What is a warm roof NZ?

A warm roof (for low slope roofs) is “a roof where the roof insulation is installed on top of the structure” i.e. insulated from the outside of the building. … 713), insuring it meets New Zealand building code requirements.

What is a warm roof system?

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.

Is a warm roof better than a cold roof?

A warm deck roof can be very simple to install and offers higher thermal performance at the cost of a higher roof profile. … Warm roof insulation ensures the entire roof structure is insulated, meaning a warm deck roof is more energy efficient than a cold roof.

What is the main reason for using a warm deck roof?

Warm deck roof:

Contrasted with the cold deck roof, this construction has a much lower risk of condensation as the void will be of a comparable temperature to the roof. Ventilation is also not required with this type as the design works by conserving heat.

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Does a warm roof need ventilation?

A warm flat roof usually does not require ventilation. What space do I need to allow for the ventilation? To ensure sufficient ventilation, enough space must be provided to allow for the movement of air, preventing the risk of condensation forming within the roof.

What are the advantages of a warm roof?

Advantages of Warm Roof

Insulation on the entire roof structure keeps all the components in the roof space at the same temperature. Therefore, there is reduced thermal bridging which prevents heat loss from the living room. Houses with warm roofs are less expensive to keep warm than those with cold roofs.

Can you turn a cold roof into a warm roof?

Cold bridging occurs when there is a continuous path created through the insulation. 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.

Does a warm roof need a Vapour barrier?

Warm deck flat roofs can be constructed on most modern construction material types such as concrete, timber and timber based sheets. … A vapour barrier will then need to be installed to reduce condensation in the roof structure.

Can you put insulation between joists on a warm roof?

Why you can’t just insulate between the rafters

The general advice we give is that you should always insulate between and above the rafters (warm roof) or between and under the rafters (cold roof).

How does a warm flat roof work?

A warm flat roof or a built-up roof (BUR) is one where all the insulation is above the joists/deck, making them part of the warm fabric of the building. The insulation is immediately below the waterproofing layer. The vapour control layer is above the decking but below the insulation.

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How much does it cost to insulate a warm roof?

When insulating one, you’re aiming for a value of 0.25 W/m2K or less. To achieve this, you should insulate your flat roof with insulation boards totalling around 150mm thickness.

What is a warm roof conservatory?

A ‘warm roof’ conservatory has an insulated tiled roof system that’s made with composite tiles rather than slate. Warm roofs are designed to look and feel like a ‘real roof’ and allow your conservatory to become more like an extension.

Do you vent a warm deck roof?

Warm Deck – this is where the insulation is placed on top of the rafters/joists and the roof covering is then placed over the insulation. No ventilation is required for these types of roofs.

Does a cold roof need to be ventilated?

Cold roof voids are typically required to be ventilated; however, where vapour permeable underlays are specified, this requirement may be relaxed. The enclosed void of a warm pitched roof does not require to be ventilated.

How do you ventilate a warm pitched roof?

A sealed warm roof construction can also be achieved by creating a 50mm ventilated air gap between the surface of the insulation and the undertile lining to allow water vapour to be safely removed from the roof construction.