BS 8212:1995 download.Dry lining and partitioning using gypsum plasterboard.
1.1 Scope
BS 8212 code of practice gives recommendations for dry lining walls, ceilings and partitioning using gypsum wallboard. Composite products such as gypsum plasterboard backed with insulation materials are also included.
This code does not deal with linings to heated ceilings.
1.2 References
1.2.1 Normative references
BS 8212 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on page 46. For dated references, only the edition cited applies; any subsequent amendments to or revisions of the cited publication apply to this standard only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments.
1.2.2 Informative references
BS 8212 refers to other publications that provide information or guidance. Editions of these publications current at the time of issue of this standard are listed on the inside back cover, hut reference should be made to the latest editions.
1.3 Definitions
For the purposes of this code the definitions given in
BS 1191-1 and BS 1191-2, BS 1230.1, BS 4022,
BS 6100-1, BS 6100-6.1 and BS 6100-6.6.2 apply,
together with the following.
1.3.1
face
surface of gypsum plasterboard on which the paper extends continuously to cover the edges
1.3.2
back
surface of gypsum plasterboard having a double thickness of paper along the two edges
1.3.3
insulating gypsum wallboard
gypsum wallboard backed with a film having a surface of low emissivity, e.g. aluminium, to improve thermal insulation when used in conjunction with an air space
1.3.14
resilient wallboard adhesive
adhesive made from synthetic rubber/resin used to bond plasterboard to plasterboard
1.3.15
decorative textured coating
plastics based textured coating used as a decorative finish
1.4 Exchange of information
When preparing dry lining details the designer should take into account the following points.
a) The choice of dry lining systems to be used in various parts of the building depends on functional requirements and the nature of the background. The background, including building and manufacturing tolerances, and its dry lining should therefore receive consideration together.
This is particularly important where plasterboard is to be fixed to trussed rafters. A thickness of rafter conforming to BS 5268-3 and perfectly adequate from a structural point of view may be unsuitable to permit adequate fixing of the end of the plasterboard in accordance with the recommendations given in 4.3.3.
b) The type of surface finish and any other points affecting the final appearance, particularly the compatibility of the dry lining with the proposed decorative finish.
c) The area and types of finish and thickness required together with sufficient details of the nature of the surfaces to be dry lined and the junctions with window frames, door frames, ceilings and linings, so that the most suitable dry lining materials and methods can he selected.
d) The effect of the thickness of the dry lining on:
1) the finished sizes and heights of rooms or
other spaces:
2) the thickness of grounds: timber framing
requirements;
3) flames which are to be flush both sides in
thin walls and partitions;
4) the positioning of frames and other joinery
relative to dry lining faces;
5) grooves in joinery that are to receive dry
lining;
6) the positioning of and provision of adequate
support for heating appliances and other
installations, fixtures and fittings;
7) any other items, the specification for which can be drawn up in detail only after the dry lining thicknesses have been determined.
2.1 Materials
2.1.1 Gypsum plasterboard
Gypsum plasterboard for dry lining and partitioning should conform to BS 1230-1 and should be in accordance with the following types.
a) Gypsum wallboard. Gypsum wallboard (type 1) can be used for dry lining walls, ceilings and roofs, for the construction of partitions and cavity barriers and for encasing steel beams and columns.
b) Gypsum wallboard F. Gypsum wallboard F (type 5) should be used in the same situations as gypsum wallboard when a greater degree of fire protection is required.
c) Moisture resistant gypsum wallboard. Moisture resistant gypsum wallboard (type 3) resists absorption of water both by its paper surface and core and can be used as a backing for ceramic tiles as a form of sheathing and for other applications where there is a risk of gypsum wallboard being exposed to moisture.
NOTE 1 See Table 1 of BS 1230-1:1985 for gypsum wallboard types.
NOTE 2 All the above types of gypsum plasterboard are available with square or tapered edges.
2.1.2 Composite board
Gypsum wallboard which has a material attached to the face or the back as a secondary operation of manufacture should be one of the following:
a) insulating wallboard;
b) thermal wallboard laminate;
c) predecorated wallboard;
d) prefabricated wallboard panels.
NOTE Insulating wallboard and thermal wallboard laminate are available with an integral vapour check.
Prefabricated gypsum wallboard panels should conform to BS 4022. They can be used in conjunction with timber perimeter framing and jointing battens to provide hollow plasterboard partitions and wall linings.
Where thermal wallboard laminates incorporate a backing of man-made mineral fibre the backing should be of sufficient density to resist compression under normal usage.
2.1.3 Gypsum cove
Lightweight gypsum cove such as a gypsum core encased in a paper liner suitable to receive direct decoration can be used as a cornice at the angle between wall and ceiling. It should be fixed with a suitable adhesive.
Where the trueness of the background cannot be corrected by the thickness of adhesive (see 3.2.2) consideration should be given to the following measures:
a) correction of the background to which the lining is to be applied:
b) adjustment of framing members, window boards, linings and grounds around openings in the background:
c) modifications which may be required to accommodate the position of services, e.g. switch boxes have to be packed out or chased in.
The above measures are likely to lead to an increase in the width of the zone occupied by the wall and may have an effect on adjacent components such as suspended ceiling grids.
3.3.5 Localized build-up of the surface
3.3.5.1 Crown of joint
The maximum increase should not exceed 3 mm when measured using a 450 mm straightedge. Measurements should be taken with the ends supported on board to board surfaces, see Figure 3 a).
3.3.5.2 External angles
The maximum increase should not exceed 4 mm projection from either face when measured as shown in Figure 3 b) using the external angle reference edge shown in Figure 4.
3.3.5.3 Internal angles
The maximum increase should not exceed 5 mm projection from either face when measured as shown in Figure 3 c) using the internal angle reference edge shown in Figure 4.
3.3.5.4 Boxed studs
The increased thickness of the partition should be not more than 4 mm.
3.3.5.5 Around openings (door heads, access panels and backing plates)
The maximum increase should allow the partition or lining to conform to 3.3.3.
3.3.6 Thickness of partitions
The thickness of a partition in its finished state should be within a tolerance of± 5 mm.
3.3.7 Prepared openings in partitions Door, access panel or other openings in partitions should be within the following tolerances:
5.1 General
Consideration should be given to the need for good site administration to avoid unnecessary costs. Inappropriate trade sequencing in relation to the dry lining and partitioning operations can lead to the need for costly patching and making good. Blemishes caused to the surface of the lining in this way may lead to delays in obtaining acceptance of the finished surface.
It should also be appreciated that the full economic use of the labour available can only be achieved by creating conditions which permit a full continuity of work.
5.2 Environmental conditions
The environmental conditions of a building under construction will vary considerably depending upon its state of completion, time of the year, the weather and number of wet trades involved. Where possible the lining, and in particular the ceiling installation, should be programmed to a time when conditions will have improved and close to occupancy, when the external doors and windows have been fitted.
Whilst it may be difficult to exercise control over the ventilation of the building outside working hours because of the need to retain suitable levels of security, windows and doors should he opened whenever possible to remove excess moisture. In extreme conditions where excessive moisture is present and conditions are not conducive to early improvement, consideration should be given to the use of drying methods using forced ventilation equipment.
In those buildings where design permits rapid weatherproofing, and wet operations are kept to a minimum, dry lining may contribute to early completion and handover.
5.3 Organization prior to the commencement of dry lining and partitioning works
Sufficient areas in proper sequence should be available to enable the dry lining or partitioning work to commence and maintain reasonable continuity as part Df the programme.
The areas to be dry lined or partitioned should be watertight, weatherproof and sufficiently dry to ensure that the fixed wallboard will not suffer subsequent deterioration due to moisture absorption.
Window frames and other joinery first fixings should be in position. The relevant first fixings of other trades should be finished.