Insulating Older Buildings

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 meant they retained very little heat, and even with modern insulated doors and windows older properties are still noticeably colder than more modern buildings. While insulating the walls of an older building will make it significantly warmer and reduce heating costs, it is important to use the right materials. Any insulation applied must be breathable or your walls will become saturated.

What do we Manufacture and Supply?

We manufacture and supply a number of Insulation products for older buildings but how do you choose the right insulation material for the job you’re undertaking. There are five key types of breathable insulation products available:

Natural Hydraulic Lime Insulating Render – Made with NHL2 Natural Hydraulic lime, toughened light weight aggregate and fibres. Can be applied internally or externally.
Wood fibre boards – Made from sustainably sourced softwood bound together by the wood’s own cellulose and lignin. Can be applied internally or externally.
Coarse Stuff with hemp – Uses mature lime putty blended with selected aggregates, for internal application.
Sheep wool Insulation (Cosy Wool) - Cosy Wool offers both thermal and acoustic insulation, and provides enhanced performance, breathability, durability and sustainability. For internal application only.

Natural Hydraulic Lime Insulating Render

Our Natural Hydraulic Lime Insulating Renders / Plasters are manufactured from top quality NHL2 Natural Hydraulic lime, toughened light weight aggregate and fibres. The Insulating Renders / Plasters supplied by Womersley’s are:

Cornerstone Insulating Render
Lime Green’s Ultra Insulating Plaster
Adaptavate Breathaplasta Thermal (internal only)

These insulating renders are designed to improve thermal comfort, reduce heat loss and reduce condensation. They are light weight insulating basecoats for rendering and plastering. They contain specialist light weight aggregates and each maintain their structural integrity when applied and will not crush. Providing an excellent insulation layer:

Highly breathable
Energy Saving – a 50mm application will reduce heat loss by up to 60%
Improve Thermal comfort
Builds out in thick layers at up to 20mm per pass
Natural dehumidifier
Suitable for direct application to most surfaces

The Ultra render can be finished with Lime Green Natural Finish (External), Lime
Green Solo (Internal) or Womersley’s Fine Stuff (Internal). The Cornerstone render can be finished with Ironstone Finishing Render (External), Ironstone Finishing Plaster or Ironstone Superfine Finishing Plaster (Internal) or Womersley’s Fine Stuff (Internal). The Adaptavate Thermal can be finished with Adaptavate Universal or Adaptavate Smooth.

When the Cornerstone or Ultra are used external we would always recommend
finishing with a breathable mineral paint such as Beeck Renosil.

A hydraulic lime slurry coat should be applied first to engineering bricks, such
as Ironstone Bonding Coat or Lime Green Stipple.

Wood Fibre boards
We have tried different Wood Fibre boards over the years and found that the best
product on the market is the Lime Green Warmshell system, for internal or external application. Warmshell is particularly well-suited to older hard to heat homes, irrespective of whether they are brick, masonry or timber frame.

Highly breathable
Energy Saving
Significantly limit heat loss
Tongue and Groove boards
Natural and sustainable

Installing Warmshell to your home is surprisingly straightforward. It is well within the reach of a capable DIYer, and should be second nature to most builders.

All you need to do is follow these simple steps:

1. Scour the wall with a coat of Lime Green Duro lime base coat to ensure a level surface

2. Cut the Warmshell boards to size and aim to cover as much of the wall surface as possible

3. Secure the Warmshell boards to the wall surface using suitable fixings and / or Warmshell adhesive

4. Render/Plaster over the Warmshell insulation boards with two-passes of Lime Green Natural Finish (external) with the use of Alkali resistant mesh between coats OR Lime Green Solo Plaster (Internal) with the use of Alkali resistant mesh between coats.

Coarse Stuff with Hemp

Uses mature lime putty blended with selected aggregates, for internal application.
Like all non-hydraulic lime products, it is extremely flexible and breathable which
makes it suitable for use in the restoration of old "solid wall" construction buildings and is ideal as a "wattle and daub" replacement in timber-framed buildings.

The addition of hemp fibres not only improves the strength and flexibility of the
product, but it also increases the thermal properties of the plaster and so adding
some insulation to your wall. Please be careful as some suppliers advertise this
product as Hemp Insulating Plaster which is not quite correct as the insulation values achieved are minimal in comparison to all the other products in this guide.

Hemp Lime Plaster is available in two grades - medium and fine and is manufactured ready to use in bulk bags, and tubs.

Decorating Insulating Lime plaster and renders – It is important that all finishes remain vapour permeable. If they do not then trapped moisture might eventually build up to affect thermal performance. A number of decorative finishes are affective at retaining breathability and are all available from Womersley’s Mineral paints, Natural Emulsions and Lime Wash.

Sheep's Wool Insulation

Thermafleece Cosy Wool Wool is the UK’s only British sheep’s insulation. It is very
suitable for both traditional buildings and modern construction. Cosy Wool offers
thermal and acoustic insulation, and provides breathability, durability and sustainability. Cosy Wool insulation is versatile and insulation rich, the ideal choice if you are looking for all round performance and value for money. Research shows that using 75% wool in combination with recycled fibres outperforms alternative insulation products. This wool rich blend ensures you get the full benefit of sheep’s wool with enhanced performance, durability and sustainability
Cosy Wool insulation can be used in Roofs, Walls and Floors and we supply the
insulation in a variety of sizes to suit all your performance needs. The Cosy Wool
rolls work very effectively in stud wall applications, if you just lay the roll out on the floor for a few minutes, it will fill out and become quite firm, making it ideal for placing between stud battens.

Thermal Values

Sheeps Wool Insulation 0.040
Warmshell Boards 0.044
Cornerstone insulating render 0.123
Ultra insulating plaster 0.18