Roof over decking

Could you clarify your posting, are you building a shed or a just a shelter? Is it 12'x12' or 4'x2'? What were you planning on covering the joists with?

 

It hurt my head reading it, so gave up.

 

Hello Dan, you need to make your mind up abour dimensions because that will dictate timber sizes.

I assume you're going for a regular shape, a square or oblong. Make sure you lay the deck foundations out accurately because that will dictate the squareness of the roof. Use 4x4 or 100mmx100mm. Personally I would look around for something that's par with a pencil round on each corner.

The 4x4 should act as your supports for the deck and go through the deck and act as the roof supports. The deck should be supported on 6x2 carcassing, this needs to be tanalith E treated as do your 4x4 supports. The joists need to be set out on 16'' centres.

Whilst the 4x4 supports that support the roof will be around the outside of your deck on 4 sides, the inner deck joists will also require supporting. You will need to cut 4x4 that can then be either bolted or screwed to your joists. Here you have a choice cut them by dead reckoning or cut them, fix your joists and snip them off with a reciprocating saw. Your joists need supporting every 48'' or 1.2m.

Your roof should be made up of a series of lightweight trusses. Make up a jig and knock them together out of treated 3x2 and wbp 18mm ply. Your trusses can be set out at 24'' centres. I feel that I must advise you to get a competent carpenter involved at this juncture because raising a roof, especially on such an open-sided structure, has various pitfalls. I know, as a keen diyer, you want to "have a go" but you don't want the rood ending up in next door's garden or even worse.

Your foundations, which is where I should have begun, should be poured concrete. They need laying out to a plan and I would use socks to rag into the concrete so that the 4x4 has a socket to sit in. Avoid the temptation to use pavers. There are pavers and pavers. Some have the strength of knicker elastic!

Put a nice balustrade around the deck, it will add strength but remember you must put your spindles at no more than 100mm apart.

Setting out is the key.

Wind and live loading on such a structure can be considerable but more so depending upon location.

Good luck.

 

Hi Dan, yes this seems OK but I didn't realise you were putting a pent roof on the shelter. Yes, you will need a plate to sit the roof joists on. Remember to use steel twists to secure your plate and joists to your uprights. Use truss clips to locate your roof joists but ensure you get the right size.

How far off the ground is the deck? You may need to make some steps. Remember the strings can be cut out of 9x2. The rise should not be more than 8'' including the going, which needs to be at least 12'' in depth. A handrail may help the young and older ppl get access to the deck.

Hope the weather is kind to you.

 

Hi Dan, is it important to have a clear span? I would have another 4x4 post in there and make a ledge out of 6x2 and then put 4x2 plate on top of that covering the 4x4 posts. Yes, I know, it might be considered over the top but think of those 10 nights per annum when we get wind from the Russian Steppes. I want to sleep easy. So should you.

Your other details are fine and I expect a photo on here soon.

Have fun making sawdust, that's all I do.