F.A.O. Thermo & Noseall

Hi Thermo & Noseall

I have read you excellent posts on laying paving.

I am going to take you advice and just wanted to double check my understanding.


Spreadout MOT/DTP1 ( 40mm to dust ) across the complete area where the paving slabs are to go. Foot traffic only. What thickness would you recommend 75mm or 100mm ?

Once spreadout plan to run a wacker plate over this several times and soak the MOT/DTP1 at the same time to ensure that it is well compacted.

Is there any need to use one of the geotextile fabrics laid on top of the compacted MOT/DTP1 or will weeds never find their way through as there will be no sunlight to the soil below ?

As for the mortar mix which strength and thickness would you recommend ? Plan to put down 20mm thick natural slate slabs.

Should the slabs be soaked before putting them down to stop them absorbing the moisture from the mortar ?

Look forward to hearing from you.

75mm compacted will be fine

dont get the mot to wet, or its a pig to compact

no need for the geotextile

i normally use a 1:4, about 25mm is fine if youve got the sub base right

you can wet the back of the salbs before you lay them. dont soak them.

if i lay slate or similar, i always have a clean bucket of water and sponge handy just to wipe the surface of any splashes etc as you go.

what do you guys need me for.

geo-tex is normally reserved for ground conditions that will have pockets of soft ground that cannot be dealt with by using layered hard core alone

usually deep clay.

as big 'T' has said, saturated mot becomes 'spongy' and reacts rather awkwardly to a wacker plate too. liquefaction occurs and some of the water bubbles back to the surface.

paradoxically though, mot that has been simply laid onto the surface and not compacted, will, when left alone with the elements (rain etc) become very firm with no outside interference.

i think the lime dust in the stone creates a limestone concrete.