Frequently Asked Questions

Find the answers to your questions


Is Insulmax® retro wall insulation certified in New Zealand?

Yes – Insulmax® is Certified to insulate the walls of older New Zealand homes!


The Insulmax® Retrofit Wall Insulation Method is CodeMark certified. CodeMark Certification is administered by the N. Z  Government and is the highest form of product assurance in New Zealand.  External auditing by AssureQuality ensures that our high levels of quality are always met.

Providing the product is used within the limitations of the certificate, legislation requires that building consent authorities (usually councils) must accept a CodeMark certificate as evidence of compliance with the building code. Building owners and designers can have increased confidence in the Insulmax® product and method and be assured of a smoother compliance pathway. CodeMark is the highest form of certification in New Zealand and is an unchallengeable form of product assurance.

The Insulmax® Retrofit Wall Insulation Method is CodeMark certified to be used in all existing (not new) buildings in New Zealand of any construction type or style.

Learn more about CodeMark Certification here


My house doesn't have building paper - is Insulmax® suitable?

YES – Insulmax® insulation can be installed in wall structures with or without building paper. Insulmax® insulation is highly resistant to absorbing or wicking liquid water so it does not require the additional protection from water that conventional insulation products require.

IMG_0100Conventional insulation products are manufactured to be protected from water by building paper systems because they readily absorb liquid water. Insulmax® is manufactured with an inert water repellent additive so that it is highly resistant to the absorption of liquid water.

Ask your representative for a sample of Insulmax® and test it for yourself. We guarantee you’ll get tired of watching it float in a glass of water for MONTHS!

There is some confusion about building paper since new build homes have building paper. Therefore it’s perceived every house should have building paper. However, a new build also has a drained ventilated cavity which cannot be cost effectively replicated in the renovation of an older home.

This new build need for building paper has been “adapted” to older homes by the “accepted” practice of retro fitting conventional segment insulation into the walls of older homes by removing interior wall linings and placing building paper pockets in the exposed cavities. The purpose of the paper is to protect the segmented insulation from the entry of wind driven rain which may enter the wall cavity during weather events. Conventional fiberglass insulation is hydroscopic and readily absorbs and wicks liquid water.

The paper is placed against the interior face of the exterior cladding and wraps around the exposed studs and dwangs fully encapsulating each segment of insulation on five sides. The photos below show what paper pockets look like after a year when further renovations meant the exterior cladding had to be removed. As shown below, viewed from the outside, paper pocket/segment insulation systems can be difficult to properly install.

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The paper has no ability to protect the structural timbers since the exterior cladding is not removed and therefore building paper cannot be present between the exterior cladding and the structural timbers.

Any water that enters via wind driven rain becomes trapped between the paper and the exterior cladding or trapped between the exterior cladding and a structural timber which is semi wrapped in building paper. Trapped water under gravity moves down the paper/cladding interface until it encounters a horizontal timber e.g. dwang or bottom plate.

If water enters a conventional paper pocket retro fit application, it is channelled towards horizontal structural timbers. These timbers have a reduced ability to dissipate the water via evaporation because they are semi wrapped in building paper, which has reduced ability to transmit water vapour. Or, they are wrapped in a building membrane system which is designed to restrict water vapour transfer from its external surface to its internal surface.

Insulmax® insulation as an E.U rating of negligible resistance to the movement of water vapour and is highly resistant to absorbing liquid water. It will not absorb or wick water since during manufacture it is treated with an inert water repellent additive and so does not require the protection of building paper. It therefore functions and is able to manage wind driven rain at least as well as building paper pockets / segment insulation.

Below are images of external cladding removed, to show Insulmax® blown fibre insulation filling all the available space

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How do you find all the cavities/timbers?
The vast majority of homes in N.Z are composed of vertical, horizontal and diagonal timber framing called studs, nogs/dwangs and bracing. We use a variety of techniques to find the cavities formed by these timbers, including high resolution thermal imaging which some customers compare to an X ray of their walls. Below are real images we’ve taken during installs.


How do you know the wall is full?
sample wallOur installation machinery is designed to fill wall cavities and works in a similar way as a petrol pump turning off when your fuel tank is full.

In addition, as part of our quality assurance process, we fill a sample wall during each install of Insulmax®. After a confirmation check that the sample wall is completely filled we commence insulating the walls of your property.

We also use thermal imaging cameras as a final check to assure that no cold areas of wall have been left uninsulated.



Thermal image - missed wall cavityAs a final check, high resolution thermal imaging cameras are used to ensure that all areas of the wall have been correctly filled. Cold areas of walls that are not insulated are very clear to infra red technology and appear as a distinctive darker colour.


Can you insulate brick homes?
YES – the vast majority of brick homes are built as a masonry cladding over a conventional timber framing although some are a double brick construction. We are able to insulate masonry clad homes through small holes made in the “T” joint of the exterior brick cladding. Alternatively by customer request, we can install via the internal lining, which works well if the plan is to redecorate.

Due to the drafty 150mm deep cavity found in most brick homes, they are one of the thermally least efficient wall structures in New Zealand. Before we install, some of our customers struggled to keep more than one room of their home at an adequate temperature. Customers with brick homes experience the greatest improvement in their property as the 150mm drafty cavity is converted to a wall structure containing insulation with a thermal rating of R – 4.2.  New build walls typically contain insulation with a rating of R – 2.2.

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Left – Interior wallclining removed to show the 150mm cavity to the back face of the brick cladding.

Right – property with brick cladding removed to show timber framing

Will Insulmax® settle or shrink over time?
NO – Insulmax®  mineral fibre insulation is installed under slight pressure and is packed into the wall cavity so it cannot slump, settle or shrink.  The product has an E.U. Standard rating of S1 in relation to settling. This rating corresponds to settling measured below 1% or unmeasurable.

The installed density of Insulmax® is over 50% denser than most conventional segmented fiberglass insulation products which contributes to it’s stability and high thermal and acoustic insulation properties.

Insulmax® is not a water based foam injected insulation.

Should I insulate my walls?

Why should I insulate my home?
To transform your home be a great place to live! Insulation will make your home warmer, drier, healthier and cost less to heat.

Sun light and heating systems pump heat energy in to your home. The resulting temperature depends upon how much energy is pumped in and how much is lost.

Imagine trying to fill a leaky bucket with water. To get more water in the bucket you could open the tap more , or, you could find and repair the leaks. Insulation acts in the same way in your home and “plugs the heat loss holes”.

Heat leaks from your home by convection, conduction and radiation. Bulk insulation products such as Insulmax® act as a barrier to flowing heat allowing the heat to build up in your home. An increase in heat energy means higher temperatures and because less energy is being lost, your home is easier and cheaper to get up to a comfortable temperature. The increased temperatures also mean that your home will feel drier and the reduced relative humidity means that the development of mold is reduced or prevented.

How much heat is lost through the walls of my home?

Heat loss screen grabA LOT – When you consider that an average home of 100 square meters has about 80 square metres of exterior walls, its no surprise that external walls lose a significant amount of heat. The large range of construction types and styles of home in New Zealand mean that it’s difficult to state an exact percentage of heat loss lost through walls. However, it’s typically it’s between 25% – 35%

Since the mid 80’s it’s been mandatory to build new homes with wall insulation, so the benefits have been recognised for many decades.

What difference will I notice after the walls are insulated?

The ability of your home to hold heat will be a lot higher. You’ll notice your home is generally warmer and after a warm day it will hold its heat longer into the evening. When you turn on heaters the temperature will rise faster and the heaters will turn off sooner. You’ll notice that your heatpump operates at a lower level to keep the same temperature. When you wake up in the morning your home will be warmer and you might be surprised when you step outside and realise how cold it is.

Please read our customers experience of how Insulmax® wall insulation has changed their homes.

Is my home suitable for the Insulmax® wall insulation process?

The Insulmax® wall insulation system has been designed and certified,  for the walls of all older New Zealand homes. It is suitable for all types of homes including but not limited to: timber clad, masonry clad, brick clad, double brick, roughcast, stucco, fibro etc. 99.9% of older homes are suitable for Insulmax®

Our system includes a Property Assessment before the installation of Insulmax®, which confirms the suitability of your home to the Insulmax® process and may highlight small items of maintenance that your home may require.

I have a lot of windows - Is there any point insulating my walls ?

YES – Walls are the second highest heat loss surface in most homes with an average amount of glazing. If your home is architecturally designed and has a lot of glass, walls are likely the third highest heat loss surface.

Most homes have about 3 times more wall area than glass area.  Most wall construction types have a cavity of 100mm to 150mm that can be filled with high performing insulation. Adding 100mm of insulation to existing wall cavities reduces heat loss though the wall structure by approximately 85%, which is a huge reduction over a larger area.

Double glazing reduces heatloss through the window by about half compared with a single glazed window. Double glazing is the most expensive surface to tackle with the lowest percentage improvement to the smallest area.

Everyone should live in a double glazed home but for the best bang for your buck – insulate ceilings, walls and floors before you tackle double glazing.

Do I need a building consent for Insulmax® wall insulation?
YES – All types of external wall insulation, including Insulmax® and common household name insulation products require a building consent even when installed in a home that has been built for many years.

Some local councils have given Insulmax® an exemption to this requirement and your local independent Insulmax® license holder will be able to advise you of your local situation. Insulmax® is fully compliant with the applicable New Zealand building code clauses and demonstrates compliance using the CodeMark Certification Scheme. Insulmax® is the only retro wall insulation method to hold CodeMark Certification.

Don’t worry about the consent process, as all paper work and consent applications are made by your Insulmax® representative.

Common Concerns

Does your product affect electrical cables?

No – Insulmax® has no detrimental effect on wiring or other existing building elements. However we recommend replacing older rubber coated wires before the installation of any wall insulation. TPS is the newer form of wiring and has been used for many years and is the wiring with the white/cream plastic insulating outer sheath.

Rubberised wiring is becoming rarer since it’s generally required to be ungraded to TPS for insurance purposes, as the age of the wiring and it’s nature can lead to problems of degradation of the outer rubberised sheath.

Polystyrene insulation has been shown to degrade the outer sheath of TPS cables (the polystyrene effects the plasticisers in the plastic sheath causing it to become more brittle) and should not come into contact with standard TPS wiring. Insulmax® is not polystyrene.

Can you install around pipes?
YES – Insulmax® is blown into wall cavities at high velocities to create a swirling effect in the wall structure which allows the insulation to flow around pipes present in the wall. Below is a Perspex trial wall showing Insulmax® fully insulating the water pipes and the wall cavity.


Will Insulmax® burn or absorb water?
NO – Insulmax® has the highest rating of non combustibility – A1 and  is made from inert mineral fibres with a water repellent additive so it will not absorb or wick water.

Is Insulmax® a good sound deadening acoustic insulation?
YES –  Warm AND quiet homes. The performance of acoustic insulation is largely dependent upon its density and how well it fills the available space. Insulmax® is over 50% denser than most conventional fibrous acoustic products and because it’s injected into the wall it fills all available space so there are no gaps.
Will Insulmax® fall out if I renovate?
NO – Insulmax® wall insulation is packed into the wall cavity and is about 50% denser than conventional fiberglass products. The  packing of the product means that it is able to support its own weight, so that if small renovations are required in the future, like changing weatherboards etc., Insulmax® will not fall out.

The below photos show Insulmax® in place after several weatherboards have been removed during renovation. It is advisable to remove a board and replace and move onto the next board. If the area has to be exposed for longer periods, it’s advisable to protect the insulation and your internal wall structure by temporarily covering the area.

Boards off2Boards 0ff

Will Insulmax® attract mice or insects?
NO – Insulmax® cannot sustain rodents or insects.
How does Insulmax® compare to traditional segment insulation?
The main difference is installation. We inject Insulmax® into the wall cavities. This means wall linings stay intact and the process takes 1-2 days, with very little mess or disruption. Some customers comment that when they got home from work they couldn’t tell the work had been completed, apart from their home was considerably warmer.

The cost of installing Insulmax® is considerably cheaper than removing wall linings. The finished insulation rating of the wall structure is at least the same as conventional products and often up to 50% higher in some construction types.

Insulmax® fills all available space within the wall, whereas conventional segment insulation can have gaps and joins.

Insulmax® is faster, tidier, quicker, cheaper and gives better insulation than removing wall linings.


Common misconceptions

I thought walls need to breathe?
Insulmax® is a fully breathable product and has an E.U classification of having negligible resistance to the movement of water vapour. The product is also very resistant to liquid water so like breathable clothing, water runs off but water vapour can pass through Insulmax®.
Will Insulmax® make my home damp?
NO – Increasing the insulation in your home will increase the average temperature and so will make your home feel drier. You will notice that your home will feel drier and dampness in bedrooms, wardrobes etc. will be reduced.

Last generation injected wall insulation products included water based foams that sometimes caused very short term moisture issues due to the amount of water they contained at the time of installation. Insulmax® is not a water based foam.

Cold surfaces, like uninsulated walls, tend to become damp by condensation. Damp walls provide the perfect conditions for mould growth, especially in sheltered areas like the bottom corner of the bedroom wall. Insulating the wall reduces the amount of condensation and the drier wall cannot support the growth of mould.



What about the cavity in brick homes?
Under conditions of prolonged driving rain, exterior masonry claddings can absorb water to a degree that the interior face can become damp. There is a cavity of between 35mm – 50mm between the back of the bricks and the timber framing that prevents possible dampness from the bricks bridging to the framing timbers.

During manufacture Insulmax® is treated with inert water repellent and has been independently tested to be very resistant to the absorption of water and it will not wick water. By installing a highly water repellent insulation that will not wick liquid water into a brick home, the function of the cavity is maintained.

Ask your Insulmax® representative for a sample of Insulmax® insulation and test it for yourself in a glass of water. We guarantee you’ll get tired of watching it float – for MONTHS!





IMG_0623As an additional insurance, your Insulmax® contract includes surface sealing exposed brickwork with an inert invisible water repellent coating. This photo shows beading rain on the surface of a red brick property after the water repellent surface sealer has been applied.

Water repellent dry fibre insulation systems like Insulmax® are present in over 6.5 million brick homes in the U.K. alone. The U.K. Building Code allows water resistant dry fibre systems to be used in all areas of the U.K. – including the Outer Hebrides!

Will Insulmax® solve my mold problem?
Most mould issues are caused by moisture created inside your home by breathing, showers, cooking and drying clothes. Whenever possible, ventilate while cooking and showering and dry clothes outside.

However, breathing is something that has to happen so cold surfaces, like uninsulated walls, tend to become damp by condensation, especially in bedrooms. Damp walls provide the perfect conditions for mould growth, especially in sheltered areas like the bottom corner of the bedroom wall. Insulating the wall reduces the amount of condensation and the drier wall cannot support the growth of mould.

Mold and its associated spores are very detrimental to internal air quality.  Insulmax® wall insulation will reduce or remove a mold issue by reducing the amount of water vapour that is able to condense on a wall surface. Mold finds if difficult to grow on dry walls.



What happens if a pipe leaks in my walls?
Insulmax contains an inert water repellent so it will not absorb water. Once the leaking pipe is repaired, any water present in the wall cavity will evaporate because Insulmax® is a fully breathable product.

Your Insulmax® install

How many holes do you make?

Our aim is to make the least number as holes as possible but the exact number of holes depends on how your home was constructed and the location of  framing timber.  Your independent licensed Insulmax® representative can give you detailed information about the installation of Insulmax® in your home.

How big are the holes?
SMALL – The team at Insulmax® has developed proprietary installation machines so that we can deliver an install process with the smallest hole size of any injected dry fibre wall insulation product. We use  a 16 mm (10c coin size)  in timber clad/plasterboard cladding and 16 mm diameter holes (10c coin size)  in brick / masonry cladding. The hole in the brick cladding is small enough to be made in the mortar joint between three bricks.
Can you install Insulmax® through the interior plaster board lining?
Yes. For some customers this is the preferred option and for some installs with high or difficult external access, installing through the plasterboard is the most cost effective option. You local independent Insulmax® representative will advise you of what install options are available for your property.
How do I know you have installed Insulmax correctly?
Your installation of Insulmax® will be carried out by trained and accredited installers using the best practices developed over 10 years of installing injected wall insulation products.

However as a final check that the product has been installed correctly, we use high resolution thermal imaging cameras to ensure that all areas of the wall are correctly insulated. The photos below show uninsulated areas before being filled with Insulmax®

Thermal image - missed wall cavity FLIR0021 FLIR0031 FLIR0032

Who carries out the work?

Insulmax® is a licensed installation system with installs carried out by independent regional Insulmax® license holders. It’s not a DIY process. Insulmax New Zealand Ltd. is responsible for the training and auditing of regional license holders to ensure installations are carried out correctly.

Our policy is – you’re only as good as your last install so make every one the best.  Insulmax® staff will always treat your home with the utmost respect.

Insulmax® Installation Procedures

Timber Stud Walls – Insulmax® will be installed via small holes made in the exterior or interior wall lining. The cavities between the timber structural members will be filled with Insulmax®

Masonry Veneer Walls – Insulmax® will be installed via small holes made in the interior wall lining or the exterior mortar joints where visible. The cavity from the inner face of the brickwork to the interior wall lining will be filled with Insulmax®

Finishing – holes will be made good with the appropriate filler / mortar and made to match the existing wall as closely as possible. Unless agreed with your installer, it is the customers responsibility to supply the top coat to ensure a satisfactory colour match. Holes made in interior linings will be filled with plaster and left proud to be finished when the plaster is completely dry by the customer or their agent.

General Information : Power will be needed during the installation and vehicles may need to be parked close to your property. There will be a degree of noise during the installation. Your installer will ensure that your property is left tidy but small amounts of insulation may be left in gardens and borders etc. Small amounts of insulation may enter through existing gaps in the interior lining but will be tidied by your installer.

What if I have a problem?
Insulmax® is a licensed installation system, with installs carried out by independent regional Insulmax® license holders. If you are in any way not happy with the service you have received, please contact your local representative.

If you feel you are unable reach a resolution with your local representative please contact head office via our contact page.

Technical information

What does R value mean?
R values are a measure of the ability of a product to resist the flow of heat. This measure allows the effectiveness of different insulation materials to be compared. The higher the R value number, the better insulation properties of the product.

Because Insulmax® fills all available space, we state the R value as – R 2.8 over 100mm.

So, if your wall was 50mm thick the R value of the product would be R 1.4 and if it were 150mm thick the R value of the insulation would be R 4.2

For older homes, R values of the material are important but not as important as the realisation that the R value of the wall with no insulation is in the region R 0.2.


Is Insulmax® environmentally considerate?
YES! Insulmax® is made from natural materials and post-consumer materials. It is CFC and HCFC free and classified as zero Ozone Depletion Potential and zero Global Warming Potential.

Creating a warmer, drier, more energy efficient home is also great for the environment!

I love Insulmax – how can I become a licensed installer?
If you are motivated by doing a job as well as you can and feel rewarded by the benefit you’ve made to a clients life and home then you could be the right person to become an independent Insulmax® regional license holder.

We give license holders all the support they need to operate an independent and successful business. If you’re interested, please email Phil Jackson or contact head office via our contact page.