Is inadequate roof or attic ventilation a defect?

[Brian A. MacNeish]

Originally Posted by fbartlo

I did another inspection yesterday in which there was buckled sheathing where there was insulation right up to the sheathing.

By buckled, do you mean delaminated veneer layers (or is it chipboard)?

Could be caused by moisture or poor quality material. Is there any water staining or mould on the innermost layer of veneer?

In 1992, I saw delaminated plywood in the attic of a $500,000 (probably $1,000,000 now) home in its first winter. I was hired by the owner's lawyer to check the attic framing and sheathing for the "moisture" that the supplier was asserting caused the failure. All attic wood was under 19% humodity. On further inspection of the plywood stamps, it was discovered that the plywood was from the deep south and made from yellow pine, if I remember correctly. It was not even supposed to be in Canada as it did not meet the requirements of the plywood standard recognized by our code.

This roof had a double failure as the trusses were also underdesigned. I had noticed some rippling in the shingles that may or may not have been caused by the plywood. A civil engineer was hired and called the trusses. In the summer ,the whole roof was replaced at a cost of $80,000!

[Ed Fako]

I tried to upload some photos of several jobs we havwe done, but I can not get the hang of how to do it.

On one forum I created for my family to communicate, I only get these monstrosity sized photos which need to be scrolled up and down and also left and right.

I am not too techie on thjis stuff. Any help? I would like to share the photo views with you guys.



The plywood I wanted to show photos of was so severely buckled, from a total lack of ventilation, both intake and exhaust. There were none of either.

The insulation was not packed solidly to the top of the rafter bays. (Vaulted/cathedral style ceilings throughout)

There was no roof leakage in the home but the 12 or so year old shingle were completely delapitated and the decking all needed to be replaced. There was black mold growing on the under side of the decking when we removed it.

A lack of ventilation was the only causation of this premature degradation, IMO.

Ed

[Roy D. Cooke, Sr]

Originally Posted by Ed Fako

I tried to upload some photos of several jobs we havwe done, but I can not get the hang of how to do it.

On one forum I created for my family to communicate, I only get these monstrosity sized photos which need to be scrolled up and down and also left and right.

I am not too techie on thjis stuff. Any help? I would like to share the photo views with you guys.



The plywood I wanted to show photos of was so severely buckled, from a total lack of ventilation, both intake and exhaust. There were none of either.

The insulation was not packed solidly to the top of the rafter bays. (Vaulted/cathedral style ceilings throughout)

There was no roof leakage in the home but the 12 or so year old shingle were completely delapitated and the decking all needed to be replaced. There was black mold growing on the under side of the decking when we removed it.

A lack of ventilation was the only causation of this premature degradation, IMO.

Ed

Sorry It sounds like moisture getting into attic to me ,
Ventilation can make up for some excess moisture but no moisture and ventilation not needed .
This has been the way in Europe for a while and its comming to North America.
....... Cookie

[Jack L. Gilleland]

If there is black MOLD. There is moisture.
No ventilation is a defect due to manuf. requirements. If home owner wants to use the warranty on materials the OEM can claim improper installation of roofing without ventilation.

[David P. Valley]

Originally Posted by Ed Fako

I tried to upload some photos of several jobs we havwe done, but I can not get the hang of how to do it.

On one forum I created for my family to communicate, I only get these monstrosity sized photos which need to be scrolled up and down and also left and right.

I am not too techie on thjis stuff. Any help? I would like to share the photo views with you guys.

Ed

Go here

[Brian A. MacNeish]

Originally Posted by Ed Fako

The plywood I wanted to show photos of was so severely buckled, from a total lack of ventilation, both intake and exhaust. There were none of either.

The insulation was not packed solidly to the top of the rafter bays. (Vaulted/cathedral style ceilings throughout)

There was no roof leakage in the home but the 12 or so year old shingle were completely delapitated and the decking all needed to be replaced.

Either these shingles were part of a bad batch/style, like the "Shangles" by Certainteed or others by IKO (I believe) we've seen earlier and I've seen in my area or........there was so much moisture from the house ending up in these cavities due to air leakage that if you added venting, the moisture problem may get worse. What??????

This was mentioned in the paper from Canada Mortgage and Housing Corp. (CMHC) that I referred people to earlier. I have personally worked/ consulted on 4-5 of these. Here's how it works: You have a home that has inherently high moisture levels from a number of sources that may include: damp basement, basement leakage, high numbers of plants, aquariums/terrariums, no kitchen or bath fans, dryer vents indoors, clothes are hung to dry indoors, hobbies/crafts (pottery, paper mache, etc), wet firewood stored indoors, high #'s of occupants.

With a tight, unvented roof/attic and a "loose" ceiling, air (carrying the house moisture) is leaking upward (by buoyancy in fall, winter, spring.....called "stack" or "chimney" effect) through any of a number of paths that incude wiring (drilled holes, octagon and switch/receptacle boxes) and plumbing penetrations (square holes, round pipe), firecode gaps around chimneys, loose attic hatches, dropped ceilings in closets, house junctions (especially homes with split levels), shrinkage gaps behind drywall/wall top plates, unsealed vapour barriers, and on and on. The tight roof and relatively tight eaves and any exterior walls above the insulated ceiling actually act as a dam and stop most of the air in the attic from escaping. I say "most" because if air is leaking upward from the house, some air is leaving the attic also.

This moisture laden air from the house causes problems such as mould/plywood delamination/rot over a period of time. Some will notice this before a major catastophe occurs and add ventilation. If the moisture was a marginal case, the ventilation may help (as mentioned in the CMHC paper). If you have a "wet" house, the moisture problem gets worse since the attic was quite "tight" and restricting upward air movement.......with vents added, you now have cut holes into it, allowing the air that was there out, allowing more moist air from the house to move upward, bringing more mopisture to the attic. Problem is now worse!!! And energy loss increases. My analogy is: you have water in the bottom of your boat, so let's drill a hole to let it out!!

I'm not against venting but it's being touted as the solution to many problems:


1) attic moisture- better solution- dry the house by cleaning up inherent moisture problems, vent bathrooms/kitchens and other rooms as necessary to the outdoors (not into the vented soffits-that's not outdoors), seal the air leaks (this also saves energy.....a good thing). In most cases, the attic is OK by now or there is so little condensation that no problems result from it. Usually the existing vents are all that are needed. Maybe a bit of venting need be added if none is installed at all; maybe not as all attics are not airtight (as mentioned above). In many attics if you turn your light off, you can see a fair amount of outdoor light through the eave cracks, etc.- this is also ventilation.

2) reduces air conditioning costs- the Florida Solar Energy Center put that thought to rest with a 114 year payback for savings by increasing attic ventilation; better insulation depth and a light coloured roof does way more to reduce cooling costs.

3) extends roof shingle life- possibly but by so little as not to be really significant- see earlier post

4) saves/extends life of roof sheathing and framing- some have seen darkening caused by moisture and mould and thought it was "charring" caused by high attic temps. There is a thread in the last few days insinuating this. Any pyrolysis/charring would only occur at temps over 300 deg F, which we don't get in attics, vented or not


There was black mold growing on the under side of the decking when we removed it.

A lack of ventilation was the only causation of this premature degradation, IMO.
Or way too much moisture getting to these areas, IMHO.

Ed

anyways- my thoughts, Ed

[Ed Fako]

David,

Thank you for the tutorial, but is there one on how to resize an image that the manage attachments pop up tells me is too large to be uploaded?

On another board with the same size restrictions, (ContractorTalk dot com in the roofing section), I was able to upload the exact same images I tried over here. Go over to that site to check out the images I am referring to. Even on that site, the better photos that I wanted to upload would not go through due to being too large.

Wuz Up w/dat?

Ed

[Jeffrey R. Jonas]

Ed,

Go to: http://www.irfanview.com/ it's free and will let you do damn near anything to photo's

Jeff

[David P. Valley]

Originally Posted by Ed Fako

David,

Thank you for the tutorial, but is there one on how to resize an image that the manage attachments pop up tells me is too large to be uploaded?

On another board with the same size restrictions, (ContractorTalk dot com in the roofing section), I was able to upload the exact same images I tried over here. Go over to that site to check out the images I am referring to. Even on that site, the better photos that I wanted to upload would not go through due to being too large.

Wuz Up w/dat?

Ed

Ed,

There are many FREE image re-sizers on the market today.

Here's a few to get ytou started.

http://www.faststone.org/
http://whispersolutions.com/ImageEditLite.htm
http://www.freeserifsoftware.com/sof...s/inAction.asp
http://www.graphic-converter.net/
http://bluefive.pair.com/pixresizer.htm
http://www.irfanview.com/

[Frank L. Bartlo]

No, Brian, by "buckled" I meant very noticeably warped, so there were obvious hills and valleys on the roof. Bent, put (probably) not broken, if you will. But I couldn't see it in the attic. It obviously had expanded due to heat or moisture, and there was nothing to indicate leakage (relatively new roof with shingles that appeared good), and insulation was crammed right in from the drywall to the sheathing.

[Ed Fako]

Buckled like these?

[Ed Fako]

Same roof, but the bottom view of some of the decking.

[Brian A. MacNeish]

Originally Posted by Ed Fako

Buckled like these?

Ed:

Yes, there was moisture getting up into that attic. Where from? the bathroom fan(s), the kitchen range hood, or ???

Also, were there any "H-clips" used on the edges of the plywood or was it T&G and what thickness?

Got to go!!! Just got a call from a client (9:49 pm here on Sat night.....jeez!!!) on a consulting inspection after a flood in a church basement.

Oh by the way, see this:

http://www.buildingscience.com/docum...r-all-climates

Be on later.

[Brian A. MacNeish]

Originally Posted by fbartlo

No, Brian, by "buckled" I meant very noticeably warped, so there were obvious hills and valleys on the roof. Bent, put (probably) not broken, if you will. But I couldn't see it in the attic. It obviously had expanded due to heat or moisture, and there was nothing to indicate leakage (relatively new roof with shingles that appeared good), and insulation was crammed right in from the drywall to the sheathing.

Looks like you and Ed are seeing the same phenomenon!!

[Frank Magdefrau]

Originally Posted by gliebig

I've been running across many homes during the past several weeks that have ventilation issues. I use the 1 sq foot of free venting for every 300 sq feet of attic space. Usually the vents should be split 1/2 on the high side and 1/2 on the low side.

I was asked why inadequate venting is a "defect" and my response is

1. Inadequate ventilation can significantly reduce the life of the roof due to the excessive heat
2. Inadequate ventilation can lead to moisture build-up in the attic which can reduce the effectiveness of the insulation and/or lead to possible mold/mildew issues

Also, whenever I see a bathroom fan of kitchen fan directly into the attic, I call it out as a significant problem

I'm looking for some feedback on this issue. Is it a defect the seller should take care of or is it a maintenance item the home buyer needs to deal with?

The problem with the bathroom vents around here is that every new home has them venting in the attic. I called all the local code departments in my area and they all said it is OK, so as far as I am concerned it is OK as well. I would suggest you do the same.

Yes, inadequate roof ventilation is a defect and a very big one in the south in my opinion. Add web site links to your report. I use this one allot. http://www.owenscorning.com/around/v...ofandattic.asp