"grouting" between interior sandstone flagstones

[James W]

I really couldn't think of any other word to use other than grouting!! Anyway. I'm about to polish up and treat some internal sandstone flagstones, and all the edges (between each flagstone) needs "re-grouting". What would be the recommended material to use for this?

I remember someone telling me to use a polymer based material as it is much tougher than other materials such as sand and cement.

Thanks in advance

James

[BigWallop]

A flexible polymer filler is the best idea because it allows the floor to move and breath easier than hard sand / cement mixtures. But a word of caution on using either method.

Try NOT to get any of the mixture on the surface of the stone.

The fillers, all of them, can easily stain the surface and is difficult to remove, so cover the stones with a sheet of newspaper or cardboard and tape the edges down a bit to stop this happening to much. The same sheets of paper can be used again and again all over the floor, so you don't need to cover everything before starting the job. Just make sure you keep the surface of the flags as clean as you can.