Decking on Clay - sunken`

[checkmate]

Hi all

5 years ago via my builder i did composite decking. As my house was high up we had to have a decking quite high up. after 5 years the whole decking frameworks has sunk down, there's like a arch now and can see its sunk.

I have attached pic on how it was pre decking installed. The pic is missing noggings but these were installed.

I am now looking to re-do everything and either stick with decking or porcelain tiles.

Just wondered how can i do groundworks different this time to avoid the sink? esp if i go via tile route i am assuming it be visible by cracks this time.

When i did my extension, the builder dumped all clay rubbish under decking to avoid it being skipped! Not sure if this is reason too!

Thanks in advance

 

[JohnD]

When you dig it up, look and see how big the concrete pads are that the legs stand on.

There is no need to bury the legs like fenceposts, and that accelerates rot.

 

[catlad]

Use old flags under your posts too maximise the base plate.

 

[Captain Nemesis]

porcelain tiles.

Do you mean tiles?

Laid on what?

if i go via tile route i am assuming it be visible by cracks this time.

Cracks?

 

[Captain Nemesis]

When you dig it up, look and see how big the concrete pads are that the legs stand on.

Lets open a book on their size, and include one odds for "there are none".