P333-I

Underlayer bituminous felt

Application:

Undercoating bituminous felt in multi-layer flat roof coverings on stable substrates
Undercoating bituminous felt in pitched roof coverings
Damp-proof insulation of buildings

Properties:

Traditional undercoating bituminous felt with building cardboard reinforcement
Fixed with asphalt adhesives and mechanically

Available packaging:

15 m

Type of reinforcement	building cardboard
Top finishing	fine-grained
Low temperature flexibility	≤ 0 °C
Width	≥ 0,99 m
Straightforwardness	≤ 20 mm per 10 m roll length
Reaction to fire	class E
Watertightness: waterproof at a pressure	≥ 2 kPa (method A) ≥ 10 kPa (method A)
Basis weight	2,0 kg/m² ± 10%
Durability: - durability after artificial ageing, watertightness - durability against chemical	≥ 2 kPa (method A) acc. to annex A of the standard EN 13969
Maximum tensile force: - longitudinal extension - transversal extension	500 ± 300 N/50 mm (3 ± 2) % 400 ± 200 N/50 mm (3 ± 2) %
Resistance of the joint: - shear strength • longitudinal joint • transversal joint	400 ± 200 N/50 mm 500 ± 300 N/50 mm
Resistance to tearing: - longitudinal - transversal	125 ± 75 N 125 ± 75 N
Resistance to static loading	≥ 5 kg (method B)
Resistance to impact	≥ 250 mm (method A)
Dimensional stability	≤ 0,5%
Reference document(s)	EN 13707:2004+A2:2009 EN 13969:2004 EN 13969:2004/A1:2006

On roofs with a substrate sloped from 3% to 20%, two layers of NEXLER P333-I bituminous felt and a layer of top bituminous felt are required. In individual roof covering layers, the bituminous felt sheets should be shifted relative to each other by 1/2 of the sheet width in the case of two-layer roof covering, and by 1/3 of the sheet width in the case of three-layer roof covering.
A roof protected with one layer of bituminous felt should be covered with a top covering made of roof tiles, metal roof tiles, etc. Within a month after installing the bituminous felt.
Do not carry out insulation work during strong winds and precipitation.
The substrate should meet the following requirements:
- dry substrate (without visible traces of moisture and darkening caused by moisture, the humidity of the concrete or cement finishing coat substrate must not exceed 6% and the humidity of the plank substrate must not exceed 21%),
- clean substrate (the surface is free of dust, oil stains, grease and other contaminants),
smooth substrate (local unevenness and cavities in the surface of concrete do not exceed ± 5 mm),
- even substrate (the gaps between the surface of the substrate and a 4 m long patch placed on the concrete substrate do not exceed 10 mm),
- roof slope inclination min. 3%.
Before installing NEXLER P333-I bituminous felt on old bituminous covering, concrete substrate or OSB, the substrate should be primed with solvent asphalt agents, e.g. NEXLER Penetrator G7 or water-based asphalt preparations, e.g. NEXLER BITFLEX Primer. Substrates made of underlayer bituminous felt do not require priming.
NEXLER P333-I bituminous felt should be attached by gluing to a concrete substrate or to an old, renovated bituminous felt roof covering. The bituminous felt can be installed using nails and washers directly to the wooden substrate, provided that the overlaps of the felt are glued with asphalt adhesive, which should also be applied to the visible nails and washers.
NEXLER P333-I bituminous felt should be glued using only asphalt adhesives in accordance with the recommendations of their manufacturers. When using cold-applied asphalt adhesives, e.g. NEXLER Cold Glue, ensure sufficient time for the solvents contained in the applied layer of asphalt adhesive to evaporate (from approx. 30 minutes to 2 hours in summer and more in periods when the ambient temperature is approx. +10°C). NEXLER P333-I bituminous felt and cold-applied asphalt adhesives for gluing bituminous felt should not be used at ambient temperatures below +10°C. The application temperature of hot-applied asphalt adhesive should be between +160°C and +180°C.
The bituminous felt sheets should be joined with overlaps of no less than 10 cm in width and the length of the glued roofing felt section must not exceed 8 m. On roofs with a slope of less than 30%, attach the roofing felt strips parallel to the eaves and on roofs with a slope of more than 30% perpendicular to the eaves.
Before use, please read the application details in the product's Technical Data Sheet.