Do I need a header under a truss?

[tomgarage50]

I want to build a 18' (gable end) by 28' garage with an 8' ceiling and a 7' by 16' door. For the gable end door can I use a standard (not gable end) truss and just nail a 2x4 ladder under it for the siding? As far as I know the door adds very little weight to a standard truss. Using an end truss means I have to use at least a double 2 by 12 for a header just to hold up the truss.

 

[Scsmith42]

Several of my barns have standard trusses on the gable ends. The engineers told me that they would work fine. The principle advantage of the special gable end trusses are the vertical members for siding attachment.

 

[buddyboy]

yes I would use a header,

the other gable side of your building will be sheathed and that will 'stiffen' up that side of your garage.

the header on the door side of your garage will 'stiffen' up that door hole.

 

[buddyboy]

i think you don't have to use the gable end truss but it would be harder to sheath it.

the header doesn't hold up the truss your side walls hold them up

 

[LB-1911]

I want to build a 18' (gable end) by 28' garage with an 8' ceiling and a 7' by 16' door. For the gable end door can I use a standard (not gable end) truss and just nail a 2x4 ladder under it for the siding? As far as I know the door adds very little weight to a standard truss. Using an end truss means I have to use at least a double 2 by 12 for a header just to hold up the truss.

You need to talk to the Dane County Bldg Dept -

A 16 foot door on an 18 foot wall?

There will be a Shear-wall requirement and you may find out you'll need more than a foot on either side of the door - meaning a wider bldg or a narrower door.

Dane County Zoning Permit

http://danedocs.countyofdane.com/webdocs/PDF/plandev/zoning/Zoning_Permit_Application_Bundle.pdf

 

[tomgarage50]

Can a double 2x12 span 16'? I can't find a definite answer, but that is what made me think of going the standard truss route in the first place. I think the 7' door would just fit under the 2x12. The slab is already there at 18', so if I had to I would go with a 14' door, not really what I want for two cars.

 

[6768rogues]

The truss is made for a clear span, it needs no support other than the bearing points on the ends as shown in the design.

 

[schor]

I want to build a 18' (gable end) by 28' garage with an 8' ceiling and a 7' by 16' door. For the gable end door can I use a standard (not gable end) truss and just nail a 2x4 ladder under it for the siding? As far as I know the door adds very little weight to a standard truss. Using an end truss means I have to use at least a double 2 by 12 for a header just to hold up the truss.

I have an 18x28 garage and I did a hand cut roof, 2x8 ceiling joists and 2x6 rafters. Gives me lots of storage up there for things like the storage boxes for all the different seasons, christmas, haloween, .... Nothing hugely heavy but a 2x8 at 18' is no problem handling the loads.

I also built a mezzanine about 5' deep at the back of the shop. I used hurricane clips for the rafters where I cut out the joists, the mezz floor is only 3' below the old joists so nothing is going to pull apart. I also build a room below it that I keep heated in the winter for glues, paints, etc. I climb up using a charin (with the box of brava on it) onto a file cabinet, then onto the shoe rack and up ontop of the fridge, makes it easy to stage things to the top of the fridge before moving it up to the mezz.

Wow, that was long winded, here's a pic.

Oh, almost forgot, you NEED a header for the door. Most likely 2x12, its got nothing to do with the truss.

 

[LB-1911]

Can a double 2x12 span 16'? I can't find a definite answer, but that is what made me think of going the standard truss route in the first place. I think the 7' door would just fit under the 2x12. The slab is already there at 18', so if I had to I would go with a 14' door, not really what I want for two cars.

A definite answer would come via Dane County / City of Madison

I would use a 16'9" lvl supported by three jack studs on each end.


You need a permit to build any garage, whether attached to or detached from the house. At any time during the planning or construction of your garage, you can call Building Inspection if you have questions. They are happy to answer your questions and suggest solutions to your problems.
http://www.cityofmadison.com/developmentcenter/residential/garage.cfm

Find out if your proposed detached garage meets the size, placement and driveway requirements.

http://www.cityofmadison.com/dpced/bi/documents/garage.pdf

 

[tomgarage50]

What height and width for the LVL?

 

[rburke65]

I would think any lvl supplier can size that for you.

 

[JCByrd24]

If you use a regular truss than the roof load is going to the side walls not the gable wall, so no you do not need a full structural header to support the roof like you would if the door was on a side wall. You do still need something that will not sag under its own weight and the weight of the wall above. I would not hang the wall from the truss, the truss needs to carry the roof load, but in doing that it greatly reduces the necessary strength of the wall.

What is an issue though is the 16' opening in an 18' wide building. This will need an engineered solution for shear so the building doesn't rack over.

 

[BFBOB]

Make your ceiling height at least 9'. Ten is better. You'll thank me.
An 8'tall door would be better too, but changing it later is a picnic compared to raising the ceiling and roof.

 

[joe_padavano]

If you use a regular truss than the roof load is going to the side walls not the gable wall, so no you do not need a full structural header to support the roof like you would if the door was on a side wall. You do still need something that will not sag under its own weight and the weight of the wall above. I would not hang the wall from the truss, the truss needs to carry the roof load, but in doing that it greatly reduces the necessary strength of the wall.

What is an issue though is the 16' opening in an 18' wide building. This will need an engineered solution for shear so the building doesn't rack over.

^^^THIS!!!

A full truss (not a "gable end truss", which relies on the end wall for strength) can support the roof in the middle of the building, so naturally it can also support the roof at the end wall. You do not need a header. The discussion of the shear wall and racking is important. On the other hand, there are simple solutions - internal diagonal bracing from the poles to the trusses can be an acceptable solution, if sized and positioned appropriately. As noted, this requires some engineering smarts.