Dear BP family,

I hope all of you had wonderful holidays!!!

Now back to flipping, renting, rehabbing and improving our communities.

A quick question here. When I'm rehabbing/building a new bathroom, do I absolutely need to apply Redgard to waterproof it or the moisture resistant sheetrock is enough ( purple or green) ? Do I absolutely need both?

Thank you all in advance and have a great winter,

Eli

Do you mean in the shower or the whole bathroom?  Yes moisture resistant drywall is beneficial in the bathroom.  For the shower I would use some type of concrete board(several brands out there) and waterproof it.  You can waterproof it yourself if you don’t want to pay someone to do it.  There are even better options out there like the Kerdi system but I’m assuming you are trying to save money. 

@Eli M. Late reply, but I just happen to be scrolling around today. In bathrooms, use regular white drywall, with semi gloss paint and a good exhaust fan. I often suggest a humidistat for the fan. No need for "green board" as it's not required by code and any moisture that penetrates the paint is already a much bigger problem.

Use "denshield" in the shower surround. It's better than durock because it doesn't need to be painted twice with redguard as it already has a moisture barrier. It cuts and installs just like drywall, far less mess than durock and the debris doesn't scratch your pan/tub like durock. Install tile right on top same day as hanging the denshield.

@Andy Thompson

You’ll fined the full array of answers from the minimum requirements to the absolute best assemblies available today with matching price range for each.

As a contractor as well as a buy and hold investor, I look at choices like this through the lens of I guy who do only wants to spend this money once. For that reason, I tend to follow best practices for the most reliable assemblies. Redguard and other waterproofing options, when used correctly, are only going to eliminate the need for future rework items down the road.

Maybe a better question would be, what is the most cost effective way to do my project way in a manner that’s consistent with best practice for longevity?

That said, I like denshield as well. It’s quick, waterproof, reasonably priced and easy to work with. I’ve also seen guys prove the practice of Redguard over plain drywall. Not saying I’d do it myself but it makes the same point.