Alreflex Platinum: Reducing the Cost and Risk of Retro Fit Insulation

Alreflex Platinum: Reducing the Cost & Risk

The Climate Change Committee have recommended in the Sixth Carbon Budget that the UK has less than fourteen years reduce carbon emissions by 78% to stay on track with the net-zero carbon target by 2050. Buildings are the third biggest contributor to UK greenhouse gas emissions, and make up 16% of the UK’s greenhouse gas emissions.

The environmental impact of buildings can be relatively easily reduced in new-builds because energy efficiency can be designed in; but improving the energy efficiency of homes can be a challenge, particularly in older homes built with solid masonry walls or walls with a hard-to-treat cavity (HTTC). HTTC walls are defined as cavity walls when the cavity is no greater than 50 mm, and is thus unsuitable for blown-in cavity wall insulation.

Options for solid masonry & HTTC walls

Solid masonry walls and HTTC walls are normally good candidates for either External Wall Insulation (EWI) or Internal Wall Insulation (IWI). As a rough guide: Estimates for EWI are usually about £100 per square metre, and IWI tends to be between £40 and £50 per square metre. However, it should be possible to reduce the costs of IWI even lower.

Typically, an IWI system comprises an insulated plasterboard, which could use phenolic foam or polyisocyanurate (PIR) as a thermal laminate. Both of these materials are in high demand at the moment, and prices have been rising steadily.

At Thermal Economics, we manufacture the Alreflex Platinum dry-lining board as a suitable product for retrofitting to solid masonry and HTTC walls. The board is fixed directly to the brickwork / blockwork on brackets, and the wall is finished with a standard plasterboard on metal or timber studs. Additionally, the foil face of the Alreflex Platinum dry-lining board also provides a vapour control barrier to prevent the risk of interstitial condensation, so a separate VCL membrane is not necessary.

Risks with insulated plasterboards

Older buildings with solid masonry or HTTC walls tend to be leakier compared to newer buildings constructed today. Cold air from outside often makes its way into the building and creates more work for the heating system. The reduction in the ambient air temperature due to this is called infiltration heat loss.

Although infiltration heat loss reduces the overall energy efficiency of the home, it does also have an added benefit of helping to ventilate the home by providing a pathway for vapour pressure to force out the warmer, moisture-laden; which reduces the overall humidity in the building. Adding insulation to the inside face of the wall will change the temperature distribution, so that the brickwork / blockwork is colder and it reaches dewpoint somewhere between the brickwork / blockwork and the internal wall insulation, forming interstitial condensate.

This is readily prevented by installing a separate VCL membrane behind the insulated plasterboard, which normally prevents interstitial condensation. However, it is still possible for the relative humidity in the layers between the VCL membrane and the back of the plasterboard to reach the points where toxic black mould can grow hidden from view.

Preventing moisture risk with Alreflex Platinum

When Alreflex Platinum dry-lining boards are correctly installed, the vapour control barrier is in front of the primary insulation layer, so that the plasterboard and the cavity behind it are at a similar temperature and relative humidity to the ambient air inside the home. This stops any risk of unseen mould growth.

This can provide better indoor air quality, and a safer environment for occupants with respiratory conditions; as well as prolonging the life of the plasterboard finish.

How we can help

To find out more about the suitability of our Alreflex Platinum dry-lining board for retrofit insulation work, including:

• U-value calculations

• Thermal bridging

• Condensation risk

Contact our technical team on 01582 544255 or e-mail: [email protected].