Creating A Mortar Bed For A Shower Installation Using Sakrete Sand Mix #shower #floor #installation


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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 tiled adhered to it for 28 days.)

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Comments:

Lee-Technical Service

Rey, yes the Sand Mix is the correct product to use. Wait until the material is set and then begin tiling. The surface should be tiled before 24 hours.

Lee-Technical Service

Roy, yes the Sakrete Sand Mix is the product for that application. Hold out a little water to make a stiffer mix. This will help the Sand Mix to hold shape as you press the pan in place. If you mix it with the recommended amount of water it may be too loose. Less water will make it stronger as well.

Lee-Technical Service

David, If our product is installed over the waterproof membrane, then you can install the tile as soon as it is set and don t wait longer than 24 hours. Longer than 24 hours and you will have to wait 28 days. If you try to put the waterproofing over the top of our product then you will have to give it 28 days to cure before applying the waterproofing. Unless the waterproofing manufacturer requires you to wait longer.

Rey

I have my shower pan with the pan liner already in place. Now I m doing the pre-slope. Is the Sakrete Topping and Bedding Mix the right mix to use? Should it still be a dry-pack consistency and how long to wait? Thank you. – Rey

Roy

Doing a shower pan without tile, just the standard acrylic over fiberglass. A leading manufacturer of fiberglasss shower pans lists Sacrete Sand Mix Topping and Bedding Mix among others, as approved for the MANDATORY subbase under the pan. The pan is first dry set and leveled, with position marked for future reference. Then the mortar is poured on the substrate. Then the pan is placed on top of this pile or mortar and pushed down until it returns to level. The excess squeezed outis then removed. I read somewhere that the consistency of the mortar for this was somewhat like pudding. That makes sense as it has to squish up and cover the entire bottom of the pan or thre will be weak spots. QUESTIONS: May this Sacrete sand mix be watered to the point of pudding consistency so that it can be mashed into all areas beneath the pan as the pan is presssed into it to achieve level? The thickness at that point would vary from about 3/8 to 3/4 as I read it. There would be no practical way to pre-form it in a near dry codition for this application. If it is watered to this consistency, will it have the strength needed for this application? Weight bearing without cracking is all it has to do. And maybe a bit of cracking could be tolerated in this case. How long to wait before could stand in the pan after instaling with the mortar support? Thanks.Roy

David

I want to use Durock waterproofing membrane. If this is installed after before 24 hours, will I still have to wait for 28 days to lay the tile?

Lee-Technical Service

Jim, if you added more water then you would have to wait longer before setting your tile. You want to get the tile set before 24 hours so that the bed and the thinset will cure together. If it is set later than 24 hours, you run the risk of the thinset delaminating from the surface. However, if more water was added and you cannot tile before the 24 hours green period, you could tile the surface after 28 days. After 28 days the mud deck would be fully cured.

Jim

What to do if we added too much water?

Lee-Technical Service

Jim, no that will not matter as long as you did a dry-pack. With a shower floor you should use a dry-pack, so there would be very little water in the material to begin with. So you should be fine.

JIm

I was up late putting in the mud deck for my showerpan using Sakrete sand mix, but I didn’t cover it to keep it wet while it cured. I don’t see anything about doing that in the instructions above. Will the fact that I didn’t cover it while it cured be a problem after tiling?

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