Installing a 75mm Insulation Segment in a 70mm Cavity

Pricewise Insulation is one of New Zealand’s best known online retailers of Knauf Insulation, Pink Batts, Bradford and Autex Greenstuf. One of the questions our staff are often posed with is as follows:

My house is framed with 70mm studs, leaving a 70mm gap for insulation. Can I still install a 75mm insulation batt, such as a high density Earthwool R2.0/430mm? Or will I risk damaging the plasterboard?

Before we answer that question, let’s take a look at the two most common options available to the home owner who wants an R2.0 insulation in their wall cavity.

Standard R2.0 Wall Batts

A typical R2.0 wall insulation segment is 90mm thick. These thermal wall segments are most commonly installed in the exterior wall cavities, providing an effective thermal barrier around the home. A standard R2.0 insulation segment has no particular acoustic (sound deadening) benefits, though the mere presence of glasswool or other bulk insulation in a wall cavity will always to some extent reduce the amount of noise which finds its way through the wall.

Hi Density Acoustic Wall Segments (R2.0)

From a thermal perspective, these perform identically to the standard R2.0 segments; after all, the “R-value” is the standard way to measure the insulating material’s “resistance” to heat transfer. The difference lies in the density of the material, and the corresponding increase in acoustic or sound blocking benefits. Being only 75mm thick, the R2.0 acoustic wall segment is an excellent option for home owners who want to address both the thermal and acoustic issues, i.e. they want to protect their home from both excessive temperatures and also from the transmission of unwanted sound. As such, acoustic wall segments are commonly installed in the interior walls of the home, between bedrooms, bathrooms, laundries and of course TV rooms and music studios.

… back to the 70mm Cavity Issue

So, you’ve decided you want R2.0 acoustic insulation in the interior walls, and a quick check with the measuring tape confirms what you already suspected – the gap is 70mm, while the insulation you plan to install is 75mm…

While in the bag, insulation segments are typically compressed – either slightly or greatly – to a thickness which is below their officially stated out-of-the-bag thickness. Earthwool, made by Knauf Insulation, for example comes compression packaged which allows a significant number of insulation segments to be squashed into a single bag, reducing storage and transport costs, and of course reducing the number of bags that insulation installers need to lug around the building site. Now the theory is that insulation segments, whatever their squashed dimensions, will expand out of the bag to their full, recommended thickness. But the reality may be somewhat different. In fact, it would be fair to assume that a significant percentage of Knauf Insulation’s R2.0 acoustic segments will never expand beyond 70mm thick, making them perfectly safe to install in a wall cavity the same size. And even if they did expand to the full size – it’s hard to imagine the extra 5mm causing sufficient pressure within the wall cavity to have any impact on the plasterboard or other wall lining.

While the official advice will always be ‘never install bulk insulation which is thicker than the wall cavity’ it’s safe to assume that the likelihood of any issues occurring from installing a 75mm insulation segment inside a 70mm cavity is very low.

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Installing Home Insulation in Ceilings For First Timers

Roof insulation can be installed before or after plaster. Often the installers will find it easier to install the home insulation before plaster. The roof insulation segments are simply pushed up into place between the ceiling joists with long sticks. The roof segments are precut to ensure a snug fit between the ceiling joists assuming that the joists are spaced at the industry standard; 450mm or 600mm. If the spacing is excessive or uneven it can make it difficult for the installers to insert the roof insulation from underneath and the decision may be made to preload the roof with unopened bags of insulation and install them from above.

Calculating the amount of insulation needed

The number of bags required is easily calculated by dividing the number of square metres in the roof space by the number of square metres of insulation in the bags and then deducting 10 percent to allow for the timber framing itself. R2.5 segments are on the thinner end of the scale and less rigid, making them more difficult to install from underneath, even if the joist spacing is optimal. This may also provide a reason to opt for installing the insulation after plaster, from within the roof cavity. Installing home insulation in the roof cavity of a new house is usually a much more pleasant experience compared to older homes. Unlike old houses, new buildings haven’t had time to accumulate the layers of dirt and dust that an old roof will inevitably accumulate over a number of decades.

The retrofit installation process

While it is fully possible for someone to install home insulation in the ceiling on their own, installers will often choose to work a fellow team member. Working as a team of two has several benefits. Apart from the social element of doing a tough job together with a mate, working as a team of two can use less than half the time the installer would need on their own. Benefits are especially felt when loading bags through the manhole which can be quite tedious and time consuming to do alone.

Installing home insulation from within the roof cavity

Roof cavities are typically very hot, so installers usually prefer to start early, before the temperature inside the roof cavity becomes too high to work in safely. Installers often bring a couple of extra bags of insulation with them “just in case”. Up in the ceiling space the installer will split one bag open at a time and, using their installer sticks, (this might be as simple as a broom handle with a nail fixed to the end), will get to work deftly fitting the insulation segments between the ceiling joists, starting in the furthest corner. Once the home insulation installation is complete installers can be expected to clean up any leftover scraps before fitting the final piece of insulation over the manhole cover.

Roof insulation is by far the most cost-effective way towards keeping your electricity bills down and maintaining a pleasant indoor temperature all year round. For more information on roof insulation visit www.pricewiseinsulation.co.nz

Building for a Sustainable Future – Insulation

Insulation in the 21st Century

Insulation has in recent decades become an integral part of modern building structure. Most buildings need insulation, or at least benefit greatly from it. Insulation can broadly be categorised into two categories; thermal and acoustic. The purpose of thermal insulation is to restrict the transmission of heat and cold into the building, whereas the purpose of acoustic insulation is to restrict the transmission of sound into and within the building.

Significant heat losses in uninsulated homes

Without insulation in winter time, much of the heat produced inside, by wood stoves or other heat generators, will be lost through the ceiling, walls and underfloors. Windows can also cause significant heat loss during winter (and conversely allow a lot of excess heat to enter the building during the hotter months of the year). Tinting the glass helps to reduce the impact of the sun on windows that are exposed to direct sunlight. For those who want to take it a step further, double glazed windows are an excellent option.

Insulating homes with glasswool or polyester

Thermal bulk insulation can be made from a number of different materials, the most common of which is fiberglass, also known as glasswool. Insulation made from polyester is also becoming increasingly popular. Polyester insulation such as Greenstuf, is completely itch free to install and is also favoured among allergy sufferers due to the absence of tiny breathable fibres. With a bit of know how and some basic tools it’s fully possible to install your own bulk insulation in the walls, ceilings and even under a raised timber floor.

Using foil insulation to reflect radiant heat

Foil insulation works differently to bulk insulation. While bulk insulation slows down the transfer of heat, foil insulation acts as a reflective barrier against the radiant heat of the sun. This type of insulation is commonly installed inside the roof cavity immediately beneath the roof tiles or under metal roof sheets. In the past it was common practice in some areas of New Zealand to staple foil insulation directly onto the ceiling joists. However, this is not recommended due to the high risk associated with stapling through live metal wiring which can often be found running across the timbers of older homes. When installed in the wall cavities, reflective insulation can add an r value of approximately 1.0 and it’s very common to be installed in combination with bulk insulation.

Acoustic insulation for soundproofing

Acoustic insulation is more dense than ordinary bulk insulation and is specially designed for soundproofing, or at least restricting the transfer of unwanted noise between floors and walls. Wall insulation is typically installed at the time of construction of the new building. Before deciding what type of wall insulation to use, consider carefully the potential impact outside noise, for example, traffic and barking dogs, might have on your quality of life, and the level of soundproofing that you will need.

Essential in domestic and commercial construction

Commercial buildings also require insulation. These often take the form of rigid panels which are fixed directly to the building framework or concrete structure using special screws. A properly insulated building will in many cases be more than twice as energy efficient as a building with no insulation. As such, insulation is usually the best investment a building owner can make towards reducing the long term energy usage and cost of the building occupants.

Installing a 75mm Insulation Batt in a 70mm Cavity

Pricewise Insulation is an online retailer of insulation batts in New Zealand. One of the questions our staff are often posed with is as follows:

My house is framed with 70mm studs, leaving a 70mm gap for insulation. Can I still install a 75mm insulation batt, such as a high density Earthwool 14kg/m3 75mm insulation? Or will I risk damaging the plasterboard?

Before we answer that question, let’s take a look at the two most common options available to the home owner who wants an R2.0 insulation in their wall cavity.

Standard R2.0 Wall Batts  

A typical R2.0 wall insulation batt is 90mm thick. These thermal wall batts are most commonly installed in the exterior wall cavities, providing an effective thermal barrier around the home. A standard R2.0 insulation batt has no particular acoustic (sound deadening) benefits, though the mere presence of glasswool or other bulk insulation in a wall cavity will always to some extent reduce the amount of noise which finds its way through the wall.

Hi Density Acoustic Wall Batts (R2.0)

From a thermal perspective, these perform identically to the standard R2.0 batts; after all, the “R-value” is the standard way to measure the insulating materials “resistance” to heat transfer. The difference lies in the density of the material, and the corresponding increase in acoustic or sound blocking benefits.

Being only 75mm thick, the Earthwool 14kg/m3 75mm acoustic wall segment is an excellent option for home owners who want to address both the thermal and acoustic issues, i.e. they want to protect their home from both excessive temperatures and also from the transmission of unwanted sound. As such, acoustic wall batts are commonly installed in the interior walls of the home, between bedrooms, bathrooms, laundries  and of course TV rooms and music studios.

Photo of a woman in front of a wall with wall insulation batts installed

… back to the 70mm Cavity Issue

So you’ve decided you want R2.0 acoustic in the interior walls, and a quick check with the measuring tape confirms what you already suspected – the gap is 70mm, while the insulation you plan to install is 75mm…

While in the bag, insulation batts are typically compressed – either slightly or greatly – to a thickness which is below their officially stated out-of-the-bag thickness. Insulation brands such as Knauf Earthwool have developed ‘compression packaging’ which allows a significant number of insulation batts to be squashed into a single bag, reducing storage and transport costs, and of course reducing the number of bags that insulation installers need to lug around the building site. Now the theory is that insulation batts, whatever their squashed dimensions, will expand out of the bag to their full, recommended thickness. But the reality may be somewhat different. In fact, it would be fair to a assume that a significant % of R2.0 acoustic batts will never expand beyond 70mm thick, making them perfectly safe to install in a wall cavity the same size. And even if they did expand to the full size – it’s hard to imagine the extra 5mm causing sufficient pressure within the wall cavity to have any impact on the plasterboard or other wall lining.

While the official advice will always be ‘never install bulk insulation which is thicker than the wall cavity’ it’s safe to assume that the likelihood of any issues occurring from installing a 75mm insulation batt inside a 70mm cavity is very low.

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What is the Best Time of Year to Insulate Your House?

Choosing a season to insulate your home

You might be wondering what the best time of year is to insulate, when is the ‘insulating season’? If you have no insulation in your roof, then ‘right now’ is probably a pretty good answer. Well not exactly ‘now’, but as in as soon as you can manage to get hold of some insulation segments of a half-decent R-Value, and either set aside time to DIY, or book in a professional insulation installer to do the job for you. Almost every uninsulated house will benefit significantly from getting insulation installed in the ceiling. Apart from the noticeable cooling effect in summer and reduction in heat loss in winter, ceiling insulation is the single most effective way to reduce energy bills relating to heating and cooling appliances, including split air-conditioning systems. Bulk thermal insulation in the roof cavity also has other benefits such as reducing the incursion of airborne noise, such as aircraft noise. But urgency and energy savings aside, there are o

Photo of a man installing ceiling insulation in the roof

f course a number of obvious and perhaps not-so-obvious reasons why insulating at certain times might be more or less ideal.

Summer – when you’ll notice the biggest difference

For an immediate uplifting ‘so glad I just did that’ moment, the hottest season of the year is likely to be your best bet. Roof spaces without insulation become extremely hot, and without thermal insulation segments to block the temperature transfer, much of this heat passes through with relative little resistance into the living areas below. On really warm sunny days, the ceiling plasterboard may even feel hot to touch; like a gigantic flat heating-element against which a standard size home air-conditioner will stand little chance of combatting the heat simply oozing through it. The first heat-wave often serves as a reminder to home owners, to service their air-conditioner and to think seriously about getting some insulation installed in their ceiling.

Winter – the best time of year to DIY

Installing insulation is not everyone’s cup of tea. Glasswool can be a bit itchy to work with, and even if you’re installing a zero-itch polyester product such as GreenStuf, the roof cavity is not exactly the most inviting room in the house to spend the morning, day or weekend. However, if you’re prepared to do what it takes to save the extra dollars, then the coldest season of the year might be a good option for you. Typically a roof cavity will be colder at night than the rest of the house, but once the sun hits the roof in the morning, it will quickly warm up to a pleasant working temperature. In summer time, insulation installers will often aim to start as early as possible, and aim to finish their work day by around lunch time. During the coldest months of the year, this is usually not an issue.

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Is a Hot or Cold Shower Best After Working With Insulation?

How or cold shower after installing insulation?

You’d be surprised how many times we get asked this question. The common theory is that a cold shower is better than a hot shower, because hot water will cause the skin pores to open up, exposing them to any minute glasswool strands which might be lying on your skin..

How Itchy is Modern Day Glasswool Insulation?

Glasswool (also known as fibreglass) insulation manufacturers have come a long way in developing clean, safe and comfortable products. Knauf’s “Earthwool“, Fletcher’s “Pink Batts” and CSR Bradford’s “Gold Batts” are all quality insulation products. Knauf Earthwool is without question the softest and least ‘itchy’ of these three brands. This is because the fibres are longer and softer, resulting in less ‘ends’ to cause irritation.

Any itchy sensation experienced from installing Earthwool is purely ‘mechanical’ – i.e. it has nothing to do with binding agents or other chemicals, but may rather be caused by some almost invisible strands clinging to your clothes and rubbing on your skin. While we can’t claim to have conducted any extensive testing and research on this topic, our installers will definitely agree that initially rinsing off in cool water first, before taking a hot shower, is the recommended approach.

Want Zero Itch and Dust?

If you want insulation with no dust and no itch then consider a polyester option like GreenStuf Ceiling Insulation. It will cost you a bit more, but it does top the list for comfortable handling during the installation process.

Polyester vs Glasswool

Polyester vs Glasswool Insulation - New Zealand

An Investment For the Life of Your Home

Insulation is an investment in the future comfort and energy efficiency of your home. When deciding on a brand and type of insulation, you need to ask yourself some key questions. We hope this article will help you to make an informed decision.

Most insulation brands sold in New Zealand are made from glasswool, also known as fibreglass. Glasswool has numerous benefits which make it such an effective insulation material. It’s main ingredient being recycled glass and sand, it can’t catch fire, does not attract vermin, doesn’t rot, and isn’t prone to absorbing airborne moister. It’s fairly easy to cut with a sharp knife, and quite simple to install. The millions of tiny air pockets give glasswool its fantastic insulating properties.

So What Are the Advantages of Polyester Then?

In this example we’ll compare glasswool with GreenStuf, which is manufactured by Autex from 100% polyester. GreenStuf has practically all the above-mentioned benefits, and it also has some additional benefits. It contains no breathable fibres and is certified as being not flammable.

This may be significant for asthma sufferers or those suffering from serious dust allergies, and is probably one of the main advantages of polyester insulation. Now how much dust (say in your ceiling space) will actually find its way into the living area? That’s a very good question, and the answer is probably ‘not much.’ The most dust you are likely to experience invading your home from the ceiling space will be when you attempt to change a ceiling downlight globe. However here it’s important to point out that in an old ceiling, there is likely to be a lot of dust anyway – regardless of whether or not there is insulation in the roof space, and regardless of whether any insulation installed is polyester or glasswool. But it would be fair to assume that if all other factors were equal, polyester would be the least dusty alternative, particularly in a new building.

Which is better? Glasswool insulation or polyester?

Huge Difference in Delivery Costs

A key difference worth noting if you’re planning on ordering insulation, is the cost of getting it delivered. Polyester is typically a bulkier product when compared to glasswool. If you live in or near one of New Zealand’s biggest cities, this will probably be of little concern. However, once you move away from Auckland, Wellington, Christchurch or Hamilton, then delivery can become very costly.

For example, you have a 130m2 ceiling, and you plan to insulate it with R3.5 Earthwool ceiling insulation. This will easily fit onto one pallet, whereas you would need around 4 pallets (or pallet spaces) to ship the equivalent R3.5 Autex GreenStuf ceiling insulation. In practice this means you might quickly find yourself needing to factor in an extra 30% – 40% of the material’s cost simply to cover the freight costs, especially if you live in a remote area. With glasswool, in most cases the delivery fees will be more be in the order of 10%- 20%. These are not exact figures, but can provide a helpful indication.

Summary and Conclusion: Glasswool vs Polyester Insulation

  • Polyester insulation from Autex is exceptionally soft to handle and has no dusty particles, making it an extra attractive option for allergy sufferers
  • We recommend you use our website shopping cart to calculate the cost of either option, and confirm the delivery cost with us if you live outside Auckland or Wellington
  • Then compare the difference in costs, and determine whether the extra cost of the poly insulation option is justifiable.

If you need more advice, don’t hesitate to contact us on 0800 697 742!

 

Is there a difference between glasswool and fibreglass insulation?

What is the difference between fibreglass and glasswool insulation?

What’s the Difference Between Fibreglass and Glasswool?

Fibreglass vs Glasswool – What is the Difference

Glasswool insulation is made from recycled glass bottles, sand and other materials. Glasswool is just another name for fibreglass insulation. It’s also sometimes referred to as glass fibre insulation or fibreglass segments. These are melted at very high temperatures and then spun into fibres. The result is millions of tiny air-pockets being created inside the insulation, which is what gives glasswool insulation its excellent insulating properties. Knauf Earthwool, Fletcher Pink Batts and Bradford Insulation are among the most popular glasswool brands available in Australia.

Fibreglass Batts – Like Sheep’s Wool and Down Feathers

You may be surprised to learn that glasswool insulation works in a very similar way to natural sheep’s wool and down feathers. Various binders can be used to hold the insulation together. Glasswool segments have for decades been associated with irritation of eyes, nose, skin and throat, but thankfully technological developments have resulted in a vast improvement in the product design, resulting in far softer and more pleasant insulation products now being available on the market. Brands such as Knauf Earthwool have taken the low-itch factor to a new level, and you’d have a hard time guessing that it was indeed glasswool insulation.

Glasswool Insulation – Keep Dry at All Times!

Wet insulation is a dilemma at the best of times, and glasswool insulation is no exception to this. It’s not difficult to understand why wet insulation doesn’t work, and will cause no end of trouble for the home owner if it is installed while wet. Firstly, glasswool relies on the microscopic airgaps inside – technically speaking it’s the airgaps which are the actual insulators. Now if these get soaked with water, there goes your thermal insulation! Also, wet glasswool insulation will be susceptible to mould, and will introduce moisture to whatever area of the building it is installed, with potentially destructive results. For this reason, glass insulation should always be stored high and dry, and if any part of a glasswool segment should become wet, it should be cut off, discarded and never used.

Why is Glasswool Insulation Still so Popular?

Glasswool insulation remains hugely popular, and with good reason. The bulk of the insulation originates from sand, which is one of the world’s most abundant natural resources. Other additional benefits of fibreglass insulation segments is that they are resistant to vermin, and are non-combustible (won’t catch fire) – an obvious bonus considering they are most always installed within the actual building frame. When properly installed in the roof, ceiling or underfloor of a home, glasswool insulation can be expected last as long as the home itself.

Is Fibreglass Insulation Itchy to Work With?

All fibreglass insulation can be a little bit itchy to work with, especially if you have sensitive skin. The itch caused by working with modern day quality glass wool insulation isn’t caused by chemicals, but simply by the tiny glass-fibre ends which make up the consistency of the glass insulation. For this reason, it’s recommended to wear a long sleeve shirt and gloves when handling glasswool, and should you still find that your hands and arms are itchy at the end of the day, a good rinse under cold water should resolve that without much trouble.

How is Fibreglass Made?

As the name suggestions, recycled glass is a key ingredient in the manufacturing of glass wool insulation. Together with other ingredients, such as soda ash, limestone and a significant portion of sand, this mix is then heated to melting point, before it is spun into long, super-thin threads of glass fibre. A binder is added to the mix, and after being baked in a large oven, the insulation is sliced up and cooled off, before being packaged.

 

Pink Batts vs Earthwool Glasswool

Pink Batts vs Earthwool Insulation New Zealand

So which product is actually better, when you compare Pink Batts vs Earthwool? Well that may depend on what’s most important to you.

Pink Batts vs Earthwool – Which is the Better Product?

First let’s look at the similarities. Both Pink Batts and Earthwool are both “glasswool” insulation, and the segments are in large part made from sand and recycled glass bottles. Both Pink Batts and Earthwool insulation segments are available in a variety of “R-values” to suit different climates. When making the insulation comparison Pink Batts vs Earthwool it’s important to realise that once the insulation is installed, the thermal benefit is practically the same. So an R2.0 wall insulation segment will give you the same thermal protection, regardless of whether it is branded Pink Batts, or Earthwool, or any other brand for that matter.

The Pink Insulation Batts come with a “life time guarantee” and Earthwool comes with a standard 50 year guarantee, which in practice means you can expect the insulation to last as long as your home.

Compare Insulation: Ease of Storage and Handling

Among all the home insulation types, Earthwool Insulation has gained popularity in recent years primarily for two reasons. Firstly, it uses a different binder, which makes it less itchy to work with. This is a real plus for DIY home renovators, not to mention professional installers who work with insulation on a daily basis. Secondly, Earthwool comes in a highly compressed packaging, which can significantly reduce the need for onsite storage space, and also help to reduce freight costs if you’re paying the full cost to get the insulation delivered to your home or on site.

No smell? Best ceiling insulation based on odour(less) factor

If you’re old enough to remember the insulation being installed in the ‘old days’ you’ll remember the smell associated with all roof insulation products. The longer the insulation lay there, the worse the smell, no doubt exacerbated by any number of vermin who had chosen to take refuge in the roof-space. Knauf genuinely claims that Earthwool is a better insulation as it has practically no smell, and the truth is that this is a fairly accurate statement. It smells like nothing, whereas most other glasswool products seem to have retained at least some of the odour, usually only noticeable in confined spaces. No doubt we will see more and more insulation brands setting their sights on an ‘odourless’ product range in the future. So if the no-smell factor is important to you, then the best home insulation for your roof may be Earthwool.

Our verdict – Pink Batts vs Earthwool

We recommend Earthwool insulation as the most comfortable to work with glasswool insulation, and it definitely is one of the best ceiling insulation products to work with. Price is obviously a key consideration, so we recommend you calculate carefully the full cost of buying the insulation and getting it delivered to you, and then make an informed decision on what is the best insulation for you and your project. Please don’t hesitate to contact us on 0800 697 742 or via the contact us page if you have any questions.

 

Ceiling insulation in Auckland- What R-Value?

Ceiling insulation in Auckland - What R-value is best?

Auckland’s climate is characterised by pleasant warm summers and cool winters. When the weather outside is even just a few degrees hotter or colder than your preferred indoor temperature, then the solution is thermal insulation.

Ceiling insulation R-Value matters

Without ceiling insulation, the indoor temperature will ‘follow’ the outside temperate, and even with a heater on, you will likely find yourself struggling to maintain a comfortable indoor temperature, especially on chilly winter evenings. The solution is ceiling insulation with a sufficient R-Value. Bulk insulation such as glasswool and polyester contains millions of tiny air-pockets. These drastically slow down the heat transfer process, which is how insulation works. A thicker insulation segment will have a higher R-Value, and will be more effective.

Analysis: Benefits of insulation vs cost

Doubling the insulation R-Value will not double the energy efficiency of your home. The law of diminishing returns is very applicable here. And it’s not a fixed equation either – should energy prices skyrocket a few years down the track, then there may be many home owners wishing that they’d installed a higher R-Value at the time. We are frequently asked, ‘How much does it cost to insulate a house?’ The real question, however, considering energy prices on the rise, is ‘How much will it cost me NOT to insulate a house?’

What we recommend at Pricewise Insulation

As a rule of thumb, if you’re building a new home or installing ceiling insulation in a new home in or around Auckland, we recommend R3.6 or higher. This is typically around 17cm thick, and provides a good level of thermal protection. Upgrading to an R4.1 or above will moderately increase the energy efficiency of your home, and could also result in real $$ savings if energy prices continue to rise.

 Buy ceiling and roof insulation online in Auckland, New Zealand