garage roof with no rafter or collar ties.

[Bill Dufour]

I saw a picture of a house for sale with a fairly new stand alone garage. Looked to be a 4 in 12 roof, 2 car garage with a standard looking ridge down the middle. The inside showed it had a very deep ridge board and no cross ties of any kind. It was rafters and not trusses.
I have never seen this type of construction but I read it is not uncommon. You could even hang a light duty crane trolley under the ridge beam.
Of course you have no attic storage.
Bill D.

[ray grundhoefer]

My parents house was built like that back in the 1960's .If the is no ceiling of any kind below the roof to tie the walls together a crane of any kind below the ridge would be a bad idea

[Edward Dyas]

If the ridge is of sufficient size there shouldn't be any problem. A lot depends on whether the building is where there is heavy snowfalls. The ridge would be carrying the entire load of the roof.

[Jim Becker]

The whole reason for ties is to insure that the long-side walls don't buckle out with the weight of the roof structure and anything attached to it. I'd also be very hesitant to put any additional weight under that ridge beam for this reason alone. At the very least, I'd add some cable ties or hard ties across the structure at a few points even without hanging anything and that's whether or not there are gussets! The upstairs to my shop building has ties at four foot intervals and that's with a block wall structure below. I suspect that if it was stick built, there would be more support.

[Bill Dufour]

I guess that is how the so called cathedral ceilings are built. Seems like the walls have a lot of outward force on them. A real cathedral would have flying buttresses at the base of each rafter. I think it makes the gable walls a structural wall.
Bill D.

[Malcolm McLeod]

Gable wall is the key. If the ridge beam is sufficiently supported by columns at each gable end (and possibly a center column), and of sufficient size (cross-section), it shouldn't sag. And so, the rafters can't drop with it - and so push out on the walls.

But I do mean SUFFICIENTLY. Columns have to carry all the way to the foundation and NO deflection in the column or ridge beam.

[Jack Lilley]

Gable wall is the key. If the ridge beam is sufficiently supported by columns at each gable end (and possibly a center column), and of sufficient size (cross-section), it shouldn't sag. And so, the rafters can't drop with it - and so push out on the walls.

But I do mean SUFFICIENTLY. Columns have to carry all the way to the foundation and NO deflection in the column or ridge beam.

This exactly correct. The ridge carries much of the load, much like a girder, and is structurally supported at the gable ends so it does not put downward force on the side walls causing them to push out. The key to this type of construction is sizing the ridge correctly and supporting it at the gables correctly. This method of construction is fine when done properly.

[Mike Kees]

As a carpenter that seems like a real dumb way to build. About twenty years ago I bought an old building for my first shop. I t had a roof like this with rafters that someone tried to make into trusses later. The walls had about a one foot bow out on each side and the roof had a sag as well. I bought some cable and added two across the building, it worked for about ten years until I tore it down and began to build my new shop.

[Bill Dufour]

As a carpenter that seems like a real dumb way to build. About twenty years ago I bought an old building for my first shop. I t had a roof like this with rafters that someone tried to make into trusses later. The walls had about a one foot bow out on each side and the roof had a sag as well. I bought some cable and added two across the building, it worked for about ten years until I tore it down and began to build my new shop.

Do you remember how big was the ridge board?
Bill D.

[Bill Dufour]

Do you remember how big was the ridge board?
Bill D.

Just saw pictures online looked like about 4x14. All rafters had simpson clips top and bottom. I would guess not more then 24 feet long. It looked to be one of those beams made from strands of wood all compressed and glued together.

[Jim Andrew]

When you purchase a beam like that, an engineer sizes the beam for you. I mean the company selling the beam has a person who looks at the application and sizes the beam, so the city building inspection office will OK the building.

[Bill Dufour]

My understanding is that, in Califorina, as long as it is all wood any builder can build a house with no engineering if it is two stories or less, maybe three. If they use a steel beam they have to get an engineer to sign off on that part of the structure. I assume that is also true for steel studs?
Bill D.

[Rick Potter]

Just finishing a new garage addition built that way. I wanted as much height as I could get for possible future car lift.

Garage is 22'Wide and 32' long, with the ridge beam being 23' or so long and if I remember correctly it is gluelam that is about 7 1/2" wide and 24" tall.

Lifted it with a small crane. Big posts holding it up with bolts into a 24" foundation. The whole garage is shear paneled for rigidity. Wide open inside.

[Bill Dufour]

Any idea how much that beam cost? Would a steel beam be cheaper? I assume that is a special order item with some lead time required.
Bil lD.

[Jamie Buxton]

Use a scissors truss. It does have the desirable load-carrying strength of a truss, but looks like an open v-shaped ceiling once you put the drywall on.