"RBM" wrote in message
...
On 1/30/2012 9:57 AM, mcp6453 wrote:
When I watch some home construction and repair shows, I often see them
use open
and closed cell spray foam insulation. Often the spray the foam in the
attic
between the rafters and in direct contact with the roof. Does the foam
preclude
the need for the roof to breathe? When the attic is insulated this way,
is the
air flow through the eaves intentionally blocked?


In the last year, I've worked on two house renovations where this was
used. They used open cell on the walls and closed cell on the basement
ceilings and attic rafters. This stuff will really make any new wiring or
plumbing a real chore. It also effectively makes the attic space part of
the heated envelope. Because it seals the house so tightly, they had to
install a whole house ventilation system so the house could "breath".
I'm not sure what the energy savings will be, but my initial thinking is
that it can't be good for indoor air pollution

Depends on the foam. There are various types of "Green" friendly foam which
have no harmful effects.