Leveling the floor for an attic with OSB boards

Hello everyone,

I want to lay a new floor made of OSB panels in an attic. However, the collar beams are uneven. In the longitudinal direction of the beams, there is an average height difference of 12.5 mm more on one side. Diagonally across the entire room of 5.6*6.4 m, it is 22.5 mm. The flatness of the surface on the beams is about 3-5 mm.

How would you compensate for this?

I have tongue-and-groove boards with which one could wrap the collar beams as a pair on the left and right side of the beam and thus level the floor.

However, the drywall installer told me that for the later finishing work, this could also be leveled with a leveling compound, which in his opinion would be easier. However, leveling compounds for wooden subfloors are generally only to be used for thicknesses of 20 mm. The screeds I found further on have a minimum thickness of 30 mm.

It is also questionable how a leveling compound behaves on the flexible wooden floor?

Many thanks for your opinion and best regards

Billie

Hello Billie, basically you have summarized it perfectly yourself. Compensation "mass" whatever, is the worst solution. So doubling up wood (whatever) and putting boards on top. Lasts forever and also easily copes with the enormous temperature differences.

Hello "Billie". The only reasonable solution given the local situation has already been presented as correct by "Vicky Pedia". Trying to work with a leveling compound is not sensible for several reasons. First of all there is the new ceiling load of 500kg to 600kg over about 35m² due to a leveling compound. Added to that would be the new substructure, i.e. chipboard or OSB panels. An estimated total of over 1,000 kg would likely be placed on the supporting beams. Moisture, a second point, should ideally remain outside with wood construction. With a filler compound, you would introduce considerable amounts of water into the structure. The load-bearing capacity of the supporting beams should not be overestimated, especially in existing buildings (see point 1). Furthermore, with the construction method recognized as correct by "Vicky Pedia," you could also integrate satisfactory impact sound insulation into the structure. With the "Spama solution," the feasibility of implementation is not initially apparent. ----------------------------------------- Regards and success with the renovation: KlaRa

Hello everyone,

thank you very much for your answers!!! Then I will level the floor with the tongue and groove boards + impact sound insulation.

Best regards

Billie