The wall at the windows side

Because of the rain I decided not to cut the other 3 windows, on the right side. Instead I focussed on the insulation of the wall with the existing 3 windows, then added the final panelling.

This is how it looks:

Still needed is a frame around the edges inside.

Using some small curtains which I had, I tried to give it a cosy look. But the center curtain is a bit too short. Need to get three curtains of the same kind.

These were the steps when adding the insulation:

The wall after the windows had been installed. No insulation yet.

The wall after adding the initial 3cm thick Styrofoam plates.

Filling the gaps with smaller Styrofoam pieces and with mineral wool.

Then adding a 1cm thick Styrofoam plate to cover the gaps between the horizontal wooden bars.

Then adding a plastic foil, as an air / humidity barrier. This is necessary to avoid internal condensation of the humid inside air at the cold outside metal walls. 

Then adding the GrossFillex wood imitation panelling. 

My neighbor Manfred scolded me for initially using nails to affix these panels. He gave me a set of narrow wood screws and an electric drill, so now the panels are attached with his screws onto the wooden bars.