Clients arrive at a first meeting having been told that their project has been approved, meaning planning permission, and assume the drawings are therefore finished. They are not, and the distance between the two is where a great deal of money is lost on domestic projects.
What each of them is actually for
Planning permission concerns the effect of a building upon everybody else: its scale, where it sits, what it does to the street, what it does to a neighbour’s light and privacy, and whether it sits comfortably within a conservation area. It is determined by the local planning authority, it is a matter of judgement, and it may be refused upon grounds that have nothing whatever to do with whether the building would stand up.
Building Regulations approval concerns whether the building is safe and performs properly: structure, fire, insulation, ventilation, drainage, stairs, glazing and accessibility. It is administered by Building Control, and it is a matter of compliance rather than of opinion. A detail either meets the standard or it does not.
The two are independent of one another. A scheme may hold planning permission and fail Building Regulations. It may satisfy Building Regulations and be refused planning permission. Work requiring no planning permission at all, which includes a great many extensions built under permitted development, still requires Building Regulations approval.
Why the planning drawings are not enough to build from
A planning application is assessed upon what the building looks like and where it sits. The drawings accompanying it are prepared to answer that question and no other. They show form, position and materials. They do not show how the roof meets the wall, where the steel is to go, how the floor is built up, how the extension is drained, or how the insulation is carried through a junction without a cold bridge.
Handing planning drawings to a builder and asking for a price produces a figure that is not truly a price. It is an estimate against an incomplete picture, and every decision left unmade on paper is instead made on site, ordinarily at the very point where it is most expensive to change.
What the technical package changes
The Building Regulations package resolves those decisions in advance. It sets out the construction, coordinates the structural engineer’s information, and specifies precisely what is being built. That has two effects well worth paying for.
The first is cost certainty. Builders pricing from a complete technical design are pricing the same job as one another, so the returns may genuinely be compared, and far less is left to be priced later as a variation.
The second is that you receive the house you were shown. The detail is where a design either survives or quietly erodes: the flush threshold becomes a step, the concealed gutter becomes a fascia, the junction that was meant to disappear acquires a trim. These are not building failures. They are the consequence of a decision being taken by whoever happened to be standing there on the day.
Where they sit within a project
In practice the sequence runs planning first, then Building Regulations, then tender, then construction. There is little sense in resolving a junction in detail upon a scheme that may yet be refused or amended, and none at all in approaching a builder for a price before the technical design exists. We set that sequence out at the beginning of every project as a written design programme, so that the order and the timescales are clear before anything begins.
If you hold planning permission on a project and are uncertain quite what it is you are holding, it is worth a conversation before you begin collecting prices.
Written by Thurston King Architects, a RIBA Chartered Practice in Sutton Coldfield. This is general guidance rather than advice on your property: what a particular site will support depends on the property, its setting and the view your local planning authority takes.
