New Carport

[J5]

Evenin'

We plan to make a Carport in the back garden approximately 3m by 6m. It will be just after the gates that separate the drive from the garden. The canopy itself is most likely to be polycarb or corrugated plastic sheets on a timber frame. The back 6m will sit on an existing 2m high brick wall and the two front corners are likely to be supported on thick timber posts. Straight forward DIY so far...

The problem is that apart from the back wall it has to be completely open so we can manoeuvre cars in through the 3m opening near the gates and out of the 6m front side. What can i use to support the roof between the two post on the front? I was thinking of 2"x6" joist but not sure if it will eventually sag across that 6m distance. An RSJ or rolled steel lintel seems a bit hardcore though.

Would appreciate any thoughts.
Thanks
Jas

 

[cmother1]

That's one hell of a span. Timber seems the best compromise, but expect it to sag in the middle after time, even with a light roof. You'll need to go bigger than 6x2 I think.
A scaffolding pole (or 2) would probably do it, but might look a bit gothic.
Good luck.

 

[Bankrupt]

One hell of a span indeed - You'll need to anchor it down extremely well to stop the entire structure taking off on the first stormy night.....

 

[joe-90]

If you've got decent anchor points you could use a wire cable that you could tension up and re-tension every now and again. Think tight rope walker.

 

[J5]

Cheers for the pointers chaps.

Scaffolding poles might work but considering there only a couple of inches diameter i reckon they will still have lots of give over that distance. As for the wind catching it, i did think about that but it will be tied together pretty secure so i'm sure it will be ok. There can be some strategically placed 'big holes' to let the pressure out if needs be.

At the moment i'm looking into I-Joists like the ones below, anyone used them before?...

http://www.masonitebeams.co.uk/products/component-products

Jas

 

[freddiemercurystwin]

They're designed for internal floors not exteranl use. Just increase the size of your timbers. 6x2 will be way undersized, a rule of thumb is the depth should be 1/20th span so theoretically more like 12" deep joist are required to avoid much sagging. Of course they're £££ for 12" deep timbers so go with something like a 10". Might have a bit of grief getting 6m long lengths too.

Scaffold poles sag when they're sat on the back of a transit under their own weight let alone spanning 6m with a load.

 

[cmother1]

Just a final thought: you could nick the Masonite idea and make up your own I beam from 18mm exterior ply and some decent (3x2?) timber:
//media.diynot.com/56000_55605_13658_48248454_thumb.jpg
Could be pretty strong if you used plenty of glue and screws

 

[noseall]

Maybe a scaffold 'bridge' section will do the trick. These can span several metres and are designed to carry a fair load.

 

[J5]

freddymercurystwin: First of all, excellent name . I think even if do find 10'' or 12" timber at 6m lengths the cost would be astronomical but i'll look into it.

noseall: also a good idea, not sure where i'd even get a scaffold bridge but i'll look into that too.

cmother1: You might have hit upon a solution, i'm liking your thinking.

Will post my findings and let you know if it all falls down

Cheers all

 

[isettaman]

Hi J5

I've got 6m 9" x 3" joists holding up my garage roof.

£37 each.

Dave