FLAT ROOF DORMER CONSTRUCTION

1. Installation of new lead flashing dressed into sill and skirt.
   All lead flash to be Code 4 lead, and laid in accordance to lead development association.
2. Treated timber frame constructed using 100 x 50 mm head and soul plates and vertical studs
3. Breathable roofing membrane installed to the full external cottage dormer structure – having a vapour resistance of not more than 0.6MNsg.
4. External quality 12mm heating plywood, or other approved.
5. New dormer cheeks and front tiles to match roof colour existing. Tiles hung vertically on 25 x 38. Preservative treated batten.
6. 100 mm Celotex GA4000 insulation installed in between new 4 x 2 dormer frame structure, Installation to interior wall of vapour married to create thermal barrier.
7. 2 nr 7″ x 2″ header nailed together to create new dormer header.
8. Tri Iso Super 10 Thermal Quilt & Celotex 100mm Insulation Boards to be installed in dormer rafters. Installation of new 3 x 1 timbers to be installed to provide support for 12.5mm plaster board and skim finish.
9. New roof timbers to be structurally calculated to correct size As per structural engineers calculations.
10. New rubber flat roof covering.
11. New fascia to match existing roof colour.
12. New Gutter system to match existing colour.
13. New dormer window as per customer design. New window design A rated as standard.