Vapor barrier in floor

[kohage]

Hello!
I am in the process of building an isolated storage house on piers (which will not be enclosed), hence completely okay "draft" underneath.

In winter, half of the space will be heated to around 5-10 degrees (for tools, bikes, outdoor furniture, winter storage of plants, etc.), and the other half perhaps just over 15 degrees (for "fine items"). The sections are separated by an insulated wall. The second half may potentially be used as a guest room later on, with higher temperatures at times.

Since the building is only slightly heated and will vary in temperature throughout the year, I've understood that I should use a vapor retarder (such as Tecca T-Vap) instead of a vapor barrier in the walls and roof. What I can't figure out is whether I should have a vapor retarder over the insulation in the floor as well, or if I should just lay the floor directly on the joists?

At the bottom of the joists, I have oil-hardened underflooring boards, and on top of that mineral wool insulation.

 

[Håbbe01]

Hello!
I am in the process of building an insulated storage house on pillars (which will not be enclosed), hence totally fine with "blow" underneath.

During the winter, half of the space will be heated to around 5-10 degrees (for tools, bikes, outdoor furniture, winter storage of plants, etc.), and the other half maybe around 15 degrees (for "fine items"). The sections are separated by an insulated wall. The other half may possibly be used as a guest room later on, and then with higher temperatures occasionally.

Since the building is only slightly heated and will vary in temperature throughout the year, I understand that I should use a vapor retarder (such as Tecca T-Vap) instead of a vapor barrier in the walls and roof. However, what I cannot figure out is whether I should have a vapor retarder over the insulation in the floor as well, or if I should just lay the floor directly on the joists?

At the bottom of the joists, I have oil-hardened trossbotten boards, and on top of that, mineral wool insulation.

Would probably consider this as a "summer house" with temporary heating
Wind protection and no barriers

 

[Larsa]

Usually, there is neither a steam brake nor a steam barrier in floors, unless it is underfloor heating or a slab on the ground. I would suggest using roofing felt at the bottom and then insulation...