Joist size for decking

Blinkydamo · 4 May 2009

Hi all,

I'm about to start my first decking project and have a few questions I hope someone can answer for me.

1. Is there a set dimension that I have to use for the joists?? 6x2 or can I use 3x3. I will be using cheap slabs to support the joists as I am spanning mud and concrete.

2. Do I screw or nail the joist together, I have seen both, but I prefer the idea of screwing them.

Any info or guidance would be great as I only get the one shot at this.

Cheers in advance

Damian

Thermo · 4 May 2009

either 6 x 2 , or 4 x 2, but youll need more supports for 4 x 2

you can screw or nail, but if you nail you need to use annular nails

WDIK · 4 May 2009

you could do a proper job using L brackets, joist hangers and coach bolts?

here one i prepared earlier..

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WDIK
4 May 2009
2

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WDIK
4 May 2009
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Thermo · 4 May 2009

how are your L brackets held on then?

whats not proper about using screws or shot fired annular skew nails?

WDIK · 4 May 2009

Thermo said:
how are your L brackets held on then?

whats not proper about using screws or shot fired annular skew nails?

nothing at all, minor point you didnt say shot fired 1st time around.

I use a bostitch that will put a 90mm brad in.
socket head deck screws i would recommend.

goodmow · 6 May 2009

what are the minimum distances for supports if you are using 6 x 2 or 4 x 2 and also the centres distances for the joists?

Thermo · 6 May 2009

WDIK said:
Thermo said:

how are your L brackets held on then?

whats not proper about using screws or shot fired annular skew nails?

Click to expand...

nothing at all, minor point you didnt say shot fired 1st time around.

I use a bostitch that will put a 90mm brad in.
socket head deck screws i would recommend.

aha point taken. From a maintnance point of view socket head screws are a nightmare to undo in later years.

Thermo · 6 May 2009

goodmow said:
what are the minimum distances for supports if you are using 6 x 2 or 4 x 2 and also the centres distances for the joists?

centres for joists should be 400mm. supports normally around 1.5m. No real hard and fast rule. we always do the bounce test after its done and put in any extra if needed

WDIK · 6 May 2009

Thermo said:
WDIK said:

Thermo said:

how are your L brackets held on then?

whats not proper about using screws or shot fired annular skew nails?

Click to expand...

nothing at all, minor point you didnt say shot fired 1st time around.

I use a bostitch that will put a 90mm brad in.
socket head deck screws i would recommend.

Click to expand...

aha point taken. From a maintnance point of view socket head screws are a nightmare to undo in later years.

everything is a nightmare

Blinkydamo · 8 May 2009

Cheers for the replies people, the problem that I am having is that I cant use 4x2 or 6x2 joist as the height of the decking is going to be to high for the area. I have already built a wooden retaining wall and if I use either of these two sizes of joist then the decking will be half way up the wall.

I need to use 3x3 but I dont know how far apart I have to place the joist to be able to support the planks on top so as not to have any owing when I walk on it.

Will placing the 3x3 joist 300mm apart be ok for what I am trying to do??

Cheers in advance all.

Damian

WDIK · 8 May 2009

you will need to increase the number of verticle supports or it will flex like trampoline

pantsmachine · 9 May 2009

At that size of beam i would be fitting the post supports no more than 0.75M metre apart in any direction. 300MM sounds fine, just fit plenty of noggins to go with the joists.

diynot

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Joist size for decking

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