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Leaky walls causing the biggest energy loss in UK homes


A possible deep freeze this winter and high energy bills are really focussing attention on to what it takes to properly insulate a home.

A well insulated home can make the difference between living in freezing conditions or feeling warm and comfortable this winter.

Insulating walls is the biggest challenge landlords face when improving the energy efficiency of their properties.

Tenants on low incomes in particular tend to suffer because the accommodation they are living in is poorly insulated, and that means it's too expensive for them to heat to an acceptable level. Quite simply too big a percentage of the money they spend on heating goes out through the roof, walls, windows and floor of their property.

Besides that, insufficient heating in a home leads to condensation and toxic mould.

Landlords should be aware of these facts and tackle the energy efficiency of their properties starting with the easiest fixes first, in order of priority:

1 - supplying adequate loft insulation is perhaps the easiest, cheapest and most effective fix

2 - upgrading the heating boiler -modern boilers are by far the most efficient to run

3 - double glazing and draughtproofing

4 - fitting automatic extractor fans in bathrooms and kitchens to prevent condensation issues

5 - floor and underfloor insulation

6 - internal and external walls insulation.

UK housing stock deficiencies

A recently published study by the Resolution Foundation (RF) shows that around 20 per cent of UK homes have no roof insulation and forty per cent have walls that are rated as poor or very poor for insulation. One of the key findings of the report is that the problem is worst in large cities like London where uninsulated walls contribute to the biggest heat loss.

With older properties, typically with no cavity between inner and outer walls, this aspect is the most expensive insulation issue to tackle - it's a big challenge for landlords. Loft insulation, double glazing and even floor insulation are the easiest and cheapest lines of attack on cold. But insulating walls with solid brick or stone walls is often tricky and expensive. The RF report estimates that tacking wall insulation in a typical three-bedroom, semi-detached property with solid walls costs an average of £8,000.

It is perhaps understandable that many landlords are reluctant to lay out that sort of money when they are already under pressure themselves, some paying out additional interest payments on their mortgages. But sooner or later they will have to do something with their property when the Government is planned for improvements in energy efficiency targets for rental properties - ultimately they will be reaching for EPC "C" and even higher.

There is help available

To tackle heat loss through solid walls there are several systems now on the market, making it possible to achieve a reasonable standard without too much cost or disruption. One major consideration for landlords is the prospect of doing the insulation work while the property is tenanted, not easily achievable, that's why every landlord should consider up-grades as and when their properties become vacant.

According to the RF report around 29mn UK homes need to reduce their carbon emissions from their gas-fired heating systems in order to meet the targets the UK Government has set for 2050, and it seems that 'Leaky walls' are one of the main barriers to achieving full energy-efficient standards in English homes.

The Chancellor has recently pledged an additional £6bn in grants to improve the housing stock as the previous approached to providing assistance (Green Deal etc) have largely failed to deliver improvements at the scale needed to make an impact.

Britain has some of the oldest and most inefficient housing stock in Europe for energy efficiency, where its buildings are hot in the summer and cold in winter. The only way to improve this situation is for individuals, landlords, companies and Government to invest money in insulating homes which will improve comfort and help keep down gas, oil and electricity bills.

Wall insulation systems.

If your property was built before the 1920s, its external walls are probably solid walls rather than cavity walls. Solid walls have no gap, so they can't be filled with cavity wall insulation and an alternative insulation method must be used.

There are various methods available for internal application, from foil and foam backed dry wall plaster boarding to battening out the wall with fibre glass or solid Celotex insulation inserts, both of which are cheaper than insulating the outside of the wall.

The issue with internal insulation is the reduction in room size, not an issue with large rooms but certainly one where the rooms are restricted in size. External wall insulation systems are considerably more elaborate and expensive to install and often present problems matching adjoining properties, and around window openings and with different soffit widths. These solutions are expensive and because they alter the external appearance of a property, there may be council planning issues so you need to check.

Both internal and external insulation systems have the potential to cause issues with dampness, condensation and thermal bridging if the wrong materials are used or they are not installed correctly.

Internal wall solution 1

Celotex backed plasterboard laminate 2400mm x 1200mm from builders' merchants such as Builders Merchant Direct This material can be fitted internally by the average DIY person.

Internal wall solution 2

Xtratherm Thin R XT/TF PIR 100mm Rigid Insulation Board from This system fitted internally is much more elaborate but also is more effective that the Celotex backed plasterboard alone, but has the disadvantage of reducing the room size.

External wall solutions

Various types of external wall insulation coverings provide a continuous layer of insulation that is fixed adhesively and/or mechanically to the outside of a building and is coated with a decorative weatherproof render. This can be finished in a wide variety of textures and colours. Check with your local authority about issues with changing the appearance of your property before going ahead with any changes.

Insulation on the outside of walls eliminates thermal bridging and reduces air, wind and moisture penetration into the walls, but it requires expert installation.

Key findings of the Resolution Foundation study

(Hitting a brick wall - how the UK can upgrade its housing stock to reduce energy bills and cut carbon NET ZERO) include:

- 9 million homes in England alone with walls that need significant upgrading

- 64 per cent of homes in London, and more than 40 per cent in other core cities, have poor or very poor walls

- four-in-ten (40 per cent) homes in the poorest neighbourhoods have inefficient walls compared to just over three-in-ten (32 per cent) in the richest of places.

- insulating homes would not overly burden the construction industry as a whole according to RF, adding just 2 per cent to annual working hours, but there some key practical and desk-based skills shortages that need to be addressed.

The report's recommendations include:

For rental properties stricter requirements apply

- owners should be mandated to improve the energy efficiency of their properties by 2035

- penalties for non-compliance should be introduced

- support made available for households with lower means.

- local skills should be developed to ensure local labour markets are capable of meeting high levels of demand.

Thermal Wall insulation - the ugly truth

Good advice from Skill Builder - video

See also Tom's top tips on condensation and mould


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