Unvented first-floor sub-floor void

[mointainwalker]

Having read another thread about the absolute necessity of sub-floor ventilation, I am a touch queasy and hence my question.


The barn I am renovating has a vaulted stone-ceiling from the stable to the barn above(photo 1). The way this is built means that the original upstairs floor had two lines of deep hollows 2 m across and 40 cm deep ( mirror-image of vaulting below). Three in each line (photo 2).

Since this is the first floor, this is a minimum of 120 cm , max 280 above ground level ( on a steep hillside ).

Untitled

• mointainwalker
• 11 Oct 2010
• 1

Untitled

• mointainwalker
• 11 Oct 2010
• 1

My joists (50 x 200 - 3 m span) touch the old ceiling and effectively separate the six hollows.

Since I am well above ground, I decided that ventilation would serve no purpose.

Since the heating is UFH , I also decided to fill up the hollows with lots of PSE packaging material that I had been collecting , topped up with fibre-wool.

To paraphrase
1) Ground-floor is heated, with 30 cm thick stone-ceiling
2) Above is unventilated void with up to 40 cm of insulation surrounding
untreated joists
3) Joists do not go into wall but sit on small cast concrete blocks adjoining
walls.
4) Walls are 60 cm stone. Min outside temp -18 C.
5) UFH floor-screed temp above joists likely 30 C, temp in void ????

Have I cocked-up big-time ?

 

[mointainwalker]

Hoping for some replies here on the Building forum. Floors etc was deathly quiet !

 

[noseall]

Surely the environment (temperature and humidity) within the floor space will be similar to that within the rooms surrounding the space?

 

[mointainwalker]

Well will it/does it ? Please don't ignore the fact that there are two outside walls at up -18 C whereas the the others are at prob +3C

You have my description above but i am way from certain .

I really am looking for people's ideas whether I have created a multi-year (how-many ? )condensation-filled swamp and/or if yes what I can do ? Or perhaps a well-constructed underfloor enviroment with the best-possible amount of insulation etc


Now, over to you

Thanks