redguard sealer in shower stall?

I’m replacing my fiberglass surround above the bath tub with hardie board and ceramic tile. My question is, due I really need to apply a sealer such as Redgard to the hardie backer cement board? I thought that the grout would keep the water from getting behind the tiles and it’s not like a shower only stall where the walls and floor get soaked. Maybe I’m being cheap, but that stuff is $50 per gallon and it would take two at least.

Seems like cheap insurance to me.

go ahead and not use it.
then you can replace the shower in 5 years

Grout is not a sealer. When tile is used to make a pan you have to install a waterproof liner under the tile. that liner is sealed to a specific type of drain and then a porous mix of sand and cement is laid down under the tile.

I'm not a tile guy. I have never seen or heard of having to seal the walls with Redguard or any type of sealer.

I have seen a lot of tile installed on green board with just thin set and it becomes a mess after a few yrs.
You're using hardie board. I will hold up a bit better.

You don't have to seal it.

But any Moisture leakage into the wall may never be seen for decades, but it can do a lot of damage over time

I’m also worried about how well the thinset will stick to the redgurd. I’ve painted lots of cars and the paint job is no better than what’s under it.

lamothe1 said:

I’m also worried about how well the thinset will stick to the redgurd. I’ve painted lots of cars and the paint job is no better than what’s under it.

Click to expand...

seeing how it was designed for thin-set, I really do not understand your question

When installed 1200 sq. ft. of wood look floor tile, I used a gallon of Redguard on a slab crack and the tile stuck great to it. The manufacturer said to paint a layer of Redguard 4 tiles wide as a substrate on each side of the crack, so if the ground shifts at all, the Redguard will flex without the tile cracking. That stuff worked great.

I was going to say I have never seen that stuff used before but I did see someone use it on the outside of building a couple weeks ago.
How to install Redgaurd

Great video Dave! Thanks for posting.

I personally prefer https://www.schluter.com/schluter-us/en_US/Shower-System/c/SS

thanks guys, i'm on my to Home Depot to get the Redgurd.

I only use it for the floor, bench tops, flat areas, corners, joints and change of plans, after taping with ALKALINE RESISTANT TAPE and thinset.
Hardie on the walls will last forever without Redguard unless, perhaps, it is a steam room.
BTW, if you do water proof the entire shower with Redguard or Schluter, remove the vapor barrier behind the Hardie so you don't create a "Mold Sandwich". If dealing with a blown insulation in the walls, use Tyvec house wrap to hold it while you hang your Hardi. (Tyvec opens up when moisture is present to allow drying.)