Creating a Mortar Bed for a Shower Installation using Sakrete Sand Mix

So you’ve finally decided that you need a second shower in the house. Good idea. You’ve scoped out of the spot, taken all of your measurements and rounded up all of the supplies. If you’re reasonably handy and have access to the internet you should be able to figure this out.

Since the purpose of this blog is talk about the mortar bed, we will not be addressing or advising on any of the other concerns such as plumbing, walls, shower doors and a host of other things.

Before building the mortar base insure that the substrate that the mortar bed will be placed over is structurally sound and has the ability to support the weight of the mortar bed and the remainder of the project. Like with any job getting the base correct is essential. In this case you need a good solid mortar bed to support everything. Sakrete Sand Mix is a prepackaged cement mix ideally suited to this application. Don’t be fooled by the words “sand mix”. This product is actually a high strength mortar made with sand and portland cement which I will henceforth refer to as “mortar”. As a side note, Sakrete Sand Mix can be used in many other projects like a bedding mix for brick and flagstone walkways or a topping mix for rejuvenating old concrete surfaces.

There are two ways to install a shower. One is by using a preformed shower pan. Unless your significant other is dead set on having tile, this is the easier way to go. However if there is no talking him or her out of tile, then by all means you can lay the tile on the mortar bed. Either way you still need the Sakrete Sand Mix.

Since water tends to run downhill you will need to make sure that the tile drain is at the lowest point. Typically the drain is dead in the center but you can put it anyway as long as it’s in the lowest spot. The important thing is to begin placing your mortar at the drain and work your out and up. Typically ¼” per foot is the amount of slope required to get the water to cooperate.

The overall thickness of the mortar depends on a variety of factors. If you are using a preformed shower pan, the manufacturer of the pan should provide instructions as to how thick the mortar bed needs to be. If you are installing tile, the mortar bed should be 2-3 inches thick on the outer edge and slightly less at the drain.

When mixing the mortar use only enough water to obtain a “dry pack” consistency. A good way to tell if you have the right “dry pack” consistency is to make a ball with the mixed mortar similar to a snowball. You need just enough water so this ball holds its form without breaking, if so you’ve added the correct amount of water. By the way please wear gloves when messing with mortar. Some folks have more sensitive skin than others but overexposure can cause burns and irritation.

Once the mortar has reached the “dry pack” consistency place the mortar in position and using either a wooden float or a stout rubber trowel shove the mortar into place. Unlike concrete this type of mortar isn’t troweled with the intention of putting a nice smooth finish on the surface. The intent is simply to push hard on the trowel until all of the mortar is tightly in place and relatively smooth. Once the mortar is in place allow it set overnight. Once the mortar is set you can continue the process of placing either the shower pan or tile.

(Note for tiling: Tiling should begin within approximately 16 hours of the mortar bed installation. After 24 hours, the mortar bed enters a green state and should not have tile adhered to it for 28 days.)



  • Keith

    I am installing a walk- in shower and am in the process of getting the area ready for the tiler to come in and complete the tile work. I have decided to use RedGard as a water proofing method on the walls and over the shower pan, in which I am about to first install your Sakrete Sand Mix before applying the RedGard to it. The RedGard site says the concrete must cure for 28 days before applying their product because they say it takes 28 days for your product to cure. Other internet sites say that the 28 day rule is a myth. Please clarify.
  • Lee-Technical Service

    DK, you should be using the Sakrete Sand Mix for your shower floor, not the Crack Resistant Concrete Mix. The Crack Resistant has stone in it and you could run the risk of puncturing your liner. Sand Mix is just a concrete sand and Portland cement. There is nothing in it that will run this risk of damaging you liner.
  • DK

    The people at Home Depot recommended your Crack Resistant Fiber Reinforced concrete mix for my shower mortar bed. This blog seems to indicate Samd Mix is the preferred material. Which should I use? I will be laying tile over the mortar bed
  • Lee-Technical Service

    xhiker, unfortunately your best bet would be to replace what you have. The last thing you want to do is install something that will have the potential to leak and damage the walls and floors.
  • xhiker

    I have a 48 inch fibreglass shower that came in 3 pieces. the bottom piece is about 18 inches high and includes the floor/base. The base has cracked but I have no way to remove it. Should I try to cut out the old base and use cement or what other option do I have without buying a new shower.
  • Lee-Technical Service

    Barry, no you would only have the Sand Mix in the shower floor area only. The curb would be waterproofed along the same time that you did the pan liner. After you installed the Sand Mix for the mud bed and it has had time to harden, you would then thinset and tile the floor, curb, and walls. Wait for your thinset to dry and then grout.
  • Barry

    Do you continue the layer of mortar up the shower bed liner and over the "entrance step" into the shower. If so, how?
  • Lee-Technical Service

    Kerry, you will need to ask the grout manufacturer how long you will have to wait before using the shower. The grout is the last product that would be installed.
  • Kerry

    I need to raise my shower pan 3/4 inch. You are saying lay tile within 16 hours. How long until it can be used once tile is laid?
  • Lee-Technical Service

    Jon, this material can be used for that application and it does fall within the realm of what you are looking. Do not add sand, just water and mix to a dry-pack consistency. Sorry I cannot give you the exact ratio of the product because it is proprietary information.
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