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It's MOT sub base :(
It's a mate's engineer husband and colleague who are looking at setting up some sort of trade business in the next few years. As a result is £3,6k - which is much cheaper than every other quote we've had. He did a full reno and extension of their house and all the finishing is to a high standard.
However, there are a few things like the lawn drainage to drain he doesn't really want to do, and my OH doesn't want to pay more for.
But yeah there are some things I'd of liked. However, I don't really have much say in this anymore.
Once they're here and we see what's what I might suggest concrete around the bay.
The lawn drainage is my main bug bear as based on the solutions he suggested I don't think he appreciates the combination of heavy clay, proximity to a water source, height of water table and the runoff from of uphill adjacent gardens. Or more likely he dgaf.
Also as my OH doesn't spend time in the garden over winter and spring they dgaf either.
hugo7-
There's a degree of you get what you pay for. Over clay I would definitely use concrete as a base. The general guideline would be to use at least 200mm/8" of type 1, compressing every 2", this will mean digging to 250mm/10" of finished surface, I doubt they will. Is there a clear run left beyond the patio to your mains drainage? If not, insist that they fit a perforated pipe encased by 4"/100mm of shingle to it and run the pipe beneath the new patio out to the lawn, this will allow you to attach lawn drainage at a later date.
It's easy to get a perfect finish over 2" of type 1 it just won't be there in 5 years.
ColinTheBald
Ensure that they're building it on a slab of concrete at least 3"/75mm thick, falling slightly towards wherever you're sending the surface water. If its going right up to the house the finished surface should be a minimum of 4"/150mm below your damp proof course. This way you'll get no root problems OR give your house damp problems.