decking footings - advice needed

[ddtaff]

I'm in between jobs so I've started landscaping the garden. Last year I had some sleeper beds put in and a new patio layed.

I'd like to install a small area of decking in between the sleeper beds. This will be edged with a sleeper dug into the ground. This will match the edging that was installed at the same time as the patio, on the other side of the decking. On the other side of the decking will be grass

View media item 31869 View media item 31870 View media item 31872
I'd like the decking to be at the same level as the patio and grass either side. I was planning on digging down 15cm and filling with hardcore or crusher run.

I've never done anything like this before. A friend has pointed out that i will be creating a lower level in one area of the garden, which may encourage water to be drawn to it.

The questions i have at the moment are

1. What sort of footings are necessary? Should i dig holes then fill with concrete? Or can i use pre cast footings which sit on the hardcore base? Or is there a better\easier way

2. Should i be concerned about the area under the decking attracting water? should i be digging lower for the hardcore for better drainage?

3. Is crusher run the correct material for the sub base?

Any advice would be appreciated.

Thanks

 

[plstering]

pile footing 2ft/3ft deep filled with concrete then have a metal joist stand pushed in too it as it is drying level them as you go
treated 4"/4" posts concreted in 2ft deep then coach bolt the deck too them
or set in pad stone using paving slabs in a 4/1 leen mix of sharp sand and cement agen level as you go
no hardcore needed sorry just spray it over with weed killer then cover with terram landscap fabric peged in sorted