Rigid Frame Formers


The Manthorpe Rigid Frame Former can be used in place of dummy timber frames – and beat more traditional methods of window construction on all counts.

  • Description & Key Features

    Product Description

    The Manthorpe Rigid Frame Former can be used in place of dummy timber frames – and beat more traditional methods of window construction on all counts.

    Strong, extremely simple to install and available in a multitude of widths, the product has been designed to improve efficiency, speed up installation and save man hours.

    Use of the Rigid Frame Former eliminates the site clutter that arises from dummy timber frames, which are prone to damage when left lying around.

    The product provides a framework for the masonry construction around the window aperture and remains in place as a base for the window frame.

    The Manthorpe Frame Former meets all current building regulations and achieves the required thermal break at the reveal of the window and door openings when fixed to allow a 30mm overlap into the cavity. This applies to sills, doors and rebated reveals.

    Ready Assembled or Flat Packed

    Choose the option that suits you best – just one phone call to Manthorpe and we can supply either ready assembled frame formers or cut-to-length, palletised flat packs.

    Easy to transport and easy to store on-site, the flat pack version has proven to be extremely popular in tests, reducing clutter (no more piles of frames) and leading to quicker, better organised ways of working. Assembly is easy and fast – just click to fit.

    Rigidity Ensured

    Quick-to-fit corner braces and horizontal battens, secured with self-tapping screws, ensure that rigidity is maintained. For larger doors and windows, where extreme rigidity is required, a diagonal brace is also provided. Braces and battens are re-usable.

    Project Specific Take-Off Service

    For larger projects we offer builders, architects and developers a project specific take off service. Simply let us have the information or drawings and we will calculate the size of the window openings and supply Manthorpe Rigid Frame Formers specific to that particular development, streamlining operations, saving more time and increasing efficiency even further.

    As well as windows and doors Manthorpe also offers P, T and Q shaped frames. With these larger frames we recommend that they are transported flat pack for reasons of safe delivery.

    Key Features

    • The rigid box design allows the cavity walling to be built up to the frame former without the need of manufacturing dummy window formers
    • Allows the cavity closer to be tied into the masonry construction.
    • Provides a thermal break to the cavity
    • Acts as an effective DPC barrier
  • Technical

    Fitting Requirements

    Brick up the cavity wall to sill height in the conventional manner and place the preformed Rigid Frame Former in the correct position.

    Continue to brick up wall construction using a fixing tie every third course or every 225mm in alternate internal and external construction.

    Once completed, remove all corner strengtheners and top brace.



    Regulations & Standards

    BS 5250:2011 Control of condensation in buildings.

    Approved Document L1 & L2:
    Conservation of fuel and power.

    NHBC Technical Guidance 6.7:
    Doors, Windows & Glazing

    BRE Digest Report 262: Thermal Insulation: Avoiding Risks.

    BRE Information Paper IP 1/06: Thermal Bridging at Junctions & Openings

  • Specifications

    Size Information

    FF - made up to spec
    FP - flat pack assemby

    G280: double glange 75mm to 130mm cavity widths

    G282: single flange 75mm to 130mm cavity widths


    Extrusion: UPVC

    Foam: Expanded Polystyrene



    Quantity Information

    To order