Home Forums General Discussion What is the best way to insulate walls without removing the wall panels? Reply To: What is the best way to insulate walls without removing the wall panels?

Vicki Cowan

Hi Renee,

I have drafted this response to your question, with some consultation from my colleagues at Beacon.  Hopefully it will help you!



Walls are complex – they serve many functions beyond hosting your art! A key role is keeping out the weather: NZ construction these days generally uses a cavity system designed to allow any moisture that gets in to dry out.  So any changes you make to your wall system (such as adding insulation) has potential to alter the breathability of your walls and also the weather tightness of your home.  This is why many new wall insulation products such as the spray in foams are not favoured by BRANZ or the government.  In addition, you don’t really know what you have in your walls until you look!  Is there building paper  present (plays an important role in moisture management)? Is there already rot that needs to be remedied?  Are your electrical wires in good condition?

The best way to insulate walls, a great intervention to improve the performance of your home, is to remove the linings or the cladding and do it properly following the solution set out in NZS 4246:2006 Energy Efficiency – Installing Insulation in Residential Buildings.  Ideally you’d get good advice from a trained insulation installer (you only want to do this once and so do it right) on what product is best and how to install it to optimise warmth and the other weather tight functions of the wall.

Industry is looking hard at wall insulation, particularly in Christchurch, where relining or recladding of many earthquake damaged walls will ideally happen with wall insulation at the same time.  Industry is working on insulation installation training – research shows effectiveness is strongly related to how you’ve put insulation in.

Beacon’s research on the value of wall insulation would indicate that any time you ‘intervene’ in your wall, even simply painting inside or stripping wall paper, it is worth considering removal of the lining and insulating.  Once you have painted/relined etc. you are unlikely to disturb that wall again for a long time – a missed opportunity to improve the warmth of your room and bring down the price of your energy bills.