Flat Roof Dormer Construction
FLAT ROOF DORMER CONSTRUCTION
- 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.
- Treated timber frame constructed using 100 x 50 mm head and soul plates and vertical studs
- Breathable roofing membrane installed to the full external cottage dormer structure – having a vapour resistance of not more than 0.6MNsg.
- External quality 12mm heating plywood, or other approved.
- New dormer cheeks and front tiles to match roof colour existing. Tiles hung vertically on 25 x 38. Preservative treated batten.
- 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.
- 2 nr 7″ x 2″ header nailed together to create new dormer header.
- 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.
- New roof timbers to be structurally calculated to correct size As per structural engineers calculations.
- New rubber flat roof covering.
- New fascia to match existing roof colour.
- New Gutter system to match existing colour.
- New dormer window as per customer design. New window design A rated as standard.