Dry Lining and Internal Partitions for London Victorian Terraces: British Gypsum Gyproc and Steel Frame

THE METAL STUD PARTITION FRAME FOR AN INTERNAL WALL IN A LONDON VICTORIAN TERRACE RENOVATION IS CONSTRUCTED FROM GALVANISED STEEL TRACK (U-SECTION — FIXED TO FLOOR AND CEILING) AND STUDS (C-SECTION — FIXED INTO THE TRACK AT REGULAR CENTRES).

STUD WIDTH SELECTION (THE STUD WIDTH IS DETERMINED BY THE REQUIRED OVERALL PARTITION THICKNESS — WHICH DEPENDS ON: ACOUSTIC PERFORMANCE REQUIREMENT, SERVICES ROUTING WITHIN THE PARTITION, HEIGHT OF THE PARTITION, AND STRUCTURAL CONSIDERATION): C50 STUD (50MM WIDE — 50MM DEEP FRAME — TOTAL WALL WIDTH INCLUDING 12.5MM PLASTERBOARD BOTH SIDES = 75MM): APPROPRIATE FOR SHORT NON-LOAD-BEARING PARTITIONS UP TO 3M HEIGHT WITH STANDARD ACOUSTIC REQUIREMENTS. C60 STUD (60MM WIDE — 60MM DEEP FRAME — TOTAL WALL WIDTH INCLUDING 12.5MM PLASTERBOARD BOTH SIDES = 85MM): THE MOST COMMON STUD SIZE FOR RESIDENTIAL INTERNAL PARTITIONS IN LONDON VICTORIAN TERRACE RENOVATIONS — 2.5-4M HEIGHT, STANDARD ACOUSTIC REQUIREMENTS, SERVICES WITHIN FRAME. C100 STUD (100MM WIDE — 100MM DEEP FRAME — TOTAL WALL WIDTH INCLUDING 12.5MM PLASTERBOARD BOTH SIDES = 125MM): USED WHERE: ACOUSTIC PERFORMANCE IS THE PRIMARY REQUIREMENT (100MM STUD FRAME WITH ROCKWOOL RWA45 ACOUSTIC SLAB INFILL + 2 LAYERS GYPROC SOUNDBLOC EACH SIDE ACHIEVES Rw 50 DB — MEETING PART E 2004 AIRBORNE SOUND INSULATION REQUIREMENT FOR PARTY WALLS IN RESIDENTIAL BUILDINGS). PARTITIONS OVER 4M HEIGHT (TALLER PARTITIONS REQUIRE WIDER STUDS FOR BENDING STIFFNESS). WHERE SERVICES (WASTE PIPES, SOIL STACK, MVHR DUCT) ARE TO BE CONCEALED WITHIN THE PARTITION.

STUD CENTRES: STANDARD 400MM OR 600MM CENTRES (400MM CENTRES WHERE: BOTH FACES RECEIVE TILES — THE CLOSER STUD SPACING PROVIDES A STIFFER SUBSTRATE FOR THE TILE ADHESIVE; HEAVY WALL FIXINGS SUCH AS WALL-HUNG BASIN OR SANITARY WARE ARE ANTICIPATED. 600MM CENTRES: STANDARD FOR PAINTED PLASTERBOARD FINISH WITH NO HEAVY FIXINGS). TRACK TO CONCRETE: USE HILTI X-DNI 25 PINS (POWDER-ACTUATED FASTENER) AT 600MM CENTRES TO FIX TRACK TO CONCRETE SLAB. TRACK TO TIMBER: FIX WITH TIMBER SCREWS 60MM TW FIXINGS AT 600MM CENTRES TO EXISTING JOISTS OR BATTENS.

BRITISH GYPSUM GYPROC IS THE DOMINANT PLASTERBOARD BRAND IN UK RESIDENTIAL CONSTRUCTION. THE CORRECT BOARD SELECTION FOR EACH LOCATION IN A LONDON VICTORIAN TERRACE RENOVATION IS AS FOLLOWS:

GYPROC WALLBOARD (STANDARD — GREY PAPER BOTH FACES — 12.5MM THICK): THE STANDARD PLASTERBOARD FOR INTERNAL PARTITION WALLS AND DRY-LINING OF EXISTING SOLID WALLS IN DRY INTERNAL AREAS (LIVING ROOMS, BEDROOMS, HALLWAYS, LANDINGS): BOARD SIZE: 2400X1200MM (STANDARD SIZE — MATCHING STUD CENTRES OF 400MM OR 600MM). FIXING: DRYWALL SCREWS TW SERIES 35MM (TO STUDS) — COUNTERSUNK JUST BELOW BOARD FACE — 200MM CENTRES ON STUDS, 150MM CENTRES ON EDGES.

GYPROC MR (MOISTURE-RESISTANT — GREEN PAPER FACE — 12.5MM THICK): APPROPRIATE WHERE MOISTURE IS PRESENT — BATHROOM, EN-SUITE, SHOWER ROOM, KITCHEN SPLASHBACK AREA. NOTE: GYPROC MR PROVIDES MODERATE MOISTURE RESISTANCE — IT MUST STILL BE FULLY TILED OR WATERPROOFED ON THE WET FACE (IT IS NOT A TANKING BOARD): WHERE FULL WET AREA WATERPROOFING IS REQUIRED (SHOWER ENCLOSURE): USE WEDI BOARD (EXTRUDED POLYSTYRENE WITH GLASS FIBRE MESH FACE — FULLY WATERPROOF) OR HARDIE BACKER (CEMENT BOARD) — NOT STANDARD PLASTERBOARD OF ANY TYPE.

GYPROC SOUNDBLOC (ACOUSTIC — DENSER GYPSUM CORE — 12.5MM OR 15MM): FOR PARTITIONS WHERE ACOUSTIC PERFORMANCE IS THE PRIMARY REQUIREMENT: 2 LAYERS GYPROC SOUNDBLOC 12.5MM (EACH FACE — TOTAL 4 LAYERS — 2 EACH SIDE) + C100 STUD FRAME + ROCKWOOL RWA45 50MM ACOUSTIC SLAB: Rw 50-53 DB (MEETING OR EXCEEDING PART E 2004 AIRBORNE REQUIREMENT). EACH GYPROC SOUNDBLOC LAYER MUST BE SCREWED WITH A LAYER OFFSET — THE OUTER LAYER VERTICAL JOINTS MUST NOT ALIGN WITH THE INNER LAYER JOINTS.

GYPROC FIRELINE (FIRE-RATED — GLASS FIBRE-REINFORCED CORE — 12.5MM OR 15MM): FOR FIRE-RATED PARTITIONS (E.G. FLAT CONVERSION — HABITABLE ROOM TO STAIRCASE ENCLOSURE — REQUIRED TO ACHIEVE 30 OR 60 MINUTES FIRE RESISTANCE — APPROVED DOCUMENT B): BRITISH GYPSUM GYPROC FIRELINE 12.5MM: 1 LAYER EACH SIDE C60 FRAME = 30 MINUTES FIRE RESISTANCE (BS 476-22). 2 LAYERS EACH SIDE (DOUBLED) = 60 MINUTES. USE IN CONJUNCTION WITH INTUMESCENT SEALANT (HILTI CFS-S ACR ACOUSTIC SEALANT OR BRITISH GYPSUM GYPROC JOINT CEMENT — FIRE-RATED) AT ALL PERIMETER JOINTS AND SERVICE PENETRATIONS.

ACOUSTIC PERFORMANCE IS ONE OF THE MOST IMPORTANT REQUIREMENTS FOR INTERNAL PARTITIONS IN LONDON VICTORIAN TERRACE FLAT CONVERSIONS — WHERE THE PARTY FLOOR/CEILING (BETWEEN UPPER AND LOWER FLAT) AND PARTY WALL (BETWEEN FLATS IF SIDE BY SIDE) MUST MEET BUILDING REGULATIONS PART E 2004 MINIMUM AIRBORNE SOUND INSULATION REQUIREMENTS.

APPROVED DOCUMENT E (RESISTANCE TO PASSAGE OF SOUND — 2004 AMENDED 2013): AIRBORNE SOUND INSULATION REQUIREMENTS FOR A FLAT CONVERSION (CHANGE OF USE TO FLATS — CLASS B BUILDING — PART E SECTION 2): SEPARATING FLOOR/CEILING (BETWEEN FLATS — FLOOR ABOVE / CEILING BELOW): DnTw + Ctr ≥ 43 DB AIRBORNE SOUND INSULATION (FIELD-TESTED — NOT LABORATORY). SEPARATING WALL (BETWEEN FLATS — COMMON WALL): DnTw + Ctr ≥ 43 DB.

TYPICAL SPECIFICATION FOR A PART E SEPARATING WALL (COMMON WALL BETWEEN FRONT AND REAR FLAT IN A LONDON VICTORIAN TERRACE FLAT CONVERSION): OPTION 1 — DOUBLE-LEAF METAL STUD (INDEPENDENT LEAVES — MOST EFFECTIVE): TWO SEPARATE C60 STUD FRAMES (60MM STUDS) — 10MM GAP BETWEEN FRAMES (STRUCTURALLY ISOLATED — NO MECHANICAL CONNECTION BETWEEN LEAVES). EACH LEAF: 2 LAYERS GYPROC SOUNDBLOC 12.5MM (SCREWED TO STUDS — JOINTS STAGGERED). MINERAL WOOL INFILL (ROCKWOOL RWA45 ACOUSTIC SLAB 50MM — FRICTION-FIT BETWEEN STUDS IN ONE OR BOTH LEAVES). TOTAL WALL THICKNESS: 60 + 10 + 60 + 4 LAYERS 12.5MM = 180MM TOTAL. EXPECTED ACOUSTIC PERFORMANCE: DnTw + Ctr ≈ 50-55 DB — EXCEEDING PART E MINIMUM.

OPTION 2 — SINGLE-LEAF C100 STUD (SIMPLER — LESS SPACE — LOWER PERFORMANCE): C100 STUD FRAME — 100MM STUDS AT 600MM CENTRES. 2 LAYERS GYPROC SOUNDBLOC 12.5MM EACH FACE (4 LAYERS TOTAL). ROCKWOOL RWA45 100MM ACOUSTIC INFILL (FULL STUD DEPTH). TOTAL WALL THICKNESS: 100MM STUD + 4 LAYERS 12.5MM = 150MM TOTAL. EXPECTED PERFORMANCE: DnTw + Ctr ≈ 48-52 DB — TYPICALLY MEETING PART E MINIMUM BUT WITH LESS MARGIN. RESILIENT BARS: ADDING RESILIENT BARS (BRITISH GYPSUM RESILIENT BARS — RB SERIES — FIXED HORIZONTALLY TO STUDS AT 600MM CENTRES — DECOUPLING THE OUTER PLASTERBOARD LAYER FROM THE STUD) IMPROVES PERFORMANCE BY 3-5 DB IN FLANKING-SOUND-CONTROLLED ENVIRONMENTS — PARTICULARLY USEFUL ON THE CEILING FACE WHERE IMPACT SOUND TRANSMISSION FROM ABOVE IS A CONCERN.

DRY LINING OF EXISTING SOLID WALLS (I.E. APPLYING A PLASTERBOARD FINISH TO THE EXISTING SOLID BRICK INTERNAL FACE OF AN EXTERNAL WALL OR A SOLID-BRICK INTERNAL PARTITION WALL) IS ANOTHER COMMON APPLICATION IN LONDON VICTORIAN TERRACE RENOVATIONS — USED WHERE: THE EXISTING LIME PLASTER IS IN POOR CONDITION (DELAMINATING, CRACKED, LOOSE) AND FULL REPLASTER IS NEEDED. AN INSULATED DRY LINING IS REQUIRED TO IMPROVE THE THERMAL PERFORMANCE OF A SOLID EXTERNAL WALL (INTERNAL WALL INSULATION — IWI — AS AN ALTERNATIVE TO EXTERNAL WALL INSULATION).

METHODS OF DRY LINING EXISTING SOLID WALLS: DOT-AND-DAB (PLASTERBOARD FIXED DIRECTLY TO WALL WITH BLOBS OF GYPROC BONDING COMPOUND — MOST COMMON METHOD FOR DRY LINING SOLID WALLS IN LONDON VICTORIAN TERRACE RENOVATIONS): BOARDS FIXED WITH 5-7 DABS OF GYPROC BONDING COMPOUND PER BOARD (APPLIED IN ROWS TO THE WALL FACE — BOARDS PRESSED ON AND LEVELLED). ADVANTAGE: FAST AND CHEAP. DISADVANTAGE: CAVITY BETWEEN BOARD AND WALL (TYPICALLY 10-15MM) IS A POTENTIAL PATHWAY FOR AIR AND SOUND FLANKING — AND IS A FIRE RISK IN MULTI-STOREY CONSTRUCTION (REQUIRES FIRE BREAKS AT FLOOR AND CEILING LEVEL WITH MINERAL WOOL OR GYPROC JOINT CEMENT). METAL FRAME (C-STUD — AS FOR A NEW PARTITION): MORE CONTROLLED — ALLOWS INSULATION WITHIN THE STUD FRAME — BETTER FOR THERMAL AND ACOUSTIC PERFORMANCE. PLASTERBOARD ON TIMBER BATTEN: HISTORICAL METHOD — SOMETIMES FOUND IN VICTORIAN TERRACE RENOVATIONS OF THE 1970S-1980S — TIMBER BATTENS FIXED TO EXISTING WALL FACE, PLASTERBOARD NAILED OR SCREWED TO BATTENS.

INSULATED DRY LINING (FOR IMPROVING THE THERMAL PERFORMANCE OF THE SOLID EXTERNAL WALL — INTERNAL WALL INSULATION IWI): KINGSPAN KOOLTHERM K17 INSULATED PLASTERBOARD (PHENOLIC FOAM INSULATION BONDED TO 12.5MM GYPROC WALLBOARD — SUPPLIED IN THICKNESSES OF 37.5MM TO 72.5MM TOTAL): 37.5MM (25MM PHENOLIC + 12.5MM BOARD): U-VALUE IMPROVEMENT FOR A 215MM SOLID BRICK WALL FROM 1.8 W/M²K TO APPROXIMATELY 0.50 W/M²K. 62.5MM (50MM PHENOLIC + 12.5MM BOARD): U-VALUE FROM 1.8 TO APPROXIMATELY 0.35 W/M²K. FIXED BY DOT-AND-DAB (SPECIALIST ADHESIVE) OR METAL FRAME. THERMAL BRIDGING AT WINDOW REVEALS AND FLOOR JUNCTIONS MUST BE CAREFULLY DETAILED.

DRY LINING AND INTERNAL PARTITION WORKS IN LONDON VICTORIAN TERRACES HAVE SPECIFIC BUILDING REGULATIONS IMPLICATIONS DEPENDING ON THE SCOPE OF THE WORKS AND THE USE OF THE BUILDING.

WHEN BUILDING REGULATIONS APPLY TO DRY LINING AND PARTITION WORKS: CHANGE OF USE (FLAT CONVERSION): WHERE A LONDON VICTORIAN TERRACE IS BEING CONVERTED FROM A SINGLE DWELLING INTO FLATS, ALL NEW INTERNAL PARTITIONS (SEPARATING WALLS, ESCAPE CORRIDOR WALLS, FIRE DOOR ASSEMBLIES) MUST COMPLY WITH APPROVED DOCUMENT B (FIRE SAFETY), E (ACOUSTIC PERFORMANCE), L (ENERGY EFFICIENCY), AND M (ACCESSIBILITY). FULL PLANS APPLICATION REQUIRED — BUILDING CONTROL APPROVAL BEFORE WORKS START. NEW HABITABLE ROOMS (LOFT CONVERSION — WHERE A NEW HABITABLE ROOM IS CREATED IN A LOFT SPACE): THE PARTITION WALLS AND FIRE ESCAPE ENCLOSURE MUST COMPLY WITH PART B (FIRE) — TYPICALLY REQUIRING FIRE-RATED CONSTRUCTION (30-MINUTE FIRE RESISTANCE — GYPROC FIRELINE BOARDING) FOR THE STAIRCASE ENCLOSURE AND HABITABLE ROOM WALLS ADJACENT TO THE ESCAPE ROUTE. BATHROOM OR SHOWER ROOM PARTITION (IN AN EXISTING DWELLING): GENERALLY DOES NOT REQUIRE BUILDING REGULATIONS IF: THE PARTITION IS NON-LOAD-BEARING. THE BATHROOM IS WITHIN AN EXISTING DWELLING (NOT A CHANGE OF USE). NO STRUCTURAL ALTERATION IS REQUIRED. HOWEVER: ANY ELECTRICAL WORKS IN THE NEW BATHROOM OR SHOWER ROOM ARE NOTIFIABLE UNDER PART P (ELECTRICAL SAFETY).

FIRE-RATED PARTITION SPECIFICATION REQUIREMENTS (PART B — APPROVED DOCUMENT B): FOR A FIRE-RATED 30-MINUTE PARTITION (E.G. STAIRCASE ENCLOSURE WALL IN A LOFT CONVERSION OR FLAT CONVERSION): 1 LAYER GYPROC FIRELINE 12.5MM EACH FACE OF C60 OR C100 STUD FRAME — MINERAL WOOL INFILL — INTUMESCENT SEALANT AT ALL PERIMETER JOINTS AND SERVICE PENETRATIONS. FOR 60-MINUTE FIRE RATING: 2 LAYERS GYPROC FIRELINE 12.5MM EACH FACE OF C100 STUD.

DRY LINING AND METAL-STUD PARTITION COSTS IN LONDON (2025) DEPEND ON THE BOARD SPECIFICATION (STANDARD, MOISTURE-RESISTANT, FIRE-RATED, SOUNDBLOC), THE STUD SIZE, AND THE FINISH REQUIRED (SKIM-COAT PLASTER OR DIRECT-DECORATE TAPING AND JOINTING).

METAL STUD PARTITION WALL (C60 STUD — 12.5MM GYPROC WALLBOARD EACH SIDE — STANDARD INTERNAL PARTITION — TAPE AND JOINT FINISH — LONDON): FRAME (C60 STUD 600MM CENTRES — FLOOR AND CEILING TRACK — LABOUR AND MATERIALS): £8 TO £14/M² WALL FACE AREA. PLASTERBOARD (GYPROC WALLBOARD 12.5MM — ONE LAYER EACH SIDE — SUPPLY AND FIX): £12 TO £20/M² (BOTH FACES). TAPE AND JOINT FINISH (GYPROC TOPPING COMPOUND — 3-COAT SYSTEM): £8 TO £16/M² (BOTH FACES). TOTAL (FRAME + BOARD + T&J — NO SKIM): £28 TO £50/M² WALL FACE AREA.

ACOUSTIC PARTITION (C100 STUD — 2 LAYERS SOUNDBLOC 12.5MM EACH FACE — ROCKWOOL RWA45 INFILL — T&J FINISH): FRAME (C100): £10 TO £16/M². PLASTERBOARD (2 LAYERS SOUNDBLOC EACH FACE — 4 LAYERS TOTAL): £28 TO £45/M². ROCKWOOL RWA45 (100MM — SUPPLY AND INSTALL): £8 TO £14/M². T&J FINISH: £10 TO £18/M². TOTAL ACOUSTIC PARTITION: £56 TO £93/M² WALL FACE AREA.

DRY LINING EXISTING SOLID WALLS (DOT-AND-DAB — GYPROC WALLBOARD 12.5MM — T&J FINISH): MATERIALS AND LABOUR: £20 TO £35/M² WALL FACE AREA.

INSULATED DRY LINING (KINGSPAN K17 INSULATED PLASTERBOARD — DOT-AND-DAB — 37.5MM TOTAL — T&J FINISH): MATERIALS AND LABOUR: £35 TO £60/M² WALL FACE AREA (37.5MM K17); £45 TO £75/M² WALL FACE AREA (62.5MM K17).

SKIM COAT FINISH (BRITISH GYPSUM DIAMOND SKIM — 2MM FINISH PLASTER OVER TAPED PLASTERBOARD — ALTERNATIVE TO T&J DIRECT DECORATE): ADDITIONAL £8 TO £16/M².