Norris Green, L11, is a large estate built by the council in the 1920s and 1930s, made up mainly of semis and short terraces, with some streets rebuilt more recently. Condensation is the cause of most of the mould we see here, usually because the home has lost ventilation over the years rather than because of anything the household is doing. We check fans, vents and heating, treat the mould and put the ventilation right.
What being built in the 1920s and 30s means for damp
Homes from this period were designed for coal fires, open flues and draughty timber windows, which moved a lot of air through the house. Since then most have had fires removed, chimneys capped, windows replaced and gaps sealed. That makes them warmer and cheaper to heat, but the moisture from daily life now has fewer ways out. The result shows up in predictable places: the corners of back bedrooms, the ceiling above the bath, behind wardrobes and around window frames.
Replacement windows and missing trickle vents
Trickle vents are the small slots at the top of window frames that let a little air in all the time. Some replacement windows were fitted without them, and many households keep them shut to stop draughts. The 2021 edition of Approved Document F expects replacement windows not to reduce the background ventilation a home already had. Where vents are missing, we can add them; see trickle vent fitting for how it is done.
Fans that make a noise but move little air
A bathroom fan should extract at least 15 litres per second under Part F, and a kitchen fan 60 litres per second unless it is a cooker hood. Older fans, or fans connected to long flexible ducting, often manage a fraction of that. We check what yours is actually doing. If a replacement is needed, the electrical side is done by a qualified electrician and notified under Part P. Where condensation is spread through the whole house, a PIV unit in the loft can help by gently pushing fresh, filtered air in.
Social tenants and Awaab’s Law
A good share of homes on the estate are rented from housing providers. Since 27 October 2025, Awaab’s Law has required social landlords in England to investigate a potential significant damp and mould hazard within 10 working days of becoming aware of it, give the tenant a written summary of findings, and carry out relevant safety work within 5 working days of the investigation. If you are a social tenant, report the problem to your landlord in writing. Our social housing and Awaab’s Law page explains how we support providers with investigations and written records.
Owner-occupiers and newer homes
Many houses here have been bought, extended or modernised, and the rebuilt streets are newer still. The same principle applies to all of them: work out where the moisture comes from, get it out of the house, and keep surfaces warm. In newer homes we often find that a fan was never commissioned properly or that a vent has been painted shut.
Neighbouring districts
Norris Green borders West Derby to the east and Walton to the west, both of which we cover. For more about our wider work, see our damp and mould specialists in Liverpool page, or learn how we approach condensation and mould problems across the city.
Condensation and mould in Norris Green?
Phone 07777 659786. Let us know whether you rent from a housing provider, rent privately or own the home, and we will call back.
Frequently asked questions
We have new double glazing and the mould got worse. Is that connected?
It can be. Well-sealed windows cut draughts, which is good for heat, but they also cut the air that used to carry moisture away. If the new windows have no trickle vents, or the vents are kept shut, condensation often rises. Adding or opening background ventilation and improving extraction usually helps.
Does Awaab’s Law apply to my home?
Awaab’s Law currently applies to social housing in England, from 27 October 2025 for damp and mould and emergency hazards. Plans to extend it to private renting are proposed but not finalised, so private tenants should check the latest GOV.UK guidance. We do not give legal advice; Shelter can help.
Can you work for my housing association?
We can provide damp and mould investigations, mould treatment and ventilation work, and we produce written findings with photos that suit a housing provider’s records. If you are a tenant, report the problem to your landlord first so it is logged.
How warm should I keep the house to stop mould?
There is no single figure, and we understand heating costs are a real pressure. A low, steady background heat usually helps more than short bursts, because it keeps wall surfaces from getting cold. We look at the whole picture, including ventilation, rather than just telling you to turn the heating up.
What does a PIV unit cost to run?
Running costs depend on the unit, the fan speed and whether a heater element is switched on. We explain the options for your home at the visit and leave you to decide whether it suits you.