How much weight will my garage roof take?

[jammy_basturd]

I'd like to do a body lift on my Tiv, and trying to work out the best/easiest way of lifting the body. I'm hoping I can sling some ropes over the joists of the garage roof and hoist it up, at least for a few minutes whilst I drag the chassis from underneath. Obviously though, I don't want to overload the roof and have it come down on top of me.

Is there any way of calculating or estimating how much weight a roof can take?

EDIT: Just to give some useful info! The garage is brick walls with timber frame roof joints supported on RSJs with ceramic tiles. Joists are I think 1"x2", some a bit thicker, and I'd guess the span to be roughly 5m.

Edited by jammy_basturd on Monday 18th July 20:45

[shimmey69]

Pictures needed and measure the joist as 1x2 is very very small!!

If it's a normal sound garage roof then there should be no reason why it shouldn't hold the weight!!

Just make sure you lift it from all 4 corners straight up, just like they do when removing illegally parked vehicles as if you lift from one point you damage it!!

[jammy_basturd]

Yea, after I posted I thought that it didn't sound too big, though I've just been and measure, and the bulk of it is 3"x1.5".

If you look at the pictures below, the first full length span in from the side of the garage is made of two 4x1.5" lengths, and there are a couple of 3.5x1.5" lengths in there too. Though one problem maybe that the 5m spans aren't one piece, they're two lengths of joist nailed together in the middle.

The thing is, I can support the rear of the body using my engine lift, so it only needs to take half the weight of the body (plus all the interior), which I'd estimate to be about 400kg in total?

~ ~

[shimmey69]

Looks like a newish built garage

I would say as long as you spread the weight so you attach a length of wood accross as many of the joist as possible you should be fine as it's only half the body weight!!!

I'm presuming it not going to stay suspended for weeks??

(i accept no responsibility if you pull the garage down on top of you and your car)

[jammy_basturd]

Lol, thanks shimmey, I promise not to sue you!

Yea, it's quite a new build, about 5 years old. I'll try and get some pulley wheels across three or four of the joists.

I'm planning on just suspending the body for all of about 15-30 minutes. I'll stick the chassis/wheels on little trolleys so I can move the chassis easily from out beneath the body, and then the body will be lowered back down on to axle stands/wooden beams.

[Simpo Two]

Haven't tried it but I suspect that hanging it from the sides of the roof (rather than the middle) would help - more of the force will be sent down the walls.

[spikeyhead]

I'd add some structural stell as a frame to ensure you don't end up in a horrible mess.

What price to avoid a squashed tiv?

[MikeyT]

I'm sure you'll be fine but I would invest in FOUR good wooden fence-type posts - 8ft tall or so and fit them under the roof joists but as close to the body as you can (of the car) at each corner - so resting against the two rear lights and the two headlights - so in effect you're creating a box frame around the body of the car. 4" square posts should do it.

4" posts ain't gonna snap!

[davepoth]

Simpo Two said:

Haven't tried it but I suspect that hanging it from the sides of the roof (rather than the middle) would help - more of the force will be sent down the walls.

Very much this. If you can get a very hefty beam and wedge it across the top of two of the walls you should be good to lift. I don't think I'd want to take the risk on those rafters TBH.

[Mr Dave]

Can you not remove some of the interior as well to save some weight? Also allows you to give it a really thorough clean as well.

[jammy_basturd]

Thanks for all your suggestions. I had a few thoughts to add some timber to the roof to shore it up, and the fence post idea sounds very good.

And yea, I'll take out at least the front seats and my tax disc from the interior to remove some weight.

[mickk]

Outriggers Jammy? Please don't squash it.

[BuzzLightyear]

MikeyT said:

I'm sure you'll be fine but I would invest in FOUR good wooden fence-type posts - 8ft tall or so and fit them under the roof joists but as close to the body as you can (of the car) at each corner - so resting against the two rear lights and the two headlights - so in effect you're creating a box frame around the body of the car. 4" square posts should do it.

4" posts ain't gonna snap!

What he said except I would suggest hiring Acrow props which are designed to support a roof or ceiling and have height-adjusters built-in (so you don't have to cut the wooden posts for the right fit). A decent local plant hire shop should have them.
HTH

[Handie Andy]

May i suggest





Too slow!! What he said ^^^^^^^^^^

[jammy_basturd]

Thanks Buzz!

mickk said:

Outriggers Jammy? Please don't squash it.

I think mine are OK, bit of surface rust, but seemingly no holes as far down as I get shine a torch. But then who knows once I get the body off and start poking around. Mainly doing it because all the powder coat around the rear of the chassis has flaked off, plus near the manifolds, and just generally it is looking a bit scrappy.

[Jonboy_t]

How about drilling some heavy iron hooks through the brick on all four corners, as high up as possible. If it's a single skin wall, drill through the wall and put some kind of weight spreader on the outside (like a big, thick washer or something) and then bolt them on from the outside.

That would be more than strong enough to hold it, plus you could attach a pulley to all of them so you'd only have one rope/chain to pull to get the shell off.

[thinfourth2]

Jonboy_t said:

How about drilling some heavy iron hooks through the brick on all four corners, as high up as possible. If it's a single skin wall, drill through the wall and put some kind of weight spreader on the outside (like a big, thick washer or something) and then bolt them on from the outside.

That would be more than strong enough to hold it, plus you could attach a pulley to all of them so you'd only have one rope/chain to pull to get the shell off.

Which would give you a inward loading on the wall which it ain't designed to take.

If you are doing alot of car work i would be damn tempted to get an engineer involved and get 2 steel beams across the garage that each can take 1 ton in the middle.

It gets you a nice safe method to lift the body and it can be used later for engine lifts etc.

That said a 2 post lift would be of the same price range

[jammy_basturd]

Yea, I'm not planning on doing work like this too often and my engine lift does me for 99% of the work I do, but thanks for the suggestion all the same.