Retrofit Ceiling Insulation

Retrofitting ceiling insulation means adding or upgrading the insulation in the ceiling of a house that is already built. Heat rises, which means an uninsulated or poorly insulated ceiling is the biggest source of heat loss in most homes. As much as 35% of a home's heat can escape through the ceiling in winter, so it is usually the first and most cost-effective part of a house to retrofit.

As with any retrofit, the work has to meet the NZ Standard NZS 4246:2016 and the ceiling should be assessed individually before it begins. Where a whole home is being upgraded, this sits within our whole-house retrofit insulation capability.

Assessing whether a ceiling needs retrofitting

A ceiling is usually worth retrofitting where the home was built before 2008, when insulation requirements were lower, or where there is no ceiling insulation at all. Older insulation tends to settle and compress over time so that it no longer performs as it should, and in older homes the spacing between joists is often inconsistent, which leaves gaps and missed areas. If you are not sure what is already in place, an assessment will confirm it.

Topping up or replacing the existing insulation

Whether a ceiling can be topped up or needs replacing depends on the condition of what is already there. In many cases new insulation can be installed over the top of the existing insulation, covering the joists and lifting the overall thermal performance; this is the more straightforward option where the existing material is sound but no longer reaches the required R-value.

Where the existing insulation shows evidence of rodent or pest infestation, water damage or moisture, musty odours or visible deterioration - or is in such a condition that new insulation cannot be installed properly - it needs to be removed before the new insulation is laid. Our insulation removal service handles this.

R-values for a ceiling retrofit

A retrofit should bring the ceiling up to the minimum R-value required for its location rather than simply matching the original. In the Auckland, Bay of Plenty and Waikato area that figure is R2.9 for ceilings. Where the existing product cannot be identified, an assessor measures the ceiling thickness instead.

Getting started

We assess what is in the ceiling, advise whether a top-up or a full replacement is appropriate, and install retrofit insulation to NZS 4246:2016. Because every ceiling is different, the best starting point is an assessment - see our ceiling insulation installation service or get in touch for a free quote.