ᐅ Laminate Flooring on OSB and OSB on Wood Joist Ceiling

Good evening everyone,

We have a house here built around 1955.

Between the ground floor and the upper floor, there is a wooden beam ceiling with the following layers from bottom to top:

Wood paneling
Roof battens
Vapor retarder (could also be a standard foil)
Wooden beams

and then nothing on top of that.

Between the wooden beams, there appears to be an infill of clay.

Both floors are heated; this is not an unheated attic or similar space.

So, here is my plan:

I want to fill the missing infill between the wooden beams with dry clay filler. On top of the wooden beam ceiling, OSB boards will be screwed down. Then, a soundproofing underlayment and laminate flooring will be installed.

Is this a suitable approach?

If soundproofing to the floor below is not achieved, that is not a problem.

I just want to know if this can be done this way.

Have a nice evening!

Clay mixed especially with straw is really excellent. However, you also need to consider the weight, so you don’t end up with the ground floor ceiling collapsing like a bowl of soup. Maybe you could also consider using cork granulate as infill between the joists. For OSB boards, choose ones with low load levels. This is easy when manufactured in Germany, but exercise caution with bargains from abroad.

Enjoy your work
Gabriele

Due to the weight of the loose fill, I would consult a professional. A structural engineer told us that this ceiling structure cannot support much weight. We also have a timber beam ceiling (filled with something, probably slag; built in 1921). On top of that is the original wooden floorboards, then OSB panels screwed down, followed by impact sound insulation and laminate flooring. This setup works, but it’s far from quiet. It all vibrates.

Hey, thanks in advance for the two replies. It’s strange that I only just received notifications for both, but never mind.

I had already considered the issue with the weight. Essentially, nothing has really changed except that I am now replacing the old floorboards with OSB panels and laminate flooring.

Regarding the fill material, so far the spaces between the joists have been filled with clay. The fill material is more or less at the same level as the joists—about 5mm (0.2 inches), if anything.

I was thinking of leaving that space as it is. Otherwise, I’m a bit concerned that if the OSB panels should sag at some point, too much pressure might be applied to the fill, pushing the clay downward and causing the ceiling below to sink.

The plan now is:

Attach 15mm (0.6 inch) OSB panels to the wooden joists with fully threaded screws, then install another 15mm (0.6 inch) OSB panel on top, laid floating and staggered relative to the first layer. Then add an impact sound insulation layer and finally the laminate flooring.

Would anyone else do it this way?

I figure that whether I install a single 30mm (1.2 inch) OSB panel or two layers of 15mm (0.6 inch), it probably doesn’t make much difference. Two layers might even be better, right?

In our house, the floor was covered with nailed wooden boards, which were installed about 35 to 40 years ago. On top of that, we screwed down 21mm (about 0.8 inch) OSB panels, followed by impact sound insulation and then vinyl flooring. It works perfectly, but everything tends to vibrate, and there is practically no impact sound insulation.

We did it the same way on the upper floor. Since it’s many layers of wood stacked on top of each other, you can hear elephants marching upstairs from the ground floor. However, it wasn’t much better before with carpet flooring.