Rainproof underlay panel for pre-construction
Gutex Prefatop increases the efficiency of the prefabrication of diffusion-permeable roof and wall elements, thanks to its dimensions of 2500 x 1200 mm and its joints and ends that can be sealed quickly and securely. The width of a roof element can be produced with a single moisture-insensitive underlay panel - without vertical joints between the panels, which further increases rain resistance and stability. Unlike a roof underlay, the Prefatop rainproof underlay panel provides additional thermal insulation and improves acoustic insulation.
- Quick, easy and safe sealing of joints and panel ends
- High resistance to rain and stability thanks to installation without vertical joints between panels
- Robust strength and high dimensional accuracy for quick and easy installation
Nominal value of thermal conductivity λD
0,042 W/mK
Design value of thermal conductivity λB
0,044 W/mK
Product details
Diffusion-open underlay panel for energy-efficient new buildings
Gutex Prefatop is a diffusion-open wood fibre insulation board with a hydrophobic treatment, which allows roof and wall elements to be insulated safely from a building physics perspective in new constructions. The board is windproof and does not require additional windproofing tape. It is possible to create a ‘joint- and perforation-protected underlay’ (UDP-A) in accordance with the ZVDH guideline without using tape or nail seals. In addition, Prefatop can be exposed to the elements for up to four weeks, which increases flexibility during installation on site. Whether insulating a passive house or a low-energy house, Prefatop is the ideal underlay panel.
- Diffusion-open, windtight wood-fibre insulation board with hydrophobic treatment for secure insulation without additional windtightness strips
- Greater flexibility on site thanks to exposure to the elements for up to four weeks and installation without the need for nail-on waterproofing strips
- Environmentally friendly and recyclable, made in Germany from sustainable wood fibres
A comprehensive guarantee
With a guarantee deposit with the Central Association of German Roofing Craftsmen, Gutex offers cover for dismantling and assembly costs, as well as any scaffolding costs, in the event of a claim, in addition to replacement of materials.
Ingredients
- Untreated fir and spruce wood
- 4% PUR resin
- 0.75% paraffin
Gutex Prefatop sub-roofing panel: specially designed for effective pre-construction
Storage and processing
- Store and use Prefatop in a dry place.
Important notes
- Prefatop is not a load-bearing element (e.g. for snow loads).
- The plate must not be applied statically
- Cross joints are not permitted.
- Only use undamaged panels.
- Avoid increased humidity loads on the room side.
Cutting
- When using standard woodworking machinery, the legal requirements for handling wood dust must be observed.
Installation
- Lay the panels with the marked side facing outwards, flat, perfectly fitted and with watertight joints with rising tongues; cross joints are not permitted.
- Blunt plate joints must be recessed.
- Fix the panels immediately with counter-battens.
- Glue joints and penetrations with the Gutex adhesive system so that they are protected from rain.
Use as wall insulation
- Maximum centre-to-centre distance: 83.3 cm.
- Four months of exposure to the elements.
Use as roof insulation
- Maximum centre-to-centre distance: 110 cm.
- Immediately seal the smallest joints with Gutex sealant or the Gutex bonding system.
- The spaces between the rafters are not accessible.
- No sealing strip or nail joint is required.
- Can be exposed to the elements for up to four weeks as a temporary roof.
Roof pitch and waterproofing
- Roof pitch <15°: cover with a suitable sheet required.
- Roof pitch ≥15°: panel joints do not need to be glued, provided the regulatory roof pitch is not more than 8° lower and there are no additional requirements under the ZVDH rules (in accordance with the "Professional Rules for Tile and Roof Stone Roof Coverings").
Fixing Prefatop (thickness ≤ 60 mm, building height ≤ 10 m, inland)
Important notes
- Fixings must be at least galvanised.
Standard conditions
Rafter spacing ≤ 85 cm Counter-battens 60 x 40 | Distance for Paslode 4.2 x 160 Round-Drive groove in cm | ||||
|---|---|---|---|---|---|
Load coverage | Snow | Wind zone | Roof pitch | ||
kN/m2 | kN/m2 | 1 à 4 | 15° | 30° | 45° |
0,30 |
≤ 0,85 | Wz 1 | 70 cm | 40cm | 45cm |
Wz 2 | 50cm | 40cm | 45cm | ||
Wz 3 | 35cm | 35cm | 35cm | ||
Wz 4 | 25cm | 25cm | 25cm | ||
0,60 |
≤ 0,85 | Wz 1 | 60cm | 30cm | 30cm |
Wz 2 | 55cm | 30cm | 30cm | ||
Wz 3 | 40cm | 30cm | 30cm | ||
Wz 4 | 30cm | 25cm | 25cm | ||
0,95 |
≤ 0,85 | Wz 1 | 45cm | 25cm | 15cm |
Wz 2 | 45cm | 25cm | 15cm | ||
Wz 3 | 45cm | 25cm | 15cm | ||
Wz 4 | 30cm | 25cm | 15cm | ||
Source ITW; data not guaranteed.
Specific conditions for smooth nails (Haubold or Paslode)
Rafter spacing ≤ 85 cm Counter-battens 60 x 40 | Spacing for Haubold or Paslode 4.2 x 160 smooth (bare or galvanised) | ||||
|---|---|---|---|---|---|
Load coverage | Snow | Wind zone | Roof pitch | ||
kN/m2 | kN/m2 | 1 à 4 | 15° | 30° | 45° |
| 0,30 | ≤ 0,85 | Wz 2 | 35cm | 35cm | 30cm |
Wz 3 | 25cm | 25cm | 25cm | ||
Wz 4 | 20cm | 15cm | 15cm | ||
0,60 |
≤ 0,85 | Wz 1 | 55cm | 30cm | 30cm |
Wz 2 | 40cm | 30cm | 30cm | ||
Wz 3 | 25cm | 25cm | 25cm | ||
Wz 4 | 20cm | 20cm | 20cm | ||
0,95 |
≤ 0,85 | Wz 1 | 45cm | 25cm | 15cm |
Wz 2 | 45cm | 25cm | 15cm | ||
Wz 3 | 30cm | 25cm | 15cm | ||
Wz 4 | 20cm | 20cm | 15cm | ||
Source ITW; data not guaranteed.
| Bulk density ρ | ~ 180 kg/m³ |
| Vapour diffusion (μ) | 3 |
| Nominal value of thermal conductivity λD | 0,042 W/mK |
| Design value of thermal conductivity λB | 0,044 W/mK |
| Compressive stress strength | ≥ 150 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-T4-WS1,0-CS(10/Y)100-TR20-MU3-AF100 |
| Tensile strength perpendicular to the board surface | ≥ 20 kPa |
| Application according to ZVDH regulations | UDP-A |
