Garage without a support in one corner

[Matty F]

I wish to build a temporary garage as a leanto against a fence. To get a car into it, the door will have to be L-shaped and the full width of one end plus half the length of the garage, and the car will have to be reversed into it. Once a week! So the corner support of one end of the garage will be missing. Garage 4.8 metres long and 2.4 metres wide with the 2.4 metre door hinged to another 2.4 metre door along the side. The roof support will be 150x50mm on all sides, cantilevered on the side where the door is, and bolted to two 125mmx125mm poles in the ground. The roof will be extremely lightweight, i.e. the roof support will basically have to support its own weight. Except in a hurricane, but we don't have hurricanes. Thoughts?

[Gib Bogle]

Wind loads can be surprisingly high - I've been talking to builders about getting a carport made, and they pay close attention to the attachment to the house. I suggest you seek the advice of someone who has experience with such things in your area.

[Matty F]

I was intending to have the middle of the door attached to the roof when it is closed, as it will be 99% of the time.

[Tabby]

If its a temporary job you could perhaps keep roof load down some by using a tarpaulin as roof covering. And fence panels for wall cladding are quick and easy.

NT

[Jules Richardson]

That doesn't sound too bad; I think you have a solid trapezoidal solid structure (sides 4.8M, 2.4M, 2.4M, 3.39M) and then a triangular overhang (2.4M, 2.4M, 3.39M), right?

The overhang will project a maximum of 1.7M from a fully-supported section, with a cantilever of twice that - 3.4M - anchored halfway down the 4.8M wall.

I don't think that's significant; we get overhanging porches on houses of around that up here, and we get tornadoes too. And if it's anchored when the door's closed, even better.

cheers

Jules

[Jules Richardson]

That doesn't sound too bad; I think you have a solid trapezoidal solid structure (sides 4.8M, 2.4M, 2.4M, 3.39M) and then a triangular overhang (2.4M, 2.4M, 3.39M), right?

The overhang will project a maximum of 1.7M from a fully-supported section, with a cantilever of twice that - 3.4M - anchored halfway down the 4.8M wall.

I don't think that's significant; we get overhanging porches on houses of around that up here, and we get tornadoes too. And if it's anchored when the door's closed, even better.

cheers

Jules

[Matty F]

Correct, except that I was assuming that the large beam along the side would support the corner OK. Perhaps I'd better put some diagonal timber in the roof, and the side wall. I was going to use plywood but now will use recycled plastic billboards that have no strength at all.

Hmm, everybody else around here thinks I'm mad and that it won't work. But they are unable to visualise anything until it's built. I'm off to buy some timber.

[John]

Have a look at this

[Jules Richardson]

Yes, it probably would... I don't know what lumber prices are like there though, but they're pretty cheap here, and so it doesn't hurt to add a little more strength (and as it's a temporary structure I'm sure you can find somewhere to reuse it when it all gets dismantled :-)

:-) I don't think you're dealing with a significant load - and as you mentioned, it'll have additional support from the door except for the few minutes that you'll have it open.

cheers

Jules

[Andrew Mawson]

anchored when

Can you engineer a vertical pole into the opposite corner, and have a wire in tension from the top of it down to the otherwise unsupported corner?

AWEM

[fred]

In article , Andrew Mawson writes

That might handle the roof weight but not any risk of wind lift.

The span involved in a cantilevered side beam seems eminently do-able and the mechanics are simple, o/p just needs to consider anchoring for forces pulling up as well as pushing down with plenty of diagonal bracing in the vert & horiz to keep things in the square.

On wind lift, perhaps the idea would be to leave plenty of ventilation up in the roof so that wind can escape.

[Matty F]

I don't think wind lift will be a problem. The fence is basically a concrete block wall. The two humungous posts holding the other side are now in place, with the side beam. The posts will not lift out of the ground.

It all looks rather large. I think the top half of the garage will be trellis, to make it look a bit less dominant. So I will have to make a double door about 5 metres wide hinged in the middle with trellis on the top half, and plastic billboard material on the bottom half. The basic requirement is to keep most of the weather off the car and to hide it. It is one that is particularly likely to be stolen, even with its burglar alarm.

[fred]

Though you might go big :-).

Wise move, I think visibility (or lack thereof) is half the battle.

Don't forget the pics! (perhaps with a person hanging off the unsupported corner).

[Geo]

Do they still have capital punishment down under?

[Matty F]

No. The unsupported corner is only six feet high, so would only be any good for short building inspectors!