Abstract
There is the spase under the Floor to control partially both temperature and humidity in the room. The more the space is closed by the fondation wall, the more it controls temperature in the room, but the worse it controls humidity there. The damp under the floor brings decay to timbers there. In this report we have got the rapidity of decay to a timber by many experiments, then K=F (m, θ, 〓, f) K=Coef. of diffusion of decay (cm^2/week) m=Material (timber) θ=Temperature (c) 〓=Humidity (%) f=Fungus We may define the superior limit of damp under the floor in some condition, in wich a floor joist (4×4cm, cryptomeria) will decay with poria vaporaria to grow so week as 1/3 strength for 50 years.
