You can usually get the builder on site quickly, but "quickly" comes from choosing the right building control route, not from skipping the drawings. A building notice lets work start two days after it is given, with no plans checked in advance; full plans take up to five weeks for a decision but the builder works from an approved set. Either way the builder needs construction drawings to price and build from. Our building regulations drawings are £545 drawings + £150 survey (£695 total), the survey is usually done within five working days, and the drawing time for your job is confirmed at the quote stage.
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What is my builder actually asking for?
Usually one of two things, and it helps to ask which. Some builders want a set of construction drawings so they can order steel, set out foundations and price the job properly. Others want building control "sorted" so they can legally start. These are different problems.
The first is a design job: plans, sections and specification notes covering structure, fire safety, insulation, ventilation and drainage, written to the Approved Documents, which GOV.UK describes as guidance on ways to meet the building regulations (GOV.UK). The second is a paperwork job: telling building control the work is happening, by the route the regulations allow. A good set answers both, but only the second has a legal clock attached.
How fast can work legally start?
Regulation 12 gives two routes: a building notice or an application with full plans (Building Regulations 2010, regulation 12). GOV.UK says that with a building notice "you can start work 2 days after your notice has been submitted", and that with full plans "you can expect a decision within 5 weeks, or 2 months with your consent" (GOV.UK).
Whichever route you use, regulation 16 adds two steps people miss in a rush: notice of intention to start, with at least two days passing before work begins, and a commencement notice within five days after the work is regarded as commenced (regulation 16). Put both dates in the diary the day the builder confirms.
So the honest answer to "how urgently can we start" is: two days after a valid notice, if the job is allowed to use a building notice. Whether it should is a separate question.
When is the quick route not allowed?
Regulation 12 requires full plans in three cases: building work on a building the Regulatory Reform (Fire Safety) Order 2005 applies to, a building fronting onto a private street, and work where paragraph H4 of Schedule 1, the requirement about building over sewers, applies (regulation 12).
The third one catches London houses more often than owners expect. Rows of Victorian and Edwardian terraces were often drained by one pipe running behind the houses, and a rear extension or side return infill can land on top of it. Thames Water says you will likely need a build over agreement for work within 3 metres of a public sewer or 1 metre of a public lateral drain, and that you should not start construction before getting one (Thames Water). If the sewer map shows a pipe under the new floor, the building notice is off the table and the build over agreement joins the critical path.
The first case matters for flats. If your flat is in a block with shared hallways and stairs, ask building control whether the Fire Safety Order brings your work into the full plans rule before you promise the builder a date.
Is a building notice really faster on a London extension?
On paper, yes. On site, often not. With a building notice nothing is checked before you build, so the inspector judges the work as it goes up. If a steel bearing, a cavity tray or a fire-rated ceiling is not what they expect, the fix happens to built work, and the builder stops while it is sorted.
A side return infill or a rear extension that opens up the back of a terrace almost always involves a new beam carrying the wall above, a party wall, drainage near the rear and insulation targets for the new roof. That is the profile of a job where full plans pay for themselves. GOV.UK itself says a building notice "is only for smaller projects" (GOV.UK). Our building control drawings post sets out sheet by sheet what a full plans set contains.
There is a middle path some London owners use: a registered building control approver instead of the council, who works from an initial notice and agrees fees directly with you (GOV.UK). The drawings they expect are the same; the difference is who checks them and on what timetable.
What should I send to get the drawings back quickly?
Most delay on an urgent job is waiting for information, not drawing. Send these on day one:
- The planning decision and approved drawings, if the work needed permission. The construction set has to build what was approved.
- Any drawings you already have, even rough ones, plus the builder's own notes or sketches.
- Photos of the rear, the side, the loft and the ceiling where a wall is coming out.
- Whether you know where the drains run, and any sewer map or build over correspondence.
- The engineer's details if structural calculations are already under way, so beam sizes go onto our sections.
- The builder's start date, so we can tell you straight away whether it fits the route.
We then book the survey, which is usually done within five working days. The drawing time depends on the job and is confirmed at the quote stage; we will not quote a date we have not checked against the work.
What does it cost, and what is outside our fee?
Our fee is £545 drawings + £150 survey (£695 total): the measured survey at £150, the construction drawings at £425 and the submission at £120. The building control charge itself is set by your council or approver and paid to them. A Thames Water build over agreement has its own charge, paid to Thames Water. Structural calculations are an engineer's work; if you need those as well, see our building regulations drawings cost post for how they fit together.
If planning permission has not been granted yet, the drawings can be prepared, but the builder cannot build anything that still needs permission. The difference between planning and building regulations drawings explains why one set cannot do both jobs.
Frequently asked questions
Can my builder start on a building notice and we add drawings later? Legally the work can start two days after a building notice is given, unless regulation 12 requires full plans. Practically, the builder still needs drawings to build from, and the inspector can ask for changes to work already done.
Does my builder's own building control contact speed things up? It can help with scheduling inspections. It does not change the regulations: the same notices are due and the same standards apply.
Can you guarantee the drawings by a set date? We publish that the survey is usually done within five working days. The drawing time is confirmed at the quote stage once we have seen what you send.
What if the extension sits over a sewer? Then full plans are required under regulation 12, and Thames Water says you should not start construction before getting a build over agreement. Check the sewer map first; it changes the start date more than anything we draw.
