Shower Mud Floor

Each spoke represents a weak seam in the mix. I think it will crack.

I've never used them, but it looks like a good idea.

The spokes look to be like an "I" beam construction. I could see potential cracking problems if air pockets are left under the upper lip, but it seems like if you make sure to trowel the concrete back and fourth, (perpendicular), over the spokes and fill all voids, you should be fine.

Another thought would be to use the spokes to get the proper angle, pull them out while the concrete is wet, and fill the voids that they left.

I agree, I think it will crack after time.

Hey....how about one of these pre-manufactured shower pans?

No cement, no concerns about slope, they are strong, no muss, no fuss!

Try this link.

You will have cracking especially in the area close to the drain where the width of the slab is reduced by the geometry of the radiating spokes. I never allow a floor/deck slab to have any dimension less than 6" in any horizontal plane (not depth), and 12" is preferred.

Are you still working on this?

Agree with the others, it will probably crack. Is that a big deal? After curing, tile it. Beautiful and watertight. And best of all, it is finished.

Each plastic spoke has holes in it to allow the concrete to be pushed through in the horizontal direction so that the concrete is connected between adjacent radial spokes.

Is there any first hand experience out there on observations of cracking along the spokes? What I am hearing is predictions,

EMIL

Ciao, adieu, au revoir, adios, guten tag, BCNU.

None here. Bye.

Is there any first hand experience out there on observations of cracking along the spokes? What I am hearing is predictions,

Hmmm, then maybe in your original post you shouldn't have said...
"Any thoughts on the use of plastic spokes",

I think you've scared away the natives now.
Del

I looked at the demo video, and it appears to me that if you make sure the holes are filled that tie the mud into a solid mass through the tapered stick then you will have a floor that is stable, as long as the floor beneath is has the needed rigidity. I say this because they seem to have about 60% free space in the holes, which will make a solid base as long as the mud is fully flowed through the holes. Remember, cement is brittle, so it is critical that the sub floor be rigid

thank you for your comment about the holes in the plastic spokes. the subfloor was mud prepared from sand topping mix plus sand (ratio 2, 1). it is stable.

Angus

Add a plasticiser and waterproofer to the cement mix to reduce the likelihood of cracking.

Dear Fellow Scot: Thank you for thinking about this problem. They sell mud components here (Washington DC area)that recommend adding latex emulsion, which is also provided. This will provide extra strength and enhance waterproofing to the cement. Would this be a positive or negative from cracking standpointment? Does it conflict with additon of plasticiser?

Now regarding plasticisers what would you recommend and how much?

Angus

I've only done this DIY - and found using washing up liquid (15-20ml per 30kg mix) a good basic plasticiser! Now whether you would want to try that, or go for one the mud supplier would recommend is up to you.

Captain: Thank you for your thought-provoking comments

"1. Don't install a slab any less than 4-inches in minimum thickness."

My shower has a prepan that is made from Sand Topping mix:Sand (2:1) and is around 2 1/4" in depth. It sits on top of metal lathe that sits on top of foofing felt. Below the roofing felt is the plywood.

The water proof shower liner sits on top of the prepan and is secured to the studs all the way around the shower.

What I have in mind for the mud floor on top of the shower liner is depth of 1 3/4".

So it will not be 4" in depth.

Water can seep through the mud floor and reach the liner and is removed by the weep holes at the drain.

That is what I have. So now that I have given this informtion can you reevaluate.

Angus

Hello Angus,

I didn't realize you had a liner and the weeps, so you're slab thickness should be more than adequate IMO. Just make sure you don't plug-up those weep holes!

Good luck with your installation!

Thank you Captain for taking the compass coordinates: my own feeling is that we are in uncharted waters here. I am thinking to include acrylate emulsion in the cement mud, since this is a polymer and it will act as a plasticiser in the cement. It ought to make the cement floor less likely to crack.

ANGUS

"... my own feeling is that we are in uncharted waters here."

You have got to be kidding me.