Building Regulations in England are a common source of confusion for homeowners planning dry lining. The honest answer is: it depends on the scope, the wall, and what the dry lining is replacing. This post walks through the four parts of the Building Regulations that affect most dry lining work in Peterborough and Cambridgeshire, when you do and do not need approval, and what to expect from building control here.
The short answer
You do not need Building Regulations approval for like-for-like dry lining in an existing room, where you are replacing old plasterboard with new plasterboard, with no change of use, no fire-safety impact, and no change to the thermal or acoustic performance of the wall.
You do need approval (or at least a Building Notice) when dry lining is part of:
- A loft conversion
- An extension or other structural alteration
- A change of use (e.g. converting a garage into living space)
- Work that affects fire safety (escape routes, garage-to-living-space separation, commercial partitions)
- Acoustic separation between dwellings (Approved Document E)
- Thermal upgrades to the building envelope (Approved Document L)
- Any work in a conservation area or on a listed building where materials are controlled
Which Building Regulations apply
Four parts of the Building Regulations are most relevant to dry lining. None of them stand alone — they often interact, especially on older Cambridgeshire properties that combine heritage construction with modern performance expectations.
Part B — Fire safety
Approved Document B requires fire-rated plasterboard in any wall that forms part of a fire-separating function. In a typical Peterborough home, that means:
- Between an integral garage and the living space (30 minutes fire resistance, single layer of 12.5 mm pink FireLine on the garage side)
- On escape routes in houses of two or more storeys (stairs, landings, hallways)
- In loft conversions, where the new walls and ceilings typically require 30 minutes fire resistance
- In commercial partitions, where 30 or 60 minutes fire resistance is the norm depending on building use and floor area
Part C — Moisture
Approved Document C covers resistance to moisture. For dry lining in Cambridgeshire, the most common Part C issue is in Fens properties — March, Whittlesey, Chatteris, Ramsey, parts of PE13 and PE15 — where high water tables and historic salt damp make any sealed dry lining system fail. A competent contractor will test for moisture and treat with a salt-resistant base before dry lining.
Part E — Sound (acoustic separation)
Approved Document E sets minimum airborne and impact sound insulation standards for separating walls and floors between dwellings. In a typical terraced house in central Peterborough (PE1 to PE4), converting a single dwelling back to flats, or building a new separating wall between attached properties, requires 40+ dB airborne resistance. That is achieved with acoustic plasterboard (British Gypsum SoundBloc or similar) and dense mineral wool between studs.
Part L ��� Thermal performance
Approved Document L sets U-value targets for walls, roofs and floors. For dry lining on a solid wall — common in older Peterborough terraces — insulated plasterboard (PIR-backed, 50 mm typical) is the most cost-effective route to hitting a U-value of around 0.30 W/m²K. Material and labour together is usually £35 to £55 per m², with the work completed in days rather than weeks.
Who handles building control in Cambridgeshire
Building control for the county is administered jointly by Cambridgeshire County Council and the unitary City of Peterborough. For most domestic alterations, you will be dealing with the shared Cambridgeshire building control service unless you are inside the Peterborough unitary boundary, in which case the City of Peterborough building control team handles the application.
Application fees for domestic alterations are typically £150 to £400 depending on the scope of work. For a full loft conversion with structural alterations, expect the upper end. For a thermal-upgrade dry lining on an existing wall, a Building Notice may be sufficient and cheaper than a Full Plans application.
If your property is in a conservation area (parts of central Peterborough, parts of Stamford, central Cambridge, historic parts of Ely and Huntingdon) or is a listed building, contact the local conservation officer before any work begins. Some materials and finishes (lime plaster on solid walls, for example) may be required, and consent may be needed before installation.
Common Cambridgeshire scenarios
A few real examples we have worked on in 2025 and 2026 to illustrate when approval is and is not needed:
- Re-dry-lining a bedroom in a 1930s semi in Orton (PE2) — no approval needed. Like-for-like replacement, no change to fire, acoustic or thermal performance.
- Loft conversion in Bretton (PE3) — full plans approval needed. New walls and ceilings trigger Part B (fire safety) and Part L (thermal). Building control fee around £350.
- Garage conversion in Werrington (PE4) — full plans approval needed. Change of use triggers Part B (separation from the rest of the house), Part L (insulation to new external wall), and Part C (damp-proof course).
- Internal solid wall insulation in a Victorian terrace in PE1 — Building Notice sufficient. Thermal upgrade only, no fire or acoustic change. Fee around £200.
- Acoustic plasterboard between a converted flat in a central Peterborough terrace — full plans approval needed. Change of use to flats triggers Part E.
- Commercial office fit-out in Lynch Wood — full plans approval needed. Part B (fire-rated partitions), Part L (insulation to external walls), Part E (acoustic separation between units).
Frequently asked questions
Do I need building control sign-off for simple dry lining?
Not for like-for-like dry lining in an existing room with no change of use. You do need it for: dry lining as part of a loft conversion, a structural alteration, work that affects fire safety (escape routes, between garage and living space), acoustic separation between dwellings, or thermal upgrades to a wall that forms part of the thermal envelope. A competent contractor will tell you at the quote stage.
Which Building Regulations apply to dry lining in Cambridgeshire?
Four parts of the Building Regulations typically apply: Part B (fire safety) — fire-rated plasterboard on escape routes and between garage and living space. Part E (resistance to sound) — acoustic plasterboard between dwellings. Part L (conservation of fuel and power) — U-value targets for walls, roofs and floors. Part C (site preparation and resistance to contaminants and moisture) — damp-proofing before dry lining in older properties.
Who handles building control for a project in Peterborough?
Building control in Cambridgeshire is administered by Cambridgeshire County Council (which runs the shared service for South Cambridgeshire, Huntingdonshire, East Cambridgeshire and Fenland) and the unitary City of Peterborough. Fees for domestic alterations are typically £150 to £400 depending on scope. For work in a conservation area or on a listed building, contact the conservation officer before work begins.
What fire-rated plasterboard do I need in Cambridgeshire?
Under Approved Document B, fire-rated plasterboard (typically 12.5 mm pink British Gypsum FireLine or 15 mm Fire Board) is required: on escape routes (stairs, landings, hallways) in houses of two or more storeys; between a garage and the living space; in loft conversions; and in most commercial partitions. Acoustic plasterboard (SoundBloc, 40+ dB) is required between dwellings under Approved Document E.
How do I upgrade an old solid wall in Peterborough under Part L?
Internal solid wall insulation via dry lining is the most cost-effective route. PIR-backed insulated plasterboard (50 mm) typically costs £35 to £55 per m² installed and brings wall U-values down from around 1.7 W/m²K (typical uninsulated 1930s solid brick) to 0.30 W/m²K or better, well within Part L targets. External wall insulation is often impractical on street-facing elevations in central Peterborough terraces.
What happens if I do dry lining work without approval?
Unapproved work that should have had building control sign-off is a problem when you come to sell the property. Solicitors and buyers will request a Regularisation Certificate, which Cambridgeshire building control will issue after a retrospective inspection. The fee is typically 50% to 100% higher than the original application would have been, and you may be required to open up finished work to allow inspection.
Sources: Approved Documents B (Fire Safety, 2019 edition, amended 2020 and 2022), C (Site Preparation and Resistance to Contaminants and Moisture, 2004 amended 2010), E (Resistance to the Passage of Sound, 2003 amended 2015) and L (Conservation of Fuel and Power, 2021 edition) — published by HM Government under the Building Act 1984. Cambridgeshire building control fee schedule (2026). Last updated 1 October 2026.