Chapas de Drywall

Drywall sheet calculation

Take the total wall area, divide by the area of a single sheet, then tack on a 10–15% waste margin to cover cuts and openings. Standard plasterboard comes in 1.20 × 1.80 m = 2.16 m² or 1.20 × 2.40 m = 2.88 m². The system hangs on a metal frame of studs and tracks (montantes/guias) set 40 or 60 cm apart. As for the boards themselves: ST is the standard one for dry rooms, RU is the green moisture-resistant board for bathrooms and kitchens, and RF is the pink fire-resistant board. Say you have a 30 m² partition, 2.16 m² sheets and 15% waste — that works out to ⌈30 ÷ 2.16 × 1.15⌉ = 16 sheets.

Applications and standards

It shows up in internal partitions, suspended ceilings, fast remodels and acoustic insulation. The appeal is practical: drywall goes up in days where masonry takes weeks, it weighs about 25 kg/m² against 250 kg/m² for a brick wall, and you can route wiring and plumbing through the cavity. The Brazilian standard is NBR 15217 (gypsum plasterboard sheets for drywall). Pack mineral wool into the cavity and you can reach acoustic performance up to Rw 45 dB.

FAQ

Single or double layer? A single layer, one sheet per side, is what most homes use. Doubling up boosts both acoustic and fire performance, and it is required in hotels and offices.

Can drywall get wet? Standard ST sheets cannot handle it. Switch to RU (green) in bathrooms and kitchens, and waterproof the wet area with a membrane before you tile over it.

How much weight can it hold? A plain screw is good for about 5 kg. Anything heavier, like a TV or a run of shelves, needs purpose-made drywall anchors, or you add wood reinforcement inside the frame while it is being built.