Insulating window reveals

Last year I decided to do something about the growing about of mould on my window reveals in the bathroom, but what?

My situation was as follows:

High humidity (bathroom)

Thin double glazed windows

Cavity wall construction (that has been 'filled')

Single storey with insulated pitched roof above

Sill is tiled

Max of 10mm between reveal and glazing (frame recessed into wall)

So basically I was suffering from condensation associated with cold spots along the reveals.

The easy answer was to insulate the reveals internally, but I only had around 10mm of depth available to take any. The thinnest boards are 25mm and this includes plaster board of 12.5mm. They also come in 244 x 122cm boards and this was far too much for the reveal area.

So what was my solution? 

Cork tiles were ideally sized as they were thin and came in pack sizes that minimised any potential wastage

I bought a pack of cork tiles and cut them to size. The reveals were cleaned and then I applied a coat of adhesive all over the reveals so that moisture would not be able to get behind the tiles (this is important to stop mould growing behind the insulation). I then fitted the tiles, waited for them to adhere properly and then repeated the exercise so that there was a double layer of cork. The cork adhesive was then left to dry again.

I used a breathable natural paint on the cork (earthborn eco-pro emulsion) and so I had to pre-coat the areas where the adhesive was visible using the earthborn Isolating Primer. This was to stop the paint drawing the oils in the adhesive through it. Once the Isolating Primer had a second coat and dry I painted the reveals.

To date (and this includes a winter and spring) there has been no condensation on the reveals and consequently no mould growth. This solution was cheap, effective and resource efficient (as I only used what I needed with very little waste generated).