New Roof Option &nbsp;- 20 Year System Insurance Backed Guarantee Strip off in stages the existing roofing system and assumed plywood decking, back to the assumed timber purlins, which we assume are in good order and structurally sound. The old ply would we carefully removed, however, depending upon how these were originally secured and the strength of the support structure they may have to be prized out, we make no allowance for repairing any cracks this could cause in the ceiling below.&nbsp;&nbsp;<br />
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Supply and mechanically fix new 18mm thick roofing grade plywood decking to the existing joists. The new ply would be screwed rather than nailed, to try and avoid cracking the ceiling below. Then apply the following Index Building Products Limited, torch-applied, high performance felt system which is covered by a 20 Year Insuranced Back Guarantee. Primer: &nbsp; Indever Bituminous primer and allow to cure Vapour Barrier: Defend Alu felt Insulation: &nbsp;110mm thick PIR Boards laid in Index Adhesive. &nbsp; &nbsp; &nbsp; &nbsp;A 110mm timber batten would be secured around the open eaves of the roof &nbsp; &nbsp; to provide a framework within which the new boards would be laid, this will &nbsp; &nbsp; form a solid edging to prevent the ends of the new insulation boards from &nbsp; &nbsp; &nbsp;being crushed. Base Layer: &nbsp;3mm Helastopol P felt Cap Sheet: &nbsp;Proteaduo Mineral Surface felt Details: &nbsp;Form all perimeter upstands, kerbs, welted drips and new to old junction, &nbsp; &nbsp;together with any other associated roofing details to complete the new roof &nbsp; &nbsp; to the Guarantee Standard. &nbsp; &nbsp;The new felt system would be dressed up and over the parapet wall &nbsp; &nbsp; &nbsp;between this roof from the lean to roof. &nbsp; &nbsp; The overall roof area (flat) is some 72 m2&nbsp;