1F Undertile Slaters Felt

The Traditional Choice for Professional Roof Underslating
While modern breathable membranes have grown in popularity, traditional bitumastic 1F slaters' felt remains the preferred choice for thousands of contractors across the UK. It delivers reliable, heavy-duty secondary protection beneath tiles or slates, catching any wind-driven rain, snow, or dust that breaches the primary roof covering.
Formerly classified under BS747 Type 1F, this product complies with strict British Standards for open rafter roofing systems. Thanks to its dense, multi-layer composition, it also functions effectively as a dependable vapour retarder in built-up flat or pitched roofing systems.

• Hessian Reinforced Base: Built on a tough felt fibre base woven with open-weave hessian for excellent tear resistance during installation. 
• Premium Bitumen Coating: Extensively saturated and coated with heavy bitumen to form an impermeable water barrier. 
• Sanded Anti-Slip Surface: Surfaced with a fine layer of sand to reduce slippage during handling and to prevent the roll from sticking to itself in transit. 
• Cold Vent Optimization: Perfectly suited for standard cold, ventilated loft spaces and traditional timber rafter setups. 
• Proudly UK Manufactured: Produced to high standards of quality control and material consistency.

1. Rafter Setup: Ensure timber rafters are securely fixed. 1F felt is explicitly designed for open rafter layouts. 
2. Lay Horizontally: Start at the bottom of the roof (the eaves) and unroll the felt horizontally across the rafters.
3. Allow a Slight Drape: Do not pull the felt completely taut. Allow a slight drape (roughly 10-15mm) between the rafters to allow any water to flow freely down to the guttering away from the timber.
4. Overlay Requirements: Secure successive layers with appropriate horizontal and vertical overlaps (typically 150mm), nailing into the rafters using galvanized extra-large head clout nails.
    
   Ventilation Note: Because 1F is a traditional non-breathable bitumastic felt, ensure your roof space is equipped with adequate ridge, eave, or tile ventilation to manage condensation