Patio foundationsm² - Confused about what is required

[dcb]

Forgive me if I'm asking something that is on the main site but I've spent several hours searching through and have only got myself more confused.

I'm building a patio of 16m² and has a boundary of railway sleepers with the ground (fairly compact soil) currently levelled to the botton of the sleepers.

What I don't really understand is if I need to put a base down of MOT or DTP (not sure what the difference is between them) and then what depth of bedding layer I need to put on top of that.

Any help greatly appreciated.

[lutonlagerlout]

100mm compacted type 1 (read MOT stone for thsi)
30-50 mm of bedding material(read grit sand mortar)
then your slabs/flags 38-50 mm

so you earth need to be around 200mm below finished height
LLL

[Rich H]

The DTp used to be the Ministry of Transport. They produced the specification for highway sub-base construction and materials, hence MOT/DTp Type 1, etc.

If they're old railway sleepers, filling up the void with type 1 is a pretty expensive way to do it. You might want to consider hardcore or crushed concrete for the first few inches, then type 1 on top. If the hardcore is well compacted, you need only then blind over a couple of inches of type 1. Bring the total sub-base up to 100mm below the paving height (allowing for the fall, of course) as LLL says.

[Tony McC]

T'other road round, Rich: MoT used to be the Ministry of Transport which became the Dept of Transport (DTp), but as the building trade is so up-to-date with its terminology, we still refer to "MoT", despite it disappearing in the early 1980s.

[Rich H]

Isn't that what I said?

[lutonlagerlout]

ye i thought so :;):
i still order 5 tonnes of MOT,rarely call it anything else
i worry when people ask if i want type 1 instead,they invariably mean crushed concrete,wood,cement bags,pram wheels etc
IYKWIM
LLL