Build your frame first in the position that you want it, then using old flags/bricks or concrete
blocks level the frame to your position.
I would add two rows of noggins in a deck that large.
buy a dozen post spikes 3x3" and some lengths of treated posts.
If you are putting a rail on the high side then use the spikes and posts
to support the deck as well as the rail, you can put a string line across the posts
at the end to level the rail.
lay all you decking loose over the frame so you can walk on it to see if there is any bounce
in the deck and if so add another column of blocks were necessary.
when laying the blocks or flags you will have to scrape the ground level first.
I would fix the decking to the pool using 100mm expanding frame anchors.
The more columns you put in the less likely it is to subside, and if the ground is
soft then compact it first.
blocks level the frame to your position.
I would add two rows of noggins in a deck that large.
buy a dozen post spikes 3x3" and some lengths of treated posts.
If you are putting a rail on the high side then use the spikes and posts
to support the deck as well as the rail, you can put a string line across the posts
at the end to level the rail.
lay all you decking loose over the frame so you can walk on it to see if there is any bounce
in the deck and if so add another column of blocks were necessary.
when laying the blocks or flags you will have to scrape the ground level first.
I would fix the decking to the pool using 100mm expanding frame anchors.
The more columns you put in the less likely it is to subside, and if the ground is
soft then compact it first.