Interstitial Condensation Elimination (aye, interstitial)

Well it's a new year and i've had a good festive break, but now it's back to work and my goodness there's still plenty of it!

The Velux windows are still not fitted and it doesn't look like there's going to a decent window in the weather for months to come, so i'm going to push on with some bits of internal attic work which can be done to progress things.  

The second layer of 80mm insulation board was fitted to the hip elevation of the roof and was also fitted to other parts of the roof where it would not get in the way of the future fitting of the Velux windows.  

I applied a grab adhesive (Gripfill) to the back side of the boards which means that the boards are now glued to the roof trusses and to the 80mm boards which were previously fitted inbetween the roof trusses.  To provide additional securing i cut some 100mm x 50mm packers and screwed through these with 120mm size 12 screws into the roof trusses.  Eventually the final plasterboard sheets will be fixed to these insulation boards and i will use the same Gripfill adhesive and screws to defy gravity.

To allow me to construct the partition for the en-suite i would have to complete the works to the party wall.  This meant that I would have to fit the air-vapour control layer then two sheets of 12.5mm plasterboard.

The air-vapour control layer is a reflective breather membrane which is airtight and vapour tight.  The reflective element reduces heat loss, the air tight element eliminates draughts and the vapour barrier aspect prevents vapour, in the form of condensation, passing through into the wall and insulation where it would condense into water and cause rot, damp and mould growth.  The entire 'box' of the loft conversion will be wrapped in the air-vapour control layer prior to the fitting of the final layer of plasterboard.  This will prevent interstitial condensation (aye, interstitial).

 Each of the joints of the air-vapour control layer were overlapped and sealed using adhesive aluminium tape.  And yes, my American friends, that's Aluminium with 2 letter 'I's.

 The first layer of plasterboard was fitted and screwed in place.  The second layer will be fitted shortly and will be positioned to ensure that there are no overlapping joints vertically or horizontally.