# Forum Home Renovation Decking  Deck joists between bearers?

## ::Dan::

Hi all, 
I'm building a deck with not too much ground clearance and was wondering whether there are any disadvantages to running joists between bearers rather than on top. 
My original plan was to have the joists on top of the bearers as follows: 100x100 bearers and 100x50 joists on top, with 100x100 posts 1200 apart in a grid and 450 spacing between the joists. 
Would I be better to run the joists between the bearers using 150x50 for both (or 150x75 if needs be). 
Also, will pairs of 12g or 14g bugle head screws converging slightly down towards each other do much to prevent cupping if I use 140mm boards? Are there any highly recommended hardwoods which are less likely to cup? 
Thanks very much, 
Dan

----------


## binda

Probably having the joists level with the bearer will restrict air movement slightly.
I was considering the same method for my deck as I had a height restriction.
Will you be using joist hangers or checking the joists into the bearers?

----------


## ::Dan::

Thanks for that Binda, I hadn't thought about air flow at all. If I was going to have the joists level with the bearers I was planning on using joist hangers, but now I think I'll just dig deeper and put the joists on top of the bearers. 
I guess the question now is just whether 100x100 bearers 1200 apart with a post every 1200 (making a 1200x1200 grid of posts), and 100x50 joists will be enough to prevent bouncing? I'd be prepared to make the grid of posts 1000 apart if needed but I'm not sure if that's overkill.

----------


## Bloss

> Probably having the joists level with the bearer will restrict air movement slightly.
> I was considering the same method for my deck as I had a height restriction.
> Will you be using joist hangers or checking the joists into the bearers?

  Either way makes little or no difference to airflow or anything else. Simply a practical choice in a situation of restricted space. And the size of the joists don't have to change if between rather than on top of the bearers. You can use a timber ledger rather than hangars - either will be OK - I wouldn't be checking in.  I'd use triple grips or mini grips if on a ledger. 
The spans you suggest will be OK - make the 1200mm your maximum and work out the number of bearers you need to get the distance you want - it might end up at an odd number - 1100 or 1127 or some such. I like 400mm for joists spacing, but that's just me. As I've said before the additional cost to close up spans and make a deck which has a more solid feel is trivial in the scheme of things. The span tables are minimums - for your own deck why would you want to build to the minimum (but you don't want to waste money over-building either).  :2thumbsup:

----------

