| Author |
 Topic  |
|
fivedaily
USA
258 Posts |
 Posted - 02/21/2004 : 11:48:11
|
Would someone please explain what deflection is as it relates to bowing between roof rafters and the age of a residence?
Jennifer |
|
|
Ghostbuster
476 Posts |
Posted - 02/21/2004 : 11:57:25
|
From my experiences, the bowing twixt the rafters is from the decking being too thin to support itself. This is due solely to the cheapness of the contractor in buying the decking. Age of the structure is not a factor other than the time it takes for the decking to sag.
Also, the rafter spacing can be a factor as well as the type of rafter, which can cause bowing of the roof downslope if it is not properly braced. The topic of bowed decking was quite common back in the 1970's on houses with 4/12 and 5/12 pitch roofs with 3/8" decking on 2x4 rafters on 24" centers. One was alot safer on those roofs if you weighed less than 100lbs. |
Edited by - Ghostbuster on 02/21/2004 12:03:18 |
 |
|
|
katadj
USA
315 Posts |
Posted - 02/21/2004 : 12:01:15
|
Deflection is the depression created between roof supports, (rafters or trusses), due to the weight of the products installed above, (roofing materials and substrate), and/or the deterioration of the substrate due to heat/cold conditions.
The use of products such as OSB or Stran board in lieu of plywood or 1"X decking, and sometimes the failure to use "H" clips on the 4x8 roof decking sheets is also an issue. The use of less than the recommended thickness of plywood, (3/8" in lieu of 1/2 or 5/8") can also contribute to this condition.
Age of the product can also create this condition. This old-timer has seen a deflection of almost 2 inches in a 24" span on truss construction.
In losses, there may be issues that will bear on the coverage, such as latent defect, inherent vice, etc.
There also may be some contractor liability issues. Suggest a through investigation be made. Interesting outcomes may be viewed.
|
|
|
|
Johnd
USA
110 Posts |
Posted - 02/21/2004 : 12:56:54
|
Anybody care to comment on the "nailable surface" ruling as it relates to extreme deflection? As Ghost said above, older 2X4 trusses 24" OC with substandard decking over a time frame will deteriorate (deflect) to a degree requiring complete replacement. By the way, you can drive down the street and spot this malady in many older tract home developments.
PS Thanks JIMF, when you get so old you cannot keep track of the proper way to spell tract! |
John Durham
sui cuique fingunt fortunam |
Edited by - Johnd on 02/21/2004 18:38:30 |
|
|
|
okclarryd
USA
106 Posts |
Posted - 02/21/2004 : 15:41:21
|
I really wish you wouldn't refer to my house as an "older track home".
I'm doin' the best I can with what I got. |
LARRY D HARDIN |
|
|
|
JimF
USA
1014 Posts |
Posted - 02/21/2004 : 17:41:49
|
Actually, the correct term is tract (with a "T" not a "k") home, unless of course you live on the wrong side of or in the middle of the tracks!
The term comes from builders or developers building a neighborhood on a tract of land, which is why some are known as tract builders.
PS: JohnD, I suppose if one lived in an abandoned Pullman car on a sidetrack down by the river, they could claim they live in a track home. |
Edited by - JimF on 02/21/2004 22:03:11 |
|
|
|
Johnd
USA
110 Posts |
Posted - 02/21/2004 : 23:51:57
|
| That does not sound very "attractive", I have often let my train of thought lead me to ponder if living in an attractive train car if you were on the wrong side of the track or not. If there were many pullman cars parked on the track would they be considered tract housing on track. I am not trying to make a wisecrack about track, please answer back. |
John Durham
sui cuique fingunt fortunam |
|
|
|
catmanager
USA
102 Posts |
Posted - 02/22/2004 : 08:18:49
|
Although katadj touched on the weight issue, Jennifer,
The additional weight of even 1 extra layer of fiberglass three tabs can wreak havoc on the roof framing below, especially on plywood decking installed on houses built within the last 30 years, almost regardless of thickness.
By the same measure, older homes with 1" decking seem to be able to take much more (no significant deflection in decking) weight without visible signs.
I saw a house in Ft Worth in '95 that had 7 layers of asphalt based roofing (T-Locks, 3 tabs, 30 years & ROLLED!) The exposed soffits showed the rafters has moved out 1 1/2".....and showed deflection in the middle of a relatively short rafter span of around 8".
|
|
|
|
Roof_Dr_Sr
USA
27 Posts |
Posted - 03/10/2004 : 05:52:56
|
Jennifer,
As a roofing contractor, I see this problem everyday. Most homeowners understand when I tell them it will be the same when we finish as it is right now,unless they wish to replace the decking. Poor ventilation in my opinion will cause more damage to the rafters and decking than 1 extra layer of three tab shingles. In almost every case where this problem exist, there is poor ventilation. Of course when the decking was installed, clips would have also added extra support to the system. 99% of the insurance companies do not do anything about this problem because of hail or wind damage. They consider this maintenance. |
Roof Dr.Sr. |
|
|
|
richc222
USA
8 Posts |
Posted - 03/25/2004 : 21:54:42
|
| Poor to none attic ventilation traps humidity in the attic. Plywood will delaminate, rafters will bow due to moisture absorption. Many wood shingle roofs on older homes were redecked without ventilation as wood shingles were installed over lath and ventilation was deemed unnecessary. In many older homes insulation is non existent, with the roof being relied upon to "insulate". Inadequate ventilation also has resulted in fumes from a attic fire being forced down into the dwelling asphyxiating the occupants. Excuse the long note, I have seen premature roof failure/attic/decking damage for years from the lack of ventilation. |
Edited by - richc222 on 03/26/2004 08:04:06 |
|
|
|
alanporco
USA
112 Posts |
Posted - 03/25/2004 : 22:41:37
|
| Roof Dr. Sr. Sir, your post of 3/10/04 seems to imply that you feel insurance companies should pay to correct the roof decking problem of deflection when there has been hail or wind damage to the shakes or comp material. Why would this the responsibility of the carrier? The problem stems from poor design, inadequate materials or faulty construction; all of which are excluded. Am I seeing more than there really was? |
|
|
|
DEMIGOD
99 Posts |
Posted - 04/16/2004 : 22:45:55
|
This is a good topic as our company has in the last year inplemented a waiver for deflection and sagging of roof decking. We give the home owner server options that they agree to by signature before any work is started.
{demi} whips out his handy dany Liability waiver.
Lets see, first off the home owner sings that "company name" has informed them of deflection if the condition exist's.
Then at this point they can choose 4 options.
1. Deck over existing decking
2. Remove and replace all problem decking do to rot and or deflection and sags.
3. Remove and replace rotten areas, but DO NOT replace areas of deflection or sagging.
4. Instal new roof over existing decking, as is.
bla bla bla it goes on to cover us depending on the course of action the home owner decideds but in almost every case they home onwer only elects to replace rotten decking or decking unsuitable as a nailable surface.
This is repsonsible business and makes sure we don't get any suprises come time to collect final payment. |
|
|
|
alanporco
USA
112 Posts |
Posted - 04/16/2004 : 23:02:00
|
| Demigod: At least you seem to understand that the problem is not covered by most insurance policies. Don't know about Roof Dr Sr, he hasn't replied to my inquiry. Can only imagine what Brand X thinks? |
|
|
|
DEMIGOD
99 Posts |
Posted - 04/16/2004 : 23:41:46
|
Ha! Oh we also have an attic ventilation waiver of liability and a mold / ice damm liability waiver. If the home does not have proper ventilation it's our reasonable and responsible obligation to inform the home owner and also inform them that they will not be eligable for a manufacturers warranty if they do not pay for how ever much additional ventilation is needed. If they elect not to pay the extra they sign over thier first born releasing us of ANY recourse if the shingles fail and it's determined the failer is a result if not having proper ventilation on the roof.
The other waivers are there to just remind the home owner that just becuase we are replacing thier roof were not allways at fault for every thing that might go wrong in the future. It's thier responsibility to monitor their home for mold and keep thier roof clean and free of ice build up in the winter bla bla bla. But as thing have it they must sign so they have no chance to come back and say something to use about it in court. haha |
|
|
|
kmil579
6 Posts |
Posted - 04/19/2004 : 10:48:42
|
| Demigod, No offense but it seems to me that your company is trying to force the homeowner to add additional ventilation by tricking or scaring them by saying they will not have a warranty and making them sign a waiver. To the untrained homeowner(which most are) if you tell them thier warranty will be void then they will want to do anything to keep it valid. This opens the door to ethical questions as they are taking your word for it and I am sure that the vetilation your company suggests is very costly to the homeowner. I know the decking is. It sounds to me that your companies business pratices leave much to be desired. Do you have a leak after the first rain waiver? Or a when we are gone waiver? |
Edited by - kmil579 on 04/19/2004 10:49:55 |
|
|
|
DEMIGOD
99 Posts |
Posted - 04/19/2004 : 11:55:24
|
kmil579,
Ok, lets get off your high horse, mr. self righteous roofer dude. If you know anything about roofing you'd konw that if a roof does not have the proper amount of attic ventilation that it can cuase problems for a home owner down the road if they file a defective shingle claim against. The manufacturer comes out and says, oh you don't have the recommended amount of ventilation on your roof, warranty claim denied! Guess that happens next mr roofer dude. You get a letter from the home owners layer becuase they want to sue you for not informing them that they should have additional ventilation. Which any responsible and responsible roofer would do at the time of evaluating the home owners roofing needs and then offering solutions. Of course the home owner has every right to reject the solutions provided but at the same time they release us from any recourse should problems arise later.
You know nothing about me or the company I work for so I would suggest you keep your comments directly related to the context within the post's instead of making direct attacks and assumptions about things.
Don't think that calling into question my companies business practices will make you look better in the eyes of all the adjusters who post here becuase every one here is smart and I'm sure they see throught right through it, I know I do. |
|
|
|
Topic |
|
Deflection
Forum Locked
