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Posted: Wed Oct 25, 2006 6:19 pm
by Grant paving
I am laying block paving and have ended up getting my depths a bit wrong firstly I dug down to deep so used a load of MOT about 15 -20 cm but thought that this would be o.k. because it will be a stronger base but now that I have done my edges and brought it level with the existing road and 15cm below the houses membrane level I still a depth of around 10 -15 cm which I have started to fill and level with sand my question is will there be any long term problems having this kind of depth of sand or will it be o.k.?
Posted: Wed Oct 25, 2006 7:37 pm
by Stuarty
That sort of depth is far too deep for the sand. It will sink. Alot. Recommended depths for sand are between 35mm and 50mm. I would take out the sand you have put in and get the level with the MOT.
Posted: Wed Oct 25, 2006 9:26 pm
by Grant paving
Thanks for the reply just one last question is 50mm the most i can use as i now have a load of sand and that i need to use up ?
Posted: Wed Oct 25, 2006 9:58 pm
by lutonlagerlout
dont make 1 mistake into 2 ,dig the sand out add more type 1 till you get to the correct level ,then put your 35-50 mm layer of sand on this
most lads use electrical conduit as screeding bars and this is only an inch
years ago i was forced/coerced into laying a drive on 100mm of sand,i went back last year and the result was pretty much catastrophic 
confession over ,how many hail marys stuart????
cheers LLL
Posted: Wed Oct 25, 2006 10:21 pm
by Stuarty
I got cornered into something similar, at the time i didnt really know any better cos i was just a new start back then. Passed the job a few months back, the image still haunts me. If i pass something ive done i normally have a good look and think to myself, "i did good there". But on this occasion i was ashamed to admit i had a part in that job. If i recall correctly the sand was around 110 / 120mm sand. Was with a guy who "done it all". Didnt want to tell the boss he buggered up the calculations, so he just put the stuff in regardless. Needless to say once he was found out he was sent marching, tbh i thought i would have been too.
Posted: Thu Oct 26, 2006 10:48 am
by Grant paving
Thanks again for the feedback have my MOT ordered and will make sure i get me depth right this time 
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Finally i read that you can't lay block paving on wet sand but due to the recent weather all the sand is wet or damp can you please clarify if this will casues a problem if i do and if so do i have to wait for the sand to dry out a bit?