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Posted: Sun Jun 26, 2005 8:22 pm
by wilsonr
Hi Tony,
You have a flag bedding calculator at:
http://www.pavingexpert.com/calcall.htm#focus03
Can you tell me what thickness of mortar the bedding calculator is working to as I am due to lay some Indian sandstone paving and am allowing for up to 30mm of full mortar bed to allow for differences in slab thickness.
The area I am paving is 35 square metres. Your bedding calculator tells me I only need 11 bags of cement and I had manually calculated I needed almost 3 times that amount.
Is your bedding calculator working to a smaller thickness than I need or are my own calculations simply way out?
Regards
Rod
Posted: Mon Jun 27, 2005 11:09 am
by InfAddict
I believe the bedding calculator allows for a 50mm bedding layer.
It is telling you you need 11 bags of cement + 2.7 tonne of sharp sand. This calculator is for a 10:1 semi-dry bedding mix (i.e. 10 sharp to 1 cement) which is why the amount of cement may be less than you calculated for a full mortar bed.
Posted: Tue Jun 28, 2005 8:45 pm
by Tony McC
50mm and it's for a 10:1 semi-dry mix, as InfAddict said. Using a wet mix full mortar bed, you probably need summat more like a 6:1 mix for a patio area, so you might be better off using the Mortar calculator.
Posted: Mon Jul 11, 2005 8:21 pm
by wilsonr
Hi Tony,
Thanks for the reply. Sorry for the delay ... but I've been busy working on the patio!!
I've gone for the 6:1 mix you mentioned. I've used half sharp sand and half building sand plus portland cement.
So far so good. I laid the upper level last weekend. It was very hot ... and I was getting hot tempered at times!!
I really appreciate all of the help you have given me, both in answering my posts and the overall information on the site.
I could not have done it and avoided many of the pitfalls without your help and this site.
I promise to send you pics once I have finished ... hopefully only a few more weekends to go!
BTW, I never realised how hard Indian sandstone was to cut. I have a small angle grinder with a diamond blade and it won't even score a line! I've still not decided what to do about that yet, but I may have another go at hand cutting ... when the temperature is not so hot!
Many thanks again for all of your help.
Rod
Posted: Tue Jul 12, 2005 11:20 am
by Tony McC
A diamond blade should whizz through the sandstone like a knife through margarine! Is it a 'quality' blade or one of those cheapies from a place such as Poundsaver?
Don't force the blade - don't press down too hard. Allow the blade to use it's own weight to cut into the stone. Often with diamond blades, the harder you force it, the less progress is made.