Long span deck over garage

[Wildman]

Hi All.

I have a flat roof garage with a 7m short span that I want to put a deck over to make it useful. Due to various constraints, I dont want to raise the total garage height by much more than 300mm. I am planning on using 250UB31.4 Steel bearers at 1.8m spacing with 175x38mm KD joists at 500mm spacing recessed into the beam to sit flush with the top of the beam. The decking will be hardwood bringing the total deck thickness to around 280mm. I was wondering what the recommended ventilation gap to a roof for a deck should be and if I should prepare the roof in some way to maximise its life such as a coating of bitumen to at least make it last as long as the joists and decking will as the joists and deck will have to come out to replace the roofing sheets anyway (gal channel style roofing).

Also, what would the best way to get 220KG beams into place as the driveway is quite narrow and I dont want to think about the costs of a crane from the street. Is there some easy way to manipulate such a beam to get it on to the garage roof? it is about 3 m high. A backhoe might fit down the driveway. The garage is besser brick with reinforced columns in the corners so should take the weight easily, I will reinforce the beam bearing location anyway. I will be doing this job myself as well and want to do it as cheaply as possible. Materials are already looking like about $7000 which makes it a very expensive deck even before labour is involved.

Cheers
Ben

[jow104]

In days of old when men were bold and steel wasn't invented ######################################

Ancient Britons used A frames.

[Toggy]

Woody,

I think he wants to make a nice elevated beer garden (probably to overlook next doors pool) LOL. Would not be a good feeling having the pointy ridge bit wedged in the butt, and trying to balance after a few stubbies; not to mention trying to stop the stubbies/esky sliding off the roof.

Wildman,
you could always use a tall tripod with an endless chain and some scaffolding to slide it across; as well as a few "mates" who are big on brawn and lacking in grey matter.


Ken

[soundman]

A crane is strating to look good.
For the $70 to 100 per hour you will pay for a small crane it would be money well spent.

Or get the steel delivered by a crane truck & have it placed straight off the truck if you can.

There are all sorts of lifting aids & machines of diferent sizes, don't bust you gut when you can just point.

[Wildman]

It is a nice large beer garden that I am after, mainly to cover the ugly expanse of north facing reflective galvanised roof that is right outside the kitchen window. Unfortunatley there is no pool next door, perhaps I should suggest one.


The only issue with a crane truck is that the driveway is too narrow for a truck to back down. This is also the issue with a crane, the size of the crane required to send the beams over the house from the street costs a little more than $100/hr. (they cost more than that just to sit there when not even doing anything). I have figured that 4 blokes should be able to haul the beams up once one end was up. Perhaps a forklift is the way to go, they are nice and narrow.

Any suggestions on air space and roof preparation?

Cheers
Ben

[johnc]

The ancient Britons also used sheer legs and block and tackle, but the A frame with the endless chain is probably safer than 4 blokes up ladders. If you can use a forklift sideways to lift the whole beam to height you still have to get it off, try two pieces of 100mm x 50mm hardwood laid out flat and level and a few rollers, 25mm to 35mm thick no larger, providing you use twin planks wider than the steel beam you should get there. Just make sure that at no time is anyone standing underneath, blood on the footpath becomes a hazard on its own when there is to much of it. Whatever you are planning it will probably give a worksafe inspector a heart attack. If you can use the forklift front on just lift it up and plonk it on, you can spin it easily on a couple of 25mm pieces of rough pine. Simply put one on top of the other, plonk the steel on top and spin slowly the timber will happily oblige by spinning on itself. Whatever you do it will probably involve some sort of packing on the roof to allow the steel to be landed and moved into position with out destroying the roof in the process.

[vsquizz]

Wildman, we have just finished putting up some limestone walls at out place. Funny thing is the bricks weighed 220kg each. We used a small Kubota excavator with the bucket removed. His full extension was about 6 metres, had plastic tracks so no damage to driveways and its narrower than a car. $65 - $90 /hour is the going rate. A plastic track job can pick up from out the front and walk the beams down your drive.Might be worth a shot.

Cheers

[soundman]

As I said before there are a number of compact lifting devices available these days.
For example we had a cement grey water tank installed using a mini excavator that weighed a lot more than 250kg.

But If you want to do it the "old way" check out a book called "A guide for riggers" published by the NSW government. probably out of print & out of step with current WHS but it does detail all the old methods.
It was once the standard text for riggers in this country.

BTW its probably riggers work.

[Wildman]

I think the mini excavator sounds like the way to go. Pity I will have to hire it, my father has 3 backhoes but is a few hundred kilometres away although a mini excavator is a lot narrower and I would be able to get it down the driveway a lot easier.

Does anyone have any opinions on putting a deck over a roof and the associated clearance and maintenance issues?
Cheers
Wildman

[jow104]

Making it waterproof is a good idea :rolleyes: :rolleyes: :rolleyes:

[vsquizz]

Wildman, I'd say make sure you at least have access to any gutters, downpipes. Presumably this could be by ladder from the ground but any down pipes, valleys etc that you may have to get at. As for paint, well only if it really needs it. There are a number of new solar/roofing paints on the market and the topic has been flogged on this BB before.


Cheers