Basically I'm getting a guy to do my tile around my tub/shower. He swears you don't need Redgard and we are on a tight timeline so applying it when hung would put us behind anyway (We really have 2 days to do everything). I have two questions.

1) Do I even need Redgaurd. The internet has mixed reviews. 2) Can I apply the Redgard BEFORE hanging the cement baord so we don't have to wait for them to dry once they are hung?

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    I put up many walls with nothing over 20 years ago, they are still there. Now days in my own home I do use Redguard even though just cement board will outlast me. If you don't have time skip it but make sure to seal the grout. – Ed Beal Mar 16 '16 at 12:23
  • I will be sure to seal the grout. Thanks! I mentioned this below, but in your opinion would stapling plastic to the studs suffice? – DigitalMC Mar 16 '16 at 14:43
  • I have used plastic in the past a few times (shower stalls) I always wonder if it helps because of the screws punch holes but figure it makes a good vapor blearier. I think Redguard would be better especially if using 2X2 tiles Larger 4X or 6X tiles dont have as many grout seams. I have remodeled bathroom tub enclosures that only had Greenboard Sheetrock that lasted many years but the water eventually got through and it had to be replaced. – Ed Beal Mar 16 '16 at 14:55
  • I think due to time I'll use a plastic barrier and maybe just silicone the screws. I don't see any point paying for the expensive barriers if plastic works as well. Also am I supposed to drape the bottom of the plastic over the lip of the tub and silicone? This seems to make the most sense. – DigitalMC Mar 17 '16 at 14:50
  • you do want the plastic to extend to the lip and a bead of silicon would make a great seal. – Ed Beal Mar 17 '16 at 15:03

As long as it's Cement Board & not some crappy "almost" cement board stuff. You really don't need the RedGard, but the more protection the better...so go for it. And yes, you can do the boards beforehand. But, hit the filled seams & screws (your weak points) as soon as a panel is ready to give it some time to setup. You'll have to wait for the fills to dry or at least setup anyway. Just try not to anger your helper too much. Plan for a lunch, cigarette, drink, phone or snack break, flip-off the circuit breaker or sneak Mom in with the baby to delay the job a little, it sucks but he's got to grin & bear it.

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    Ha, I defiantly plan on sealing the edges now. Thanks so much for the advice. I'll come up with a creative distraction for sure. – DigitalMC Mar 16 '16 at 14:42
  • A simple, oops we're out of screws let's head to the store. On the way you notice you need gas too. I have faith in you. :) – Iggy Mar 16 '16 at 14:50
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    Oddly enough we were going to replace my service panel that morning... I think we can work out a power failiure ;) – DigitalMC Mar 17 '16 at 14:45

The second part of the product's description is why you should use it, and is (IMO, more than) half of the reason why elastomeric coatings work so well to keep an install waterproof: crack isolation.

If your grout never cracks, the install will never leak. If it does, and you didn't, it will. Applying it before hand will provide you with neither the proper crack isolation nor any useful waterproofing.

  • Yeah good call, they are definitely helpful. Just curious how necessary. What about stapling plastic to the studs? Would that work as a waterproofing method? – DigitalMC Mar 16 '16 at 14:42
  • @DigitalMC - "Proper installation of cement and fiber-cement backers, according to the current Tile Council of North America Handbook for Ceramic Tile Installation, requires the use of a membrane in wet areas." Note, this is not code AFAIK and this "council" might be monetarily backed by the industry but that doesn't mean they're incorrect IMO. – Mazura Mar 16 '16 at 22:44
  • Gotcha, thanks for the link. I'll definitely use something at this point, just figuring out what now. – DigitalMC Mar 17 '16 at 14:48

Grout is porous, sealing it won't protect you. Also, You need one vapor barrier either behind it or over it. Redguard would be an over it application. You can't have 2 or you create a moisturizer sandwich. After much research I used Kerdi so I am familiar with that. But I did do a little research on redguard in the beginning. Please do further research on johnbeard.com or houzz.com in the advice section. Formerly gardenweb.com in the home section / bathrooms. Water will destroy a shower if it finds the tiniest way to get behind.

  • Wow Kerdi is expensive. That goes under the tile though eh? I think a vapor barrier under tile is the way to go seeing our time crunch. Thanks for the advice! I didn't even consider the issue of having 2 vapor barrier so this was helpful. – DigitalMC Mar 17 '16 at 14:47

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