Consider geography budget and use for the roof to determine the best option.
Cold deck flat roof specification.
The definition of a flat roof according to bs 6229 is having a pitch less than 10 o to the horizontal however some in the industry would consider up to 15 o as their definition of a flat roof.
The epdm rubber roof membrane is then installed using the contact adhesive onto the deck.
Thickness varies according to the manufacturer s specifications.
The insulation is placed below the waterproof covering and is either mechanically fixed or bitumen bonded on to the top of the deck.
The insulation boards in an inverted warm deck are laid over the structural deck and the waterproof covering.
This is placed over the roof joists and an board normally external ply is laid on top.
From there the flat roof system you choose will determine the materials you apply.
Others would treat even steeper pitches as flat roofs.
In bs 6229 a roof is defined as flat if it has an overall pitch of 10 degrees or less.
Inverted warm deck roof.
How are flat roofs defined.
The 18mm roof grade deck is then fixed on top of the rafters leaving suitable air flow between the insulation and the deck.
Usually flat roof constructions are defined as either cold or warm depending on how the thermal insulation is positioned in the construction.
The sandwich warm deck roof is the most common type of flat roof.
In this case ventilation is required and the roof can still become wet with condensation which may cause materials to decay.
Thickness varies according to the manufacturer s specifications.
The two variations of flat roof.
This is placed over the roof joists and a board normally external ply is laid on top.
When building a flat roof it is vital that a degree of falls is built into the construction to ensure rainwater run off.
Ventilated roof void.
General when constructing flat roofs please consider the following.
There are two types of flat roof.
Flat roof u value 0 18 w m2k 2 warm deck flat roof the type of insulation for this is usually of a rigid type and the thickness will vary depending on the manufacturer s specifications.
If insulation is installed below the flat roof deck this is called a cold roof.
A note to consider before construction.
The roof covering is then laid over the ply.
This is known as a cold roof because the roof deck and roof space are close to the external air temperature.
Materials used must be suitable for use in flat roofs roof needs to achieve an external fire rating vapour barriers should be used flat roofs should be.
Cold roofs have the waterproof layer placed directly onto the roof deck and the insulation inside the roof just above the ceiling.
The cold deck roof as shown above has the insulation at ceiling level and.
Cold deck roof construction.
Cold deck the thickness of insulation required will vary depending on the material you decide to use and the manufacturer s specification.
