Deck design - is this enough support

[mcdermottc]

Hi

I have been planning a deck project and wonder if the below would be ok.

The garden currently looks like this

pic 1

• mcdermottc
• 7 May 2013
• 2

pic 1 current garden

I plan to put a deck on the right hand side removing the 4 slabs on the floor and the 4 of the raised area but leaving the support walls underneath as extra support for the deck. I wondered if the below design was ok with enough support legs to raise and hold it off the ground by 30cm.

deck design

• mcdermottc
• 17 May 2013
• 1

All joists will be 6x2 as will the ledger board which will be screwed to the house using M12 x 180mm through bolts (not sure how many I would need).
All leg posts will be 4x4 and will sit above the ground. I plan to dig holes and pour concrete into them (leaving for 3 days to cure) then drill holes into the concrete and use post shoes to bolt the legs onto the concrete so it looks something like this.

pic 4

• mcdermottc
• 7 May 2013
• 3

pic 4 concrete pillars

The 8 support posts will then be bolted to 6x2 frame using M12 180mm bolts with nylock nuts.

The question does this design look ok and will it be solid enough or converesly is this overkill and I should just sit the raised frame on some concrete slabs ?

Any advice or comments on any of the above would be greatly appreciated.

chris

 

[Sombrero]

Chris, I'm a diyer, but have built a 'floating' deck. And your design looks sound to me... just think of how you'll use it... everyday family use will be fine i reckon, but a 30 man rugby squad round for a BBQ might just test you calculations !!

 

[mcdermottc]

Thanks sombrero

Do you think it would benefit from more support legs or noggins to give it more strength. I would like it to be as solid as possible without going OTT - makes sense to do a good job now

Cheers

 

[WabbitPoo]

I would suggest you support every joist - if you have the room underneath the easiest way is to have a couple of 6x2s running perp. to the joists, so supporting your joists from below.

 

[mcdermottc]

Hi wabbit thanks for reply

Would these be bolted to posts just like the joists or somehow screwed to the joist frame

Thanks

 

[WabbitPoo]

Not much point just attaching supporting joists to the frame........


Put three posts in a line and attach to them a pair of 6x2s across, either side.

 

[mcdermottc]

Wabbitpoo

I remeasured and i dont have enough room underneath for another 6x2 im only raising the deck 30cm at maximum point so take 15cm for frame only leaves 15cm so it would effectively be sitting on the ground.

I thought if it was 4x2 I would need extra support but 6x2 wouldnt need as much as less likely to flex ?

Would more noggins help ? Again I was told that on 3m run of 6x2 I would only need 1 set of noggins in the middle.

Youve got me worried now lol especially since I dug my holes today

Cheeers

 

[WabbitPoo]

Noggins dont add much structural support - they really only stop it shearing.

Therefore I believe each joist needs supporting in its middle somewhere.

You can have one post supporting two, by clever positioning of noggins either side of the post (so two joists "share" a post)

 

[mcdermottc]

wabbitpoo

what alternatives do i have if i don't have enough height to as you suggest have a 6x2 perpendicular to the floor joists underneath.

could i use 4x2 or have the middle support on slabs ? or any other ideas



thanks

 

[peterperfection]

Floating deck is easier, cheaper and so very much quicker.
Sit the deck on pallets -screw pallets together . Screw the decking boards to the pallets . Rolls Royce job.
Make sure pallets are all the same size .

 

[WabbitPoo]

Do as I said - use one post to support two joists.

 

[Sombrero]

wabbitpoo

what alternatives do i have if i don't have enough height to as you suggest have a 6x2 perpendicular to the floor joists underneath.

could i use 4x2 or have the middle support on slabs ? or any other ideas



thanks

Could you dig out a channel for the supporting joists?

 

[mcdermottc]

Do as I said - use one post to support two joists.

wabbit - sorry Im being thick here but how would i do that ?

also if i am using the below base anchors - what length M12 anchor bolt would i need to use ?

http://www.toolstation.com/shop/Lan...alwork/Post+Base+Bolt+Down/d130/sd3224/p29420
[/url]

 

[mcdermottc]

wabbit

sorry to be a pest....

i noticed in another post you mentioned using these

http://www.screwfix.com/p/fastenmas...3-x-100mm-pack-of-50/56926#rating_link_anchor[/url]

do you think i should forget the coach bolts altogether and use these to secure joists to posts

cheers

 

[masona]

Do as I said - use one post to support two joists.

wabbit - sorry Im being thick here but how would i do that ?

Dog tooth connectors

Plate washers

Coach bolts