GYPSUM PLASTERBOARDS - SUSPENDED CEILINGS, PARTITION WALLS AND LININGS
This Technical Specification refers to installation of:
- suspended ceilings;
- partition walls;
- wall linings on metal substructure and
- bonding of plasterboard linings direct to solid backgrounds.
1. Relevant standards
EN 520 (2004+A1:2009) Gypsum plasterboards - Definitions, requirements and test methods
EN 14195 (2014) Metal framing components for gypsum board systems - Definitions, requirements and test methods
EN 13963 (2014) Jointing materials for gypsum boards - Definitions, requirements and test methods
EN 14566+A1 (2009) Mechanical fasteners for gypsum plasterboard systems - Definitions, requirements and test methods
EN 14353 (2017) Metal beads and feature profiles for use with gypsum plasterboards - Definitions, requirements and test methods,
EN 16703 (2015) Acoustics - Test code for drywall systems of plasterboard with steel studs - Airborne sound insulation
EN ISO 12944 Paints and varnishes - Corrosion protection of steel structures by protective paint systems
The material manufacturer must have a certificate proving that the system elements comply with the above standards.
The material should meet the following requirements:
- the thickness of gypsum plasterboards should be 12,5mm (±0,5mm tolerances);
- the edges - four-sided tapered edge
Dimensions and type of gypsum boards should be marked on the back of each board, as well as on the label or on the packaging.
In rooms with moderately high humidity (constant relative air humidity not bigger then 70%, e.g. bathrooms, kitchens, etc.), gypsum boards resistant to moisture should be used (impregnated) - type H1, H2 or H3, according to EN 520.
Metal framing components should be made from low carbon steel sheet, zinc, aluminium-zinc or zinc-aluminium coated (Z, AZ or ZA). The minimum thickness of the steel sheet is 0.6mm. Elements need to be straight and cannot be twisted.
In areas with high humidity, such as outdoor or swimming pool areas, profile systems including accessories should be with C3 coatings (as defined by EN ISO 12944).
Acoustic and fire characteristics should be in accordance with the design requirements.
All materials should be approved through the Submittal process.
- The joints of two gypsum boards should be filled with compound recommended by manufacturer and reinforced with self-adhesive tapes. When the coats have dried, surfaces should be sand with sandpaper (manually or mechanically). Quality level of joint implementation should be Q3;
- Joints of walls and ceilings to be sealed with white acrylic sealant;
- External corners to be protected with aluminium angular profiles.
- The Contractor has to submit Statement that all material is installed in accordance with manufacturer technical documentation.
For complex ceilings, ceilings with larger amount of installation accessories or decorative elements and for two-layer cladding ceilings, the Contractor is obliged to produce workshops drawings.
Minimum requirements (for simple ceilings) are:
- Metal grid consists of double layer CD profiles (60x27mm) and perimeter U profile (30x30mm, maximum fastening space is 50cm);
- The bottom row of the CD profiles is fixed for the upper row by intersection connector;
- The maximum distance between the profiles in the upper row is 100cm and between the bottom row profiles is 50cm;
- Two CD profiles to be joined by CD longitudinal connector;
- The maximum distance between the suspenders is 100cm. Anchoring to reinforced concrete ceiling with sleeve anchors (plastic impact anchors are not acceptable);
- Sound insulation tape or aqustics sealant to be installed between wall and U profiles;
- Gypsum boards should be fixed for metal frame by screws 3,5x25mm, screw spacing cca 17cm (6 screws per 1m). The screw heads should be drowned in the depth of the board about 1mm;
- In large ceilings, movement joints must be carried out at least every 10 m.
Unless otherwise provided by the manufacturer's catalogue or design, lamps of up to 0.3kg should be installed on a gypsum board, for heavy lamps it is necessary to reinforce the substructure, lamps weighing more than 1 kg should be fixed for the supporting structure above the suspended ceiling
The distance between the vertical CW profiles in the partition walls is 600mm. If the wall is clad with ceramic tiles, the distance of vertical profiles in the walls should be 400mm.
Unless otherwise provided by the manufacturer's catalogue or design, the maximum height of the partition walls is as follows:
Vertical profiles Distance between vertical profiles (cm) Maximum height of wall (m)
CW50 60 2,6
CW50 40 3,0
CW50 30 3,3
CW75 60 3,0
CW75 40 3,5
CW75 30 4,0
CW75 two-layer cladding 60 4,25
Minimum requirements for simple partitions are:
- CW profiles should be shorter by a couple of millimetres due to the bending of the concrete ceiling;
- UW profile on the floors and ceilings should be covered with a self-adhesive tape for sound insulation and fixed for floor and ceiling by screws with plastic anchors.
- Gypsum boards should be fixed for metal frame by screws 3,5x25mm, screw spacing cca 25cm. The screw heads should be drowned in the depth of the board about 1mm;
- The substructure around door openings to be made by UA profiles, if the wall is higher than 2.8m, if the door is wider than 90cm or if the weight of the door is more than 25kg,
- Installation walls in the bathrooms to be erected with a double substructure (due to the pipes of larger diameters). To increase stiffness and stability, substructures to be connected with smaller pieces of gypsum boards with a width of about 30 cm, which are screwed onto CW-profiles. For the walls of the usual floor heights this reinforcement to be done in two places in height.
- Penetration of installations from the wall: the hole in the gypsum board should be 10 mm wider from the diameter of the tube, the cavity should be filled with a permanently elastic, fungicidal sealant (the substrate should be treated by primer according to manufacturer instructions).
Wall linings on metal substructure:
- Vertical C or CD profiles should be fixed to the solid background by the brackets, in at least three places in height, at distances not exceeding 1m.
- U or UD profiles and brackets should be covered with a self-adhesive tape for sound insulation .
- Gypsum boards should be fixed for metal frame by screws 3,5x25mm, screw spacing cca 25cm. The screw heads should be drowned in the depth of the board about 1mm.
Bonding of plasterboard linings direct to solid backgrounds:
- Gypsum boards should cover the entire height of the walls (board height = wall height reduced by 15mm). The boards should be raised by 10mm from the floor (on gypsum board pieces), at the top should be the gap of about 5mm.
- The adhesive should be applied in three vertical rows, for the installation of gypsum boards 12.5mm thick and in four vertical lines for slabs of thickness 9.5mm. The boards should be aligned with the masonry ruler that seizes at least three boards. In the window niches, entire surface of the gypsum boards should be covered by adhesive.
- When uneven or damaged wall surfaces should be covered, the tight vertical tapes of gypsum boards at distance of 60 cm should be made (if the substrate is not in required condition, the tape should be additionally fixed with anchors and screws to the wall, the distance of the anchors and screws is about 60 cm). On aligned tapes, the gypsum boards should be bonded.
4. Supervision and measurement of works
After the material is delivered to the site, the Supervisor should check whether the material is packed and marked as required by this technical specification and whether it is properly stored.
Supervision is obliged, before the beginning of the works, to check that the Contractor has verified that the rooms are ready for gypsum plastering works, visually check the condition of the rooms and approve the commencement of works.
During the execution of the works, Supervisor is obliged, on daily basis, to visually check the quality of the performed works. Verticality of the walls, horizontality of ceilings and corners in the rooms to be checked by the mason's bubble level and square. Special attention should be paid to accuracy of the installation outlets position.
The Contractor's responsible representative and Supervisor shall, before closing the partition walls or ceilings, inspect the performed works, including the installations, and confirm it in writing.
The executed works to be calculated per sqm of cladded area visible from the premises. Unless otherwise stated in the BoQ, the vertical surfaces between denivelated ceiling areas and surfaces of small elements (cladding of pipes, ducts, pilasters, etc.) are also calculated by m2. Parts of the walls remaining in the suspended ceiling area, if the joints between plasterboards are not filled, or the substructure which is not cladded by plasterboards, unless otherwise stated in the BoQ - should not be calculated.
EN 520 Gypsum plasterboards.
Type A: Plasterboard suitable for gypsum plasters or decoration.
Type D: These boards have a controlled density, with a face suitable for gypsum plasters or decoration.
Type E: Specifically manufactured to be used as sheathing board in external walls. They are not intended to receive decoration or be permanently exposed to external weather conditions. This type of wallboard has reduced water absorption rate with a minimum water vapour permeability.
Type F: Gypsum plasterboard with improved core adhesion at high temperatures: Plasterboard suitable for gypsum plasters or decoration. These boards have mineral fibres and / or other additives in the gypsum core to improve core cohesion at high temperatures.
Type H: Plasterboard with reduced water absorption rate: Boards suitable for special applications in which reduced water absorption properties are required to improve the performance of the board. These boards are designated Type H1, H2 and H3, with different water absorption performance.
Type I: Gypsum plasterboard with enhanced surface hardness: These boards are used for applications where higher surface hardness is required. Suitable for gypsum plasters or decoration.
Type P: Gypsum baseboard: Boards which have a face intended to receive gypsum plaster. They may be perforated during manufacture.
Type R: Gypsum plasterboard with enhanced strength: Boards for special applications where higher strength is required have both increased longitudinal and transverse breaking