18' Garage door header size (no load)?

[Jayhem]

I'm designing a 26W garage. The trusses will span the 26' and the 18' garage door is parallel to the trusses.

This means my garage door header will carry no load whatsoever as the trusses do not require center support. What size would you go with? I'm looking at doing TWO 2x12's with 3/4" ply sandwich. A 2x6 on the underside and top side.

I can't find anything in my local code for header size where the header is not bearing floor or roof load.

 

[GMCGarage]

Just check your deflection. I would say you would be in the range of 3/8" for self weight.
Install crown up.

I have never seen anything for headers that are not load bearing. common sense has to prevail I guess.

 

[n20junkie]

My 30 wide garage has trusses on the end walls, and one end wall also has the garage door.

I still used doubled 1.75 wide x 11.25 tall LVLs. Thats a long span, and you don't want that area sagging, even with the trusses taking most of the load.

 

[handymancanfixit]

I'm designing a 26W garage. The trusses will span the 26' and the 18' garage door is parallel to the trusses.

This means my garage door header will carry no load whatsoever as the trusses do not require center support. What size would you go with? I'm looking at doing TWO 2x12's with 3/4" ply sandwich. A 2x6 on the underside and top side.

I can't find anything in my local code for header size where the header is not bearing floor or roof load.

This should answer your question......

http://www.southernpine.com/span-tables/

 

[Jayhem]

This should answer your question......

http://www.southernpine.com/span-tables/

That is a handy link but again it doesn't have anything on headers that aren't at least supporting the roof load at 20psf. All my header is supporting is it'self and 24" of siding.

Also you can't get 2x12's in over 16' usually so an LVL probably makes most sense here.

 

[Homerr]

Some gable end trusses will be designed to transfer all the load directly to the wall underneath. They have a wall load (the triangular area) which is usually 10psf for wood frame, or 13psf for stucco. Also, if you have several feet above the garage door opening to the top plate that area would be counted. Additionally, the tributary area from the gable end truss to the first regular truss and all of any roof overhang should be calc'd using your local load criteria.

As an example with 2' door to top plate, 2' overhang, 4/12 pitch has 87 square feet (sf) of wall area. I'll use roof loading in my area, 25psf live load (snow) and 15psf dead load (structure).

wall area: 87 sf x10 psf = 870#
roof overhang: 2' x 18' x 40# (live+dead loads) = 1440#
roof tributary area: 1'x 18' x 40# = 720#
==============
Total = 3,030#

Quite a bit for a header 'with absolutely no load' on it.

 

[Jayhem]

Some gable end trusses will be designed to transfer all the load directly to the wall underneath. They have a wall load (the triangular area) which is usually 10psf for wood frame, or 13psf for stucco. Also, if you have several feet above the garage door opening to the top plate that area would be counted. Additionally, the tributary area from the gable end truss to the first regular truss and all of any roof overhang should be calc'd using your local load criteria.

As an example with 2' door to top plate, 2' overhang, 4/12 pitch has 87 square feet (sf) of wall area. I'll use roof loading in my area, 25psf live load (snow) and 15psf dead load (structure).

wall area: 87 sf x10 psf = 870#
roof overhang: 2' x 18' x 40# (live+dead loads) = 1440#
roof tributary area: 1'x 18' x 40# = 720#
==============
Total = 3,030#

Quite a bit for a header 'with absolutely no load' on it.

Good points! My Trusses are 10/12 pitch attic trusses bearing on the outer walls only.

 

[Homerr]

You're sure the gable end truss(es) are only bearing at 0' and 26'? Talk to your truss people if you are unsure.

 

[Jayhem]

You're sure the gable end truss(es) are only bearing at 0' and 26'? Talk to your truss people if you are unsure.

I did ask them.

Yes, the end trusses are identical to the rest of the trusses, designed to support themselves at 0 and 26' bearing points and I'll frame them in for my end windows. The gable truss also fully supports the overhang I'm adding.

 

[RVDan]

Your sheeting on the outside will keep it from sagging, use whatever you want, support it in the middle until your sheeting is screwed on.

 

[Jayhem]

Your sheeting on the outside will keep it from sagging, use whatever you want, support it in the middle until your sheeting is screwed on.

Good call. I'll be using exterior construction adhesive on the sheathing there as well as screws to make it one big laminate beam!

 

[rslaback]

Also you can't get 2x12's in over 16' usually so an LVL probably makes most sense here.

If you are having a hard time finding 2x12s longer than 16' you need to find yourself a real lumber yard. All our local yards stock them up to 20' long as that is needed oftentimes for stair jacks.

 

[The Tool Tyrant]

You only want to do this once, and the last thing you want is your header sagging after 5 years. To be safe and have no worries, go with a 5-1/2"x 9-1/2" Parallam and be done with it.

 

[rburke65]

What does the local build dept. have to say about the header? The requirements are out there.

 

[Hanger]

I built a 30wx40dx12h garage with a 26wx11h overhead door and used two 16"x1.75" lvl beams for a header over the door.