For additional stability you can also use steel joists that are built into one or both of the walls.
Flat roofing warm flat roof fascia detail.
A vapour control layer must be used below the insulation.
This is where the insulation is typically packed between the rafters.
Traditionally domestic flat roofs use two or more built up layers of bituminous felt as their weather proofing.
Cad details document name pdf dwg download all cad construction details 37 1 mb 3 4 mb mc01 identification of roof areas 694 kb 167 kb mc01a single layer underlayment 678 kb 302 kb mc01b double layer underlayment 711 kb 322 kb mc02 vent pipe flashing 626 kb 349 kb mc03 valley.
A timber decking is then constructed and its weight supported by the joists.
Whatever new flat roof covering you choose epdm rubber kemper liquid rubber triflex mariseal etc.
Good question theoretically when building a warm roof the vaper control layer goes on the warm side of the insulation.
From there the flat roof system you choose will determine the materials you apply.
Flat roofing is a popular choice for garages homes garages extensions and many other types of buildings.
Having a manual for warm flat roof construction with details and a summary of rules to follow helps.
This approach uses insulation with no air gap either immediately above or below the roof deck.
Single ply membranes are also used but are particularly suitable for larger roofs.
The basic construction of a flat roof starts with roofing timber that is laid across two upright items usually two walls.
A 50mm air gap must be left above the insulation and allowance for venting must be made at roof perimeters.
If you put insulation under the decking and between the joists you lower the temperature of the decking and lower the due point thus bringing it closer to the danger point of being in the building.
Liquid applied systems such as glass fibre were introduced and are now quite widely used.
Front fascia flat roof detail.
If the specification of the insulation is not correct you could have problems.
This option avoids the requirement to ventilate the roof.
Flat roof joists spanning the shorter length of the roof form the load bearing members of the structure.
The roofs have a timber frame as the supporting structure.
In this video our principal surveyor steven dickinson explains problems with insulating a roof using the warm and cold roof construction methods.
Underneath the basics flat roofs are usually constructed with a ceiling nailed to joists which support a deck usually wood in residential construction a vapor barrier insulation and a roof board.