I am planning to build a 15m2 standalone sauna with overnight accommodations in the relaxation area for guests. It will normally not be heated in the winter, but it should be possible to quickly warm it up for guests, and ideally, it should be easy (cheap) to maintain the heat afterward. I am considering insulating with 15cm in the walls and 30cm in the ceiling, but I am wondering if this could lead to moisture problems. The reason I am unsure is that I have heard at some point about the risk of over-insulating. The idea is to either have gypsum or asphalt board at the outermost under the outer wall panel, with studs for insulation, and then tar paper (or another breathable wind barrier), followed by wood paneling or possibly gypsum and wallpaper.
Are there any disadvantages to insulating with 15cm (besides the cost)? Should I stick with 10cm?
I am planning a concrete slab with underfloor heating and a wood-burning stove and oven in the sauna area.
Are there any disadvantages to insulating with 15cm (besides the cost)? Should I stick with 10cm?
I am planning a concrete slab with underfloor heating and a wood-burning stove and oven in the sauna area.
I don't think the amount of insulation poses any particularly increased risk of moisture problems. Such problems probably depend on other factors. However, perhaps 15+30 is a bit overkill in a space that will almost never be heated. I have 70mm in the walls, 135 in the floor, and 120mm in the ceiling of the shed. It will definitely never become permanently heated with this modest insulation; it requires at least 1000W to achieve a decent temperature at -20°C outside.
If you don't have any issues with cost and "wasting" the permitted building area, then go ahead with your plan, otherwise, you can probably settle for, say, 120mm in walls, 145 in the ceiling, and something suitable in the floor (120-170).
If you don't introduce any moisture into your shed when it's not heated, then not much will happen. Place a dehumidifier if you're very concerned.
I have 70mm in the walls, 135 in the floor, and 120mm in the ceiling of the shed. It will definitely never become permanently heated with this modest insulation; it requires at least 1000W to achieve a decent temperature at -20°C outside.If you don't have any issues with cost and "wasting" the permitted building area, then go ahead with your plan, otherwise, you can probably settle for, say, 120mm in walls, 145 in the ceiling, and something suitable in the floor (120-170).
If you don't introduce any moisture into your shed when it's not heated, then not much will happen. Place a dehumidifier if you're very concerned.
As Mikael writes, I think you are oversizing, and you should barely need to heat 8-10m2 of the space at most.
So around the entire relaxation area, I would stick to 95mm (or 120mm).
If you choose to cast a slab, which I did for a guest cabin of 16m2, you lay 2*100mm of cellfoam there.
In the ceiling, 120-145mm of insulation is sufficient. For a ridge beam, less since you need an air gap; with a regular ceiling, just fill in an appropriate amount, but 145-195mm will be well-insulated in your case.
You lose interior space in a cabin as small as 15m2 by building too thick walls. It becomes quite cramped when you get the furniture in place, so unless necessary, I would have chosen 95mm studded walls.
I do not recommend using the sauna area as living space since, after all, there will be some smell from the sauna and wood burning.
So around the entire relaxation area, I would stick to 95mm (or 120mm).
If you choose to cast a slab, which I did for a guest cabin of 16m2, you lay 2*100mm of cellfoam there.
In the ceiling, 120-145mm of insulation is sufficient. For a ridge beam, less since you need an air gap; with a regular ceiling, just fill in an appropriate amount, but 145-195mm will be well-insulated in your case.
You lose interior space in a cabin as small as 15m2 by building too thick walls. It becomes quite cramped when you get the furniture in place, so unless necessary, I would have chosen 95mm studded walls.
I do not recommend using the sauna area as living space since, after all, there will be some smell from the sauna and wood burning.
It depends on the span and the snow zone.jakim said:
But a 2.5-meter long 45x95 in fine lumber can support more than 1 ton if it is protected against buckling in the weak direction.
Which means that such a wall studded at cc600 can support over 20kN/meter (2 tons/m), and then there's usually a wall on the other side of the house so it can support a roof load of 40kN/meter roof measured in the direction of the ridge.
So answer: Your friggebod can manage perfectly fine with 45x95 in the walls regardless of the snow zone and even if you also lay 4 layers of concrete roof tiles on top of each other.
But a carport might not manage unless you put in braces or similar, which protect against the studs buckling in the easily buckled direction. But if you, for example, put drywall inside, then you have braced sufficiently in the weak direction.