Internal Insulation in Old Solid Wall Buildings

Woodfibre Internal Wall Insulation System


This straightforward system of woodfibre board and Solo lime plaster is suitable for solid-wall masonry.

The breathable system uses natural materials that will maintain a healthy internal climate.

The Woodfibre Internal Wall Insulation System is designed and tested to allow solid walls to stay dry, while offering modern levels of insulation and ease of application.

Wood fibre board is a rigid natural insulation material, manufactured in accordance with EN13171. It has good thermal conductivity properties in the range of 0.039 to 0.044 W/mK and Fire Class Rating E (EN13501-1)

Solo lime plaster is a highly vapour permeable product which is used to create a smooth surface to the boards.

The boards are available in thicknesses 40mm, 60mm & 80mm and are applied with fixings to a flat surface and the Solo plaster is applied in two passes with and embedded fibre mesh. We supply a range of breathable paints, each with its unique colour range, which can be used to decorate the plaster finish.

View breathable paints here

Ultra Insulating Plaster


If the project is not suited to wood fibre boards then the Ultra insulating plaster can be used in place of the boards.

Ultra is a thermally insulating lime basecoat for rendering and plastering. Ultra is a high quality insulating plaster made with light-weight mineral aggregates and natural hydraulic lime. It is highly breathable and has enhanced resistance to salts from its open poured structure. Ultra is applied and built up in coats up to 30mm thickness. It is lightweight on the trowel and contains additions for improved workability making it very pleasant to use.

Table of typical U values
The table shows walls without insulation and improved performance with Woodfibre and Ultra.

UValue w/ m2K

20mm Lime Plaster 35mm Ultra & Solo 40mm WFB & Solo 60mm WFB & Solo
215 Brick wall 1.73 1.10 0.63 0.48
330 Brick wall 1.28 0.90 0.55 0.43

(Assumed Thermal Conductivity W/mk – Woodfibre = 0.04)


Where to buy


Ultra and Solo are available for collection from The Lime Centre or delivery.
Stock levels fluctuate please telephone before arranging collection.

Woodfibre boards and fixings are delivered within a couple of working days.


Quantities and Coverage


We are happy to work out quantities required.

1 bag covers 1m2 at 15mm thick.
15 litre bags, 80 per pallet


For advice on our services and products call us on
01962 713 636