Hello would appreciates some information please .
Will be 1st time laying paving and am confused as there seems to be many different answers .
I'm thinking of laying slightly riven indian sandstone callibrated 22mm thick . I have taken off existing paving and the base is concrete .
As its a sound base can i use it ?
One supplier told me i dont need to seal these slabs only if im using honed slabs its required is this correct ?
What type of sand should I use for laying the mortar please and what ratio and is there any additive i need to use in the mortar and under the slab ?
thanks in advance
Indian sandstone riven
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r896neo
- Posts: 521
- Joined: Wed Feb 22, 2012 9:38 pm
You dont need to seal any paving although with some (in particular sawn/honed paving) it is recommended.
Sealing is very much up to you, it will make maintenance easier but really you need to spend a good chunk on a quality sealer, the sort of stuff you buy in diy sheds like thompsons paving sealer are awful and more trouble than they are worth. There is good info on the sealing page on the main site.
I laid kandla grey riven sandstone at my own house and haven't sealed it and never will.
As for the mix You need to use a coarse grit sand 6:1 with some plasticiser. I like most on here prefer to use a wet mix like a bricklaying mortar or a fraction stiffer, its easier to get a good solid bed as it spreads under the flag when tapped down. Dry mix is cleaner to work with but harder for a diyer to get the slabs fully bedded.
After you lay a few lift one to check its fully bedded i.e. no voids ( a few small low spots here and there are ok but aim for 90% of flag in contact.
Your concrete base could be an issue, construction wise its solid and therefore perfect as a sub base however some guys on here have experienced or at least seen problems with flags staining when laid over a concrete base. The concrete is obviously pretty impervious so any water drying out of the bedding can try and escape upwards through the flags. This can cause issues with staining. I must be clear though this is just a disclaimer so you can be aware there is a small potential for a problem here. Using a bond bridge (page dedicated to this on main site) should allieviate any risk.
Perhaps wait for others opinions to confirm though.
Sealing is very much up to you, it will make maintenance easier but really you need to spend a good chunk on a quality sealer, the sort of stuff you buy in diy sheds like thompsons paving sealer are awful and more trouble than they are worth. There is good info on the sealing page on the main site.
I laid kandla grey riven sandstone at my own house and haven't sealed it and never will.
As for the mix You need to use a coarse grit sand 6:1 with some plasticiser. I like most on here prefer to use a wet mix like a bricklaying mortar or a fraction stiffer, its easier to get a good solid bed as it spreads under the flag when tapped down. Dry mix is cleaner to work with but harder for a diyer to get the slabs fully bedded.
After you lay a few lift one to check its fully bedded i.e. no voids ( a few small low spots here and there are ok but aim for 90% of flag in contact.
Your concrete base could be an issue, construction wise its solid and therefore perfect as a sub base however some guys on here have experienced or at least seen problems with flags staining when laid over a concrete base. The concrete is obviously pretty impervious so any water drying out of the bedding can try and escape upwards through the flags. This can cause issues with staining. I must be clear though this is just a disclaimer so you can be aware there is a small potential for a problem here. Using a bond bridge (page dedicated to this on main site) should allieviate any risk.
Perhaps wait for others opinions to confirm though.
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lutonlagerlout
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r896neo
- Posts: 521
- Joined: Wed Feb 22, 2012 9:38 pm