Joist Seals


Manthorpe Joist Seals solve the problem of air leakage around the timber joist and effectively mount the joist in the wall, eliminating the need for clumsy joist hangers.

  • Description & Key Features

    Product Description

    The G913 range is designed to solve the problems of air leakage associated with built in timber joists. The box is placed over the end of the joist and built into the inner leaf of the external wall construction with a foam gasket sealing up the penetration. As the timber dries out and shrinks the seal is still maintained between the box and the masonry, thus preventing air leakage into the cavity.

    Located around the inner flange are a number of push out pockets for the location of restraining straps as required.

    Key Features

    • Substantial time saving on site
    • Compliant to Building Regulations Part L (Air Leakage)
    • 1 Hour Fire Tested (Warrington Fire Research) in party wall detail
  • Technical

    Fitting Requirements

    Push joist seal onto the end of each joist and build into the blockwork.

    Restraining straps can be fitted through the seals as required.

    If using joists smaller than the joist seal or timber-engineered joists the gaps around the joist should be filled to prevent movement and maintain the thermal and fire performance of the wall.


    Warrington Fire Certificate No. 142893 - Manthorpe Joist Seal.pdf

    Ceram Air Tightness Test Report No. SW031-04 - Manthorpe Joist Seal.pdf

    Regulations & Standards

    Building Regulations Part L

    Robust Details: Part E: Resistance to the Passage of Sound.
    (Appendix A, Pages 2-3).

  • Specifications

    Size Information

    Height 302mm
    Width between 38 and 180
    Block size from 100 to 140


    Foam Gasket Seal


    Translucent White

    Quantity Information

    To order