More decking woes...

[Dackers]

This is the problem with reading so many different sets of instructions on how to build a deck!

I'm attempting to construct a deck about 23cm off the ground (I know it's not a lot but the ground underneath is very far from being level enough for a ground level deck). It's about 5.3 meters long by 1.8 meters wide. The joists are going across the 1.8 width.

My problem is that I've read some things that are telling me to put secondary bearers in and some that don't mention them at all.

Looking at the relatively small space, it seems like overkill to me to dig another 8 holes for concrete feet with another 8 support posts in to attach two support bearers for a distance of 6 feet! Surely hardy old lengths of 4x2 would hold up OK over that distance?

Any advice would be much appreciated as I'm tearing what little hair I've got left out over this!

Cheers.

 

[masona]

Can you do a drawing? Not quite sure yet what you mean. What are the joists centre?

 

[Dackers]

I'd love to but my computer skills aren't quite up to it!

The basic question is - do I need secondary bearers for joists 1.8 meters long? Joists are at about 42cm centres.

Sorry I couldn't do the picture!

 

[Thermo]

for that height of the ground, you will be fine with 50 x 100mm. Its best to run some noggins through the deck as well to give some additional bracing, but the decking acts as a bracing as well. You may need to put some additional vertical supports in to give it more rigidity, but as masona says a drawing would help.

 

[Dackers]

Thanks Thermo. So you think I'd get away without putting the secondary bearers in then? THAT would be handy!

 

[Thermo]

its not a matter of getting away with it, it shouldnt need them. theres no need to over engineer it, it may need additional vertical supports though.

 

[Dackers]

Right - that's what I'll do then. Thanks for the advice! By the way - what's your opinion on deck clips vs screwing the deck boards down from the top?

 

[Thermo]

screw them down, much more secure and cheaper. Personally i use a nail gun, but if thats the choice youve got go for screws

 

[pitbull]

I would lay some boards loose on your framwork and have 2 or 3 people stand on it if it does'nt move fine but if it does just to give it some extra support just put some broken slab/brick/block down and stand a short support on it and screw to the framework.

 

[Dackers]

Ah, that was going to be my next question to Thermo - what form should the vertical supports take?

 

[Thermo]

youve got a few options, blockwork placed on a dry mix of concrete and levelled up or 75 x 75 treated posts concreted into the ground. The advantage with the later is you can put them in the ground and then simply chop the tops of at the right height once the deck frame has been constructed. The problem is eventually they will rot away

 

[megawatt]

Or the best of both approaches, posts sitting in anchors fixed into the top of concrete piers ... Nice and strong and, as the posts are off the ground, they don't rot.

I agree with Pitbull and would test the 100x50's to make sure it's not too "springy", should be okay though.

If not, you always have the option to step up to 150x50's across the 1.8m span which would definitely be solid and not cost significantly more.

With deck building there are always options ... Loads of options