Plywood boards instead of sparse paneling behind drywall in the ceiling?

[Martin_B]

Has anyone installed plywood sheets (or other wood fiberboard) instead of spacing paneling behind drywall in a ceiling?

Here's what I'm thinking, from top to bottom:

Outer roof
Cellulose insulation
Roof beams/studs (max spacing 555 mm)
Vapor barrier
12 or 15 mm Plywood
Drywall

The advantage of 12 or 15 mm plywood compared to 28 mm spacing is that there's always wood to screw and attach things into in the ceiling, which is not the case with drywall (I really hate attaching things only into drywall). Another advantage is that it takes up less space, about half the thickness.

A disadvantage, however, is that it becomes more difficult to run electrical across the ceiling beams.

Has anyone used plywood instead of spacing with good results? I think it's very worthwhile to be able to mount lamps and more anywhere in the ceiling without having to worry.

 

[justusandersson]

Plywood behind gypsum works excellently both in ceilings and walls. 12 mm is a fully sufficient thickness. 15 mm has as many layers as 12 mm (5 layers) and is not a real improvement. Then you have to go up to 18 mm (7 layers).

 

[Rickard_C]

In the garage, we did it, but we first put up gles and then plywood and plasterboard. We wanted to be able to screw things up everywhere. If you don't put up gles, there might be trouble with the vapor barrier/plastic if you're going to have it in your construction.

 

[Rickard_C]

However, lamps are in most cases very light, so no problem hanging in the plasterboard. A little different in the garage where we wanted to be able to mount various things on the ceiling.

 

[Martin_B]

Plywood behind plasterboard works excellently both on ceilings and walls. 12 mm is a fully sufficient thickness. 15 mm has as many layers as 12 mm (5 layers) and is not a real improvement. You need to go up to 18 mm (7 layers).

Sure, that works fine. But the question is what happens if you skip the battens entirely and only use plywood? (and then ceiling plasterboard covering the plywood)

 

[Martin_B]

If you don't use sparse, there may be issues with the vapor barrier/plastic if you're going to have that in your construction

Will be using vapor brake since it's cellulose insulation, and then you shouldn't have a vapor barrier/plastic.

But how do you mean there can be issues with the vapor brake in the case of using plywood instead of sparse?

 

[Rickard_C]

Because you will have difficulty installing electrical wiring, setting ceiling boxes, etc., you do that in the space between the plastic and the ceiling that the furring strips create. It feels like a lot of extra work to skip the furring strips, which gives you limited benefit, and to deviate from what is standard.

 

[KnockOnWood]

The advantage of 12 or 15 mm plywood compared to 28 mm sparse is that there is always wood to screw and attach things to in the ceiling, which there isn't with plasterboard

But with sparse panels, set with c-c 300 mm, there are more than enough fastening points.
More precision is not needed for a few lamps and such, right?
And then with 28x70 mm wood to screw into, which holds well for most things.
Also, plywood is 3 - 4 times more expensive than sparse panels.

 

[Donkaffe]

There is indeed 15mm OSB. I did that in my laundry room in the basement to save ceiling height. I embedded a few extra battens here and there between the studs, but I think it would have worked fine without them. 15mm OSB plus drywall also provided a quieter construction than sparse and drywall, which is nice since the bedroom is above the laundry room.

 

[BosseHansson]

OSB may well affect the function of the vapor barrier. Maybe it only applies if you tape the joints. Could be wrong but would definitely check it out if I were considering it in combination with a vapor barrier.

 

[Martin_B]

OSB can affect the function of the vapor barrier. Maybe it only applies if you tape the joints. I could be wrong but would definitely check it out if I was considering it in combination with a vapor barrier.

I would never use OSB in places where I need good fastening, especially in the ceiling. Plywood is the only option in that case.

But do you mean only OSB or other sheet materials like Plywood as well? How does it affect the function of the vapor barrier? Plywood is vapor permeable.

 

[Martin_B]

But with sparse paneling, installed with c-c 300 mm, there are more than enough attachment points.
You don't need more precision than that for some lights and other things?
And with 28x70 mm wood to screw into, which holds well for most things.
Plus, plywood is 3-4 times more expensive than sparse paneling.

Admittedly, that's true, but if you've done a good surface work on the plaster, you can't see where the attachments are, and then you have to start searching with a magnet or stud finder, for example. Not that it's a big problem, but I think it's wonderful to be able to attach anything anywhere.
In the past, houses were built so that there was always something to attach to behind the interior surface. Today, there's air almost everywhere, and then this annoying plasterboard.
The fact that plywood is more expensive doesn't matter much; you put it up once, and then it stays there. Better to cry once than many times