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Posted: Mon Jul 25, 2005 11:31 am
by moody_gaz
Hi there and congrats on an excellent and informative forum.
I have an existing block paved drive that I am going to raise 8 to 9 inches or so to make it level with a new drive that I am getting installed. I have taken the blocks up already and the sand and subbase underneath seem very firm. Will I need to take the grit sand layer up before putting another layer of subbase material on top? or can I lay subbase and sand layers on top of what is already down?
Also, how much kiln dried sand will I need for a new block paved area of around 120 square metres.
Posted: Mon Jul 25, 2005 7:39 pm
by Nigel Walker
Remove the bedding sand. You may be able to store it and re-use. You neednt remove every last little bit of sand, just the bulk, so that the shovel is scraping on top of the sub base.
Build up the levels using Type 1 Sub-Base (Dpt1). It will be best to in-fill in 2 layers and compact well with a Wacker plate
The amount of Kiln Dried Sand depends on the type of blocks and the thickness of the blocks
If you are using a 50mm thick Driveline 50 type block then you will need approx. 12 bags of 25kg size.
If you are using a Tumbled pavior you will need slightly more.
If you are using 60mm paviors you will need approx. 15 bags of 25kg
Nigel
Posted: Tue Jul 26, 2005 7:47 am
by moody_gaz
Thanks Nigel!
I am using driveline 50s so 12 bags it is!.
I had a good trawl around the website and used the subbase and bedding sand calculators, but could'nt find any info on the amount of kiln dried sand to use. How about having a calculator on the website for this as well as the others?
Posted: Fri Aug 19, 2005 2:07 pm
by Tony McC
The difficulty I have in providing such a 'jointing sand calculator' is that there is so much variation in block pavers that it's impossible to be accurate.
Obviously, block depth affects sand coverage, and you need more sand to joint a metre of 80mm blocks than would be needed for 50mm block, but also the plan size of the blocks directly affects the linear metreage of joints poer square metre of paving. There are more joints in a square metre of 200x100 blocks than in a square metre of, say, Tegula or Brett Alpha.
And then there the issue regarding joint width. Some blocks are notoriously 'tight' when laid, having joints that are usually 1-2mm in width, whiole others are 'loose', and have joinst that may be 3-4mm on average. Then consider a paver such as Tobermore Mourne or TopPave Classico with their rounded corners that swallow up jointing sand.
The best that can be done is to rely on 'averages'. For 200x100x50mm blocks, you should get around 8-11m² per 25kg bag; for a typical tumbled paver (50mm) it's more likely to be 6-9m².