Kieran McCarthy: Making sure things are airtight on your home extension

Air leakage can lead to a litany of issues, writes Kieran McCarthy

Ventilation is an important aspect of any home, modernisation is a difficult hurdle to overcome as effective planning can change over homes of different sizes and origins.

Hi Kieran

We’re doing an extension currently on our dormer; going full height at the back of the house out to the edge of the roof. We will have new windows and doors (triple-glazed Aluclad). The builder and engineer are both saying vents on windows aren’t adequate ventilation and that we’d need wall vents in every room. I really don’t like the thought of these vents as I’ve heard they can be noisy, let in light and obviously not ideal in bad weather. The engineer feels mechanical ventilation system or heat recovery wouldn’t be an option when not a new build and that its regulation to vent rooms so the more old-fashioned method of wall vents would be our only option. What do you think? Would rooms with two windows that could be opened daily and also have vents not be enough?