Insulate a shed

[roggabear]

Currently converting our friggebod (small shed) from a cold storage space to a youth room/guest room.
Planning to insulate 100 mm in the walls and more in the floor/ceiling.
The friggebod will be heated year-round. How should I approach the vapor barrier since I have only 100 mm insulation in the walls?
Should I use vapor barrier plastic/building plastic or is a vapor retarder preferable (and why)?

 

[andersmc]

You should install a vapor barrier (a.k.a byggplast) everywhere.

 

[fribygg]

A vapor barrier is preferable, then you can set it cold in the future when the youth have moved out.

 

[nybyggarn3]

Agree with the above. Preferably in combination with cellulose cellulosic-based insulation.

 

[roggabear]

You should place a vapor barrier (a.k.a. building plastic) everywhere.

how do I do it in the floor, plastic there too? Where exactly? I will be laying chipboard and laminate on it.

 

[roggabear]

A vapor barrier is preferable, then you can cool down the building in the future when the youth move out.

That sounds reasonable. Does it then require cellulose-based insulation? I already have mineral wool at home, but maybe I need to reconsider?

 

[roggabear]

Agree with the above. Preferably in combination with cellulose cellulose-based insulation.

vapor barrier and cellulose-based insulation, you mean? It doesn't work with mineral wool?

 

[roggabear]

Came across this when I started tearing up the floor! The floor consisted of a plywood board on top of chipboard. I guess it got wet in the shed, and it seeped through the plywood and molded between the two boards. The underside of the chipboard was fine. Is that a date stamp on the chipboard, i.e., was it manufactured on 970425? If so, we've finally got an answer on when the garden shed in its current format was built.

 

[nybyggarn3]

ångbroms och cellulosabaserad isolering alltså? Det funkar inte med mineralull?

It surely works, but wood has nice properties when it comes to absorbing and transporting moisture.

 

[fribygg]

ångbroms och cellulosabaserad isolering alltså? Det funkar inte med mineralull?

It works with mineral wool, it's better with cellulose-based insulation but use what you have, skip the plastic, it doesn't belong in a friggebod in my opinion.

 

[sunnis]

It works with mineral wool, it's better with cellulose-based insulation but use what you have, skip the plastic, it has no place in a shed in my opinion.

It doesn't matter whether it's a shed or not, an exterior wall is an exterior wall...

If TS is insulating with 100mm in the walls and even more in the ceiling, then it's building like you would a regular exterior wall with wind barrier, insulation, sealing tightly with plastic before the surface layer, and ensuring proper ventilation. A well-proven and functional construction.

 

[nybyggarn3]

It doesn't matter if it's a friggebod or not, an exterior wall is an exterior wall...

If TS is going to insulate with 100mm in the walls and even more in the ceiling, it's like building a regular exterior wall with wind barrier, insulation, sealing tightly with plastic before the surface layer, and ensuring proper ventilation. A well-tested and functioning construction.

The reasoning with vapor brakes and cellulose was based on the assumption that the house should be able to be left unheated in the future.

 

[fribygg]

That doesn't matter if it's a friggebod or not, an exterior wall is an exterior wall...

If TS is going to insulate with 100mm in the walls and even more in the roof, then it's about building as you would with a regular exterior wall using wind paper, insulation, sealing tightly with plastic before the surface layer, and ensuring proper ventilation. A well-proven and functional construction.

Sure, if you keep the construction heated constantly and forever.
However, if in the future, when the kid moves out, you want to switch off the heat in the friggebod, the plastic becomes an unnecessary risk factor.

 

[roggabear]

Of course, if you keep the construction heated constantly and forever. However, if in the future when the kid moves out you want to leave the shed unheated, then the plastic becomes an unnecessary risk factor.

Interesting reasoning. Is there any disadvantage to using a vapor barrier if I will have the shed heated permanently? In other words, is there any scenario that speaks for plastic instead of a vapor barrier?

 

[fribygg]

If you intend to build a passive house, the plastic is advantageous