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Posted: Mon May 19, 2008 12:44 pm
by 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.
Posted: Mon May 19, 2008 6:11 pm
by 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 
Posted: Mon May 19, 2008 7:14 pm
by 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.
Posted: Sat May 31, 2008 10:30 pm
by 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.
Posted: Mon Jun 02, 2008 10:43 pm
by Rich H
Isn't that what I said?
Posted: Mon Jun 02, 2008 11:55 pm
by 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