Warm roof - Revision history

Designing Buildings at 07:19, 21 October 2020

2020-10-21T07:19:06Z

← Older revision		Revision as of 07:19, 21 October 2020
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	On pitched roofs, the definition of warm or cold can relate to the entire space below the pitch of the roof, but above the ceiling. This means that a warm roof might be one in which the insulation is installed in line with the rafters (rather than above the roof structure), so that the space under the pitch, ie a loft, attic or other space is insulated and warm. A cold roof in this case would typically have insulation laid above the ceiling so that the loft space below the pitched roof is cold relative to the rest of the property.		On pitched roofs, the definition of warm or cold can relate to the entire space below the pitch of the roof, but above the ceiling. This means that a warm roof might be one in which the insulation is installed in line with the rafters (rather than above the roof structure), so that the space under the pitch, ie a loft, attic or other space is insulated and warm. A cold roof in this case would typically have insulation laid above the ceiling so that the loft space below the pitched roof is cold relative to the rest of the property.

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* Cold roof.		* Cold roof.
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	* Thermal comfort.		* Thermal comfort.

−	[[Category:~~Construction_techniques~~]] [[Category:~~Products_/_components~~]] [[Category:DCN_Product_Knowledge]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Construction_techniques]] [[Category:Products_/_components]]

Designing Buildings at 12:24, 21 November 2017

2017-11-21T12:24:14Z

← Older revision		Revision as of 12:24, 21 November 2017
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−	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. This is as opposed to a 'cold roof' in which the insulation is below the roof structure, and so the roof structure is closer to the outside temperature~~, or an 'inverted roof' in which the waterproofing layer is beneath the thermal insulation rather than above it~~.	+	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. This is as opposed to a 'cold roof' in which the insulation is below, or within the roof structure, and so the roof structure is closer to the outside temperature.

−	~~A vapour control~~ layer is ~~included~~ beneath the ~~insulation to prevent~~ thermal ~~pressure from within the building forcing moisture vapour into the~~ insulation. The insulation is completely wrapped and sealed with waterproofing membranes. In contrast with cold roofs, there is no requirement for roof void ventilation, and there is less of a problem with cold bridging as the structural supports are not interrupted.	+	An 'inverted roof' is a form of warm roof in which the waterproofing layer is beneath the thermal insulation rather than above it.

−	~~This type of construction is usually recommended for flat~~ roofs ~~due~~ to the ~~simplicity~~ of the ~~design and its efficiency – the entire~~ roof ~~structure is insulated~~, ~~providing it with better thermal performance properties than~~ a ~~cold~~ roof.	+	On pitched roofs, the definition of warm or cold can relate to the entire space below the pitch of the roof, but above the ceiling. This means that a warm roof might be one in which the insulation is installed in line with the rafters (rather than above the roof structure), so that the space under the pitch, ie a loft, attic or other space is insulated and warm. A cold roof in this case would typically have insulation laid above the ceiling so that the loft space below the pitched roof is cold relative to the rest of the property.
−		+
−	If the ~~existing roof surface~~ is in ~~good condition, it can be easily modified by clearing away any debris and securing insulation boards~~ with ~~adhesive before laying~~ the ~~flat roof covering over~~ the ~~top.~~	+
−		+
−	~~In practice, it is often too complex to adapt the warm~~ roof ~~method for pitched roofs, as the slope makes the laying and sealing of the vapour-proof layer and insulation more difficult. It should also be considered~~, that the ~~warm roof method will add height to~~ the ~~flat roof~~, ~~meaning that it~~ is ~~often unsuitable for use of balconies~~ and ~~extensions with doors that provide access to the roof~~.	+
−		+
−	~~As with a~~ cold roof~~, the~~ insulation ~~should be considered on~~ the ~~basis of several factors, including:~~	+
−		+
−	* The required U-value (thermal performance) of the roof.	+
−	* What build-up thickness can be accommodated at roof level.	+
−	* The imposed weight load to the ~~deck structure.~~	+
−	* The required fire resistance and acoustic performance properties.	+
−	* The likely traffic experienced by the ~~roof~~.	+

	= Find out more =		= Find out more =
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	* Thermal comfort.		* Thermal comfort.

−	[[Category:Construction_techniques]] [[Category:Products_/_components]]	+	[[Category:Construction_techniques]] [[Category:Products_/_components]] [[Category:DCN_Product_Knowledge]]

Designing Buildings at 12:13, 21 November 2017

2017-11-21T12:13:10Z

← Older revision		Revision as of 12:13, 21 November 2017
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−	When designing a timber flat roof construction, it is important that the designer ensures the appropriate provision of insulation to control both condensation and heat loss through the roof construction.	+	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. This is as opposed to a 'cold roof' in which the insulation is below the roof structure, and so the roof structure is closer to the outside temperature, or an 'inverted roof' in which the waterproofing layer is beneath the thermal insulation rather than above it.
−		+
−	A warm roof is ~~where~~ the ~~sealed rigid~~ insulation layer is laid on top of ~~the rafters~~. This results in the structural deck and its supports being at a temperature closer to that of the building’s interior.	+

	A vapour control layer is included beneath the insulation to prevent thermal pressure from within the building forcing moisture vapour into the insulation. The insulation is completely wrapped and sealed with waterproofing membranes. In contrast with cold roofs, there is no requirement for roof void ventilation, and there is less of a problem with cold bridging as the structural supports are not interrupted.		A vapour control layer is included beneath the insulation to prevent thermal pressure from within the building forcing moisture vapour into the insulation. The insulation is completely wrapped and sealed with waterproofing membranes. In contrast with cold roofs, there is no requirement for roof void ventilation, and there is less of a problem with cold bridging as the structural supports are not interrupted.

Editor at 13:51, 12 November 2017

2017-11-12T13:51:25Z

← Older revision		Revision as of 13:51, 12 November 2017
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	* Flat roof defects.		* Flat roof defects.
	* Interstitial condensation.		* Interstitial condensation.
		+	* Inverted roof.
	* Roofing defects.		* Roofing defects.
	* Stack effect.		* Stack effect.

Editor: Created page with "When designing a timber flat roof construction, it is important that the designer ensures the appropriate provision of insulation to control both condensation and heat loss throu..."

2017-11-12T12:25:01Z

Created page with "When designing a timber flat roof construction, it is important that the designer ensures the appropriate provision of insulation to control both condensation and heat loss throu..."

New page

When designing a timber flat roof construction, it is important that the designer ensures the appropriate provision of insulation to control both condensation and heat loss through the roof construction.

A warm roof is where the sealed rigid insulation layer is laid on top of the rafters. This results in the structural deck and its supports being at a temperature closer to that of the building’s interior.

A vapour control layer is included beneath the insulation to prevent thermal pressure from within the building forcing moisture vapour into the insulation. The insulation is completely wrapped and sealed with waterproofing membranes. In contrast with cold roofs, there is no requirement for roof void ventilation, and there is less of a problem with cold bridging as the structural supports are not interrupted.

This type of construction is usually recommended for flat roofs due to the simplicity of the design and its efficiency – the entire roof structure is insulated, providing it with better thermal performance properties than a cold roof.

If the existing roof surface is in good condition, it can be easily modified by clearing away any debris and securing insulation boards with adhesive before laying the flat roof covering over the top.

In practice, it is often too complex to adapt the warm roof method for pitched roofs, as the slope makes the laying and sealing of the vapour-proof layer and insulation more difficult. It should also be considered, that the warm roof method will add height to the flat roof, meaning that it is often unsuitable for use of balconies and extensions with doors that provide access to the roof.

As with a cold roof, the insulation should be considered on the basis of several factors, including:

* The required U-value (thermal performance) of the roof.
* What build-up thickness can be accommodated at roof level.
* The imposed weight load to the deck structure.
* The required fire resistance and acoustic performance properties.
* The likely traffic experienced by the roof.

= Find out more =

=== Related articles on Designing Buildings Wiki ===

* Cold roof.
* Condensation in buildings.
* Domestic roofs.
* Flat roof.
* Flat roof defects.
* Interstitial condensation.
* Roofing defects.
* Stack effect.
* Thermal bridging in buildings.
* Thermal comfort.

[[Category:Construction_techniques]] [[Category:Products_/_components]]