Truss Built Roofs??? (floors, roof, engineered, cost)

[kingfish08]

Hey folks, recently I was in a discussion with an Engineer about Roof Trusses vs. Stick Building. He told me about this video on Youtube. Check it out. Makes me happy to know I live in a Stick Built Home vs. a Roof Truss home..

FYI the following builders build with Truss that I know of

KB HOMES
CENTEX
LENNAR
PULTE
KIMBALL HILL
MAIN STREET
NEWMARK
PLANTATION
CAPITAL PACIFIC HOMES
GEHAN

The following builders build with "Stick Building"

Highland
Wilshire
Streetman Homes
David Weekly
Toll Brothers
Drees
Taylor Woodrow
Morrison


YouTube - Wood Truss test Burn

[car957]

Both methods meet the International Residential Code. I understand the issues with wood trusses as it relates to fire performance - however, I contend that this requires tactics be changed as it relates to interior fire attack.

Depending on "stick building" methods, I can create similar failures (which I have chosen not to define). One must look at the total system when evaluating fire performance.

[Noahma]

I dont care where you go in Colorado, about 90% of all homes built here are using engineered trusses, unless the area of the roof is very complex. I agree with car957, the design of the roof itself is going to determine how quickly one collapses. Just burning a few trusses is not a way to deterimine how a fully trussed roof system will preform.

[kingfish08]

Yeah I don't guys. I looked at the average Truss built Roof and it's built with 2x4's. The average Stick Built home is built with 2x6 and 2x8's. I mean, I'm sure they both meet the "Code" but I wonder why it is that high-end builders and custom builders use Stick Building and Cheap homes like KB use Trusses. Do you think it's just cost concerns then? I don't know, I guess go look at a Stick built home during Framing and then go look at a Truss built home during framing. There's about 25-30% more lumber in a Stick built home. I don't know about you all, but I'm happy my family has that much lumber over our head.

I found a cool book that talks about Trusses and the Casatrophic Failure that occurs when a Truss collapses. In it it talks about how the Empire State Building has been hit by multiple smaller planes in the past, but it was built in an old world form of Construction. It said some cool things. Look I'm sure everyone builds a "good" home these days. But anyways the book is called, [SIZE=3]Why Buildings Fall Down: How Structures Fail. [/SIZE]

[car957]

Success = you get out. No success = you die. I can't state it as a method or manner that is simplier or as stupid. Sorry for my harshness. Residential construction is controlled by a higher party.

[Noahma]

Originally Posted by kingfish08

Yeah I don't guys. I looked at the average Truss built Roof and it's built with 2x4's. The average Stick Built home is built with 2x6 and 2x8's. I mean, I'm sure they both meet the "Code" but I wonder why it is that high-end builders and custom builders use Stick Building and Cheap homes like KB use Trusses. Do you think it's just cost concerns then? I don't know, I guess go look at a Stick built home during Framing and then go look at a Truss built home during framing. There's about 25-30% more lumber in a Stick built home. I don't know about you all, but I'm happy my family has that much lumber over our head.

I found a cool book that talks about Trusses and the Casatrophic Failure that occurs when a Truss collapses. In it it talks about how the Empire State Building has been hit by multiple smaller planes in the past, but it was built in an old world form of Construction. It said some cool things. Look I'm sure everyone builds a "good" home these days. But anyways the book is called, [SIZE=3]Why Buildings Fall Down: How Structures Fail. [/SIZE]

I design Multi million dollar homes for a living, like I said, most of them in Colorado are using engineered trusses. Not all engineered trusses are using
2X4 material, it all depends on the design and the loads they carry. Girder trusses will typically be made using two layers of 2X4 with a 2X6 bottom chord, In a trussed system, the bottom chord of the truss is where the stress, and the loads get moved to the bottom chord. You can not reach the spans you can with an engineered truss by using stick framing. Your typical rafter is not going to be 2X material anymore, more so the builders are moving to use engineered 'I'-joists instead of the 2x. (same items used for floor joists) The reason for using engineered trusses is not in the price of the item, but in the price of the labor. It is far more laborious to use stick framing than to use trusses, more people and more skill are needed. The average rafter'd roof is not using 2X6 or 2X8's anymore, the joists are typically11-7/8" tall and 2X10's are used occationaly as well.

both are good, both meet code, therefore both are used.

[Briolat21]

Uh.. around here Drees uses trusses.
Also Toll.

We're building - the builder (not Drees or Toll) is using Trusses. My husband and I have no problem with them - we understand the builder uses these methods to save money. My brother is an architecht, and pretty much all residential construction (with the exception of custom homes where the owner SPECIFIES no trusses) is trusses nowadays.

The only reason to seriously argue truss vs rafter is that with rafters we would have been able to use our attic space. With trusses - it will always be wasted empty space. We decided for the price point we were in, that was acceptable.

[windtimber]

Originally Posted by Briolat21

The only reason to seriously argue truss vs rafter is that with rafters we would have been able to use our attic space. With trusses - it will always be wasted empty space. We decided for the price point we were in, that was acceptable.

Not necessarily. There are properly engineered truss systems which include open attic spaces. In a previous life [over 30 years ago] I was a salesman/estimator for a truss manufacturer. There were professional engineers on our staff who worked hand in hand with the estimating/sales staff and the manufacturing departments.

I can not speak with authority on fire resistance, but I do recall that in commerical applications we regularly built truss systems to fire resistant specifications which largely depended on appropriate fire rated gypsum, fire blocks, and other factors NOT related to truss design - we had to design and build a system that would carry the spans, roof/floor load AND the fire resistant construction. The materials used in the truss system were not the key to fire resistance - the entire building system has to be considered.

[harborlady]

Windtimber- agreed. Balloon construction also uses solid timbers, but alas, its a death trap in a fire. The video also seemed slanted- the fire for the truss was fixed directly under the ridge, whereas stickbuilt was offset. I think that was the difference in results, along with the whole fireproof design element being absent.
I'm not a builder by trade, and much has been bragged about in favor of trusses by engineers, however, the proof is in the pudding in the field. That's the trouble with drawing boards, they aren't obliged to live in the dynamics of reality.

[Noahma]

Originally Posted by harborlady

Windtimber- agreed. Balloon construction also uses solid timbers, but alas, its a death trap in a fire. The video also seemed slanted- the fire for the truss was fixed directly under the ridge, whereas stickbuilt was offset. I think that was the difference in results, along with the whole fireproof design element being absent.
I'm not a builder by trade, and much has been bragged about in favor of trusses by engineers, however, the proof is in the pudding in the field. That's the trouble with drawing boards, they aren't obliged to live in the dynamics of reality.

balloon framing is down right scary when it comes to fires. Since there is no platorm or floor box dividing the floors, the fire can travel up the side of the walls and between floors unhindered. I did not notice where the fires were place untill you pointed it out.

As someone else said, the fire proofing also comes with the drywall board used during the construction which is missing in the test.