View Single Post
  #7   Report Post  
Posted to alt.home.repair,alt.building.construction
Jonny Jonny is offline
external usenet poster
 
Posts: 12
Default Insulation under flat roofs

"JFM" wrote in message
...
I posted this once before using FreeAgent, but it never showed up. I
even went to Google groups and searched there without finding it, so
it apparently just evaporated. I'm therefore trying again and hope it
does not result in double posting:

Post
----------
A flat roof covering an addition to my house had to be completely
re-done from the walls up--new rafters, decking, roof. I had it
framed, decked, and re-roofed by a roofer, but I must finish the
inside.

Maybe if I can describe this properly, no photo will be necessary:
The rafters run from the inside wall and rest upon (and extend beyond)
the outside wall. There is plywood decking with rubber roof on top. No
soffit yet. So it is completely open between the rafters from the
soffit area, above the walls, to the inside. I will insulate the
inside room area between the rafters. I will have vinyl soffit and
facia applied later, and the soffit, will, natrually, be vented.

The question is how should the insulation be separated from and
protected from the soffit area which will be vented to the outside?

Seems to me that I should nail up some planking or staple up some
plastic (at the walls between the rafters) to protect the insulation
from the outside air.


This is called "birdblocking" where I've been. Its the same size lumber as
the rafters. A hole make be cut and blocked with heavy galvanized screening
for air flow. If you go this route you don't need a soffit.

Or, should this be left open for ventilation purposes?


Up to you.

JFM