Floor surrounding Kerdi pan is 1/4"-1/2" higher

[Benjamin dalton]

Kerdi 38x60 shower pan listed as 1.5" thick.

First house, first DIY, brand new bathroom addition a-z.

I installed 5/4 deckboard, true 1 inch depth, and then 1/2" treated plywood. Pan and surrounding floor are ontop of original hardwood floors which I sanded.

When I finished installing the floor I then installed the pan following Schluters instructions. However, around the pan is 1/2 inch above and 1/4 inch above the pan with ditra installed.

Perhaps I should not have moved forward with pan installation or took up the surrounding floor when i realised they were not level. However, I did not.

I do not know what to do?

Drypack mud to level out the transition but keep a slope toward the drain (albeit the slope will increase in steepness)?

Pictures I tried to show where I messed up. Tiles are just out for dry fitting for prep.

Thank yall so much.

 

[wwhitney]

What is 5/4 deckboard? Dimensional lumber?

Is that marble tile? Marble is a poor choice for showers for a number of reasons, one of them being that it will often change color when it absorbs some water, and so the floor tile around the drain will appear a different shade than elsewhere.

What is your joist structure and what are the (sub)flooring layers above it? For natural stone, industry standards require a floor system with a design deflection of L/720, and if the plywood subfloor has any joints in the area to be tiled, a second layer of plywood over the subfloor with the seams staggered.

Using treated plywood is usually not a good idea, as the product is very wet and will move as it dries. Not sure if KDAT plywood exists, but it would be OK.

And is the Schluter pan directly on the hardwood floor? I would expect Schluter to specify a plywood substrate, it is worth checking.

So if you want do a very good job, you should redo some of what you have already; how much depends on the answers to the above questions. For a quick and dirty solution, if you want to replace the whole thing in a few years anyway, you could put a double layer of ditra over the shower pan.

Cheers, Wayne

 

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[Benjamin dalton]

5/4 deackwood is treated lumber for decks outside. It is actually 1/2 inch thickness.

It is natural stone. Not real marble I do not believe. $7.98 herringbone mosaic. Thank you for insight into that.

Its an old 1930s home with original wood floors. The floors are thick oak and directly onto joists (peer and beam so can see from underneath and also have boared holes for drains, vents, water lines electric etc.) There is not subfloor just straight to hardwood floors and thick at that.I can get under the house again and measure distance between joists etc.... If that would help...?

I definately messed up getting treated ply. I made an assumption as a wet area to go with treated and didnt research. First mistake. All plumbing and electric passed inpection to close the walls up so I am dissapoined I have made errors in this stage.

It looks like Schluter pan I should have installed a subfloor ontop of original hardwood. I sanded the hardwood and followed schluters recommendations for installation on plywood. The pan is jammed in tight between the surrounding raised floor however if that may help..?

This is a very low use bathroom for guests that stay. However heck no after all this work am I willing to replace it in a few years. I was hoping a slight slope of mud to smooth out transition from ditra to shower pan would work but perhaps not..?

 

[wwhitney]

As to the joists, what you need to know is their dimensions, their spacing, the unsupported span length, and the approximate species/condition (hardest thing to determine). Then I suggest the deflection calculator at http://www.johnbridge.com/vbulletin/deflecto.pl (which is quite conservative).

As to above the joists, the best thing would be to take up everything back to the oak flooring, put down 1/2" plywood everywhere (BCX or better), use a leveler under the footprint of the shower pan if necessary, install the shower pan, and then install more plywood everywhere else (BCX or better) at the thickness required so that your tiling substrate (Ditra) ends up at the elevation you want relative to the shower pan. Details on the plywood fastening pattern are important and can be found on the johnbridge.com forums.

Tiling on top of fresh treated plywood over fresh treated lumber is definitely a huge risk and not recommended at all.

Cheers, Wayne

 

[Benjamin dalton]

Thank you.
At least I learned this before starting the existing bathroom renovation. I was actually just on JohnBridge reading about deflection and plywood fastening pattern.

Time to walk things back and do them correctly.

Thank you very much Wayne!