Expert: Torin Dixon - 3/18/2008

Question
QUESTION: I am remodeling a tub surround.  I had water problems with builder using green board and a window leaking water which soaked exterior sheeting.  I have replaced the exterior sheeting, vapor barrier, studs, etc.  I used 1/2" Durock cement board on back wall and the same over 1/2" green board on sides.  I tapped all joints/corners and buttered with modified thinset mortar.  I have installed 2 rows of 16x16 travertine floor tiles just above tub with butt joint (no grout line)using white modified thinset mortar.  Did I need to leave a grout joint?  Will the tiles "grow" and crack or buckle?  I read on some other sites where a 1/16" grout line should be used??

Now above the travertine I installed a 4" high accent strip of marble, again with no grout line, butt jointed.  Was this a mistake?

I will finish with 6x6 tumbled travertine with a 3/8 grout joint on rest of wall.

When all is done do I need to seal everything?  I read where travertine does not need sealing??

Thanks for any help.

ANSWER: Terry,
You should caulk the bottom joint between tub and stone with a silicone caulk (colored) to match the tile or to match the tub color, and the vertical corner joint between the side walls and back wall. The tight joints between stone should be grouted using colored non-sanded grout. the 3/8" joints need to be grouted with colored sanded grout. After grout cures (10 days) i suggest sealing tiles and grout joints using HMK S34 Silicone Impregnating Sealer available at the following link:
http://hmk.stonecareonline.org/shop/
Travertine is a very porous stone and should be sealed. to aid in the regular cleaning (once sealed) i suggest using the HMK P24 Liquid Stone Soap.
Best regards,
Tad Dixon

---------- FOLLOW-UP ----------

QUESTION: Thanks Tad,

Some followup questions;

1.)Did I need to leave a grout joint?  Will the 16x16 Traventine tiles "grow" and crack or buckle?  I read on some other sites where a 1/16" grout line should be used?

2.) I installed a 4" high accent strip of marble, again with no grout line, butt jointed.  Was this a mistake?  Is it ok to butt joit marble?

3.) Should I seal surfaces of traventine BEFORE I caulk between tub and wall?

4.) Should I seal surfaces of traventine and marble BEFORE I grout, then reseal it again after grouting?

5.) Once all is sealed and based on daily showering how often should it be cleaned with the recommended P24 liquid stone soap?  How often should I reseal and should I use the same sealer.

Answer
1. tight joint is ok, but needs to be grouted with non-sanded grout. travertine will not grow unless it is in direct extreme sunlight where it could expand.
2.ok for butt joint, but needs grout
3.sealing prior to grouting makes it easier to clean the tile during the grouting process. Re-seal after grouting and curing.
4.Seal before caulking
5. clean with P24 weekly, re-seal every 6 months.