Is my grout waterproof

[jas1]

I finished grouting my new bathroom tiles a weeks ago. I have noticed when I wipe the tile down with a damp cloth the grout darkens as if it has absorbed water. The grout is Bal superflex colour limestone. I have since applied two coats of Fila grout protector. But the grout still discolours when wet. Do I need to apply a waterproofing agent or is this normal. I do not want to start using the shower until I am sure the grout is waterproof.
Many Thanks
John.

[rosebery]

Nope.

Only epoxy grout is waterproof. Superflex (damned good stuff mind) is cement based and is water resistant but NOT waterproof.

Your grout doesn't HAVE to be waterproof. Superflex is fine even in powershowers. I can't comment on the use of the Fila product on top though.

What adhesive did you use?

What is the substrate and how did you prepare it?

[jas1]

Hi, Thanks for the reply.
Preparation:
All plaster removed, walls dry lined with the green plasterboard, plenty of adheshive to prevent any board bounce.
Two coats of sealer applied to the boards.
Tiles, adhesive and grout came from a friend of a friend that has a wholesale outlet. I told him the bathroom layout and he supplied what he termed a good adhesive (can't remember the name. Tiles were not grouted until they had been on for a week. Grout was applied with a grout gun which ensured deep penetration and finished of in the traditional way.
A friend has recommend a penetrating silicone sealer "aquamix for showers and baths" am I better safe then sorry.
John

[rosebery]

Thanks.

What sort of sealer did you use?

It's up to you. I would think that your BAL grout will probably be fine on it's own.

Cheers