommended better upper level airsealing and closing down the attic venting and changing the insulation placement in the outer attics so that they were now heated areas that did not need to be vented.


The older homes were not insulated to today's standards which made the older homes self ventilated due to missing or inadequate insulation.
How does insulation stop the natural ventilation of older homes? Fiberglass for example is used as filter material for air moving systems...how much air does it stop?

Air would flow right through the walls and ceilings and the attic would not heat up as much due to the looseness of the house.

Today's homes are insulated to an R-39 (in my area) which makes the attic cavity tight and very hot in the summer months, which in turn causes the attic cavity to become an oven, which in turn can melt asphalt shingles and cause them to blister.
Don't think so!! So guys in Arizona have claimed 180-190*F attic temps in their area. All roofs are not tile there.

As homes became tighter, shingle manufacturer's have revised their installation requirements.

As shingle manufacturers catch up and truly understand the physical phenomena they are seeing, they're realizing some of their past understanding of the facts was off base.

[Peter C. Russell]

Brian, good info. in all your post's. I think the problem is shingle MFG. have hammered home the statement..... No ventilation no warranty and most people today still believe it. It's to bad because as a contractor I started reading studies as far back as the mid 90s and through all my continuing education have found there is a ton of info. about the subject.

Earlier this year I was hired as an expert witness in a 250K remodeling job and testified in court about not only the poor construction but problems associated with the HVAC system in the attic and outside the thermal boundary.

By using my blower door, thermal imaging, and several article's as my evidence I was able to prove that not only the HVAC system was the main culprit but the ventilation should be completely eliminated, the insulation removed from the floor and spray foam (closed cell) be added to the roof deck. This would bring the HVAC system within thermal boundary and eliminate much of the heat loss.

As you can imagine, the expert witness for the contractor tried to discredit me and one of his claims was that if my recommendations where followed the shingle MFG. would not warranty the shingle's. Unfortunately for him I had done my homework prior. I identified the shingle MFG., contacted the New England REP., who I have worked with before, and obtained the proper warranty documentation that clearly states that they will warranty a non vented roof for a period of ten years. Guess who won?

The point of all this is to stay informed, listen to other people's idea's or knowledge and do the best professional job we can no matter who are clients are. As a contractor I know the rules on building materials and codes change so quickly it's hard to keep up. As a home inspector this is even more difficult. Fortunately there is plenty of information and case studies out there.

[ROBERT V. YOUNG]

Yes Brian I have fought with rep,s and they always came at the job-site closed minded.
That was many years ago.refreshing to see there is change.
They were versed in theory and not one of them had any pratical experance nor did they hire any retired roofer to help turn theroy in pratical use and understanding.
They where book trained.

[Kenton H. Shepard, CMI]

Originally Posted by prussell

Brian, good info. in all your post's. I think the problem is shingle MFG. have hammered home the statement..... No ventilation no warranty and most people today still believe it.

As you can imagine, the expert witness for the contractor tried to discredit me and one of his claims was that if my recommendations where followed the shingle MFG. would not warranty the shingle's. Unfortunately for him I had done my homework prior. I identified the shingle MFG., contacted the New England REP., who I have worked with before, and obtained the proper warranty documentation that clearly states that they will warranty a non vented roof for a period of ten years. Guess who won?

Peter, the manufacturers I've talked to required a ventilation space on the under side of the roof deck for the manufacturer's warranty to remain valid. Can you post a link showing to a site showing that that's not true?