Floor out of level

[monte]

b/m

According to your pics above you're using particle board as a structural element in your subfloor. I'll have to concur with Tinker about doing that, that's a no-no. If you go back to my original post (#1) I was referring to floor ply that would be laid over your stringers.  If your not going to do Per's "Jersey Fix", I would strongly reconsider the use of only particle board.
Was I emphatic enough?

R.

 

[b_m_hart]

OK, so I'm confused - how is it a structural element of the subfloor?  There's 3/4" wood slats for the subfloor, and 2x4s supporting the one end of the MDF.  It doesn't seem like it's going to be doing much structurally, other than being a flat surface for me to spread thinset onto...

Also, relative to the particle board getting wet - if that happens, I have bigger issues at that point.  The schluter ditra stuff supposedly seals pretty well from above, and water will have to soak in from below, through the 3/4" subfloor.  Additionally, on the side of the building is roughly an inch of stucco.  I think I've nailed down the source of the water damage - one of the tenants set up a watering system for his planters on the side of the building, and there were several holes in the tubing he used which sprayed water up into where the room overhangs the back yard.  He has since fixed that, and I checked it to make sure that it isn't leaking / spraying water anymore (so good there).

 

[Overtime]

2 more cents

Since you will have raised a portion of the floor ( shims ) and - even with spacing 6" apart - you will have created a new sub floor in a way. In the areas that have the shims. Using the particle board in this manor is a guaranteed failure. In fact I would not use that material on (any) the floor for any reason at all, especially one that will have tile.

  Particle board is not sound enough to withstand the 6" gaps - you will have sagging and cracking in no time between every 6" gap. Wonder board, Ditra, and Hardi boards will not add any structural support in this situation. They are only a substrate for the tile. the floor must be sound.

Thinking outloud: 
1 5/8" hmmm thats kinda deep for the self leveling job.

Ideas :
Pull up only the one side of planks from the seam outward over the low area. Bolt on sistered floor joists for the portion in the low area.
Then cover with 3/4 Plywood

The sistered joists would act just as the shims would and would only be for the floor leveling, they would not effect the building structure.

Then add another sheet (thickness ?) of floor rated ply or OSB over the entire room. 

And then onto Ditra,Wonder board ect tile.  The floor just needs to be flat and sound for the tile that's all, It does not have to meet aircraft standards  ;D

*If you proceed with the shims as is you could also screed in some leveilng goop between the shims and then add your floor sheets.
But No partical board and no MDF.

 

[b_m_hart]

Ah, gotcha.  So the real issue is the lack of support from the MDF / particle board where the shims are?  What if I were to create enough shims that there was basically no space between them?  People keep saying "don't use that stuff", and I hear it loud and clear, but I'm trying to figure out why it's bad to use in areas where it isn't doing anything (no structural support, that's provided by 3/4" subfloor) but providing a surface to attach the Ditra to.

The reason I ask is because this is the same stuff that's in the kitchen under the current (linoleum) floor.  I REALLY, REALLY don't want to have to pull all of that up, heh.

 

[Overtime]

I forgot to mention - nice job on those shims !

OK , if you made enough shims that would be like the SLC goop, only lighter and would give a solid base for next layer keeping all the room on the same subfloor.

The particle board and mdf for flooring , Firstly - both absorb moisture like a thirsty Irishman. Then there is compression.
  After particle board and mdf get wet over time they can swell and get weak, and or flake as they degrade. This may take a short time or long time. Depends on conditions. Could take years or months.

Plywood and or OSB (rated for floors) are used for these reasons. They are stronger, wick less moisture and are better under compression.

Even though you would be laying down a fresh new sheet on a nice flat subfloor, using particle board or mdf is not a good idea. No.

Most of the tile substrates spec that a layer of thinset be applied over the sub floor in between the wood and the Hardi board or whatever. So first off you will be introducing moisture on the ( particle board) not a good start.

I'm not an expert on this and it's just my opinion 

 

[b_m_hart]

Ah, so it's primarily the moisture absorption, gotcha.  I can't think of how water would ever get in there, but I'm sure there are a multitude of calamitous events that could lead to such a situation.  I'll run out and get some of the proper materials this evening.

 

[Tinker]

how can water possibly get to the subfloor.
From what I have been readin here, it is a kitchen, isn't it?
THINK about that for a bit.  ???

Tinker

 

[Tinker]

Earlier, after observing your very first pics, I suggested there had been water damage.
You have corroborated my observation.  I do not think all of the water came from underneath as you have suggested.  The clue I observed was a discoloration of the lower wall (well above the floor) as well as across the corner of the floor.

your later pics indicated the unequal elevation is due to a serious lack of craftsmanship in constructing an addition at some time.

you most recently indicated the outside walls to be stucco.  I don't like to thro s--- into the game, but you might take a VERY close look at the outside stucco.  If possible, also see what sort of sub base is there to hold the stucco. If it is wood lathe, and you are finding water (moisture) damage inside the house, it is possible there has been serious damage to the lathe.  There could even be some decay.

If it is wire lathe, you could still have just as serious problems with rust if it is black lathe. Either decayed wood lathe or rusted black lathe, you have a problem you have not even suspected yet.

If galvanized lathe, you should be ok at the lathe part.

Scratch the surface of the outside stucco.  If the work has been so shoddy inside, it was probably a DIY'er who was not as serious about his work as you.  For the water to penetrate thru the stucco, it is possible either a very poor mix was used, an indoor type of plaster, too fast drying at application time or a myriade of other problems.  You are doing a very good job and getting some very good advise from this bunch here at the FOG.  don't let yourself down by not looking at the sourses of your present problems. I am now suspicious of your stucco.  sorry about that.

Tinker

PS.  I know i am probably adding to your problems, but I think it is important for you to take a good look sooner than later.

 

[Cannuck]

Nice job on the shimming.  Very tedious work, but a coplanar floor is your prize at the end.

I'm glad to hear that you're changing the subfloor material from Particle board to either OSB or Plywood.  The issue with particle board is not merely its susceptibility to moisture.  Frankly, it has no structural properties at all.  I only works under compression, and has no shear or tensile strength.  Regardless of moisture, it will sag over time between the shims (the bearing points).  With OSB or Plywood, the wood strands are oriented to provide the tensile and shear strength.

In any point load situation, there are four forces acting: compression, tension, shear and torsion.  Particle board only works in well in compression situations, where the load is evenly distributed across the whole surface, or where an additional material is sandwiched to provide the other dimensional stability (e.g. melamine). 

 

[b_m_hart]

Last night I finished screwing the shims into place, and returned the particle board and got plywood.  I'm hamstrung by the existing underlayment in the kitchen that I have to match to, so I kept the 1/2" rather than going up to the 3/4" as suggested.  I'll post pics when I get home tonight.

 

[robtonya]

I live in one of those "modular houses", and the whole thing has particle board flooring. Definetly not something you would want under tile unless you wanted to redo it later. It definetly will react to any moisture, and develop sags easier too. You did good by taking the particle board back. My $.02.

 

[b_m_hart]

Ok, just have to secure the plywood in place now...

 

[greg mann]

Looks like you are on your way. I just finished a ceramic tile floor in a kitchen. The floor was level and flat so I am counting my blessings.