Raised decking support / posts - concrete in or metal spike?

[Dundonald]

Hi,

Just about to start a decking project in my garden. I haven't built decking before, but I have spent some time planning my build out so I'm pretty much set. One question though. I've built good strong fences before and instead of concreting in the fence posts I have used metal spikes. I am wondering if something like this

be used to hold the posts that will support the raised decking instead of concreting in?

I guess my only concerns are that the spike once positioned and laden with weight from the decking and use of the decking, the spike could possibly be pushed deeper in to the earth and consequently allow areas of the decking to droop, if you know what I mean. Is this a valid concern or not?

Would be interested to learn if others have used the spikes for raised decking.

Many thanks.

[The Medway Handyman]

No. First of all they are unecessary, secondly they can twist if they hit stoney ground, and thirdly they could well sink.

I don't know if your deck is freestanding or attached to a building, but in either case the only reason to concrete in posts is to keep the deck 'square'. If you don't achieve that, then boarding it will be a big problem.

The support for the joists is achieved either by a cross beam or by using padstones to support them.

How 'raised' is your decking?

I've built sh*t loads of decks. Happy to give any advise I can.

[TheScullster]

"The Medway Handyman" wrote

snip.........

ISTR mention of a gap between deck and house wall that might be worth repeating here/googling. Can't remember why it was necessary though. Seem to think it was insect related.

Phil

[OG]

You can get cement-in versions of spikes

better than hammer in spikes.

[The Medway Handyman]

If you bolt a ledger plate to a house wall above DPC you should leave a 10mm gap between it & house wall, and a 6mm gap between deck boards & house wall. Its so you don't compromise the DPC.

[Dundonald]

Hi Dave sorry for delay (been away with no access to computer). The decking I have planned is raised about 4 ft. It's about 9 x 8 ft. Two lengths of the decking will be secured to the house exterior down one length and the conservatory exterior down another length (all above the DPC at roughly interior floor level). The joists at those ends will hang off of the 2 x 4 screwed to the walls. So I guess the decking will remain squared. But this still leaves a corner and sufficent support inbetween that corner and respective corners against the wall. So my plan was/is to support by either spike or concrete posts. The post can't simply rest on the earth surely?

[Dundonald]

Are you using a padding of some kind inbetween the house brick and the ledger to maintain the 1cm gap?

[The Medway Handyman]

A number of 'heavy' washers on each bolt to space it out by 10mm. Provides a gep between the ledger & wall.

[The Medway Handyman]

4 x 2 will need support every 6' of span to avoid bounce (assuming joists at 18" spacing) If you went up to 6 x 2 they can go 10' without support. More timber granted, but less support.

I use wooden posts supported by concrete blocks or slabs or concrete in post supports

all keep the posts off the earth. I'd be inclined to use a concrete in post support at the corner & slabs/blocks elsewhere as required.

[Dundonald]

Cool, if I use 6 x 2 then I can run each non wall lengths without additional support other than a 3 x 3 post in the remaining corner?

Actually remembering my plan down one of the lengths I will have steps down to the lawn so either side of the steps I will be running a post up in any case to support the hand rail.

[The Medway Handyman]

Yup. A 6 x 2 C16 will span 2.95m at 450mm centres.

[Dundonald]

Sorry you lost me on the 450mm centres bit, what's that, I'm assumig spacing between joists?

[The Medway Handyman]

Yup - the closer they are the longer the span.

[derekarmstrong1956]

[The Other John]

Any particular reason you've quoted an eleven year old post?