Roof space – no insulation

Causes

Insulation was not a requirement when the house was built (or has never been installed)

Loose-fill insulation has been shifted by wind or activity by house occupants or tradespeople, or insulation has been removed when work done on the house

Listed under: Interior, insulation, Roof, roof space, wind

Cause

Insulation was not a requirement when the house was built (or has never been installed)

Repair

  • install insulation to all roof spaces where practicable

  • for installation guidance (including how to install around recessed downlights), see the standard NZS 4246:2016 Energy efficiency - Installing bulk thermal insulation in residential buildings. This can be downloaded at no charge from the Standards New Zealand website

  • the schedule method in Building Code Acceptable Solution H1/AS1 5th edition amendment 1 shows the minimum construction R-levels required in new building work. Although installing insulation in an existing house that has none is not a legal requirement (except for rental houses, under separate law), you can use H1/AS1 as guidance for an appropriate level of insulation to aim for where possible

  • where the roof space is fully accessible, fit bulk insulation between and over ceiling joists, with no gaps or folds

  • where the roof space is only partly accessible and segment or blanket-type insulation cannot be fitted by hand, engage an experienced specialist contractor to install blown-in, loose-fill insulation

  • with skillion roofs (pitched roofs where the ceiling lining is parallel and close to the roof cladding) options include:

    • fitting battens under the existing ceiling, installing insulation and a new ceiling lining

    • building a suspended or dropped ceiling and including insulation (this can only be done if there is sufficient height)

    • removing the existing ceiling lining and installing insulation – the most cost-effective time to do this is when the lining is being replaced

    • removing the roofing and installing insulation, then replacing or reinstalling the roofing – the most cost-effective time to do this is when the roofing needs to be replaced

  • you can find useful information in the BRANZ House Insulation Guide

  • funding is available to help pay for insulation in the home of low-income people. See the government’s EECA website for details

  • all private rental properties must have thermal insulation installed in ceilings and under suspended floors where it is reasonably practicable to install it. This is a requirement under the Healthy Homes standards

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Cause

Loose-fill insulation has been shifted by wind or activity by house occupants or tradespeople, or insulation has been removed when work done on the house

Repair

  • top up areas where existing insulation is no longer sufficient but is still in good condition. If topping up with new loose-fill insulation, engage an experienced specialist contractor

  • where existing insulation is damaged and/or no longer effective, remove it and replace with new

  • take care around older recessed downlight fittings. For installation guidance around these, see the standard NZS 4246:2016 Energy efficiency – Installing bulk thermal insulation in residential buildings. This can be downloaded at no charge from the Standards New Zealand website

  • see the repair above for details of where to find detailed advice

  • all private rental properties must have thermal insulation installed in ceilings and under suspended floors where it is reasonably practicable to install it. This is a requirement under the Healthy Homes standards

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