This design guide is intended to help specifiers understand the factors that need to be considered when approaching a flat roof project.We can assist you with any aspect of the design, and provide a no obligation service for both new build and refurbishment projects.Flat Roof Design Guide9199 bauder.co.uk? Thermal Design 200? Deck Construction Types 202? Fire Protection 202? Wind Load Design 203? Falls and Drainage 204? Locating Equipment 204? Design for Safe Access 205? Refurbishment Projects 206? Resolving Problematic Refurbishment Details 208FLAT ROOFDESIGN GUIDE

THERMAL DESIGNThermal design is concerned with the flow of both heat and water vapour through the roof construction and their subsequent effect on the performance of the roof and the various components in the system. The designer therefore needs to consider the amount of insulation required to control both heat loss and condensation.In the case of a flat roof, insulation is usually in the form of either a rigid board above the deck, or a fibrous quilt immediately above the ceiling, depending on the type of roof construction.There are three recognised designs of flat roof construction; warm, cold, and inverted.Warm RofIn a warm roof construction the principal thermal insulation layer is located above the structural decking, resulting in the structural deck and support structure being at a temperature close to that of the interior of the building. It is necessary to incorporate a vapour control layer beneath the insulation in order to prevent moisture vapour being forced into the insulation through thermal pressure from within the building. The waterproofing membranes are placed over the insulation to completely encapsulate it.There is no requirement for roof void ventilation, and cold bridging through the system is easier to eliminate because there are no interruptions from the structural supports as there is in a cold roof construction.Although this type of construction is normally continuously supported, it can also provide a flat and stable structure directly over most profiled metal decking and is generally recommended for all flat roof applications due to the simplicity of its design.1234561. Waterproofing 2. Rigid Insulation3. Vapour Control Layer4. Structural Deck (eg plywood)5. Roof Void6. Ceiling7. Support StructureCOLD RofIn cold roof construction, the principal thermal insulation layer is located below the structural decking. The concept for this type of design is usually associated with roof constructions having independent ceilings to support the insulation. Adequate ventilation must be provided between the insulation and the underside of the roof deck to prevent the risk of interstitial condensation forming within the construction.A cold roof design is not generally recommended for new build flat roof applications due to the added requirement for roof void ventilation and the difficulties in preventing cold bridging through the system.If an existing cold roof is to be refurbished, consideration should be given to converting the design to a warm roof, or incorporating new insulation into the roofing system to improve thermal performance. However, if the latter is the case, thermal calculations will be required in order to analyse the likelihood of condensation formation.1234561. Waterproofing2. Structural Deck (eg plywood)3. Support Structure4. Ventilated Ceiling Void5. Quilt Insulation6. Ceiling7. Cross Ventilation77Manchester UniversityTypical Bauder warm roofbauder.ie200