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Posted: Thu May 15, 2014 12:19 pm
by falcs
Just looking to canvas opinion. Will be laying 25mm Black Basalt 600x400 slabs on approx. 125mm of MOT, should I just go with one of the usual bedding mixes (prob 6:1) or is the lime addition worth the extra cost?
Also, whats the view on adding sbr to the bedding mix? Aside from the working life being shortened, the cost seems to be expensive (34m2 being laid) if its 5ltrs per bag of cement.
Posted: Thu May 15, 2014 4:46 pm
by Carberry
- Overkill on the MOT, 100mm is the minimum for a driveway with 150mm recommended.
-6:1. Can use 10:1 but most on here prefer 6:1, stronger and more peace of mind for the sake of a few extra bags of cement. Very hard stone so make it a little wetter to aid with adhesion.
-Worth using SBR. Instructions on the tub are excessive and you will need a second mortgage if you use their ratios. Putting 100ml in a mix make a noticeable difference.
Make sure you have gone over the site thoroughly before you start laying. Basalt is nice stone and expensive, you don't want to ruin it.
Posted: Thu May 15, 2014 5:51 pm
by falcs
Just noticed I've posted in the block paving section, perhaps one of the mods can move it to one of the more suitable sections?
Posted: Fri May 16, 2014 10:04 am
by Tony McC
Definitely bond bridge the basalt. It's a dense stone and unless laid on a very mess high slump bed, it often fails to bond properly, so SBR helps ensure it stays put on a much-cleaner-to-handle moist bed.
Posted: Fri May 16, 2014 4:33 pm
by falcs
Bond bridge check
SBR added check
Lime added to the bedding mix?
thx so far, great site and forum.