Insulate garage, the facade consists of plywood or similar

[sir_erken]

I was thinking of insulating the garage this spring but have a few questions.

The facade consists of plywood or similar and wood paneling, see pictures.

There is no air gap if I put the insulation directly against the board on the inside, but how can I create one when the board is directly on the studs?

Is an air gap really needed in this construction?

So the panel is nailed with gaps directly on the board. It is only visible if you look really closely.

 

[sir_erken]

No one has any idea?

Is the only solution to remove the panel, put a horizontal thin strip, and then panel on it, leaving the plywood inside the air gap?

Or do you have to take down the whole plywood as well?

 

[shomakie]

Remove the wooden facade and the panels. Staple up the wind barrier and then batten at cc60 with 28*70 timber before the paneling is reinstalled. Then insulation on the inside and then plastic.

 

[sir_erken]

Thinking about leaving the plywood sheets in place instead of windbreaker?
Doesn't seem like it would do any harm to keep them?

 

[Mikael_L]

It might be possible to simply insulate from the inside in the stud bays and then attach interior walls. Plywood works excellently as a wind barrier, but depending on the paint, it can be too vapor-tight.

The problem largely depends on the color of the facade paint. If it's a very vapor-open paint, like traditional Swedish red paint, there shouldn't be any issues. If it's a fairly vapor-tight plastic paint (acrylic, latex), it gets worse, as how will the plywood and facade boards dry out? This is why having an air gap behind the facade boards is important; the wood needs to be able to dry.

If you have an unheated garage, or just minimally heated, but especially with no moisture production in the garage, then the entire wall can dry inward instead. In that case, skip all forms of vapor-tight plastic on the inside, be sure to maintain low humidity inside the garage, and preferably keep it quite cool (this way, the vapor pressure won't be as high in the air inside the garage, and it won't drive moisture into the walls in that manner).

 

[sir_erken]

I wrote a bit unclearly, I was thinking that I would take down the panel and put battens for an air gap outside of the plywood and then put the panel on that.
Then I get an air gap between the plywood and the panel.
But should I scrap the plywood entirely and put windbreaker instead?

 

[shomakie]

I think you should tear down the plywood completely. Use it on the other side behind the drywall so you have something to screw into.

So from inside out, wind barrier, battens, and then the panel.

 

[Oldboy]

Even without paint, the plywood is likely too dense (glue).

So it's safest to take it down.
(Using it outside the air gap on the exterior or on the inside behind the plasterboard is fine.)

 

[sir_erken]

What makes it too dense?
I will have plastic inside the insulation.
But if it needs to come down, I'll take it down!
If I take it down, does 28×48 work as nail battens?

 

[Oldboy]

What makes it too dense?
I will have plastic inside the insulation.
But if it needs to come down, I'll take it down!
If I take it down, does 28x48 work as nail battens?

I believe that it's the multiple layers of adhesive that make it too dense. The adhesive layers should correspond to paint layers in terms of density. So with plastic on the inside, there's a risk that if moisture gets in (e.g., driving rain from the outside or moisture from the inside through small holes, tears, gaps, etc. through the plastic), it will have difficulty drying out.

I wouldn't take the chance. (Though, like you, I would have examined every possibility to possibly avoid taking down the plywood...)

 

[sir_erken]

Then it goes down and the windproof fabric goes up!
I have a bunch of 28×48 lying around, enough for the facade battens, but is it too flimsy? Someone mentioned 28×70?
As seen in the picture, it's framed at cc 120 vertically and then about cc 60 horizontally, so I was thinking of attaching 28×48 on top of the windproof fabric on the horizontal frame.

Edit: writing from mobile...

 

[shomakie]

Works just as well with 28*48.

 

[Staraction]

Hello!
Reviving the thread and hoping for responses from those of you who have already written in it or others with experience. Hoping for answers

I have just started cleaning out the cold garage and will now insulate it. I have the exact same construction on my garage wall as in the TS garage and pictures above. I have read many threads but I'm not completely sure. I have been in contact with an acquaintance who is a skilled carpenter of the "old guard." According to him, it is fine to just place insulation in the cavities, directly against the fiberboard/plywood, and then cover the inner walls with any board of choice.

From the outside, it would be Outer panel-plywood-insulation-plywood (painted).

Additionally, we will not be using any plastic on the walls, and the thickness of the insulation will be 70mm. However, I will probably purchase Cellolusa insulation since I understand that it is more forgiving with this "approach" to potential moisture problems, etc.

The inner ceiling will be constructed and the insulation will be a total of 120 mm with that kind of paper on top. I will also install a Pax/Fresh Iq fan for any potential moisture in the garage.

The intended use is a workshop for carpentry/repairs and a home gym.

What do you think, will this work? I'm not quite sure from all the threads

Thanks in advance!

 

[sir_erken]

We tore everything down, put up new paneling with air gap, insulated, and installed an electrical installation layer. It turned out great. We plan to convert part of the garage into living space, which is why we were thorough.

The neighbor had the same facade and only put 70 insulation in the compartments on the inside and then an OSB board that he painted white. Considerably less work, and it has worked well for 10 years for him. Still looks nice.

 

[Staraction]

Thank you very much for the response, I almost understood that you did so judging by the thread. Well done by you! I have the exact same wall construction as you "had," even the same facade color

Also happy to read about the neighbor's strategy, and it seems that we will do the same thing with Cellolusa insulation and very good ventilation/moisture control.

Thanks again!