Secondary glazing in Listed Buildings by Royal Warrant Holder Selectaglaze

by Laura

Historic England is mainly responsible for the management of historic environments and guides Government Departments and Local Planning Authorities on development proposals that can considerably affect Listed buildings or conservation areas. Fortuitously, conservation professionals as well as heritage organisations understand that historic buildings need to be adjusted in order to work for contemporary usage. Many of these neglected buildings suffer from inattention, decaying fabric and are vulnerable to theft and squatters. The majority are thermally inept and draughty with a lack of good acoustic insulation which can be fixed through the sympathetic and effective introduction of secondary glazing. Listed Building Consent is an important prerequisite for any alterations that could potentially affect the character of a building; it is deemed a criminal offence to undertake work without it.

Selectaglaze secondary glazing is a reversible adaptation accepted by most Conservation Officers. It can be removed, if needed, at a later time with little impact on the original fabric of the building. In some cases, fixing holes may need to be repaired along with minimal redecoration. The considered design ensures the original windows stay unchanged and visually uncompromised. The introduction of secondary glazing traps an insulating layer of air, which can reduce heat loss by more than 50%. With the introduction of low emissivity glass, U-values of around 1.8 can be achieved. The use of high performance twin seals help to virtually eradicate draughts. However, an added benefit of secondary glazing is noise reduction. When there is a gap between the primary and secondary glazing of at least 100mm, a reduction of 45dB is possible.

Selectaglaze has a plethora of different frame styles which are sympathetically designed and can be finished in almost any colour, to match or complement the existing décor. The units are easy to maintain and a full after sales service is available. To carry out work on a Listed building, Listed Building Consent can be acquired through the Local Authority. Furthermore, if the building is located in a conservation area then a Conservation Officer at a local planning authority should be approached for advice.

Two of the latest projects using Selectaglaze secondary glazing involved Grade II Listed buildings, which came with their own challenges and irregularities.

Whitehall Museum is a 500 year old Grade II* Listed Tudor building which has received a well needed £1.6 million refurbishment and restoration.  The building located in the leafy suburb of Cheam received a grant from the Heritage lottery fund and contributions from the Local Council and the Friends of Whitehall Charity to carry out works which included tackling damp issues, improving thermal performance, removing 20th century fixtures and restoring some of the original features.

The windows at the front of the building date from more recent upgrades but are still rich in architectural history, so Curl La Tourelle Architects specified the installation of secondary glazing to make the thermal and noise improvements required without damaging the architectural features.

15 units were installed from the light weight range and 2 fire retardant units. The old Tudor building, with sloping irregular floors, bowed walls, uneven height ceilings and extremely irregular window openings, meant any works carried out there had to be very carefully planned and required high levels of craftsmanship. Tapered and splayed timber grounds were used to take up the irregularities of the building structure which were scribed on site. Once these were in place the secondary glazing was installed which was sympathetically designed to suit the original windows.

The treatment of the fire rated windows posed another challenge. Durtnell & Sons created new fire resistant reveals into which the secondary glazing was installed ensuring the integrity of the treatment.

With the work complete, all who use the building will experience a comfortable environment, with draughts eliminated and a huge reduction in heat loss. With great anticipation, Whitehall Museum  re-opened in the summer of 2018, allowing visitors to once again step over the threshold of centuries past.

The Priory is a beautiful Grade II Listed residence in the village of Blythburgh, a settlement of probable Saxon origin. A medieval chapel sits at the west side, with a 17th century farmhouse, a rebuilt 15th century timber framed property and early 20th century additions making up the remainder of the house.  The Priory shares its grounds with the ruins of a 12th century Augustine Priory which has been the subject of an archaeological investigation by Channel  4’s Time Team as well as subsequent digs which confirmed the existence of a Christian church on the site from c.700 AD.

The task of making the Priory a comfortable home for the Saunders family was paramount. One key issue was heat retention. The primary windows are a mixture of Georgian, leaded outward opening casements and fixed lights within timber or stone frames. Due to the Listed status of the building, these thermally inefficient windows could not be replaced. However, Mrs. Saunders found a solution in Selectaglaze secondary glazing.

Selectaglaze installed 15 units comprising of the Series 10 – 2 and 3 pane horizontal sliding units, finished in either walnut or black matt on the ground floor, corridors and bedrooms. The Chapel windows were treated with white Series 45 single side hung casements with a gothic arch to match the opening. In order to compliment the design of the existing windows, the secondary glazing was mullion coupled where necessary. The secondary glazing was installed, sealed and secured upon bespoke timber frames designed to suit each opening. All units were fitted with 4mm low emissivity glass for improved thermal retention.

The Saunders family were so impressed with the quality of the secondary glazing, that they decided to order more for other areas of the house. This was due to how unobtrusive the units are in relation to the original glazing and the uplift in thermal retention that could be noticed. A further 16 units were ordered and installed – a combination of the Series 10 – 2 and 3 pane horizontal sliding units.

It is a privilege to own and live in a house with a history such as The Priory, but it can be a fine balance preserving the heritage of the house whilst making it a comfortable family home. Selectaglaze has helped make this possible and we were grateful to be draught free when the Beast from the East hit us earlier this year.” Chiara Saunders

Established for fifty years and Royal Warrant Holder since 2004 Selectaglaze has a wealth of experience working on all building types, from Listed offices to new build hotels.

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