I read Charlotte Davies’ letter with interest, and it is good to see that some installers are thinking about how to improve how their windows and doors are sealed to the surrounding structure.
On the other end of the scale however, I regularly see installations where the void between the frame and the brickwork has only been partially sealed, sometimes with nothing more than a bead of silicone sealant being applied between the frame and the brickwork. This installation detail may appear trivial, but it can make a substantial difference to how a window or doorset performs in terms of both heat retention and sound reduction. It is important to ensure that the junction between the window / door frame is sealed with an insulating material and that this seal is continuous around the perimeter, with no gaps.
In order to meet current Building Regulations, windows and doorsets have to be thermally efficient. The specification that is required means that they will also have a reasonable acoustic performance. However, the way these products are installed has a huge bearing on this performance.
An unfilled void between the frame and the brickwork will create a cold bridge allowing heat transfer, as well as permitting the passage of sound to travel past the perimeter of the product into the building. The effect of this would be similar to leaving the window or door slightly open. Depending on what is being replaced, the impact of an open void could be enough to make the replacement installation worse than what was there previously. You could also argue that the installation wouldn’t meet Building Regulations, partly due to the resulting thermal performance, but also because it would falls short of the standard of workmanship required by Regulation 7.
Whether expanding foam or tape is used, I believe that the additional effort and cost associated with backfilling this void is well worth the effort, and is likely to result in higher customer satisfaction.
Letter to the Editor - Charlotte Davies, Edgetech