Decking post concrete in supports wobble :(

[MrGeo]

Hi all,

I've used concrete-in post supports for my decking posts (see http://www.screwfix.com/prods/70197...crete-In-Post-Support-100-x-100mm-Pack-of-2), using postcrete to secure them in.

I put in the posts (about 18 inches high), and after sawing off a bit on the top, the posts don't seem very secure at all now and wobble around a bit and I can see the earth surrounding them move too.

They seem pretty stable if I sit on them, and the deck will be secured to the house, so I'm wondering what I should do. Help, please!

 

[r896neo]

It sounds like you dug your holes very wide and or into loose ground. Was it original earth or fill?

 

[MrGeo]

It sounds like you dug your holes very wide and or into loose ground. Was it original earth or fill?

Hi there, not sure what you mean by fill or original earth, but it is pretty dry and stoney.

I'm not feeling confident on the best way to continue, do I rip it all out and start again , trust that as the weight should be goind downwards that all will be ok and the lateral movement will be held firm by the ledger, or add in some additional posts by concreting them directly into the ground rather than using the post supports ??

 

[r896neo]

I would throw in a few additional posts for piece of mind, a wide shallow hole will provide a good compression strength as it spreads the load but it will not be very good for lateral movement. A deep narrow hole is usually the best route.

As for the question about the ground i just meant that if you live in a new build or heavily landscaped garden the earth may not be the original height and may be fill put in to raise an area, this would be pretty obvious though.

 

[Pinnacle]

Looks like your question has already been answered above, but I jst wanted to throw in a warning about planning permission and building regs.

The ledger can not be attached to the house without a 10mm gap between the house and the decking/frame. You'll need to use a bunch of spacers between the frame and the house to make this gap.

Also have a read on various rules and regs on planning/building regs that came into effect in october 2008 as this may well effect what you are doing.