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The ceiling cover is fixed onto the ceiling to give decorative appearances, conceal projections(such as beams occurring underneath floor slab), provide a false ceiling, obtain special acoustic effects, insulation against heat and cold, etc.
The ceiling can be covered using different types of materials as listed below-
- Insulated board
- Plaster of Paris Ceiling & tiles
- Gypsum plasterboard
- Plywood and blackboard
- Asbestos cement building board
- Cloth Ceiling
- Aluminum sheet ceiling
- Expanded polystyrene ceiling
- Timber Ceiling
In this article, we discuss the preparative work, different methods of attachments used, and the procedures for fixing different types of ceiling covers.
Preparatory Work for Installing of Ceiling Covers
- The wooden or metal framework, consisting of longitudinal bearers and cross-bearers by means of which the ceiling board is supported, shall be designed for structural strength and stability.
- The suspenders from RCC slabs for supporting the framework for a false ceiling shall be of sufficient length to reach the ceiling frame.
- The ceiling boards, less than 5 kg/m2 in mass, can be directly fixed to RCC by means of fixing plugs, bolts, etc.
- Double ceiling boards must be provided in places such as air conditioning installations and cold storage rooms.
- The first layer of the ceiling board may be fixed to the ceiling with plugs or other fixing devices in the concrete slabs at required spacings.
- The typical details of the framework and methods of its suspension are shown in Figures 1 and 2.
In figure 2, the different methods of attachment of hangers to top members are illustrated in A, B, C, and G. The attachment of hangers to ceiling frames are illustrated in A, C, D, F, and G. The use of clips, studs, and hooks for fixing bolts are illustrated in H and E.
Fixing of Ceiling Covers
The fixing methodology of different types of cover is covered in detail :
1. Insulating Building Board, Hard Board, Gypsum Plaster Board, Asbestos Cement Board, Mineral Wood Board, and Plywood
- The insulating building boards may be particle boards (low density) or fiber insulating boards.
- For plywood boards, thickness of 4 to 10 mm is used, and the spacings may vary from 450 to 600 mm for longitudinal battens and 600 to 1200 mm for cross battens; for boards above 10 mm thick, the spacings maybe 600 to 900 mm for longitudinal battens and 900 to 1300 mm for cross battens.
- The nails used for the fixing of boards shall be long enough to cover the thickness of the board plus 25 mm.
- The material of nails used must preferably be galvanized-made when joints are left exposed.
- The boards are cut into the required size, and the edges shall be slightly sandpapered to make them smooth.
- The framework with battens, size ranging from 60 to 75 mm, shall then be fixed.
- The building board shall then be fixed with lengths parallel to all joints centered over the framing members.
- Where the joints are to be covered, the boards shall be spaced 3 to 6 mm apart and butt-jointed when exposed.
- The boards are first nailed to intermediate framing members proceeding from the center of the board outwards, the edges being nailed last.
- In the places where joints are exposed, the outer row of nails shall be at 100 mm from the centers and about 12 mm from the edge of the sheet.
- The nail rows in the middle of the sheet shall be at 20 mm centers. The nails in the outer rows on either side shall be paired and not staggered. The nails shall be countersunk in the underside of the board.
- Where joints are to be covered with beading, the procedure is the same as above, except that in the outer rows, the nail spaced at 200 mm may be staggered.
- The beadings shall be fixed over the sheets with screws at 200 mm centers.
- The exposed side shall be truly level; joints truly parallel and perpendicular to the walls.
2. Plaster of Paris
- In the case of sloping roofs, wooden battens of a suitable section shall be firmly fixed as main supports to the underside of the beams at required centers by means of bolts and nuts.
- In the case of flat roofs, treated battens shall be securely fixed to the walls and pillars by holding down bolts and shall be fastened to the slabs above with iron straps or mild steel bars anchored therein.
- The cross battens of 50 mm x 40 mm at about 400 mm centers shall then be fixed at right angles to the main battens.
- The underside of the framework shall be true to planes and slopes.
- Wooden strips or laths 25 mm x 6 mm shall be fixed to the cross battens in parallel rows with felt nails.
- Rabbit wire mesh shall be fixed with rails of a pitch of 150 mm to 200 mm to the underside of wooden strips.
- The wire mesh shall be straight, tight and true to planes and slopes without any sagging and slightly below the underside of the paths.
- The Plaster of Paris shall be mixed with water to a workable consistency and applied to the underside of laths over the rabbit wire mesh in suitable sized panels and finished to a smooth surface by steel trowels.
- The thickness over the laths shall be as specified but not less than 12 mm.
- The joints shall be finished flush; the surface shall be smooth and true to plane, slope, or curve as required.
3. Plaster of Paris Tiles
- The thickness of Plaster of Paris tiles shall be not less than 12 mm. Hessian cloth shall be of an open webbed texture.
- The maximum size of the panels shall be limited to 750 mm in each direction.
- The timber or aluminum frame shall be so made that each tile has supporting scantlings to fix them.
- The tiles may be fixed to the cross battens with 40 mm long brass screws at 200 mm centers.
- The tiles may be laid adjacent to each other without leaving any gap.
- The screws shall be at least 15 mm away from the edge.
- The countersunk heads of screws shall be covered with plaster of Paris and smoothly finished.
4. Cloth Ceiling
- The materials used for the framework of the cloth ceiling shall be bamboo of good quality.
- The framework shall be securely spiked to the wall plaster/ceiling joints or beams.
- The cloth shall be wetted, stretched, and nailed to the upper side of the framework.
- In the case of a bamboo framework, the cloth shall be tied to it without tearing.
- To prevent the cloth from blowing and flapping, wooden beadings shall be fixed.
- The cloth ceiling is then whitewashed and distempered.
FAQs on Ceiling Covers
The ceiling cover is fixed on to the ceiling to give the decorative appearance, to conceal projections, such as beams occurring underneath floor slab, to provide a false ceiling, to obtain special acoustic effects, insulation against heat and cold, etc.
The best type of ceiling covers concerning all the factors such as cost, maintenance, appearance, and durability are Gypsum boards, and Plaster of Paris.
If the ceiling cover is well maintained, the covers will last up to 20 years.