Construction of Giresun Wastewater Treatment Plant  Tender Dossier Volume 3 Employer’s Requirements Section 09: Building Works  15 of 24 9.1.19.5 Heat insulation boards  9.1.19.6 Lightweight Screed  9.1.19.7 Metal Roof and Wall Sheeting  9.1.19.8 Flashings and Rainwater Outlets  9.1.19.9 Roof Lights  The membrane shall be continuous and take up abutments and pipes to above the insulation layer. Ex- posed membrane shall be solar protected. The waterproof membrane shall be dressed and bonded into  rainwater outlets and under flashings. The insulation board for buildings shall be not less than 25 mm thick closed cell extruded polystyrene  loose laid in a single layer with tight staggered butt joints in accordance with the manufacturer’s in- structions. The board shall be trimmed to fit any fillets used under the waterproof membrane.  Lightweight screeds shall be laid in accordance with the manufacturer’s instructions and to falls not  less than 2.5% with an minimum thickness of 50 mm. The screed shall be laid in two courses and in  bays not exceeding 15 m², laid alternatively and finished with a mortar topping of 1:4 cement/sand  mortar. Immediately after laying, the screed shall be protected from wind and sunlight and cured for 7  days.  When required, joints shall be formed in the insulating screed. A vapour barrier and ventilation to the  bituminous roof sheeting shall also be provided. The Contractor shall submit samples and references  to the Engineer for his approval of the materials he intends to use before ordering these materials.  Trapezoidal type sheeting, including flashings, copings and the like, for roofing and wall cladding  shall be a hot dip galvanised steel substrate with zinc coating mass G 350 to EN 10143. It shall be  coated on both sides with approved colour similar bonded to the sheeting, as a protection against cor- rosion and a type and quality approved by the Engineer.  With a span of 1.0m the sheeting shall be able to bear without plastic deformation, assuming a safety  coefficient of 1.8:  The deflection of the sheeting with a span of 1.0m and a concentrated load of 1.5kN at mid-span shall  be less than 10mm. The sheeting and the fixings thereof shall be able to safely withstand uplift forces  from wind of 0.75kN/m² with a span of 1.0m.  The sheeting shall not be scratched, stained, distorted or have any other defects. The sheeting shall  without any maintenance and under the local conditions not be adversely affected by corrosion.  Flashings shall be sheet aluminium neatly cut to the width and length required. The aluminium shall  be carefully bent using a slightly rounded former so as to avoid surface cracking. Where surface fixing  is required, the sheet shall be pre-drilled and fixed with stainless steel screws to proprietary fixings or  hardwood grounds let into the surface of the base concrete or brick work.  Roof lights shall be of clear plastic confirming to TS EN 1873. Roof lights shall be permanently fixed,  and shall not be able to be readily interfered with by unauthorised persons. The mounting shall be to  up stand kerbs cast into the roof slab.  a uniformly distributed load of 0.75kN/m²   a concentrated load of 1.5 kN at mid-span.  9_Vol3_d4.3_Section 9 building works_en_GIR_rev6.docx 