best wood CLT BOX Wooden box element for large spans

best wood CLT BOX consists of best wood CLT with three glued-on glulam ribs and a CLT cover panel.
The hollow box element is a statically effective and at the same time space-creating wooden element, which is suitable for any ceiling requirement thanks to its flexible dimensions and excellent structural-physical properties. By exploiting the advantages of solid timber and timber post and beam construction, an efficient and versatile building product is created.
The combination of CLT and ribbed timber results in a high static load-bearing capacity with comparatively low weight. The crosswise construction of high-quality raw material in combination with high-quality flank and surface bonding ensures a high degree of dimensional stability. A high degree of prefabrication of the best wood CLT BOX with downstream joinery and the simple connection of the best wood CLT BOX elements ensures fast and economical assembly and guarantees a dry construction method. 


  • high static load-bearing capacity with low weight
  • large spans and thus column-free rooms possible
  • high degree of prefabrication and simple connection of the ceiling elements for fast and economical assembly
  • utilisation of advantages of solid timber and timber post and beam construction methods


best wood CLT Box
  • C24, GL 24h

    Strength class

Fields of application

  • Roof
  • Ceiling

Delivery formats

  • Type of wood & Quality

    • local spruce, industrial quality
    • scandinavian spruce, visual quality
    • local spruce, premium quality
Width (mm)
900 to 1200
Total height (mm)
Length 2.30–16.00 m, from 440 mm 8.00–16.00 m
Width 1000–1200 mm (900–1000 mm – Price on request)
GLULAM ribs width 80/100/120 mm in Abhängigkeit der Statik
Upper CLT board 60 mm
Lower CLT board 60 mm; 90 mm for increased fire protection requirements
Minimum production length per element width 8.00 m, chamfered on one side

Variant CLT BOX with FIBRE

  • •Suitable for flat roofs
  • Blow-out of the CLT BOX in the factory is possible with best wood FIBRE
  • Constructional calculation and approval with regard to moisture protection with pro clima

Filling wood

  • filling wood can be glued on in the factory
  • for passing through vertical loads

Technical data

Strength classBoard C24; rib GL 24h
Application classesUse in application classes 1 and 2 according to EN 1995-1-1
DryingKiln dried, wood moisture max. 15 % at delivery
BondingClear, water-proof gluing with polyurethane adhesives (free of formaldehyde)
LamellaeBoard: 20, 30 mm; rib 40 mm
General informationPlaned on four sides, bottom side chamfered 4 mm (measured diagonally)
Heat conductivityRib: λ = 0.13 (W/m*K); board: λ = 0.12 (W/m*K) according toETA-21/0336
Specific heat capacity1600 (J/kg*K) according to EN ISO 10456
CLT board diffusion resistanceμ 20 (damp) / 50 (dry) in accordance with EN ISO 10456
Emission classE1 according to DIN EN 717-1
Reaction to fireD-s2, d0 according to DIN EN 13501-1
FireproofingVerification possible via the free best wood STATICS software
AirtightnessAirtight after testing in accordance with EN 12114 from 60 mm


For your and our safety, we take great care to ensure a high standard of quality.

best wood CLT BOX - THE solution for multi-storey timber construction


Here you will find popular accessories for this product.

best wood CHIPPINGS

best wood CHIPPINGS

Used for putting into the best wood CLT BOX – CEILING FS and as ballast in best wood ceiling elements.

best wood HONEYCOMB 30/60

best wood HONEYCOMB 30/60

Honeycomb board made from cardboard which prevents movement and sliding of the best wood CHIPPINGS.



PUR sealing tape for fire protection for the element joints with CLT BOX – CEILING.

Suitable accessories

Find everything that is right and good for working and processing our timber products.

Reference Addition of a storey in timber construction A CLT BOX reference project

In Nonnenhorn on Lake Constance, an extension was carried out with the CLT BOX - a prime example of smart use of materials.

  • Location 88149 Nonnenhorn, Germany
  • Building type Industrial and commercial buildings
  • Building measure Extension