The detailed guide below is currently available in English.
Sheets, seams, and why the number rounds up
Drywall is sold in whole sheets, so the answer always rounds up — there is no such thing as 0.75 of a panel. The waste allowance covers cut-offs around doors and windows, broken corners, and the offcuts that never quite fit anywhere else. Ten percent is the usual planning figure for a plain rectangular room; complicated ceilings, many openings, or diagonal walls can push it to fifteen.
Choosing a sheet length
All three sizes are four feet wide, so the choice is about seam count, not coverage per hour of taping. Long walls that match a sheet length exactly — a 12-foot wall with 4×12 panels — finish with a single horizontal seam and less mudding. The trade-off is handling: a 4×12 sheet is awkward solo and often will not turn in a hallway, which is why 4×8 remains the default for most rooms.
Contexto local: Portugal
Dados locais de Portugal, úteis para cálculos do dia a dia:
- IVA: 23 % no continente (13 % intermédia, 6 % reduzida), já incluído nos preços.
- Moeda e pagamentos: Euro (€); MB WAY e multibanco são os pagamentos mais comuns.
- Unidades e números: Sistema métrico; vírgula decimal e ponto ou espaço nos milhares: 1.234,56 €.
- Subsídios: Subsídio de férias e de Natal: 14 pagamentos por ano são a norma nos salários.
- Gorjeta: Voluntária; 5–10 % em restaurantes, serviço já incluído no preço.
Atualizado: outubro 2026 · valores de 2025, fontes oficiais acima.
Perguntas frequentes
How do I include the ceiling?
Measure the floor and add that area to your wall total before entering it — a 12×15 room contributes another 180 ft². Many people board ceilings with the same sheet size as the walls.
What waste percentage should I use?
Ten percent is a safe default for typical rooms. Simple garages and basements with few openings can drop to five, while rooms with lots of angles, bulkheads, or window cutouts are happier at fifteen.
Does the cost include tape, mud, and screws?
No — the price row multiplies sheets by your per-sheet price only. A common rule of thumb adds about 15–20% to the board cost for joint compound, tape, fasteners, and corner bead.