Hi Everyone.

Been lurking on the forum for a while, extremely useful resource.

I'm in the process of applying IWI to externally facing solid walls, Fairly large task.

Very conflicted between the natural breathable route and the non breathable route.

 

For the breathable route-  Battens filled with breathable batts of approx 50 cm thickness boarded with approx 20mm  Woodfibre insulation board and then lime plastered.

 

Confused about what paints then to apply to the lime plaster finish- certainly they have to be breathable (clay paints?)  and I suspect will have to be specially sourced. Also unsure if I can applying lining paper to lime plastered walls to hide any imperfections in the plaster

 

Also in rooms where 2 of the walls without IWI intend to use non breathable paints to keep cost down worried that there will be a mismatch of colours? 

 

The non breathable route essentially similar to Ankkers method recently posted.

 

Thank you for your guidance

 

 

I assume you meant 50mm batts + 20mm woodfibre board.

 

Do you know the old and proposed u values?

 

Are the walls nice and dry?  Have you done any external work on them?

The walls are dry except for some patches of condensation on 1st floor chimney breast area which I think might be due to hydroscopic salts? (not sure if that is the correct phrase) or water ingress from open topped chimney which I'm planning to cap with readily available chimney caps.

 

Walls are mostly lime plastered although it is a bit hollow in places.

 

Couple of  walls are bare brick so thinking of getting it parge coated with lime plaster NHL 3.5.

 

Yes with regards the insulation 50mm inditherm or other type breathable batts between timber studs with thin wood fibre board thinking about 20mm so net effect of 70mm insulation.

Externally walls are brick only no work done to them.

Thanks