Sand and cement pointing of indian sandstone slabs

[Grahamh8]

I believe the ratio of 3:1 sand:cement is generally used for pointing.
Could somebody let me know if this is suitable for Indian sandstone? Is the sand, sharp or builders sand and should I add SBR to the mix?

[Grahamh8]

Any suggestions?

[dig dug dan]

Sand and cement has always failed me over the years, no matter what mix.
use easipoint or easijoint, one can be aplied in the rain, the other cannot!
both of those have been recieved critical acclaim, unlike geofix!

[lutonlagerlout]

plastering sand gives a technically stronger joint but a coarser finish
building sand has been used for years but is weaker

the key is to make the mix the right consistency so it does not stain the flags
wet enough so it bonds, but not so dry it does not set right
weatherpoint 365 is a decent polymeric which guarantees no staining and can be installed in the rain
cheers LLL

[Grahamh8]

plastering sand gives a technically stronger joint but a coarser finish
building sand has been used for years but is weaker

the key is to make the mix the right consistency so it does not stain the flags
wet enough so it bonds, but not so dry it does not set right
weatherpoint 365 is a decent polymeric which guarantees no staining and can be installed in the rain
cheers LLL

Thanks alot, and SBR does it improve the mix at all?

[Mikey_C]

yes, but increases the risk of staining

[Grahamh8]

So 3:1sharp sand to cement, plus a small amount of SBR, is suitable for pointing? If I'm going down the mortar route and have some larger joints ie 15mm.

Should the slabs be wetted before hand and the surface be allowed to dry? I'm planning on a semi moist slump and hand pointing, striking off with a pointing iron.

I'm sure my main issue will be staining of the limestone.
Would washing off with a wet sponge immediately, minimise this?

[seanandruby]

I usually adopt the saturated surface dry procedure

[sy76uk]

We all have different ways of pointing.
The thing we all have in common is that we all use at least a 4/1 mix (I use 3/1) we do out best to keep surface staining to a minimum and if there is any then it will be temporary so nothing that will need a wire brush of chisel to remove ounce cured.
Pointing well for me is on of the hardest jobs to get right and the only way to get it right is through trial and error and finding the way that suits you best.
I like to use a mix of plastering and building sand mixed to a doe like consistency when Trowelling in.
Dampen joints beforehand if trying this method.

[Grahamh8]

We all have different ways of pointing.
The thing we all have in common is that we all use at least a 4/1 mix (I use 3/1) we do out best to keep surface staining to a minimum and if there is any then it will be temporary so nothing that will need a wire brush of chisel to remove ounce cured.
Pointing well for me is on of the hardest jobs to get right and the only way to get it right is through trial and error and finding the way that suits you best.
I like to use a mix of plastering and building sand mixed to a doe like consistency when Trowelling in.
Dampen joints beforehand if trying this method.

Thank you for the info. Would sharp sand be too coarse and what about SBR? is that overkill?

[sy76uk]

I personally never use SBR in pointing.
Sharp sand will give a very strong joint but is very hard too work with.