Ceiling Board Calculator (South Africa)

Not your floor area divided by the area of one board, which is what almost every online ceiling calculator does and the reason so many people end up back at the merchant. Boards get laid out room by room, and every room has its own part-width last row and its own cut end board, so the offcuts do not carry over. Three 3m x 3m bedrooms are a clean example: 27m² divided by the 3.6m² of a 1200 x 3000mm board says 8 boards, but laying them out properly needs 9, because each room takes 3 rows of board on its own. The calculator above does the real layout for every room you enter and shows you both numbers side by side.

Brandering is the timber grid the boards screw onto, 38 x 38mm SA pine for the normal truss spacing found in South African homes, nailed across the tie beams. Gyproc's specification puts it at 400mm centres for a 6.4mm board, 500mm for a 9.5mm flush-jointed ceiling and 600mm for 12.5mm board. The runs go at right angles to the boards, and every place two boards meet end to end needs an extra pair of branders so both ends land on timber. As a worked example, the two rooms the calculator opens with, 35.1m² in total, need 21 lengths, about 2.9 linear metres per m². Gyproc's own rule of thumb allows a more generous 3.9 linear metres per m², which builds in a big cutting allowance, so if you would rather follow the manufacturer's number add roughly a third to what the calculator gives you.

For materials only, budget roughly R203 per m² for a standard 6.4mm gypsum M-strip ceiling at July 2026 retail prices, boards, brandering, cornice, joint strips, screws and nails included. The two rooms the calculator opens with, 35.1m², come to about R7 112. Supplied and installed by a contractor, the same ceiling typically runs R8 780 to R12 292, which is R250 to R350 per m². A skimmed 9mm ceiling costs meaningfully more on both sides, roughly R350 to R450 per m² installed.

Less than you would expect, and this is the honest answer most DIY pages avoid. A contractor buys the same board, brandering and cornice at trade prices, usually 20% to 30% below what you pay at the till, so a good part of their labour is already funded by a discount you cannot get. On the calculator's default example your materials come to R7 112 against an installed range of R8 780 to R12 292, so doing it yourself buys you somewhere between a modest saving and a decent one, in exchange for several weekends of work above your head. It is worth it if you enjoy the work, or if your quote came in at the top of the range. It is much less obviously worth it if the saving is the only reason.

The length of the board must run at right angles to the brandering, which means it runs in the same direction as your roof trusses. The brandering itself is nailed across the tie beams. In most South African houses the trusses span the narrow direction of a room, so the board length usually runs across the shorter dimension, which is the calculator's default. If you are not sure, put your head into the roof space and look: the tie beams are the horizontal timbers at the bottom of each truss, and your boards run the same way they do.

Gypsum ceiling board is 900mm or 1200mm wide, in lengths from 2700mm to 4200mm in 300mm steps, although most merchants stock 2700, 3000, 3600 and 4200. The 6.4mm thickness is the standard for a nailed-up ceiling, 9mm and 12.5mm are used where the ceiling gets skimmed or needs more rigidity. Nutec fibre cement ceiling board is 1200mm wide in 2400 to 3600mm lengths. The calculator prices every stocked size and picks the combination that costs least across all of your rooms, counting the knock-on effect on brandering, since a shorter board means more end joints and each end joint needs its own pair of branders.

Yes, and Gyproc's own estimating guide recommends it. A 3000mm wide room takes 2 x 900 plus 1 x 1200 with nothing left over, where three 1200mm boards would leave you ripping 600mm off the last one. A 3300mm room takes 1 x 900 plus 2 x 1200, a 3900mm room takes 3 x 900 plus 1 x 1200. The Best fit option in the calculator works this out for every room automatically and reproduces Gyproc's published table exactly, which is a useful sanity check that it is doing the right thing.

An M-strip is the metal channel that slips over the long edge of a gypsum board and hides the joint between one board and the next, so the ceiling is finished the moment the last board is up, with no plastering, taping or skimming at all. It is the fastest and by far the most forgiving way for a DIYer to finish a gypsum ceiling. M-strips only go on the boards' long edges: where boards meet end to end you do not use a strip, you fix a pair of branders at 100mm centres so both board ends are supported. If you want a seamless ceiling with no visible lines instead, that is the taped and skimmed option, which looks much better and needs real plastering skill.

The full perimeter of every room, including across the top of doorways, since the cornice carries straight over an opening. Gypsum cove cornice comes in 3.6m and 3m lengths, polystyrene usually in 3m and 2m. The trick most estimates miss is that you cannot simply divide total perimeter by length: each wall needs its own piece or pieces, mitred into the corners, and each one gets cut a little long and shaved to fit. The calculator packs the actual wall lengths into stock lengths with a 100mm trim allowance on each, which is why it will sometimes tell you to buy one more length than the raw metres suggest. Budget one 5kg tub of cornice adhesive per 50 linear metres.

Far more than people expect. Boards are fixed at 150mm centres along every brander they cross, so the screw count comes off your total brandering metres rather than off area. The calculator's default two rooms, 35.1m², take 647 screws, which is 4 packs of 200. On top of that the brandering itself is nailed to the tie beams with 75mm to 100mm wire nails, two per crossing, about 252 nails or 2kg for the same two rooms. Use coarse-thread drywall or ceiling screws, and stop each head just below the surface without breaking the paper.

Gypsum for every normal dry room, it is cheaper, lighter and easier to cut. Nutec fibre cement for bathrooms, kitchens with poor extraction, patios, carports and garages, anywhere the board is going to meet steam or the weather. Gypsum board sags and eventually crumbles once it has been wet a few times, while fibre cement does not care. Nutec is heavier and much harder on blades, and it must be cut outside with a mask on, the dust is not something to breathe. Many South African homes use gypsum throughout and Nutec only in the bathrooms, which is a perfectly sensible split.

On any new or substantially renovated habitable room, yes, SANS 10400-XA has made ceiling insulation a building regulation requirement rather than an optional upgrade, with the R-value depending on your climate zone. Even where it is not compulsory it is the single best-value thing you can do while the boards are off. Laying insulation over a finished ceiling means crawling around the roof space on your hands and knees between trusses; doing it from below before the boards go up takes a fraction of the time. The calculator has a toggle to add it to the budget at a per-m² rate you can edit.

6.4mm is the standard for a domestic nailed-up ceiling on timber brandering at 400mm centres, and it is what most South African homes have. 9mm is used where the ceiling will be skimmed, since the extra weight of the plaster on a thin board is what causes sag, and it is also a little more rigid to handle. 12.5mm is really a drywall partition board; on a ceiling it goes on brandering at 600mm centres and is worth the extra cost mainly where you want the sound insulation of a heavier board. Going thicker does not let you space the brandering out further as a rule, it is the other way round: the specification pairs a thickness with a maximum spacing and you have to honour both.

Three things cause sag, and all of them are avoidable. Brandering spaced too far apart is the first, stick to 400mm centres for 6.4mm board no matter how tempting it is to save a few lengths. Fixing light fittings to the board rather than to the brandering is the second, gypsum will not hold a fitting and a downlight cut into an unsupported panel is a sag waiting to happen. Getting the board wet is the third, which is why a leaking roof or an unvented bathroom eventually ruins a gypsum ceiling and why fibre cement belongs in the wet rooms. Level the brandering off the lowest tie beam and pack the rest down to it, do not follow the timber up and down.

No, it prices new materials only. Stripping an old ceiling out typically runs R300 to R450 per m² if you pay someone, and doing it yourself is free but genuinely unpleasant, it is dusty, heavy work and old ceilings hide surprises. The important one: any home built before the mid-1980s may have an asbestos-containing ceiling board, which is a specialist removal job under the Asbestos Abatement Regulations and absolutely not a DIY task. If your ceiling is old, hard, grey and brittle rather than chalky white gypsum, stop and have it tested before you break anything.

No. A new gypsum ceiling drinks the first coat, so budget for a sealer or a heavily thinned first coat plus two topcoats. Work out exactly how much you need with our Paint Calculator, which handles ceilings as well as walls.

Rhinoboard is Gyproc's brand of gypsum plasterboard, and it is so dominant in South Africa that most people say Rhinoboard when they simply mean a gypsum ceiling board, the way Nutec has come to mean any fibre cement board. Every merchant sells the same 6.4mm, 9mm and 12.5mm boards in the same 900 and 1200mm widths, so the quantities this calculator works out apply whichever brand you buy. The specifications it follows for brandering centres, fixing centres and board layout are Gyproc's published South African figures, which the rest of the market builds to as well.

Replacing a ceiling is the new ceiling plus getting the old one out. For the new ceiling, budget roughly R203 per m² in materials or R250 to R350 per m² supplied and installed for a standard gypsum ceiling. Stripping the old one out adds about R300 to R450 per m² if you pay someone, or your own weekend and a skip if you do not. As a rough shape, a single average room comes in around R3,000 to R5,000 all in, and a few rooms together R10,000 upwards. Enter your actual rooms above for a real figure rather than a range. One warning worth repeating: a pre-1980s ceiling may contain asbestos, which is a specialist removal job and not something to break open yourself.

Yes, and the calculator already assumes you will, but only where it is worth doing. The rule it follows is the one installers use: if what is left over covers the whole of the next row on its own, it goes straight back up, it is a clean cut and it drops in. Cut a 1.8m bathroom row out of a 4.2m board and the remaining 2.4m does the next row, so three rows take two boards rather than three. What nobody does is piece scraps together to make up a row, because that puts a butt joint in the middle of the ceiling and every joint means another pair of branders and more taping, skimming and sanding, or an extra strip across a small bathroom where a joint in the damp is the first thing to fail. The few rand of board it saves is not worth the work. This makes the biggest difference in narrow spaces: a 6m passage 1.2m wide takes two boards, not five.

About 2.8 to 3.0 linear metres per m² for a 6.4mm ceiling at 400mm centres, worked out properly from your room dimensions, which is what the calculator above does rather than applying a flat rate. The reason a flat rate misleads is that the two runs against the walls and the extra pair at every board end joint are a bigger share of a small room than a large one. Gyproc's own estimating guide allows a more generous 3.9 linear metres per m², which builds in a substantial cutting allowance, so if you would rather follow the manufacturer's number add roughly a third to what the calculator gives you. Brandering is 38 x 38mm SA pine for normal truss spacing, stepping up to 38 x 50mm where tie beams are more than a metre apart.

No, and that is deliberate. PVC ceilings are a different system: interlocking planks rather than sheets, usually 250mm or 300mm wide in 4m to 6m lengths, clipped into their own trims instead of taking cornice and joint strips, so almost none of the maths on this page carries across. This calculator covers board ceilings, gypsum with M-strip, gypsum taped and skimmed, and Nutec fibre cement. If you are pricing PVC against board, PVC typically runs R280 to R400 per m² installed, which is comparable to a gypsum ceiling, so the choice usually comes down to looks and to how wet the room gets rather than to cost.

They are South African retail reference prices as of July 2026, taken from live builders' merchant listings, and every one of them is editable. Board prices update automatically as you change size, so the figure always matches the board you are actually buying. Prices move with the timber and gypsum markets and vary quite a bit between merchants and provinces, so for a real budget spend five minutes putting your own supplier's numbers in. The quantities, which are the hard part, do not change.