Week 84 - Spray Foam Roof Insulation

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.