Drywall and Plasterboard Inspection

Per DTU 25.41 and NF EN 14195, metal framing for plasterboard systems must be installed with correct gauge, spacing, and fixing details. Studs must be plumb, tracks must be level, and the framing must provide adequate support for the specified board thickness and height.

1. Verify that metal stud gauge and profile dimensions match the specification and NF EN 14195 requirements for the partition height

2. Check stud spacing — maximum 600 mm centres for standard partitions, 400 mm for enhanced acoustic or fire-rated assemblies per DTU 25.41

3. Confirm that floor and ceiling tracks are fixed at maximum 600 mm centres with appropriate fixings for the substrate type

4. Verify plumbness of studs using a spirit level — deviation must not exceed 5 mm over full height per DTU 25.41

5. Check that additional framing is provided at door openings, junction corners, and heavy fixture locations

- Stud spacing exceeding maximum centres, causing board deflection and cracking

- Floor tracks not sealed with acoustic strip, reducing sound insulation performance

- Missing or inadequate framing at door openings leading to cracking around frames

- Studs twisted or not plumb, resulting in uneven board surfaces

DTU 25.41 specifies fixing methods, screw spacing, and board layout rules for plasterboard installations. Boards must be staggered to avoid continuous joints, and screws must be correctly set without breaking the paper face. NF EN 520 defines board types (A, H1, DF, etc.) for different applications.

1. Verify that the correct board type is used for the application — type H1 for wet areas, type DF for fire-rated assemblies per NF EN 520

2. Check screw spacing — maximum 300 mm on board edges and 300 mm on intermediate studs per DTU 25.41

3. Confirm that screws are set 1 mm below the board surface without breaking the paper liner

4. Verify that board joints are staggered between layers and between opposite faces of the partition

5. Check that boards are cut cleanly around services and that cut edges are not damaged

- Wrong board type used in wet or fire-rated locations

- Screws over-driven, breaking the paper face and reducing holding strength

- Board joints aligned on both sides of the partition, creating a weakness line

- Insufficient screw count leaving boards inadequately secured

Per DTU 25.41 and NF EN 13963, joints between plasterboard sheets must be filled and taped to achieve a smooth, crack-free surface. The finishing level must match the specified quality grade (Q1 to Q4 per DTU 59.1 preparation requirements). Joint compound must be compatible with the board type.

1. Verify that jointing compound conforms to NF EN 13963 and is compatible with the board type installed

2. Check that paper or fibreglass tape is embedded in the first coat of compound at all flat joints and internal corners

3. Inspect the finished surface with a raking light — no ridging, bubbling, or telegraphing of joints should be visible

4. Measure flatness using a 2 m straightedge — deviation must not exceed 3 mm for standard finish per DTU 25.41

5. Confirm that screw heads are covered with minimum two coats of compound and sanded smooth

- Joint tape lifting or bubbling due to insufficient compound beneath

- Ridging visible at joints under raking light conditions

- Excessive sanding exposing the paper face of the board

- Joint compound cracking due to application in coats that are too thick

DTU 25.41 requires that plasterboard partition systems achieve the acoustic performance specified in the design, measured as Rw (weighted sound reduction index) per EN ISO 10140. French regulations (arrêté du 30 juin 1999) set minimum acoustic insulation values between dwellings at 53 dB DnT,A.

1. Verify that the partition build-up matches the tested system configuration (board layers, stud type, insulation fill)

2. Check that mineral wool insulation is fully installed within the cavity with no gaps or compression per DTU 25.41

3. Inspect perimeter sealing — acoustic sealant or resilient strip must be continuous at floor, ceiling, and wall junctions

4. Confirm that services passing through the partition are sealed with acoustic compound to maintain the sound barrier

5. Review acoustic test certificates for the specified partition system confirming the required Rw rating

- Gaps in cavity insulation reducing the Rw rating below design requirements

- Missing acoustic sealant at perimeter tracks allowing flanking sound transmission

- Electrical boxes placed back-to-back without offset, creating a direct sound path

- Services penetrations not sealed, compromising the acoustic integrity of the partition

Per DTU 25.41 and EN 13501-2, fire-rated plasterboard partitions must be constructed exactly as tested to maintain their classification (EI 30, EI 60, EI 90, EI 120). Any deviation from the tested system — including board type, number of layers, fixing pattern, or service penetration treatment — may invalidate the fire rating.

1. Verify that fire-rated boards (type DF per NF EN 520) are used in the correct number of layers per the test certificate

2. Check that screw spacing matches the fire-tested configuration — typically 250 mm centres for fire-rated assemblies

3. Confirm that all service penetrations are fire-stopped with tested and certified fire-stopping products per EN 1366-3

4. Inspect that joints in multi-layer systems are staggered by at least 600 mm between layers

5. Verify that the fire rating classification (e.g. EI 60) is documented and matches the building fire safety requirements

- Standard boards used instead of fire-rated DF boards in fire-rated partitions

- Service penetrations not fire-stopped, creating a path for fire and smoke

- Insufficient number of board layers installed compared to the tested system

- Screw spacing too wide in fire-rated assemblies, reducing structural fire performance

Per DTU 25.41, plasterboard installations in wet areas (bathrooms, kitchens, utility rooms) must use moisture-resistant boards (type H1 per NF EN 520) and incorporate a waterproof membrane system (SPEC — Système de Protection à l'Eau sous Carrelage) before tiling. Board edges at floor level must be kept clear of standing water.

1. Verify that type H1 (moisture-resistant) boards are installed throughout wet areas per NF EN 520 classification

2. Check that boards are raised minimum 10 mm above finished floor level to prevent moisture wicking per DTU 25.41

3. Confirm that a SPEC waterproofing membrane is applied to board surfaces in shower and bath zones before tiling

4. Inspect all joints and corners in wet areas for continuous sealing with waterproof tape and membrane

- Standard (type A) boards used in wet areas instead of moisture-resistant type H1

- Boards in contact with floor, wicking moisture and causing deterioration

- Missing SPEC membrane in shower zones leading to moisture penetration behind tiles

- Inadequate sealing at junctions between boards and sanitary fittings