deck mud leveling [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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02-28-2007, 06:37 PM
I am working on an older house with floor joists and 1x4 t&g decking. the floor is stiff but due to some foundation settlement very uneven. I shot the elevations with the laser and the difference between the high and low spot is 4", most of the floor however will be about 2" thick.
I am planning on putting down a layer of tar paper with diamond lath stapled to the floor deck on top of which i would float the floor. i have done this before but never 4" thick. will the thickness present a problem?? would appreciate some feedback.

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02-28-2007, 06:45 PM
Hi tsquare, welcome. I've mudded that thick several times without problems, as long as your floor will handle the weight. Check your numbers with the deflecto above. :)

02-28-2007, 07:02 PM
Davy, checked the deflecto and im ok. the floors i have floated in the past were small, entries, bathrooms and such. i have noticed that when i am finished, i have not been completely level. any tips on how to set up the float strips.
i set up a perimeter screed with 1x4 ripped as needed. when i set the float strip i will set my column of mudput the float strip on top of that now to level, do i place my level on the length of flat strip and tap it level? or do i level the ends and middle to the 1x4 screed and then set the level on top of the float strip and level it lengthwise? what advise can you offer?

02-28-2007, 07:10 PM
Another poor misguided soul who thinks that the logical place to put a question about mud is in the Mudbox. :shake:


Unfortunately nothing is logical about this site so I'm moving you guys to the abode of lost souls. The Pro Hang out. :D

02-28-2007, 07:25 PM
Thanks Jim. :)

How bout a first name, tsquare.

What controls your mud height? I use mud screeds against the walls and get them level using straightedges.

02-28-2007, 07:35 PM
Davy, my name is Carlos. what i did was set a 1x4, with the laser, ripped as needed around the perimeter of the house. the top of the 1x4 is level according to the laser. in the bathroom whrere the floor is 5' wide i plan on riding a screed board on top of this 1x4 to get the mud level. there are some room though that are 15' wide. here i plan to break the area up in half with a float strip. hence the question on the finer points of setting the float strip on the floor.

02-28-2007, 07:42 PM
I've never done it with 1x4's embedded in my mud as long as your boards are straight and flat. That's the problem though, on a big room, I don't know how you will get the 1x4's flat without a long metal straightedge. Your laser might tell you if it's level from one end to the other but what about in the middle? I assume you pull up the 1x4's and fill them with mud later.

02-28-2007, 07:48 PM
Now I have a question for you guys. It's been a while since I used a level of any kind but when we did we used an optical level since lasers could be off by a 1/8". Have they improved on that?

02-28-2007, 07:54 PM
Jim, the lasers are purty accurate now, some are anyway. I'd also like to know what kind of laser Carlos has. Maybe one that shoots a level line on the wall and you simple measure down from the line to the screed. A water level is what I'd use on a big job.

02-28-2007, 08:04 PM
Davy, i have a CST berger lasermark self leveling rotary laser. with it, i shot all my elevations including the field to determine my high spot. when setting a long 1x, i set the ends first, the i set the middle, then i set at each stud. in setting the middle and each stud location i fenagled the board up or down as needed to get it all level because you are absolutely right these days you would be hard pressed to find a straight piece of lumber.

02-28-2007, 08:39 PM
If you do it like that, I can't see why you would have problems with ups and downs. You should have a flat, level floor. :tup2:

02-28-2007, 08:45 PM
my only concern is in the large areas where i will need to have float strips. i just want to know the finer points of setting the float strip. last time i used them, i was off level. it was a small entry so it didnt matter much, but that "much" in 25', now thats a different story.

02-28-2007, 08:52 PM
Just wanna be clear, when you say "float strips", do you mean mud sceeds instead of using the 1x4's ?

02-28-2007, 08:56 PM
Most folks who float deck mud dont use float strips. A compacted line
of mud is cut with a level and straightedge and polished with a darby
and flat trowel. When using this screed with no float strip in it caution
is used to not dig into it. Wood strips are harder to level in deck mud,...
thus the reason to eliminate them.

02-28-2007, 10:57 PM
hamilton, that sound interesting. can you explain how you do that.

02-28-2007, 11:12 PM
Tsquare i dont have any pics while building the screed but here
are some shots of a shower floor i did last week. The perimeter of
the shower in the second photo shows a screed with no lattice or float
strip. The third pic is the only up close pic ive got, sorry the tile is
in the way :D I would build my screeds for one area at a time as
you float your project to avoid multiple cold joints. In other words float
as you go and dont get to far ahead of yourself. Screeds can be built
in this manner anywhere you need them. Best of luck :tup2:

02-28-2007, 11:20 PM
Hamilton, thanks for the pics. Your work look crisp and clean, congrats on that. since i will be mudding a large floor approx 25'x16' can i set up a screed like the ones you show in the pic. i can understand from the pic when i am against a wall what about in the middle of the floor, how is the best way to set a screed?

02-28-2007, 11:23 PM
hamilton, i was mesmorized by your photos. i guess i didnt read the last line of your reply. if iam correct, yes you can build a screed like this in the middle of the room, is that correct?

02-28-2007, 11:25 PM
I dont float alot of big floors but when i do i let the sizes of my
straight edges tell me where to put the screeds. If i have a 6' edge
i might make my screeds 5'6" apart. The farther apart your screeds
are, the higher the risk of making errors though. Something to keep in
mind. Longer edges bend easier and are harder than short edges
to control.

02-28-2007, 11:26 PM
I have a post somewhere of a living room i floated up for a carpet install.
Ill see if i can find you a link.

Check out post 643 ( There are some pics
of a larger floor being floated with screeds in the middle of the area.

02-28-2007, 11:52 PM
thanks again hamilton. i get the picture. its time to put the pedal to the metal and get that floor floated.