Wind barrier above beam bottom

[Petrus1979]

I am planning to renovate the floor in our house from the late 1800s. The subfloor is constructed as shown in the picture, but there is no clay under the shavings. The current insulation is wood shavings that have settled over time. My idea is to remove the shavings and check the condition of the subfloor. However, I believe the condition is good except for the fact that there are quite a few gaps where air can flow through. Can I seal the boards in the subfloor with wind barrier paper, and if so, does it matter which type? The plan is then to check the condition of the beams and possibly reinforce the floor structure, then insulate with mineral wool.
We want to install underfloor heating beneath the new wooden floor, and the supplier recommends placing a vapor barrier under the heating coil. However, I am a bit concerned about the risk of trapping moisture.
Grateful for your opinions.


Regards,

Petrus

 

[Per i Hamrånge]

Yes, place wind barrier at the bottom, under the insulation. Fold it up along the joists and staple it in place. I would avoid a vapor barrier on top. However, if you encounter problems with the surface flooring, the warranties do not apply. So the advice usually ends up being to follow the installation instructions.

 

[Petrus1979]

Thanks, do you think there is a risk of trapping moisture in the joist layer if I use a vapor barrier under the new plank floor? Or why would you avoid it?

 

[Per i Hamrånge]

Thank you, do you think there is a risk that I might trap moisture in the joists if I use a vapor barrier under the new plank floor? Or why would you avoid it?

That's kind of what I'm thinking. But now you're going to have underfloor heating, and I have no experience with that in conjunction with a house/floor/foundation of your type. There are a number of factors to keep an eye on.
Moreover, by improving the insulation in the subfloor, it can lead to increased moisture load in the crawl space. So I would keep an extra close watch on what's happening down there after your renovation. Hang in a couple of moisture meters.