A ground floor unit on a high street, twelve hundred square feet, previously a card shop, three flats above it and a rear elevation that looks like it could take a flue. Your agent says the rent is good because the unit has been empty eleven months. You sign a fifteen year lease with a rent free period of six months to fit out.
In month two you find out that the lease demises the interior of the unit, that the rear elevation belongs to the landlord, and that the landlord has no intention of annoying three residential tenants. In month four the planning application is refused on odour grounds. You are now paying rent on a unit you cannot cook in.
Four separate permissions, and they are not sequential by accident
A commercial kitchen needs extraction, and extraction needs a route up. Getting one requires clearing four independent hurdles, each with its own decision maker.
Planning permission for the flue itself, because an external duct running up an elevation is usually an alteration that materially affects the external appearance of the building. Permitted development rights for this are limited on commercial buildings and are removed or reduced in conservation areas, on listed buildings, and where an article 4 direction applies. Assume you need permission and be pleasantly surprised if you do not.
Landlord's consent, under the alterations clause of your lease, and separately a right to run the duct over parts of the building you do not occupy. A lease of the inside of a shop does not automatically give you the right to fix ductwork to the outside. That is a licence for alterations at best and a deed of variation at worst, and the landlord can simply say no.
Building control approval, for structural fixings, fire stopping where the duct passes through compartments, and the fire integrity of the ductwork itself.
And the environmental health position, which is not a consent at all but a standard your system has to meet, enforced afterwards through the statutory nuisance regime.
Do them in the wrong order and you find out about the fourth after you have committed to the first. The order that works is: ask the landlord before you sign, get a pre-application view from planning before you sign, and make the lease conditional on both if you can.
Odour is assessed against guidance with numbers in it
Local authorities generally assess commercial kitchen extraction against the guidance produced for Defra on the control of odour and noise from commercial kitchen exhaust systems. It is not law, but it is what the environmental health officer will have on their desk when they comment on your planning application, and a scheme designed against it gets approved.
The guidance works by risk. It looks at the type of cooking, the size of the kitchen, and the proximity and sensitivity of nearby receptors, and produces a level of abatement required. A sandwich bar next to an office is a different problem from a charcoal grill under three flats.
Two things do most of the work. Discharge height and abatement. The usual expectation is that the flue terminates above the eaves or ridge of the building and of adjacent buildings, typically by around a metre, discharging vertically upwards at a decent efflux velocity, with no cowl that deflects it downwards. Half the odour complaints in the country come from systems that terminate at first floor level and point at a window.
Abatement runs in stages. Grease filtration at the canopy is the baseline and is not odour control. Above that come electrostatic precipitators, ultraviolet and ozone systems, and activated carbon filtration, often in combination. Carbon works, and carbon has a consumable cost and a replacement schedule that operators stop honouring in year three, at which point the complaints start again. Budget for the filters as an ongoing cost, not a capital one.
Statutory nuisance is the enforcement route and it is not a fine you can absorb
Section 79 of the Environmental Protection Act 1990 lists statutory nuisances, and includes smells arising from industrial, trade or business premises, and noise emitted from premises, where they are prejudicial to health or a nuisance.
Where a local authority is satisfied a statutory nuisance exists, it must serve an abatement notice under section 80. The notice can require the nuisance to be abated or prohibited, and can require works. Failing to comply without reasonable excuse is an offence, and for industrial, trade or business premises the maximum fine on summary conviction is £20,000, with a further daily penalty for continuing offences.
The point is not the fine. It is that an abatement notice can require you to stop doing the thing that causes the nuisance, which in a restaurant means stop cooking that way. An operator served with a notice on a Thursday has a weekend of trade and a system that does not comply.
There is also a private route. An individual can bring their own action under section 82 without involving the council, and a neighbour who has lost patience sometimes does.
The neighbours above are the risk you cannot design out
Plant noise at night is the other half of the complaint, and it is the half that tends to arrive later, because odour is noticed in week one and a fan running at half eleven is noticed in week five.
Noise from fixed plant is usually assessed using BS 4142, the standard for rating and assessing industrial and commercial sound. It compares the rating level of your plant, with penalties for tonal or impulsive character, against the background sound level, expressed as the LA90 over the relevant period. Planning conditions commonly require plant noise to sit a number of decibels below background at the nearest noise sensitive facade, and the night-time background on a quiet residential street is very low.
The fixes are all cheaper at design stage than afterwards. Anti-vibration mounts, a correctly sized attenuator, a fan speed that is right rather than maximum, flexible connections, and locating the unit away from bedroom windows. Retrofitting attenuation to a system already installed in a plant space designed without room for it is where the money goes.
Then there is the objection that arrives through the licensing system. Prevention of public nuisance is one of the four licensing objectives under the Licensing Act 2003, and residents can make representations against your premises licence application or apply for a review of an existing one. A review can result in conditions, reduced hours, or in serious cases revocation. A restaurant that has annoyed the flats above has given its neighbours a second, entirely independent lever.
One last practical item. Grease extract ductwork has to be cleaned to a standard, commonly TR/19 Grease, and your insurer will very likely require evidence of it. Kitchen ventilation design generally follows the industry specification DW/172. Neither is optional in practice, and an uncleaned duct is a fire that starts in the ceiling void.
Where this shows up in the game
Restaurants and takeaways are part of Business Baron's full game, and cafés and pubs are free to run. The game runs inspections, licensing and a local paper that remembers last year, and consents come from bodies with their own timetables. A unit is usually cheap for a reason, and the reason is often above or behind it.