Planning drawings vs building regulations drawings: what each one is for

What is the difference between the two sets of drawings?

Planning is about what you build and where. Building regulations are about how you build it.

Planning drawings show the council what you will build and where, and building regulations drawings show a building control body how it is built. One set asks whether the project is acceptable for the street and the neighbours. The other asks whether it is safe, warm, healthy and properly constructed.

GOV.UK explains when you need planning permission: building an extension, making a major change to a building or changing its use usually does. A planning set is mostly plans, elevations, a location plan and a block plan.

Building regulations are a separate legal system. The Building Regulations 2010 cover the construction and extension of buildings, and the technical requirements sit in Schedule 1, which includes structure (Part A), fire safety (Part B) and energy (Part L).

The practical result is two different readers. A planning officer wants to see the finished shape. A building control surveyor wants to see what is inside the wall, under the floor and above the ceiling.

What does a planning drawing show?

A planning drawing shows the outside of the house and its place on the plot, at a scale a council officer can measure from. It does not need to show how the walls are made.

A typical householder set has existing and proposed floor plans, existing and proposed elevations, a section where the height or levels matter, a location plan and a block plan. Our guide to what drawings you need for planning permission lists them one by one, and the location plan and block plan guide covers the two site drawings.

On a planning elevation, a wall is a line with a material label such as "facing brick" or "white render". That is enough for the officer to judge the look. It says nothing about the cavity, the insulation or the foundation underneath.

What do building regulations drawings add?

Building regulations drawings add the construction detail: what every wall, floor, roof and opening is made of, how thick each layer is, and how the building stays up, stays warm and stays safe. They turn a picture of a house into instructions a builder and an inspector can both use.

The detail follows the parts of the regulations. The Approved Documents on GOV.UK give guidance on ways to meet each one, and Schedule 1 lists the requirements themselves.

• Structure: beam sizes, steel and padstone positions, foundations and lintels, usually backed by an engineer's calculations.
• Insulation and energy: the make-up of walls, floors and roofs layer by layer, with the thickness of each material.
• Fire: escape routes, fire doors, smoke alarms and, in lofts, a protected stair route.
• Drainage: new drain runs, falls, manholes and connections to the existing system.
• Ventilation and damp: extract fans, trickle vents, cavity trays and damp-proof courses.

What does the same wall look like on each drawing?

The planning set draws the face of the wall. The building regulations set draws its depth.

The planning set draws the face of a wall and the building regulations set draws its depth. Follow one new rear wall through both to see the difference.

On the planning elevation it is a rectangle of brick with a window and a label. On the building regulations section it becomes a stack of layers from the foundation up: the footing, the damp-proof course, the inner block, the insulation, the cavity and the outer brick, each with a thickness. Above the opening sits a lintel or beam with its size written beside it.

Neither drawing replaces the other. If the building regulations set moves a window or raises the roof, the result may no longer match what the council approved, and a change like that may need agreeing with the planning department first. That is why both sets are drawn from one model of the house and checked against each other.

Do you always need both?

No: planning permission and building regulations approval are separate, so a project can need either, both or neither. GOV.UK states that building regulations approval is different from planning permission and that you might need both.

A larger rear or double-storey extension usually needs both. Work that is permitted development needs no planning application, but the building work can still fall under building regulations. A loft conversion done under permitted development is the common example.

In the other direction, a minor internal alteration may need no planning permission but still need building regulations approval where it touches structure. Regulation 3 of the Building Regulations 2010 defines building work to include material alterations, which is why removing a load-bearing wall is covered.

Your council or a registered building control approver can confirm whether a particular job is covered. We check the address and the route when you enquire, and quote a fixed fee once we know which sets you need.

Should planning or building regulations drawings come first?

Planning drawings come first, and building regulations drawings follow once the design is settled. The technical set should match the design the council approved, not run ahead of it.

Drawing the technical set before the council decides carries a risk. If the officer asks for a lower roof or a smaller depth, the technical set has to be redrawn. Waiting costs a little time and avoids paying for detail you may not use.

Doing both at once is possible when the design is firm and the council is unlikely to ask for changes, for example a modest extension within clear local policy. It saves calendar time and costs the redrawing risk above, so it is a choice about risk, not a rule.

The building regulations set then takes the approved design and adds the construction detail, with any planning conditions worked in so the builder is not caught out by one that was never drawn. If a beam or foundation needs sizing, the structural calculations come with it. Our sister site’s guide to when structural calculations are needed explains the Part A side in more depth. For the timeline, see how long planning drawings take.

Who looks at each set, and what is building control in London?

The council planning department reads the planning set, and a building control body reads the building regulations set. They are usually different people with different tests.

Building control in London is either your borough's building control team or a private registered building control approver. GOV.UK sets out how to apply, including the full plans application, which it describes as the most thorough option, and the building notice, which is only for smaller projects. The inspector usually visits at key stages while the work is built, which is why the drawings have to be detailed enough to follow on site.

A decision from one body is not a decision from the other. Planning approval does not mean the structure passes, and a building regulations pass does not mean the design suited the planning officer.

Who draws each set, and what does it cost?

Planning Drawings, a trading name of Property Architecture Ltd, draws both sets, and its MCIAT chartered architectural technologists check every sheet: a second chartered architectural technologist reviews the set before it goes out, never the person who drew it.

Our planning permission drawings start from £515 drawings + £150 survey (£665 total) and our building regulations drawings from £515 drawings + £150 survey (£665 total), both with no VAT to add. If the council asks for changes to a planning set, we redraw at no charge until approval. The measured survey is a separate fee, covered in measured survey for an extension.