Decking

[Lefty Guns]

I've been getting prices for materials to build a deck out the back of my steading. It's 22m x 5.4m

Quick question or two for anyone in the know:

1. Do I really need to buy the special decking joists or can I just use 3x2, 4x3, 5x2 etc treated timber? The joists are a fair bit more expensive. I will be laying the decking to an existing concrete slab which has a fall in 2 directions.

2. Should I use a membrane of some sort on top of the existing slab?

3. Do I need to put sand down too?

Cheers,
Iain

[rich0411]

I just finished the decking in my parents garden and i just used tanalised 4 x 2 which came in various lengths, and i used a membrane that was on a roll i bought from selco i think it was about £10 for a 30m x 1m roll.