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Design Life of Homes??

donk

Cyburbian
Messages
6,961
Points
31
I hope it didnt affect the end product.

Room is only out of square an 1/8 of an inch over 25 feet.

That is probably a days worth of beer bottles, you don't see the rye bottles on the floor.
 

Cityscape Dreamer

Cyburbian
Messages
31
Points
2
Mike D. said:


Ialot of departments won't even send their guys into houses that are built of trusses.

There is a township in a suburban county here that has banned the use of trusses all together in construction

What they don't show is how rapid fire spreads in the void spaces which result from trusses in roofs, between floors, etc.


As a builder I was unaware of this aspect. Thanks for the info!

Trusses are generally constructed of 2x4 materials, or 2x6, or whatever is the "lightest" to do the job structurally. In the "old" days(pre-truss, which could be as late as the 80's)), when the carpenters had to frame the roof themselves, they would use huge pieces as rafters, 2x8's or 10's. And we all know, the thicker the piece of wood, the longer it would take to catch and burn. Another factor that I think was not mentioned is that now, the pine lumber is grown quickly on farms, and it has been shown that the lumber being harvested now, is structurally weaker than the old-growth that was harvested from the forests in decades past. A pine 2x4 today is weaker and more flexible than a piece of pine of the same dimentions harvested at the turn of the century. They think it is due to the fact that they are just grown too quickly.

I think the design life of a home is pretty much over after a fire, whether it had truss construction or not.
 

Jeff

Cyburbian
Messages
4,159
Points
27
CarloMarx ....

I was just talking to the owner of the business about the steel beam and steel truss idea. Using steel studs or steel trusses doesn't add to the combustibility (?) of a house, but under fire conditions I sure as hell wouldn't go up on a roof I knew was built on a steel skeleton. They use thin galvanized steel, which I can just see getting hot and twisting, and there goes your structural stability.

Alot of Mcdonalds and strip malls use stell trusses. These breed their own problems in that their load bearing weight is so much greater than wooden trusses. Therefore, there's more crap on the roof when it comes tumbling down, such as a/c units vents, etc.

Chet....
Very few modern FD's that I have familiarity with will even attempt to get onto a residential roof these days. Old logic was climb on, saw through, and hose the crap out of it. New logic is get folks out and fight from a safe distance. More over, save it from spreading to the neighbors and save this one's foundation. If the ladder reaches enough that you can saw while on the ladder, maybe try it. Otherwise, thats what insurance is for

Vent, enter, search....in that order. You gotta cut the hole in the roof to let the fire breath before you enter the house. Thats the way its done. (In truss construction though the fire usually "self vents" prior to FD arrival anyway though.

Cutting the hole isn't the problem, that can be done from the relative safety of an aerial device. The problem is with roof collapse. If you ever have the opportunity to see a house of truss construction burn, watch how quick the roof sags, and then "self vents."
 

Chet

Cyburbian Emeritus
Messages
10,589
Points
34
Mike - You pretty much confirmed what I so poorly tried to convey.

Our dedicated volunteers always save the basement. :)
 
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