Garage and entrance hall ceiling: fire protection, thermal bridge and sound absorption in a single layer

Solutions & Applications · Garage and Entrance Hall Ceilings

The garage ceiling is not a ceiling — it is the floor of the dwellings above. And it is the only part of a building where three completely different requirements come together on the same surface: to resist fire, to break the thermal bridge and to absorb noise. The wood wool slab achieves all three with a single layer, screwed directly onto the concrete — without a framework and without a suspended ceiling.

Garages and entrance halls are not the same issue

	Enclosed garage	Open-plan entrance hall
Primary requirement	Fire resistance — high fire load in an enclosed space	Thermal bridge — the slab separates a heated space from the outside air
Acoustics	Critical: motors, doors, the screech of tyres in an enclosed, echoey space	Secondary — sound diffuses
Exhibition	Protected	External moisture, temperature fluctuations, coastal environment
Visibility	Technical section	Visible architectural surfaces — texture and colour matter

Why a fire in a car park is different

This is no ordinary building fire load. A modern vehicle contains large quantities of plastics, rubber and fuel, and when ignited, it releases a great deal of heat in a very short space of time. In enclosed car parks, the temperature rises rapidly and the fire spreads easily from vehicle to vehicle.

The thermal bridge in the entrance hall

The entrance hall floor slab is the classic thermal bridge in Greek blocks of flats: outside air from below, a heated flat from above. Its insulation provides some of the highest heat loss per square metre in the entire building — and the first-floor tenant immediately notices this as a warm floor in winter.

On one condition: the layer must continue round the perimeter of the beam. Insulation that stops at the edge of the slab leaves the beam exposed — and the beam is precisely the coldest point, where damp and mould appear in the corner of the flat. The sides and underside of the beam are clad with strips cut from the same slab.

Wood wool performs three functions simultaneously

The feature that makes it suitable here is its open, fibrous structure: the same material that traps air for thermal insulation also absorbs sound energy. In an enclosed garage, where the floor is concrete and there are few walls, the ceiling is the only available absorbent surface. And because the slab is structurally strong, it can remain exposed without fear of damage from vehicles or ladders.

Which slab for which requirement

Slab	Structure	When to choose it
HERAKLITH A2-C	Compact wood-fibre board with mineral binder; A2-s1,d0	When a non-combustible, durable and sound-absorbing surface is required without significant thermal demands — or as a base for rendering
TEKTALAN A2-HS	Stone wool core with wood wool on both sides · A2-s1,d0	When all three factors are taken into account — fire protection, thermal insulation and sound absorption — and particularly for integration into formwork
Tektalan A2 SmartTec	A layer of wood wool on the visible side and high-density stone wool behind it	On an existing slab, where the slab is bolted directly to the concrete without a framework

Thickness is not determined solely by the thermal target. For garage ceilings, it is determined both by the fire resistance rating required by the fire protection design and by sound absorption — three criteria that must be met simultaneously.

The distinction between s1 and d0 is worth noting, because in an enclosed car park it is just as important as the flame: s1 denotes low smoke production — and in a garage, smoke hinders evacuation and the fire service’s response; d0 means zero flaming droplets, i.e. the fire does not spread downwards to other vehicles.

Two installation methods — and one saves a step

	Integration into the formwork	Retrofit mechanical fixing
When	New build — decision on the design	Refurbishment or existing slab
How	The slabs are placed in the formwork with supports, and the concrete is poured over them	Concrete screws or plugs with washers, in a grid as specified by the manufacturer
Advantage	No drilling, monolithic bonding, no additional steps	Can be installed at any time, without interfering with the load-bearing structure
Please note	Closed joints — otherwise the concrete will seep through and show up on the façade	Dust, drilling, distance from the reinforcement

Details that make all the difference

• Alignment: in visible applications, the joint grid is marked out before the first slab is laid. Corrections cannot be made after fixing.
• Beams and perimeter: cladding should also be applied to the sides of the beams, so that the thermal and fire protection layers are not interrupted.
• Penetrations: sprinkler, ventilation and electrical conduits shall pass through clean cuts; light fittings shall be fixed to the concrete, not to the insulation board.
• Fixings in lintels: with corrosion protection, particularly in coastal environments.
• Finish: natural appearance, painted in RAL colours to order, or plastered.

Design series

• Fire resistance requirement from the fire protection design — specifies whether wood wool is sufficient or whether a composite board with a stone wool core is required.
• Enclosed or open space: garage or entrance hall, with the corresponding priorities.
• Thermal target for the slab separating a heated space from an unheated space.
• Perimeter beams: confirmation that the layer continues and does not stop at the edge of the slab.
• Installation method: integration into formwork in new builds; mechanical fixing in refurbishment projects.
• Fixings: type, length and corrosion protection.

Wood-fibre boards

Supplementary Insulation & Fixing

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