decking base

[etype]

I want to build a deck in my garden but am unsure on the gaps when building the base, I think it should be about six inches apart ? can anyone advise

[rugeleyboy]

18 inches apart.

[landscaper2]

18" (450mm) is good, make sure the bearers are off the ground, either supported by posts or resting on concrete blocks set on concrete, with a DPC between timber and concrete, Place a membrane on bare soil, with a layer of shingle to keep weeds down.

[etype]

Many thanks for the advice