|New building regulations proposed in both England and Wales are likely to increase the use of solar control glass and other shading devices in new residential buildings.
Referred to as Part S in Wales, but not yet assigned a letter in England, the proposed new building regulations are likely to see a change of glass specification in new homes, with low emissivity glass being upgraded to solar control glass in some cases.
To be published in December 2021 and in force from June 2022, the proposals for England separate Greater London from the rest of the country. A simplified method can be used to demonstrate compliance, taking into account location, dwelling type, glazing and floor area.
If using this method for residential buildings in Greater London with more than two fabric elements and openings on opposite facades, the maximum glazing area should be 13% of floor area and shading should be provided on glazing between North East and North West (turning clockwise via South). For residential buildings with two or fewer fabric elements and openings on facades which are not opposite, then maximum glazing area should be 15% of floor area. Where shading is required, glazing with a maximum g value of 0.40 and a high light transmittance of 0.70 is one of the accepted solutions.
Intriguingly, outside of Greater London, there is no requirement for shading up to a maximum glazing area of 21% of floor area. This suggests that it is only in London that residential buildings are likely to suffer from overheating, which is surprising given the number of tall apartment buildings being developed in cities such as Manchester and Birmingham. Maybe the proposals will be changed upon publication to recognise this.
Likely to be applicable from Spring 2022, the corresponding requirements in Wales do not differentiate between different parts of the country, but simplified mitigating approach number 2 identifies solar control glass as a means of controlling the risk of overheating by minimising summer solar gains. More precisely, the requirements can be met by using low g value glazing (maximum 0.40) up to a maximum glazing area of 20% of floor area in a single aspect dwelling and maximum glazing area of 35% of floor area in a dual aspect dwelling.
Although out of scope of the new building regulations, through enquiries to our Customer Contact Centre, we are already seeing an increased awareness among householders of the benefits of solar control glass in domestic glazing applications. This is particularly noticeable in the interest in products such as Pilkington Suncool™ One 60/40 for use in bi-fold doors and large, South-facing windows. Of course, this does mean that replacement windows and doors with solar control glass will need to use window U value rather than Window Energy Rating to demonstrate compliance with Part L.
Fortunately, glass manufacturers already offer a wide range of solar control products with high light transmittance such as Pilkington Suncool™ 70/35 to help meet these new requirements and the anticipated increased demand for solar control glass in residential buildings.
For more information on the proposed new building regulation for overheating in England, click here.
For an overview of the proposals for Wales, click here.