For working builders (England)
Last reviewed: March 2026
This is for the grey areas - the jobs lads argue about on site. Not new builds, loft conversions, big extensions (those are obviously "yes"). This is where people think "it's only small" and get burned at sale.
Yes, always
These are Building Regs jobs every time. How you notify varies (Building Control vs competent person scheme), but you are in the system.
Installing a wood burner / multi-fuel stove
Yes - Part J, plus CO alarm. HETAS route or Building Control; flue, hearth, clearances and ventilation all regulated.
Rewiring a house (new circuits / CU change)
Yes - Part P. Full or major rewire needs either a registered electrician (NICEIC/NAPIT etc.) who self-certifies, or Building Control notification.
Converting a garage to habitable space
Yes - full Building Regs job. Structure, fire, insulation, damp, ventilation, electrics, drainage all in scope.
Knocking down an internal load-bearing wall
Yes - Part A at minimum, plus B/E/K/L depending where it is. Needs calcs, Building Control, and a proper beam detail.
Installing solar PV on a roof (most domestic systems)
Yes - structure and electrics. Roof loading, fixings, fire spread, and Part P for the electrical side; often notified via MCS/competent person route.
Replacing a flat roof covering (warm/cold roof upgrade)
Yes if you're "renovating a thermal element" - i.e. stripping back to deck/joists. Triggers insulation upgrade and detailing under Part L and C.
Re-rendering or over-cladding external walls (significant areas)
Yes where it counts as renovation of a thermal element or affects fire/damp. You're into Part C and L (and B/Reg 7 on some buildings).
Solar panels + EV charger installed as one package
Yes - combined load and wiring, structure and fire all in scope; EV side alone is already in Part P/S territory, see below.
It depends
This is where detail matters. The same-looking job can flip from "no" to "definitely yes" based on how far you go.
Like-for-like boiler swap
- Competent person route: Gas Safe can self-certify for Building Regs, so you don't involve Building Control directly.
- But: change the flue route/terminal, move location, or alter structure, and Parts J/L/A are clearly in play - treat it as a regs job, even if Gas Safe handle notification.
Garden room / office - no plumbing, light use
- Small, detached, single storey, unheated, under certain size and distances: often exempt from full regs, beyond basic structure and electrics.
- Once you insulate, heat it or use it as a proper office/hobby room, BC will treat it as habitable in practice - expect Parts A, B, C, F, K, L, P at least.
Garden room / office - with plumbing or sleeping
- WC/shower, kitchen, or any hint of sleeping use = Building Regs job. Drainage, insulation, fire, structure, ventilation, electrics all triggered.
Boarding a loft for light storage
- A bit of chipboard across a few joists for light storage only, no stairs, no services - normally no formal Regs, though you're still liable if you overload it.
- As soon as you start treating it like a room (proper floor, stairs, heating, rooflights), you've slipped into loft conversion territory and full Regs apply.
Replacing a kitchen (units only, same layout)
- Swapping units/appliances like-for-like, no structural changes, same points - regs usually not bothered.
- Move walls/doors, new openings, change drainage runs, new circuits/consumer unit, or mess with the boiler: yes, Parts A/B/F/G/H/J/L/P can all bite.
Replacing windows / external doors
- Done by FENSA/CERTASS etc. installer? They notify Building Control via their scheme - still a Regs job, just not through you.
- If you or a non-scheme firm fit them, Building Control notification is required - Part L (U-values), Part F (vents), Part K (glazing), and Part B (egress) all in play.
Adding a porch under 3 m²
- Under 3 m², separated from the house by an external door, and not over a public highway - usually exempt from full Regs.
- If you heat it, remove the inner door, or butcher structure/escape route, you've brought Parts A/B/C/K/L/M into play and it's a Regs job.
Knocking down an internal non-load-bearing wall
- If it genuinely isn't carrying anything, not on the escape route, and you're not altering fire/sound separation - often no BC involvement.
- But: if it's part of the fire corridor to the stair, a sound-separating wall, or you mis-judge "non-load-bearing", you're straight into A/B/E and should be notifying.
Adding a driveway / hardstanding
- Often no Regs, but planning and drainage rules still bite (SUDS, visibility splays, dropped kerbs).
- If you're over/near a public sewer or manhole, building over/near rules under Part H and the water company's consent absolutely do apply.
Building a garden wall or fence
- Low garden walls/fences normally no Regs (planning may still apply for height).
- Retaining walls carrying significant loads, near a highway, or tied into buildings, can drag in Part A and Building Control - especially where failure would be dangerous.
Adding an EV charger to an existing house
- Electrically it's a Part P job - usually handled via an EV-competent electrician and their scheme, not a Building Control submission.
- If you're trenching across public footpaths or near utilities, you're into other rules (streets/highways), but Building Regs is mostly about the electrics.
Solar panels on an existing roof (small domestic)
- Structure + electrics = Regs in theory. In practice, MCS/competent person schemes often handle notification.
- If you're significantly changing roof structure or working on a tall/block external wall, treat it as Part A/B/Reg 7 as well.
No, not usually
These are generally outside Building Regs on their own, as long as you don't trigger other things at the same time.
New driveway (domestic, not over sewers/structures)
Usually no Building Regs - but you still need to respect drainage rules, dropped-kerb consent and SUDS guidance.
Small, unheated shed or basic outbuilding
Little timber shed, no plumbing, light only, not used as habitable or sleeping space - normally outside Building Regs, aside from basic electrical safety if you wire it.
Pure like-for-like kitchen/bathroom swap
Replace units/sanitaryware one-for-one, same positions, no new circuits or structural changes - typically no BC involvement.
Internal decorating, tiling, flooring finishes
No Building Regs, as long as you're not altering structure, insulation, fire/sound separation, or services.
Minor repairs to roofs/walls (like-for-like, under the threshold)
Patch repairs to tiles or render under the "renovation of thermal elements" thresholds are usually below the radar - but once you're stripping large areas, you trigger upgrade rules.
When in doubt, call your local Building Control before you start -- a 5-minute phone call is cheaper than a regularisation application later.
This page is a general guide for small builders and main contractors working on dwellings in England. It doesn't cover every edge case or non-domestic job. Always check the latest Approved Documents, your drawings/spec, planning conditions and Building Control before you start cutting or pouring. SiteKiln does not provide legal, financial or tax advice. All content is for general information purposes only. Always seek professional advice for your specific situation.
Common questions
Do I need building regs for a garden room?
Usually no, if it's under 30m² floor area, single-storey, more than 1m from any boundary, with no sleeping use. If anyone will sleep in it, or it sits closer than 1m to a boundary without fire-resistant walls, full Building Regulations approval is required. Electrical work must comply with Part P regardless.
What is permitted development?
Permitted Development Rights (PDR) are pre-approved planning rules that let you build certain works without permission. They cover certain extensions, outbuildings, and alterations under the Town and Country Planning Order 2015. Limits vary by property type and location. Get a Lawful Development Certificate to confirm in writing.
Planning Permission Checker tool.
Know someone who needs this?
Working in Wales? The building rules are different. See our Working in Wales guides.
Working in Scotland? Building standards work differently. See our Working in Scotland guides.
Working in Northern Ireland? The system uses Technical Booklets. See our Working in Northern Ireland guides.
Was this guide useful?
Didn't find what you were looking for?
Spotted something wrong or out of date? Email us at hello@kilnguides.co.uk.
In crisis? Samaritans 116 123 ·