Warm roof. On flat roofs, a 'warm roof' is one in which the insulation layer is laid on top of roof structure. This results in the structural deck and its supports being at a temperature closer to that of the building's interior..
Keeping this in consideration, which is best warm or cold roof?
The construction of a warm roof, the insulation sits on top of the rafters. Warm roof insulation ensures the entire roof structure is insulated, meaning a warm deck roof is more energy efficient than a cold roof.
Also, can you walk on a warm flat roof? For a DIY flat roof installation, the warm roof construction method is by far easier, as there is less that can go wrong. This type of construction method is not recommended if you wish to walk on the roof once completed. Because you are effectively walking on the insulation, the roof will feel soft underfoot.
Similarly, you may ask, do you need to vent a warm flat roof?
In flat roof construction thermal insulation can be placed above and below the structural roof deck or waterproofing layer. When placed below the structural deck; ventilation is required to the underside of the deck. The enclosed void of a warm pitched roof does not require to be ventilated.
How does a warm roof work?
A warm roof is a type of roof construction which has an insulation layer above the rafters, and immediately below its weatherproof membrane. A warm roof construction allows heat to be conserved within a property – without the need for a ventilation system.
Related Question Answers
What is a cold roof design?
A cold roof is roof in which the thermal insulation layer is located between the ceiling joists meaning that everything above the insulation, such as the rafters, and any roof space, will be colder than the living space below it.How do you ventilate a cold flat roof?
The cold deck roof as shown above has the insulation at ceiling level and must have a ventilated cavity of at least 50mm. The cavity must be ventilated on two opposing sides by a continuous ventilation gap of 25mm. A vapour control layer is required on the warm side of the insulation to combat condensation.How thick is a warm flat roof?
Flat roof insulation thickness The typical U-value of an existing, uninsulated flat roof is 1.5W/m2K. The target should be to achieve a U-value of 0.25W/m2K or better. To achieve this, add 100 to 160mm of insulation above the structural deck (dependant upon insulant conductivity).What is inverted roof?
An inverted roof, also referred to as a 'protected membrane' or 'upside down' roof, is form of flat roof in which the waterproofing layer is beneath the thermal insulation rather than above it. For more information, see Specifying insulation for inverted roofs.Are flat roofs hotter?
Flat roofing is quick to install In our experience, flat metal roofing is one of the quickest and most cost-efficient types of roof installation. And just like other types of metal roof installation, a flat metal roof is no hotter than a house with any other type of roof. In fact, it can even be cooler!How do you insulate a pitched roof?
The best way to insulate a pitched roof is by installing insulation between and above the rafters. This approach can be used to create an unventilated roof structure, helping to keep out unwanted drafts. As there's no insulation below rafters, headroom is maximised, creating more useable space.How does a cold roof work?
A cold roof is one where the roof deck and shingles remain a similar temperature to the outside air. Through a ventilation and insulation system, heat does not escape through the roof. A warm roof allows for snow directly touching the roof deck to heat up. It will then melt and run down the roof.Why is my roof damp?
Condensation comes from the moisture in the air and is caused by too much moisture in the air for a certain temperature. Condensation forms when warm, moist air touches a surface that is colder than the dew point of the warm air. Condensation is a common sign of inadequate insulation and/or ventilation.How do you insulate a flat roof from the inside?
Warm deck insulation (warm roof) As the diagram shows this involves putting in the insulating materials on top of the roof. The process starts by laying 100mm or more of rigid board insulation on top of the waterproof roof membrane. Doing this protects those layers underneath from the extreme weather elements.How do you provide ventilation at the eaves where insulation is between the rafters?
There must be a continuous 50mm gap above the between-rafter insulation which is vented to the eaves and the ridge. When locating the insulation between the rafters, it is common to include 50mm battens attached to the rafters in the ventilation zone up to which the insulation can butt.Do you need an air gap for insulation?
Solid walls however must be faced with an insulation product, so they can often eat into floor space depending on the thickness of the insulation as an air gap is needed to prevent condensation and moisture build up. Insulation with a moisture barrier means you don't need to leave an air gap during installation.What is the difference between a warm and cold roof?
You create a warm roof, or a cold roof, simply by applying the layers of the roof in a different order. In a cold roof, the insulation is applied between the rafters, but in a warm roof, the insulation is applied on top of the existing roof surface.Can I turn my flat roof into a roof terrace?
In most cases, an existing flat roof will be used to create a roof terrace. In concrete or steel frame buildings, the existing flat roof is likely to have enough structural strength for a terrace, because the roof is constructed like the floor structures below.Can you sit on a flat roof?
The majority of flat roofs are not built to withstand the pressure of being walked on, and doing so may cause weakness over time – not only making it a health hazard, but also putting your investment at risk.What is a hot roof?
Basically, the term “cold roof” refers to a traditional roof, or vented roof, while “hot roof” refers to a roof that is not ventilated and which has foam insulation attached directly to the roof sheathing. 
