Spurred on by the recent, rather cold winter weather, where
working inside the mill has been cold enough for cows to make ice cream, we have now insulted the
roof.
I decided to go with a spray foam insulation product that
gets sprayed directly onto the inside face of the roof skin. This means there
is no air gap where condensation can form. This is basically the same stuff
as the rigid ['kindspan'] foam boards you get with the foil on the outside, also similar to the expanding foam you can buy in cans.
So foam fans! Who knew that it would actually be made by mixing two liquid chemical compounds together? I didnt. The product gets deliver in big oil drums, which seemed a little strange. These four drums are enough to do the whole building
I paid a company to do this for us as you need some fairly specialised
equipment to do it. It took them 3 days in total to cover the entire roof in
15cm of foam.
As a point of reference this gives us the equivalent 'u'
value as using nearly 2 meters of traditional rock wool insulation. Which is
great! Still can’t say it’s the most 'rock n roll' way I’ve spent thousands of
pounds.
The first thing you have to do before starting the spray is
to cover up any surface you do not want the foam, or at the very least, over-spray
from the foam to get on, To be honest this takes almost as long as the spraying
the foam itself. It also turns your building into a very dark and kind of creepy
plastic
tent.
All the structural steel beams that support the roof, nuts
and bolts included, also get a thinner layer of foam applied to stop any
condensation forming on them and thermal bridging from the outside.
