Plaster Specification System for XRV over Block


A cost effective system to insulate masonry homes which maximizes the benefits of the thermal mass.

Supporting Documentation



PlastaBlock is a polystryene (Masons XRV) block system that will provide an R-Value of 1.0 whereas 20 mm of insulating plaster will provide only 0.2 R-Value, yet the cost of both are very similar. Since a few years tougher thermal performance standards apply to all new houses and buildings. The most difficult buildings to insulate are masonry. The insulation properties of the 40 mm EPS sheet will produce an R-Value of 1.0, which will exceed the building code changes.


Using a 5 mm notched tiling trowel apply meshing render and Plastatek™ resin compound to the 40 mm Polystyrene sheet. Firmly place on wall and fix with Dutch darts 5 darts per sheet to hold sheet in place firmly until adhesive has cured. Then use pre-meshed corner beads on all external corners. Adhere with Masons Meshing Render or Masons Adhesive.  
PlastaClad™ Meshing Render
Apply meshing render plaster coat 3 mm minimum. Embed Fibreglass Mesh into the wet plaster. Overlap each successive length by 50 mm minimum, to opening reveals mesh over the PVC flashings. Apply diagonal reinforcement strips at all corners of windows, doors and other exterior openings.  
Skimming Render (optional)
A coat of Masons Skimming Render can be applied in a thin coat to ensure plaster is forced into the surface and then brought out to a flat finish with extra product. This coat is optional. Meshing Render can be used.  
Texture Finish
Apply the coating of the selected texture, to the Masons recommended techniques and thicknesses.  
Cure Finishes
Cure and protect from rapid drying in accordance with Masons requirements.  
Paint Finish
Apply one coat of Masons Limestop Plaster Sealer and then two coats of Premium Build Highbuild Acrylic Paint to exterior plastered surfaces. Allow a minimum of 3 days for the cement plaster to dry before the application of the paint system.
To inquire about this product or to place an order please contact your Account Manager.
To find out who your Account Manager is, select your region from the dropdown below under ‘Contact a Team Member’.