[Strawbale] PEX, Concrete Slab, Fear of Death (by contractor)

[Shody Ryon]

> > This still does not address the R value of the
> > concrete floor vs wood and the roof insulation
which
> > is a good topic.
> 
>      This is a red herring.  You can make a good
> floor, with lots of  
> R-value, either way.  Both have their pros and cons
> and might be  
> better or worse for specific circumstances.

Does anyone install more than 4” of XPS rigid
insulation under a concrete floor? If it has an R
value of 5 that would be R 20. Wouldn't problem with
that be that being in direct contact with the ground
which is cooler than the desired air temp inside would
put a constant load on the heating system? That's what
Laren said. It sounds like it may be a moot in
practice in your opinion, however a wood floor would
cost less, about $500 less for approximately 900 sq
ft. Wood may be a good elect insulator but it is a
less good at thermal insulation as has been
extensively discussed on another list, thus it is a
fair conductor of heat for a radiant floor, although
the aluminum radiators fins are commonly used, can get
a little pricey and can be noisy (ticking sound of
expansion) while warming if not installed properly
with plenty of silicon.
Wood is likely more environmentally friendly. Fly ash
may make “concrete” more environmentally friendly, but
that my depend on location, but for a lot of the
northern US and Canada, wood may be more
environmentally friendly. Wood may be easier on the
body for standing and walking. Leaks in a hydronic
system in concrete may be hard to find and deal with.
Water can be a hard thing to deal with under a
concrete floor. I was advised to use the 15 mil
comercial grade plastic under concrete as the normal 6
mil will degrade quickly if subjected to pH extremes
such as concrete.

I am currently deciding if I should install a wood
below grade in my current project because of all these
advantages over concrete.


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