Rainproof underlay panel with unique tongue-and-groove profile
Gutex Multiplex-top allows rain-resistant wood-fibre insulation to be produced with a low construction height. The underlay panel is suitable for roof structures in new buildings, for internal and external roof renovations, as a cover panel for roof insulation and as protection in rear-ventilated wall insulation. High diffusion openness and a marked ability to store and release moisture ensure long-term building physics safety. The windtight tongue-and-groove joint reliably protects the insulation structure from cold air passing through it.
- Proven raintightness up to 3 mm joints
- HW4 high hail protection (TÜV tested)
- Temporary roof: 3 months of exposure to the elements
Nominal value of thermal conductivity λD
0,045 W/mK
Design value of thermal conductivity λB
0,047 W/mK
Product details
Reliable protection and easy installation
The Gutex Multiplex-top roof underlay panel impresses with its long-lasting weather resistance and is rainproof from a roof pitch of 15° without additional covering or bonding of the panel joints. Thanks to its HW4 hail protection class (TÜV-tested), it also guarantees reliable protection against extreme weather conditions. By using a wood fibre insulation panel instead of a traditional underlay membrane, Multiplex-top not only provides effective thermal insulation, but also minimises thermal bridges and improves sound insulation. Its dimensional accuracy facilitates quick and easy installation, while the tongue-and-groove assembly provides a ‘securely jointed and perforated underlay’ in accordance with ZVDH regulations, without the need for additional sealing strips or nailed joints. Multiplex-top can be recycled at the end of its service life.
A comprehensive guarantee
Gutex has lodged a guarantee for the rainproof underlay panel with the Central Association of German Roofing Craftsmen, and in the event of a claim covers not only the replacement of the material, but also the costs of dismantling and installing it, as well as any scaffolding costs incurred.
- Provides reliable protection against rain and hail from a roof pitch of 15° upwards, certified in hail protection class HW4 (TÜV tested)
- Wood fibre insulation minimises thermal bridges and improves acoustic insulation compared with traditional roof underlay
- Tongue and groove jointing and high dimensional accuracy mean that the underlay is seamless and perforation-free, including protection against the passage of cold air.
- Recyclable, made in Germany
Ingredients
- Untreated fir and spruce wood
- 4% PUR resin
- 1.5% paraffin
Gutex Multiplex-top roof underlay panel: rainproof, windproof, robust
Storage and processing
- Store and use Multiplex-top in a dry place
Rafter spacing
Maximum centres depending on panel thickness :
- 22 mm: max. 85 cm
- 35 mm: max. 100 cm
Cutting
- When using standard woodworking machinery, the legal requirements for handling wood dust must be observed.
Installation
- Multiplex-top is not a load-bearing element (e.g. for snow loads).
- The panel cannot be subjected to a static load.
- Avoid cross joints.
- Only use undamaged panels.
- Avoid increasing ambient humidity (e.g. through damp screed).
- The spaces between the rafters are not accessible.
- Lay the panels with the marked side facing outwards, flat, tightly fitted and with watertight joints, groove down, tongue up. As a general rule, the panels are laid perpendicular to the rafters.
- Immediately fix the panels with counter-battens; it is not necessary to use strips or nail seals.
- Offset joints: offset the rows by at least one rafter axis.
- Glue joints and penetrations with the Gutex adhesive system so that they are protected from rain.
- Gutex wood fibre insulation boards can be exposed to temperatures of up to 110°C, even for extended periods. Additional measures are required for higher temperatures, e.g. due to solar pipes.
- The minimum distances between combustible building materials and chimneys, etc. must be observed in accordance with the relevant Fireplace Ordinance.
Roof pitch and waterproofing
Depending on the pitch of the roof, the following extract from the ZVDH regulations must be observed:
- < 15° cover with a suitable sheet
- ≥ 15° no gluing of panel joints is required.
Guidelines for hot air welding
- Use hot air, max. 350°C, do not flame directly.
- Use the appliance for a maximum of 7 to 10 seconds per area; check for discolouration and remove if necessary.
These installation guidelines protect Multiplex-top from spontaneous combustion. The installation guidelines for the strips must also be observed.
Fixing of Multiplex-top (thickness ≤ 35 mm, building height ≤ 10 m, interior)
Important notes
- Fixings must be at least galvanised.
- Specific solutions are required by fastener manufacturers for different constructions.
- Sizes according to fastener manufacturers.
| Bulk density ρ | ~ 220 kg/m³ |
| Vapour diffusion (μ) | 3 |
| Nominal value of thermal conductivity λD | 0,045 W/mK |
| Design value of thermal conductivity λB | 0,047 W/mK |
| Design value of thermal conductivity λB ACEMI | 0,052 W/mK |
| Compressive stress strength | ≥ 200 kPa |
| Short-term water absorption | ≤ 1 kg/m² |
| Airflow resistance | ≥ 100 kPa s/m² |
| Specific heat capacity | 2100 J/kgK |
| Fire behaviour Euroclass according to DIN EN 13501-1 | E |
| Plate labelling | WF-EN 13171-T5-CS(10/Y)200-TR30-WS1,0-AF100-MU3 |
| Tensile strength perpendicular to the board surface | ≥ 30 |
| Application according to ZVDH regulations | UDP-A |
