IKO Undertile Felt 1F


The product can be used within ventilated pitched roofing.


A bitumen impregnated and fibre coated base undertile felt which is combined with a layer of jute hessian embedded in the coating on one side of the base to act as reinforcement. Formerly known as BS 747 1F, the product is a traditional under tile or under slating material for ventilated pitched roofs.

IKO has a range of essential system components, specifically tailored to facilitate the use of the IKO Undertile Felt within pitched roofing:

  • IKO Eaves Protection Strip (available separately) – available as 330 or 500 mm wide strip of high performance polyester based roofing (BS 8747 Type 5U) designed to give long term protection at the eaves position of a pitched roof arrangement.
  • IKO Flash (available separately) – a lead-free flashing system made from modified polyethylene compound, with integral aluminium mesh reinforcement and faced with a fine grey mineral. IKO Flash can be used for abutment flashings and pitched valley linings.

Features and benefits:

  • Weather resistant - acts as a secondary barrier to liquid water, wind driven snow and debris.
  • Tried and tested - proven performance.
  • Resistance to wind loading - heavyweight membrane, results in a good performance against wind uplift.
  • CE marked.


The product can be used within ventilated pitched roofing.

General information

Uniclass 2015

Pr_25_57_08_75 Reinforced bitumen roofing sheetsPrimary


J41/135 Single layer reinforced bitumen membrane cold deck roof covering

Specification data - Reinforced bitumen roofing sheets

Product Reference

IKO Undertile Felt 1F

Standard product features

Technical characteristics:

  • Composition: Bitumen.
  • Form: Roll.
  • Colour: Sanded/ black.
  • Length: 15 m.
  • Width: 1 m.
  • Roll weight: 23.5 kg.
  • Reaction to fire (to EN 13501-1:2007): F.
  • Resistance to water penetration (to EN 1928): W1.
  • Water vapour transmission (to EN ISO 12572): 15 m Sd.
  • Tensile strength (to EN 12311-1): Longitudinal >600 N. Transverse >300 N.
  • Elongation (to BS EN 12311-1): Longitudinal: >2%. Transverse: >3%.
  • Tear resistance (to BS EN 12310-1): Longitudinal and transverse: >200 N.
  • Pliability (to EN 1109): <-20°C.
  • Wind loading battened lap: ≤345 and ≤250 mm batten gauge: Zones 1-5.

Similar products from IKO PLC