New-to-me garage, question on structure and beam

[TXBDan]

Hi all,

I just bought a house with a detached two car garage. It is 21' wide and 18' deep and has a single overhead door and a simple gable roof.

The main issue with it is that the garage door height is fairly low and there is a low beam running in the center from front to back. The beam, along with a header over the door, looks to be relatively new. It's laminated 12x and looks to have been installed beneath the existing trusses effectively dropping the height a foot. The problem is that this limits how tall the garage door can be when raised. Currently, with the garage door raised, its only about 6ft high. I'm 6'4 so this is not cool. I want my foot back!

I assume this was done to convert a two-door garage to the single-door, but I'm not sure of the history.

The attached pics show the beam in question along with a shot of a side wall. My biggest question is, why is this beam even there? Shouldn't the roof trusses and side walls support the roof?

Thanks a lot

Edit: I'm starting to wonder if it was put there to support the garage door opener and the weight of the door while opening...? Obviously overkill

 

[Falcon67]

Beam is probably there because there might have been a post in the middle. It created free span. Looks like a kinda hip roof with a flat top, if those are 2x6 joists they would not be sufficient for a 21' span. They could have sistered in 2x8 or 2x10s and added a few more to do about the same thing as the beam.

 

[TXBDan]

Thanks, that makes more sense. I'm going to do more research on reinforcing the joists and maybe go that route. Like you said, i could sister in 2x8s or 10s and build a storage loft up there as a bonus. That beam has got to go.

I actually haven't moved in yet, but when I do i'll collect more measurements and details.

Thanks!

 

[Milton Shaw]

Looks to me like the roof was freestanding and didn't need the beam. If I wanted to get rid of the beam I would take it out and then put it on top of the 2x6's and then strap them to the beam giving them support from above. You probably would have to cut a hole in the gable end to slide the beam front to back above the tie joists. It does look like it was added to support the door opener as just those 2x6's would flex a lot as the door opened.

 

[TXBDan]

I was reading up on vaulted/tray ceiling conversions and it seems its possible to raise ceiling joists to an appropriate height (thus becoming rafter ties). It seems that if you stay in the lower third of the triangle its generally doable.

The rafters are 24" OC and the current ceiling joists are on every other rafter, so 48" OC. So there are only four joists.

Maybe I could add rafter ties up 1/3rd height and put them on every rafter for a total of 8.

 

[TXBDan]

I went by the house last night and got some interesting history on it. (The previous owners are still there renting from us for a couple months.) It used to be a single car garage and it was expanded to two. The roof was extended up at the exiting slope and brought back down on the new wall.

From the looks of things, the rafters don't go up to the peak of the roof. There is a little "floor" up there and the rafters stop at the joists for the floor. (sort of in a collar tie location). There is no access through this floor up to the peak of the roof. I'd estimate there is maybe 3' between the peak and this floor up there. So from inside it looks like there is flat top roof, but from the outside it is a peaked gable roof.

I'll probably need to remove the "floor" up there to see what's up there. I'll try to contact the contractors who did the work and see if they remember the details.

 

[75CrewDeutz]

The beam that the garage door opener is attached to could be moved up into the attic space. The roof would likely need to be temporarily supported while the beam is removed and repositioned in the attic.

 

[TXBDan]

The previous owners sent me some old pics and one shows the garage at an intermediate state between it being a single car and a two-car. You can see it has a flat roof. So I guess when they expanded it, they simply decked over from the old peak across. So the garage's current configuration is simply a mini gable peak on top of the old flat roof. It's interesting to see how these old structures evolve over time. Unfortunately, I think this complicates things a bit structurally. I'm going to start getting some pros in to give some ideas and estimates.