Choosing the right Lime Plaster 

Plastering onto exposed stone or brick internal walls

 There are generally two options:

 The first and most historic method uses Coarse Stuff and Fine stuff – Coarse Stuff and Fine Stuff are manufactured by Womersleys from mature lime putty and selected. Both products are completely breathable, meaning moisture isn’t trapped in the walls, they have natural elasticity, which allows for absorption of minor building movement, and they are supplied as ready to use wet mixes. 

Coarse stuff is manufactured with a blend of hair and fibres to give it strength and reinforcement within the dubbing out and scratch coats.  If you are plastering onto timber laths, then coarse stuff with extra hair is the ideal product for providing secure nibs and strength around the laths. Often customers prefer soft goat hair in the final float coat, to prevent hairs protruding through the topcoat.

The coarse undercoats are then traditionally finished with Fine stuff, a rich lime putty topcoat plaster made with fine moist silver sand and mature lime putty, this and is often applied at 2-3mm thickness. 

The second option uses more modern hydraulic lime plasters: Lime Green Duro basecoat and Solo topcoat plaster

Manufactured from Natural Hydraulic lime to create high performance coatings for internal walls, again ensuring breathability so moisture isn’t trapped. Duro basecoat lime plaster is a natural, elastic and salt resistant undercoat, that can be built out at 12mm per pass, leaving 4-5 days between coats.

The undercoats are then finished with Solo One Coat lime plaster, which is supplied premixed ready to just add water. It can be finished to a smooth or a slightly textured finish. 

Insulating and plastering the internal face of exposed stone or brick external walls

Older buildings were typically built using materials to hand, with solid walls of stone or brick bound with a lime mortar. They were often built without a cavity and certainly no insulation. The lack of insulation and poor thermal properties of the materials used means they retain very little heat. There is therefore a desire to insulate these walls but using modern polyurethane insulation damages old buildings.

Any insulation applied must be vapour permeable or ‘breathable’, or your walls will become saturated. We manufacture and supply a number of insulation products for older buildings please see our how do you choose insulation guide. The guide looks at five insulation options and how they can be plastered:

1. Natural Hydraulic Lime Insulating Render either Ultra or Cornerstone – which can be finished with either Solo One Coat plaster or Fine Stuff

2. Wood fibre boards – which can be plastered and finished with Solo lime plaster. This is applied in two 5 mm layers, with an alkaline resistant mesh pushed into first coat. The second coat is trowelled up to provide a finish or Fine Stuff can be applied instead as the second coat to get a smoother appearance.

 3. Coarse Stuff with hemp – Finished with Fine Stuff

4. Insulating Hemp plaster – Finished with Fine stuff

5. Sheep wool insulation (Cosy Wool) – Covered with Celenit render carrying boards. which can be plastered and finished with Solo lime plaster. This is applied in two 5 mm layers, with an alkaline resistant mesh pushed into first coat. The second coat is trowelled up to provide a finish or Fine Stuff can be applied instead as the second coat to get a smoother appearance.