Morgan Road, Bromley · Photo: Chris Whippet, CC BY-SA 2.0
Bromley, BR1 & BR2
Ventilation, ductwork and Part F compliance in Bromley
Where ventilation stops being optional, what building control will ask for, and what it costs to find out late.
The homes here
Solid houses, almost all of them improved
Much of Bromley is Victorian and Edwardian terraces close to the town centre and inter-war semis further out — well built, and by now nearly all of them extended, re-windowed, insulated or converted at least once.
That is the point. Every one of those improvements made the house warmer and tighter, and none of them was a ventilation decision. A new kitchen at the back, a bathroom where the box room was, a room in the roof — each moves where the moisture is made and where it lands, and each is the moment building control expects the ventilation to be dealt with.
- Extensions move the wet rooms. The kitchen that had a window of its own now sits at the back of an open-plan room under a flat roof.
- Replacement windows close the gaps the house relied on. Unless the new frames carry vents, the background ventilation went out with the old ones.
- Newer flats have units nobody has serviced. A heat recovery or extract unit on years-old filters moves a fraction of what it was set to, silently.
Bromley has the busiest renovation market on our patch, and that changes what people call us about. In Beckenham it is usually a black bathroom ceiling. In Bromley it is as often a builder, an architect or a homeowner halfway through a project, realising that the extension, the loft conversion or the knocked-through kitchen has a ventilation requirement attached to it that nobody costed.
The housing runs from Victorian and Edwardian villas near the town centre — many long since split into flats — through the interwar semis and detached houses out towards Bickley, Shortlands and Hayes, to the newer blocks around the station. Each of those wants something different.
Where ventilation actually bites here
Four situations that come up constantly in Bromley, and what each one needs.
A kitchen or bathroom being remodelled
Approved Document F sets a minimum extract rate per room, and the kitchen figure is the one that catches people out: 30 l/s if a cooker hood ducts to the outside, and 60 l/s if it does not. A recirculating hood sits right over the hob and does not qualify. Get that wrong at design stage and the fan you bought is half the size the room needs.
An extension or a loft conversion
Adding a bedroom raises the whole-dwelling ventilation rate for the entire property, not just the new room — the figure in Table 1.3 is set by bedroom count. A loft conversion also moves the dew point in the structure, which is the commonest way a house that was fine develops a mould problem. Both are far cheaper to deal with before the boards go down.
Building control wanting a number
At sign-off, "we fitted a fan" is not an answer. What is wanted is the measured airflow at each terminal against the required rate. We commission with a vane anemometer and hand over the figures terminal by terminal, which is the document that closes the item.
A newer flat with a unit nobody has touched
A lot of the flats around the town centre were built with mechanical ventilation already in them, and a good number have never had the filters changed since handover. A loaded filter set can take a third off the airflow, quietly, over years — so the system is running, the bill is being paid, and the bathroom still steams up. That is a service, not an install.
Work out what your property needs, before you ring anyone
There is a Part F check on this site that takes your rooms and your bedroom count and gives you the rates Approved Document F actually requires — the per-room extract figures from Table 1.1 and the whole-dwelling figure from Table 1.3. It invents nothing and it multiplies nothing by anything. You can take the result to us, to your builder, or to anyone else.
If you are a builder, loft converter or developer: we would rather be in at first fix, with the duct routed before the ceilings close, than be asked to find a route through a finished house. We will give you the commissioning figures for the building control pack.
Not sure where to start?
Send us a message with what you have noticed at home. We will tell you honestly whether you need a survey, a system, or neither.
Or see what it costs — unlike most in this trade, we publish our prices.
Trained on the systems we install
Certificated — and here they are
Most trade sites show you a row of logos. These are the actual certificates, held by this business. Tap either one to read it, or download the PDF.
- 12-month workmanship guarantee On top of the manufacturer’s warranty, which we register in your name. If anything we installed fails because of the way we installed it, we come back and put it right. What it covers.
- Company no. 12092552 Registered in England & Wales. Trading as Cavalli Ventilation since July 2019, and in ventilation since 2003.
- Airflow measured on every install A calibrated anemometer at the grille, recorded and handed over. The only figure that counts is the one measured in your room.