Mud Biscuit Recipe

[StevenT]

Is anybody familiar with the proper ratio of sand:portland:lime? to mix a sand mix biscuit to level a floor in preparation to lay ceramic tile?

In a previous thread there was mention of a site... DeGruchy, I thought it might be there, but I've had no luck finding the site.

[Chad Fabry]

Hi Steven,

I'm not sure how big of an area you're working on or what the depth of the mix will be. If it's any bigger than a shower floor and if any of the area's will taper to 3/4 inch or less I'd recommend using one of the pourable portland based underlayments that are self leveling. Ardex, LevelRite, Level-Rock, Quickcrete, and Durabond are the ones that I read about the most. I've used the Durabond and it worked well.

If you're building a shower look at a product named "Ditra": It'll save you a ton of time building the pan and drain systems and makes the wall installations very easy. Schluter Systems makes Ditra and all the goodies that make old style shower installations obsolete.

[StevenT]

Hi Chad,

The job involves a medium sized kitchen. I am aware no to go less than 3/4". I've thought about self leveling portland mixes, but I feel that because of the area, unless I mix it water thin, which is not what the manufacturer recommends, I might have a problem.

I am considering laying a "biscuit" the "old fashioned way", and although I'm familiar with the technique of floating the sandmix. I'm not sure of the ratio of portland to sand.

[kurt]

Originally posted by Chad Fabry

Schluter Systems makes Ditra and all the goodies that make old style shower installations obsolete.

Whaaaa....? Obsolete?

Ditra is not really the right stuff; it's an uncoupling, waterproofing sheet that has distinct advantages in shower use, but it's not what makes the old way obsolete. Ditra provides underpan drainage & prevents the pan from being waterlogged. Some old guys (me) used to use rope, but Ditra is way better. The Kerdi system is what makes the old mortar bed installs "obsolete".

http://www.schluter.com/english/product ... rview.html

Ah just loves Schluter system stuff......

[Chad Fabry]

I actually believed I used the Kerdi word. Sometimes I think my mind is turning to mush.

[mgbinspect]

Chow, Steve.

I recall that the mix for concrete is: 3, 2, 1 (3 parts gravel, 2 parts sand, 1 part cement) The aim is that each component being in a finer state progressively fills in all voids creating a completely dense end result.

The mix for a tile flooring "mud bed" is 4 parts sharp sand to 1 part Portland cement (no lime. The main purpose for lime in mason's mortar today is as a plasticizer. That is, it makes the mix work easily with a trowel. Straight sand and cement is impossible to spread.). This is mixed just like stone mortar, just damp enough to clump if squeezed. So, obviously it isn't self leveling. "Sand Mix" from HD or Lowes, etc. is already mixed to that ratio and merely needs water.

Speaking from years of experience, DO NOT ATTEMPT TO MIX ALL MATERIALS AT ONCE! You'll work yourself to death and the mix will be poor. Mix the sand and cement THOROUGHLY dry. Then add the water. The ideal way to do this is in a mortar box with a mason's hoe. But, if you don't have one you can mix it in a wheel barrow with a shovel. Turn over and chop the mix like turning over soil until thoroughly mixed. Then add water sparingly turning over the mix until quite clumpy. Keep chopping into the mix with the end of your shovel to keep it from becoming too clumpy. When you can finally reach in and grab a handful and squeeze it tight and it remains together, the mix is ready.

Using a mortar box, put the sand and cement to one end of the box and keep chopping off a portion of the mix toward the other end of the pan and fold it back and forth until mixed. Pull this portion high against your side of the mortar box. Then, drag in another portion and mix it in the same procedure. Perform this operation back and forth across the pan until thoroughly mixed. Then, add water and mix in the same manner until the finished product is, again, pretty dry, but clumps when squeezed.

http://www.ontariotile.com/deckmud.html

Have fun.

[kurt]

Originally posted by Chad Fabry

I actually believed I used the Kerdi word. Sometimes I think my mind is turning to mush.

Too many exhaust fumes...... Chad, you ain't mush, you're just overworked.

The last time I placed a "biscuit" to level floors, I understood why folks stopped doing it.

The mix Mike describes is what you want, but if you're really gonna pursue this, rent a one bag mixer for a day. Mixing up that amount of mud by hand will kick anyone's ass up one side & down the other. I still have my old one bag mixer for the (few) shower pans & drypacks I still do.

Personally, I'd advise in the strongest language I can imagine that you get leveling cement. This stuff is the bomb. It mixes up about the consistency of very heavy cream, you can feather it out to a think edge, & it just doesn't crack or break up like a biscuit will do. Pour it in place, it finds it's own level, & bonds to the substrate nicely. Running drypack for an entire floor system is my worst nightmare.

[StevenT]

Thank you Mike,

I knew you would know

In the past, what I have done is mix the dry material on a piece of plywood, on the street. Turning it over dry, until mixed and then gradually sprinkling in water and turning over until it reaches the desired dampness you described.

I have helped my tile/marble man do this in the past and being a hands on guy, I learned while helping him how to level the floor...tamping and leveling the edges and middle and less tamping, then screeding in between. I couldn't remember what the mix ratio was.

I now find myself in a situation where I have to recall this knowledge. My knees are already complaining and I haven't even started yet.

If I could ever figure out how to post pictures on this site, I would post some pictures of one of the last jobs He did with me. 24" square marble, diagonally, with brass inlays. Black and white checkered. The two different tiles were two different thicknesses and I had to connect three differnt areas, each with different sub floor heights.

This job was at Elizibeth Arden (The Red Door) in Manhatten. The owners, Mashalom Rickless and his wife, Pia Zadora checked it when we were finished by rolling quarters across the floor. Not too many bounces.

[mgbinspect]

Steven,

Posting pictures on this site is easier than any other. While in the "New Post" or edit mode, look at the bottom of the edit area. You'll see a paperclip and text that reads "upload a linked file" Click on that and then click on browse. You then have the option to search your hard drive for the photo you wish to upload. Double click on that file and then click ok. If you wish to attach multiple photos, just keep repeating the same proceedure.

[StevenT]

originally posted by Kurt

...rent a one bag mixer for a day. Mixing up that amount of mud by hand will kick anyone's ass up one side & down the other.

I have never tried using a mixer for this purpose, but I did recommend it to the man that taught me... he refused saying that it would not mix properly. We did have laborers that did the mixing. That's why I didn't know the mix ratio. I was always inside with him, laying out and then setting the biscuit. We usually needed larger amounts than a mixer could deal with anyway.

Personally, I'd advise in the strongest language I can imagine that you get leveling cement. This stuff is the bomb. It mixes up about the consistency of very heavy cream, you can feather it out to a think edge, & it just doesn't crack or break up like a biscuit will do. Pour it in place, it finds it's own level, & bonds to the substrate nicely. Running drypack for an entire floor system is my worst nightmare.

I've considered this method, I know it would be faster... and easier, but being that it is a large area, I have some concerns. In the past I've found that when adding the next mix, I end up with "valleys" where the two mixes come together. Perhaps I should consider two mixers, making one while the other is going down, so there is less "wait time" in between. Perhaps a vibrator or even a fresno trowel on a pole would help.

[StevenT]

Hi MIke,

I have tried numerous times uploading photos. No luck

I did exactly what you described. I've also tried renaming pictures, at which point I do get a screen that says I've successfully uploaded my picture. When I preview the picture, all I get is a little red x in a box. Which by the way, yesterday, your avatar looked that way. I'll try again below.

Mike O'Handly tried to help... no luck. He turned me onto someone from DevWave. He is supposed to get back to me with instructions, he has not done so yet.

[StevenT]

Here is my test photo

Download Attachment: deckrebar.jpg

493 Bytes

What I notice is that @ my photo is is named deckrebar.tif

When I try to download it that way, I get nothing. If I remove the tif and put in jpg, I get what you see. I tried numerous times, all different combos. I've just about given up. I need someone who knows and has the patience to figure this out for me.

[homnspector]

Steven, try opening your photo with your photo editing software. Click "save as" and choose jpeg. Save it as a jpeg then upload it.

It sounds like you are just re-naming it, not actually converting it to .jpeg.

Are you using internet explorer?

[mgbinspect]

Also,if your photo quality is too good (too large) it won't upload. Change the property of your photo. scale it down to about 640 x 480 Max. in .jpeg You can do this in your photo editor under properties.

[kurt]

Well Steve, it sounds like you've done enough to know if you wanna use the drypack or the floor leveler; I didn't know you had your hands in it. Go w/your experience.

I'd have to disagree, though, w/the guy that said the mixer won't "mix it right". That's just plain silly. It's only sand & portland; how can a mixer do it wrong? I was a mason's tender for a maniac that was as old fashioned as they get, but he had a mixer. I always mix my materials dry, then carefully sprinkle in the moisture to get the perfect set mix. Beats hell out of doing it by hand.