Better roof insulation

Danny Kearney, Technical Manager of Xtratherm, looks at how the latest innovations within insulation can help developers maximise their return on investment.

"Around a quarter of all heat is lost through poorly insulated roofs which is why a well-designed roof structure can make a crucial difference in the thermal performance of the whole house".

"Before 1975, most homes had little or no roof insulation whilst homes built between 1975 and the late eighties had approximately half the insulation required by today's standards".

"The end result was cold, often draughty properties that were heavy users of energy".

"However, modern roof structures can, with forethought and appropriate selection of insulation materials, create well insulated comfortable homes in addition to providing a valuable marketing tool to developers".

"When dwellings began to be built with roof insulation it was often placed between or over the joists at ceiling level which created a 'cold roof'".

"This meant that the roof space substantially colder in winter than the interior of the building which often resulted in interstitial condensation especially when adequate ventilation wasn't provided and also the requirement to insulate pipes and water storage tanks in the loft space".

"Another major drawback of this type of roof was that the loft area could not be used as living space".

"Potential house buyers are generally looking for maximized use of space because when it comes to selling the house it is floor area that makes the difference".

"Many developers are therefore looking for clever ways of adding living space to a development, without necessarily adding to the footprint of the building".

"The advent of warm roof constructions, where the insulation was taken from the ceiling level and placed along the rafter enables the use of this 'dead' space above the ceiling allowing valuable living area to be added to the previously under-utilized building footprint".

"In this type of construction, the insulation is placed between the rafters, with a second layer placed either above or below the rafter to prevent 'Thermal Bridging' in accordance with the demands for accredited detailing under the new Building Regulations".

"The drive for better performance U-values and a need to maximise available living space, has therefore lead to product innovations by manufacturers focusing on the roof structure".

"Between Rafter".

"The most effective method of creating a thermally efficient roof is to fit insulation between the rafters, either on a new build or refurbishment".

"However, a common problem of fitting insulating in this location is that the depth of rafter restricts the thickness of insulation material that can be used".

"and the rafter spacings can vary in width".

"The solution to this issue comes with the launch of innovative new products such as Rafterloc where the insulation panels, made from high performance Thin-R PIR insulation, feature a slotted mechanism that allows them to lock between the rafters".

"Previously any discrepancies in rafter widths and spacings meant the need for an excessive amount of cutting which could potentially result in loose fitting insulation".

"The slotted design of the panels on Rafterloc ensures that they achieve a tight fit between the rafters even when there is this slight variation in width".

"Where the material needs to be cut, slightly over-sizing the width of material will ensure a tight fit when installed".

"The product itself is manufactured from our CFC/HCFC free Thin-R core with low emissivity foil facings so is capable of achieving excellent thermal performances".

"Another advantage of the system is that because the panels 'lock' into place between the rafters and don't 'slump' like other non-rigid insulation materials, the required 50mm ventilated airspace between the insulation and sarking felt is assured".

"Where Rafterloc is used with an approved permeable roof tile underlay unvented airspace can be reduced to 25mm".

"The product is supplied in 360 and 565mm widths to suit standard rafter spacings and 100mm thickness".

"Each panel, because it is slotted, then has a width variation of between 20 - 30mm to allow a tight fit between rafters".

"The bottom line".

"Both developers of existing properties and new builds are now realizing the benefits of creating well insulated roof structures, both in terms of achieving the latest regulations and maximizing return on investment".

"By developing innovative insulation products, the industry has been able to provide developers with high performance insulation products that helps them add living space to their properties".

"In terms of the bottom line, any developer knows that the best way of adding value to a property and therefore maximizing their return is by adding square footage".

"New products such as Rafterloc are helping developers do just that with the homeowners benefiting from well insulated comfortable homes".

"As developers continue to face added pressure to differentiate their properties a liveable loft space is rapidly becoming a crucial marketing tool.".

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