What should decking subbase be?

[Toby]

Is it sufficient to lay decking on a pressure treated timber subbase or is there any logic to laying it on something different that won't rot? Its going on top of concrete and the area collects water when it rains. Thanks.

 

[Parker]

Hi ,

For a start , decking needs a subframe to be supported , and the reason the wood is treated is so it wont rot......hence why decking is laid on treated joists.The lifetime of these joists is approx 15-20 years.

There isnt anything else to lay decking on...unless you make a galvanised steel subframe but you wouldnt see me drilling and bolting a few hundred holes ....waste of time.

Settle for treated joists like everyone else.....alot easier.

Before you lay your decking put down a weed/damp supressant membrane and cover it with pea shingle under the area where you plan to put your deck.

 

[movax]

What I've always done and its worked a treat is to place ordinary 4" blocks on a bit of lean mix concrete at various places round the deck area , get them level relative to finished deck level , then build sub frame on top of them , then deck , nothings collapsed .....yet!