MOT or Scalpings

[DrFfybes]

I ordered some Type1 MOT for under a patio and under fake grass (the latter to be topped with sand before the grass goes down).

At delivery the driver whispered [1] that 40mm to dust scalpings do the same job, are cheaper and are what they keep in stock as not many people buy MOT.

Looking at the Paving Expert website, he was quite correct in that MOT is really only needed for high load high traffic, however they suggest that for the extra couple of quid per dumpy bag you should use MOT (or DTp1 as it should be known).

Just our of interest, I logged into my Travis Perkins account, and the price difference was £5.25 + Vat per bag, but the MOT was 10% CHEAPER than the scalpings!

Might be worth checking locally though for those wanting a few tonne for a project.

Paul

[1] He really did whisper it, despite there being nobody else in sight,

[Dod101]

This is all very technical. What, pray, is MOT or scalpings? Not that I think I will be needing a few tons of anything.

Dod

[sg31]

MOT1 is a specification by the Department of Transport for sub based material used in road construction. It's often granite or crushed concrete. It's become a standard for building projects under driveways and concrete floors.

Scalpings are basically old tarmac that has been removed from roads when they are planed off before re-covering with new tarmac. I thought local councils had stopped relaying roads so I've no idea where they come from these days.

[DrFfybes]

MOT1 is a specification by the Department of Transport for sub based material used in road construction. It's often granite or crushed concrete. It's become a standard for building projects under driveways and concrete floors.

Scalpings are basically old tarmac that has been removed from roads when they are planed off before re-covering with new tarmac. I thought local councils had stopped relaying roads so I've no idea where they come from these days.

Scalpings originally were the chippings from the quarry when they 'dressed' the stone. As it is machine cut these days then it tends to be "old rubbish crusked up".

What they both have in common is they self-bind, unlike Ballast which has nice round edges, this stuff is sharp, and when compaceted becomes almost like concrete, so excellent for under a patio/drive/road surface.

It also means it self binds in the dumpy bag, so once you get halfway down you can't even get it out using a pointed shovel and need to keep breaking it up. I could cut the side out of the bag, but then it would go everywhere and I need the bag at the back to put it in.

The first bag took nearly 3 hours to wheelbarrow around the back.

Paul

[Dod101]

Thanks for that. I am unlikely ever to need that info but will mentally file it anyway.

Dod

[Tempi]

I think the MOT Type 1 particulate size is about '75mm to dust', so a bit chunkier than the '40mm to dust' scalpings. The 'to dust' bit means you get anything smaller down to dust/sand type size. And it's the 'dust' size particulates that do the job of binding the larger chucks together. Or if its the only thing left in the builders bag, I suspect it'll behave like wet fine sand!

(I once had to consider whether to reject a MOT type 1 lorry load of approx. 15t as it contained too high a proportion of dust as part of a road base on a reservoir embankment. As it was one of the final loads of the sub-base, it was judged to be ok, as the vibrating roller would move the dust down through all the aggregate to help bind.)