Permanent formwork: VELOX, Durisol or Izodom? 2026 system comparison

Permanent formwork is the principle of assembling a wall from boards or blocks first and then pouring concrete — the formwork stays part of the structure forever. The result is a monolithic house built faster than classic masonry. There are four main routes on the market, each suited to something different.

VELOX — wood-cement boards

Large-format boards of wood chips and cement, with polystyrene integrated on the outer face. Assembled as formwork for a whole wall at once.

• Strengths: speed (walls in 3–4 weeks), excellent acoustics, the concrete core's thermal mass ("thermos effect"), rendered directly without an ETICS system, thinner walls = more living area.
• Weaknesses: the pour needs an experienced crew; plan services in advance.

Durisol — wood-cement blocks

The same material as VELOX but shaped as hollow blocks: dry-stacked like Lego and poured in lifts. The mineral-wool-insert variant insulates comparably.

• Strengths: simple stacking logic, good vapour openness and acoustics; also popular for fences and retaining walls.
• Weaknesses: more joints and a smaller format mean slower progress than board-based VELOX; less thermal mass with thin-core blocks.

Izodom and other ICF — polystyrene blocks

ICF (Insulated Concrete Formwork): EPS/Neopor blocks are stacked and filled with concrete. Polystyrene remains on both faces of the wall.

• Strengths: the best U-values out of the box — an easy path to passive standard; very fast assembly.
• Weaknesses: polystyrene on the inside too — the wall does not breathe (mechanical ventilation needed), fixings into EPS need special elements, softer interior surface.

Concrete shuttering blocks

The grey concrete "cubes" known from fences and foundations. No insulation at all.

• Strengths: the cheapest monolith — ideal for foundations, retaining walls, cellars and garages.
• Weaknesses: for a dwelling they need full external insulation — practically unused for living-space walls today.

Comparison at a glance

Why we back VELOX for family houses

For us the combination wins: a monolith with thermal mass, quiet, a vapour-open wall and speed — at a price below block masonry with insulation (turnkey from about CZK 31,000/m², material "VELOX" in our calculator). We gladly use Durisol for fences and retaining walls, and ICF where passive standard is the priority. We will advise on your specific design — the site visit and quote are free.