Decking Boards Calculator 2026 — Cost & Board Count

The price of decking boards in Poland in 2026 depends on the material: composite board approx. PLN 200–300/m², exotic wood (e.g. bangkirai, ipe) approx. PLN 250–400/m², pressure-treated pine or larch approx. PLN 80–150/m². Add joists, fasteners and installation on top.

Composite (WPC) board is moisture-resistant, needs no oiling, does not splinter and keeps a stable colour for years — but it is more expensive and heats up strongly in the sun. Exotic wood is very durable and natural but needs periodic care. Treated pine is the cheapest but least durable (8–12 years).

The board count is estimated by dividing the deck area by the area of one board. A typical board is approx. 14 cm wide and 4 m long (approx. 0.56 m²). For a 20 m² deck you need approx. 36 boards. The calculator gives an estimate — always add a 5–10% margin for cuts during installation.

Joists are the supporting structure under the deck boards — battens (wooden or aluminium) fixed to the base, to which the boards are screwed. Joist spacing is 40–50 cm for composite boards and 30–40 cm for thin wooden boards. The cost of joists and installation is a significant part of the deck budget.

Joist spacing depends on board thickness and stiffness: solid composite board 40–50 cm, hollow composite board 30–40 cm, 21 mm wooden board approx. 50 cm, 19 mm board approx. 40 cm. Too wide a spacing causes the boards to sag. Under loads (e.g. planters) reduce the spacing.

Composite board needs no oiling or varnishing, unlike wood. Periodic washing with water and detergent and removing leaves to prevent stains is enough. Exotic wood and pine require oiling 1–2 times a year to keep their colour and protection against moisture and UV.

The calculator computes the board cost (by material), the joist and installation cost and the total cost, plus an estimated board count. It does not include the substructure (paving, concrete footings), fasteners, finishing trim or drainage. Add these for a full deck estimate.

The base under a deck must be stable and drain water. Most commonly used: concrete footings or ready adjustable pedestals, with joists on top maintaining a 1–2% slope away from the building. On soil, a geotextile and an aggregate bed are needed. An improper base causes warping and rotting.

A deck made of good composite (WPC) board lasts 20–25 years with minimal maintenance. Exotic wood (ipe, bangkirai) with regular oiling — 20–30 years. Pressure-treated pine — 8–12 years. Durability also depends on the quality of the joists and proper water drainage.

Building a deck on ready adjustable pedestals is possible yourself and saves on labour. However, it requires accuracy in levelling, keeping joist spacing and slopes. For large or raised decks and load-bearing structures it is better to use a professional.