least 1233mm of channel on either side.
5. The 25mm sections are cut at these points using tin snips
6. The wider side of the channel is bent inwards at right angles to form the sides and
bottom of the frame.
!! Note: ensure that the sides and bottom sections of the frame are perfectly square.
Frame Fabrication
The (25mm) horizontal 'lips' of the side and bottom sections will overlap; those of the bottom
section should sit on the inside of the frame. Line the inside of the channel with 63mm wide
strips of Termo-flex insulation.
Frame Side and Bottom sections: a complete length of channel
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