The need to insulate

Over a third of UK homes in the UK are cold, damp, energy inefficient buildings and they have a large carbon footprint. New legislation and public demand is continuing to increase the desire for better insulation and living environment. For example the government's Green deal will aim to deal with these hard to heat homes
Constructing, occupying and maintaining buildings creates around 50% of the UK's total CO2 emissions.
If everyone insulated their solid walls, it would save a massive 16 million tonnes of CO2 - equivalent to the emissions of 2.7 million homes for a year.
Internal insulation will reduce heat lost throught the outside walls by around a quarter and save around £300 off your energy bill a year.
Solid wall insulation can reduce heat loss through the walls by as much as 80%.
Most of these houses are privately owned.
Solid Wall properties tend to be more difficult and expensive to improve in terms of adequate insulation and heating.
Living in these homes is expensive, not just in environmental terms. A high proportion of income is diverted into heating costs, and some occupants who cannot afford the cost of heating are often less healthy.
36% of the UK housing stock is solid walled construction with approx 8 million buildings built pre 1920, the vast majority of pre 1920 buildings are constructed with lime mortar/render. These are highly vapour permeable materials.
We all know that energy efficient systems and improved energy performance in old houses will save on running costs, maintain comfort and reduce CO² emissions —and if you are able to achieve this by using materials that are ecologically friendly, you will be making an additional positive contribution. However, adding insulation to old houses can often be extremely tricky, particularly where the walls are concerned. Modern materials and techniques can often be incompatible with traditional construction and the use of the wrong insulating materials could well cause serious harm to the building fabric. Most modern houses are built from hard, strong, impervious materials. To exclude moisture they rely on physical barriers such as damp-proof courses and membranes, cavity walls and cladding. Historic and traditional houses are completely different. Many have solid walls, and most have porous fabric, which both absorbs and readily allows the evaporation of moisture. This is often known as the ability of the building fabric to 'breathe'. A more technical term for it is vapour permeability.
Using inappropriate materials or non-vapour permeable material or methods to upgrade these homes can cause damp and therefore decay.

Why use lime, the main reasons

Very important is the compatibly of old structures with new "eco materials". Remember that Portland cement was invented and in use from the mid 1800s and has been used widely from the 1920s onwards.
Lime allows buildings to "breathe", and does not trap moisture in the walls.

Lime Mortars - What you can Expect

Elasticity - An essential factor in repairing old buildings without construction joints. Important in minimising shrinkage and cracking. Allows for minor movements.
Permeability - Good vapour exchange qualities allow for condensation dispersion. No rot. Great benefits to the living environment.
Condensation risk - If the materials in contact with the liquid water are tolerant, it may later be lost by evaporation leaving no permanent damage behind. If the materials wetted by the condensate are susceptible to water damage, the condensate may cause progressive deterioration.
Water may encourage fungal growth, etc which may harm organic building materials and produce spores which are injurious to health.
Water may cause dimensional changes in materials such as wood, concrete, ceramics, etc. Water needs to be removed to avoid problems. The appropriate provision of ventilation, drainage and heating can provide flexible methods of controlling condensation risk.
Natural insulation fits well with lime and possesses many of the same attributes: Principally vapour permeability and a healthy indoor climate. Natural insulating materials function as the clothing for the house. Excessive water vapour (e.g. from cooking or showering) can permeate through the structure. This vapour permeability prevents mould and construction damage. Well-being in the house comes from protection from cold weather, heat and noise, a pleasant internal climate and balanced air humidity making the property particularly Allergy friendly. In combination, lime and natural insulation can effectively and economically improve old houses.

Simon Ayers
Lime green products Ltd
Coates Kilns, Stretton Road, Much Wenlock, Shropshire, TF13 6DG Tel.
01952 728 611 Fax 01952 728 361
simon@lime-green.co.uk