Universal Dry Valley

Function and compatibility

  • Provides weathertight ventilation in the roof slope
  • Provides up to 10,000mm2 free area of ventilation
  • For natural, mechanical or soil pipe ventilation
  • Can be used with all concrete and clay plain and interlocking tiles
  • Advantages
    • Dry fix, mortar free system for a long maintenance free life
    • Can accommodate up to a 20 degree pitch variance either side of the valley
    • Can be used on pitches up to 60 degree pitches
    • Unique profile maximises discharge rates
    • Gives a finished appearance of a close cut roof
    Sitework Guide App

    Valleys are one of the most vulnerable parts of the roof. Marley Universal GRP dry valleys provide totally weathertight detailing that are fast and easy to install and compatible with all Marley concrete, clay plain and interlocking tiles.

    Accommodates up to a 20° pitch variation either side of the valley

    Continuous support for the valley through must be provided using ply boards

     Rafter pitch

     Max. valley length

     Min. lap length

     15 to 17°



     17.5 to 22.5°



     22.5 to 29°



     30 to 34°



     35 to 39°



     40 to 44°



     45 to 49°



     50 to 55°



    This table is a guide to the recommended application criteria. It assumes a standard roof intersection of 90° and a roof drainage area of 100m². For applications other than this, specific advice should be sought from our technical department.

    Here at Marley Eternit, we are always on hand to offer practical and experienced support. Select an option below or call us on 01283 722588.