Relatives have a 200+ year old house which was originally lime rendered. Slate DPC, thick solid walls etc. Old houses need to breathe with the weather and damp, moisture passing freely through the walls from what we've learnt.
In the 70's the walls were repaired with modern materials - sand and cement render, covered with masonry paint, which has all caused timber problems and horrific damp.
House is now being restored, all the sand and cement and gypsum plaster has gone, and we are re-rendering and re-plastering with lime, as it was originally built. The house smells better, is visibly drier, and the brickwork, where still on show, is no longer dripping wet.
Paint.
Dulux state their masonry paint (Weathershield smooth) is fine on lime render as allegedly it is a breatheable paint.
Everybody else says acrylic paint is a definite no-no. Other options are St Astier lime paint, or a Beeck paint system, both specifically for lime rendered walls that breathe.
Speaking to suppliers of lime paints, they say we MUST use a lime paint, which is massively less resistant to the passage of moisture than acrylic resin paints.
Dulux say the opposite.
Impartial expert advice seems hard to find - everyone promotes their paint system.
Builder is relying on the woman on the Dulux tech helpline being correct and the fact that Dulux has a 15 year guarantee to fall back on.
Johnstone's 100% advise against acrylic over lime render.
Expert opinions would be much appreciated! Many thanks in advance.
In the 70's the walls were repaired with modern materials - sand and cement render, covered with masonry paint, which has all caused timber problems and horrific damp.
House is now being restored, all the sand and cement and gypsum plaster has gone, and we are re-rendering and re-plastering with lime, as it was originally built. The house smells better, is visibly drier, and the brickwork, where still on show, is no longer dripping wet.
Paint.
Dulux state their masonry paint (Weathershield smooth) is fine on lime render as allegedly it is a breatheable paint.
Everybody else says acrylic paint is a definite no-no. Other options are St Astier lime paint, or a Beeck paint system, both specifically for lime rendered walls that breathe.
Speaking to suppliers of lime paints, they say we MUST use a lime paint, which is massively less resistant to the passage of moisture than acrylic resin paints.
Dulux say the opposite.
Impartial expert advice seems hard to find - everyone promotes their paint system.
Builder is relying on the woman on the Dulux tech helpline being correct and the fact that Dulux has a 15 year guarantee to fall back on.
Johnstone's 100% advise against acrylic over lime render.
Expert opinions would be much appreciated! Many thanks in advance.