How To Install A Tub Surround


What you need to know about How To Install A Tub Surround properly to avoid those costly mistakes! Believe it or not, there is one simple mistake that will cause major problems.


How To Install A Tub Surround


When it comes to installing a tub surround, there is one major mistake made by some installers that will guarantee you’ll have water damage every time. Whenever you run the wallboard such as gyprock, workers will sometimes rest it right on the tub past the tub flange. The problem with this is every time the water can get past the caulking that runs the perimeter of the tub and shower area; the water will do what we call wicking. The is water able to get up behind the tub and tiled wall for example when the caulking is no longer sealing between the two.

photograph of water damaged tub surround

Drywall was installed on tub now all water damaged and full of mold.

Under normal situations, any water that gets past the caulking on the tub is blocked by the tub flange where it will cause no damage or problems. If the installer has placed the drywall on top of the tub, then the drywall will absorb the water that will create mold and black fungus to start developing and if enough water gets in, rotting of the actual houses structure.

photograph of how to install a tub surround

The proper way to make sure you have installed the drywall properly to avoid all wicking is to mount the drywall just above the height of the tub flange about 1/4 – 1/2 inch. The tubs engineering with the flange will do what it was designed for until you fix the caulking seal around the tub. One of the easiest ways to recognize the problem is when you look into the bottom corners around the tub, are they straight, square and plumb or are they flared out with curved edges to allow the drywall to bend over the tub’s flange. When the bottom corners are flared out, this is one of your warning signs you probably have or will have water damage.


If you’re redoing your tub surround, then you can take the time to use better products that water will not effect when closing up your walls. One of the methods I like to do when I’m tiling tub surrounds or showers that have an acrylic base is to waterproof the walls.


You can use two main methods from what’s available.


First you can use the Kerdi membrane that is a waterproofing material that you will cement in place with thin-set. The great thing about using the kerdi is you can fasten it in place so that it just hovers past the tubs flange but just above the tub surface. The reason I do this is if any water could get past the tiles behind the grout, the water can’t penetrate the kerdi. If the water were able to run down the wall behind the tile, the kerdi would force the water to drip into the tub were no wicking could happen were the kerdi hangs lower than the drywall on the tub side with the tiles. For something like this to happen it would be a case where the house movement by shifting could cause the grout to crack in the corner where the water could penetrate its way through to the kerdi. If this happened homes without their tub surround having any waterproofing are now going to start having water damage developing.

photograph of kerdi tub surround

Kerdi passes drywall and is just above tub surface.


The second method is by using a liquid membrane like Hydra-Flex to waterproof the walls, but I still like to run some kerdi along the bottom edge just above the tub surface as before. This method is faster, easier and cheaper to accomplish than using the kerdi all the way around. Some people prefer the kerdi, so I do that method for them and the ones that have no preference I use the liquid waterproofing such as hydra flex with a kerdi band around the bottom as I mentioned earlier.


photograph of Hydra Flex tub surround

Kerdi band at bottom and faucet gaskets around faucets.


One other quick note to mention which is not dealing with having water damage but is mainly for how to install a tub surround so it looks its best is to make sure the walls are level and plumb with one another. Rather than explain all that here, I will refer you to some of my previous posts that explains some things you can do to correct the problem from shower walls that will still relate to installing a tub surround.


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  1. Hi, I was interested in this because we just rebuilt our bathroom and added tile instead of the tub surround. Also, my Dad was a ceramic tile setter, used to do some beautiful work. Your site is very informative and very readable. I learned that you don’t set the tub surround on the tub itself, if you do you will have water damage. You also told about products to use to seal from leaks, such as kerdi and Hydra-Flex. Are kerdi and Hydra-Flex expensive? I know our new shower was really expensive.
    With Kind Regards,

    • Hi, Linda and to answer your question, the waterproofing material cost used for around your average tub surround runs about $60.00 to $140.00 CAD so if you’re from the States you would be looking at a cheaper material costs. There are a few different brands out there which will also have varying cost associated with them as well.

  2. Hi Travis,
    First f all, wonderful article. Very well done / written. Secondly, as someone who has dealt with water damage done by leaky seals in tubs, sinks, and toilets over the years, I can testify that it is one of the most damaging things that can happen to your home.
    In one home that we moved into, there was a leak in the upstairs bathroom of this old house. Somehow, it wound up rotting out the floor joists underneath the kitchen floor, and separated them from the frame under the wall! All of it had to be torn out and redone.

    So needless to say, I do certainly appreciate your efforts with this blog post, giving a not to prevent small mistakes from doing large, costly, and time consuming damage.Thanks for sharing this,

    • Hi Brian and being a contractor that specializes with custom showers and bathrooms, I find any way I can help others to ovoid having water damage the better.

      I see and end up fixing a lot of bathrooms where somebody ended up taking short cuts which ultimately only leads to expensive remodels. When it comes to water, nobody should consider taking short cuts, it not only costs more money for damage but the hassle you go through redoing something that should have been done properly the first time.

  3. Very helpful article here Travis. If you use durarock on the walls as an underlayment for the tile do you still need some kind of waterproofing? I have not done tile on shower/tub walls but only on floors so I was wondering what the best underlayment would be for this area. You mentioned gyprock and I am not familiar with that. Is it similar to drywall? Thanks for your info here as there is so much to know to remodel a bathroom right.

    • Travis Smithers

      Gyprock is just another name for drywall and the other product that you mentioned durarock does not need to be waterproofed.

      The thing that should be done to durarock is all the seams need to be taped and mudded and then those same seams should be primed.

      For me, I believe in overkill, so I like to waterproof all walls involved and joints to make sure there will be no future issues from the damage water can create. For me, it is preparation time well spent.

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