grouting without filling stone texture

[pieman]

I have about 5m2 of 3inch square floor tiles to lay, in the dry(er) parts of my bathroom. They are billed as marble, though I would say closer to limestone, and have a very open texture, with cavities and voids as part of the stone character. I'm hoping this will also give me a good non slip surface.
When it comes to grouting, I don't want to fill all the stone texture with grout.
I'm assuming I'll be able to find readymix grout in cartridges, and gun it into the joints as 'pointing', and then out with the surgical glove and wet finger! No joy yet on grout cartridges on t'internet, though.
any leads/recommendations? (chipboard substrate on joists at 16inch centres)
Failing that, I'm contemplating using an icing bag. Seriously!
any better ideas?

many thanks

pie

 

[HandyJon]

Have you considered sealing the tiles first? Not with silicone sealant but with stone sealer, available from Wickes and such like.

 

[pieman]

Hi HandyJon
I definitely will be sealing the tiles first - I've got one of the HG range wax sealers lined up. The texture of the stone is on a much larger scale, though, cavities up to the size of say, lentils, which I'm sure would tend to catch the grout...

 

[Jasonb]

Don't use a readymixed grout, use something like BAL widejoint grout with GT1 additive which will make it flexible and more waterresistant.

This has a gritty texture and can be applied with a pointing trowel like sand/cement( I have done it this way on slate floors) or get a pointing gun from screwfix #17951, looks like a mastic gun but you fill it yourself.

Jason

 

[pieman]

many thanks for the pointers, Jason.
I didn't know that the pointing gun existed, but I was hoping. It sounds like just what I need.
cheers
pie