Plastic insulation in garage without electricity?

[Screed]

Hello,

I am in the process of building a garage and I'm considering the issue of wrapping insulation in the wall.

OSB as ceiling panels is in place with plastic directly under the OSB, stapled to the framework.

I will first apply a layer of 45mm and then place 95mm on top of that, followed by putting up plywood panels as walls, with no installation layer, electrical wiring will run on the wall.

I don't have a heat source yet as there is no power, should I wrap the insulation or is the risk of condensation too high?

What risks do I run if I don't wrap it?

The weather in Bohuslän is currently fluctuating between -5 and plus 10, so condensation will likely form, but I expect to have power around March.

Grateful for knowledge and tips.

 

[klaskarlsson]

Hello,

I am building a garage and am considering wrapping the insulation in the wall.

OSB as ceiling panels is in place with plastic directly under the OSB, stapled onto the frame.

I will first have a layer of 45mm and then put 95mm on top of that before putting up plywood panels as walls, no installation layer, with electrical cables run on the wall.

I don't have a heat source yet as there's no electricity, should I wrap the insulation or is the risk of condensation too high?

What risks do I run if I don't wrap it?

The weather in Bohuslän now varies between -5 and plus 10, so condensation will surely form but I'm counting on having electricity by March approximately.

Grateful for knowledge and tips.

Generally, I would consider not wrapping in a garage even if you later intend to occasionally have heating. But go with a vapor barrier so that any moisture can find its way out, but you still get protection against too much moisture pressure if, for example, you park a damp car in the garage later.

 

[Screed]

In general, I would consider not using plastic in a garage even if you later plan to sometimes have heating.
But go with a vapor barrier, so any moisture can make its way out, but you'll still have protection against excessive moisture pressure if, for example, you park a damp car in the garage later.

OK! There is a vapor barrier on the wall elements now against which I will place the insulation, but you think I should do the same against the plywood here then?

 

[klaskarlsson]

OK! There is a vapor barrier on the wall elements now that I will place the insulation against, but you think I should do the same against the plywood here then?

Now I'm not quite sure.
You should never have more than one layer of vapor barrier/vapor brake.

From inside out it usually goes: Gypsum, insulation (45mm) - which is the installation layer, if you have one. Then vapor barrier/brake, insulation, windproofing paper, air gap and panel.

In your case, without installation layer, it would be (from inside out): Wall board (e.g., plywood/gypsum/OSB), vapor brake, insulation, windproofing paper, air gap, facade.

 

[Screed]

Now I'm not really following,
You should never have more than one layer of vapor barrier/vapor retarder.

From inside to out, it usually is: Gypsum, insulation (45mm) - which is the installation layer, if you have one. Then vapor barrier/retarder, insulation, wind barrier, air gap, and panel.

In your case, without the installation layer, it would be (inside to out): Wallboard (e.g., plywood/gypsum/osb), vapor retarder, insulation, wind barrier, air gap, façade.

You're right, I meant wind barrier. But there's not much of an air gap, it's a kit with pre-built wall elements.

Spoke to a carpenter today who was more leaning towards plastic, so we'll see where that lands. After all, it's "just" a garage.

Thanks for the response!