Unless the project is a new build and secondary glazing is specified to help achieve acoustic requirements, then in general, existing buildings have never been designed with the foresight of their future state. This can sometimes cause difficulties when secondary glazed units need to be installed to upgrade the performance of the original windows.
A Grade II* Listed luxury residential property in a highly sought-after area of London, recently underwent a major renovation and opulent make-over for its new wealthy owner. From the outset, it had been mentioned that the windows needed some upgrades to improve the thermal and acoustic performance on the front façade which is exposed and facing a busy thoroughfare. Due to it being Grade II*, the only option, subject to Listed Building Consent, would be to use secondary glazing to enhance the internal environment for the new owners.
Despite having this knowledge, the refurbishment went ahead, with a great deal of time, resources and finances invested to have state of the art furnishings fitted throughout the townhouse. Rooms were redecorated, luxurious and statement furniture strategically placed, but the main fixtures that have proven to make the secondary glazing installation more challenging, are the placement of blinds, bountiful draping curtains and shock-sensor alarms against the primary glazing. The main problem posed was the newly wired electrics for the motorised blinds and alarms.
Primary windows with shock sensor alarm and motorised blinds fitted in the reveal
Secondary glazing is generally fitted within the reveal of a window opening, so there was going to be a clash with the elements that had been put in during the refurbishment. Face fixing could have been an option, but the curtains have been hung close to the reveal, so again, another clash would ensue. Also, some of the windows have wooden shutters, so siting the secondary within the reveals would not be an option for these and the only way to deal with it would be to face fix, which could impede the closing and drape of the curtains when drawn together.
Windows with wooden shutters
To add another conundrum to the mix is a window in the freshly renovated bathroom identified as requiring secondary glazing, which has sumptuous marble tiled walls and window reveal. A new blind has also been sited directly above and flush with the edge of the reveal leaving no space for the additional window. Drilling through tiles is always worrisome, in case they crack, and even more so with 'no expense spared' for these.
Tiled bathroom with motorised blind
The timing of the approach to us for the secondary glazing is unfortunate. If we had been involved from the beginning of the project as a forethought prior to the refurbishment starting, suitable treatments and compromises could have been agreed such as:



- A dedicated fixing position for the secondary glazing, allowing space for all window treatments resulting in a sleek and tidy finish
- Detailing the tiling in the bathroom such that, again, the secondary glazing had a dedicated fixing position which avoids the blinds and does not require fixing through the marble reveals
- Considering combining the privacy for the bathroom in the secondary glazing by using switchable glass or interstitial blinds
- Coordinating the works for the window alarms with the works for the secondary glazing, to ensure there are no clashes at the installation stage and there is access for maintenance at later dates