At Alexander Watson we have heard just about every question out there and so we have compiled our library of frequently asked questions.

However, if a question is not answered here, please just submit it below and one of our staff will get right back to you with an answer.

Ceiling Insulation questions :

As part of any insulation installation upgrade that we do at Alexander Watson we have to provide electrical safety clearance, the first part of the electrical safety clearance is having a safe plan for recessed downlights, which means we need to have a downlight that is IC rated (IC stands for insulation contact) or a downlight cover that is IC rated fitted to the existing light so that we can safely bury it with insulation, We need to do this because we want to be able to continue the insulation installation in a complete coverage and not leave any gaps.

If the light is IC rated and indicates explicitly that it is safe to have insulation abutted and covered, then we can cover it with ceiling insulation. In the event that there is no IC rating on the light and we are unable to find the lights data sheet and verify this information we will need to have an IC rated downlight cover fitted to the light before surrounding it with insulation.

It depends on two things, what type of insulation you will be putting over the top of the existing blow in insulation and whether or not the electrical cables in the ceiling are suitable to be completely surrounded by insulation. Any time blow insulation is present in a ceiling it completely surrounds the electrical cables and we need to be certain the cables have been correctly rated to be completely surrounded by blow in insulation. This is a check we always do as part of our electrical compliance work. In many cases though it is a lot simpler to remove the existing insulation rather than make the electrical changes in the roof and return the ceiling to a partially surrounded environment where you have got just batts in the roof. Another thing to consider is that simply laying batts over existing blow in insulation actually voids the ‘R’ rating of the insulation because you cannot guarantee the seal. There are retrofit options available though and if we can make the electrical cables safe for the blow in insulation we can blow certain blow insulation products directly over the top and this is a very cost effective way to top up the insulation whilst leaving the existing loose fill behind. It all is dependent on making the electrical cables compliant first.
Yes, electrical assessments and compliance is mandatory for any insulation installation and at Alexander Watson we adhere strictly to this.

Batts come in a standard width and length that is the same as that between standard ceiling joist spaces. Thus they fit comfortably within these gaps. We always recommend ‘cross-hatching’ the batts perpendicularly across the wooden beams to prevent thermal bridging.

Yes, and there is a range of specialist retrofit products that are suitable for mid-floor installations.

Cavity wall insulation questions :

Once cavity wall insulation has been installed to the correct density it will not go anywhere and it is Codemark certified to do so. If you ever see what appears to be cavity wall insulation having fallen out of the bottom of a wall cavity and sitting on the underfloor it is because the installer has not effectively blocked up underneath the cavity before installing the insulation, with our process, an installer always goes under the house and plugs up the cavity before pumping in any cavity wall insulation. So no bits of the cavity wall insulation will fall out. So if the cavity walls have been blocked properly no insulation will fall out on installation or thereafter.

Yes, but obviously it is a lot harder to access electrical cables once the cavity wall insulation has been installed and for that reason we suggest that if you know there is any wiring or electrical work that needs to be undertaken, that it is satisfactorily completed prior to the insulation being pumped into the walls. However installing cavity wall insulation does not kill off access to the cavity wall for an electrician, you can add wiring in at a later stage using a fibreglass straw rod, it is obviously just a bit more difficult than working within an empty cavity.

One of the benefits of using the ‘Knauf Snug & Sound’ system is that we have the technology to inject the insulation through a 16 mm hole where as many of our competitors will have to use a 26 mm hole which is a lot more conspicuous when patched up, the benefit of using our system and a smaller 16 mm drill bit and hole is that we will typically only be taking out the mortar joints rather than doing to much damage to the bricks which means we will have a much easier job to patch and a much neater finished result.

Yes, any installation of insulation requires an inspection from a licenced electrician to ensure that the circuits are suitable for being surrounded by insulation.

Knauf insulation have a system for retrofitting insulation under the windows using a drill & fill method through a 16 mm injection hole, this hole is typically drilled through the mortar joint of the brick work, so it is easily filled and will be very inconspicuous. This can also be done internally through Gyprock or externally through weatherboard cladding surfaces, once again with a smaller 16 mm hole rather that the larger 26 mm hole our competitors use is that the patching is done to a much higher standard.
Similar to retrofitting insulation under window frames the Knauf wall insulation system allows us to drill small holes into the walls and inject the insulation into the wall cavity using a specialised nozzle, the holes patches with plaster and sanded to render them smooth ready for painting.

In most cases with a tiled roof we can access the cavity from above by lifting tiles. Only in the event of the cavity being blocked from above will we need to drill and fill.

Floor insulation questions :

No, not at all, the polyurethane spray foam insulation can either be kept away from pipes and wires at request if you know you need to get them or if they’ve been covered and you need access to them at a later date the foam can be easily cut away from the pipes or cabling and if needed a solvent can be used to clean the pipework for access and pipe glue.

Absolutely, polyurethane spray foam has a ‘Zero ODP’ rating, it is fire rated and actually improves indoor air quality by creating an air seal for the home keeping out mould spores and allergens from under the floor area.
The ozone depletion potential (ODP) of a chemical compound is the relative amount of degradation to the ozone layer it can cause.

Spray foam not only provides fantastic conductive heat resistance (R rating) but also brilliant protection from convective heat transfer (draughts). Spray Polyurethane Foam is highly fire retardant, won’t sag over time, is VOC free and won’t act as a potential subfloor nest for rodents as batts do. It’s also great for squeaky floorboards and tight crawlspaces where traditional insulation types just can’t be fitted.

In new builds, where a vapour membrane can be installed and a rigid surface (such as a ceiling between floors) is present, batts are a great option for floor insulation. When retrofitting to existing buildings, however, trying to get batts to stay in place and provide an air seal by themselves is a battle that can’t be won. As long as the laws of physics remain the same, gravity will mean that eventually batts will sag away from the surface they are meant to be insulating and rest on the straps or mesh that is meant to be holding them. Also, batts never provide an air seal by themselves so they do nothing to prevent draughts.

General insulation questions :

The CodeMark Certification Scheme is a third-party building product certification
scheme that authorises the use of new and innovative products in specified circumstances in order to facilitate compliance with Volumes One and Two of the NCC, also known as the Building Code of Australia or BCA

There isn’t a one size fits all answer to that question and in most cases the installation is more important than the insulation, when choosing between batts and blow in insulation we are not only thinking about thermal performance but also the implications surrounding the building, available access, any existing insulation as well as electrical compliance.

Insulation has an ability to resist heat flow or transfer, and when this heat flow is measured it is known as the ‘R’ value. Essentially the higher the ‘R’ value, the more effective the insulation product will be. Incorrectly installing insulation, compressing it, damaging it or leaving gaps will result in the ‘R’ rating being diminished.

Heat transfer happens in three ways: radiation, convection or conduction. Radiation is rays of heat travelling through the air or space, like sunshine or the heat you feel off the grill on your BBQ. Convection is when molecules begin heating up and then move to another location. As an example, in a convection oven, the air is heated up and then blown around the food within the oven. Conduction happens when heat is transmitted through material within your home. For instance, when you place a pan on the stove top, the heat will transfer through the pan and heats up the food, that is conduction.
Batts are made up of millions of fibres layered together, these fibres create air pockets and these air pockets are very poor conductors of heat and thus they are more resistant to any heat transfer, air flow or radiation.
The higher the ‘R’ the better the insulation. The ‘R’ value does not necessarily mean a thicker type of insulation though, it really is all about the ‘R’ value, so the higher the ‘R’ the better the long term savings and the better the insulation.
The beauty about polyurethane spray foam insulation is that it is very versatile and can be fitted to just about any surface, it’s perfect for under timber and concrete floors, the underside of roofing systems, in newbuild walls to give a tight air seal, shipping containers, sheds, taks and wineries, just about any surface that would require insulation.

The transference of heat through the path of least resistance. Thermal bridging or cold bridging happens when the heat finds the gap between the wooden beam and the batt and escapes. That is why we always recommend ‘cross-hatching the batts to prevent this and result in a higher ‘R’ rating

Yes it can, our high density insulation retrofit systems not only have fantastic thermal performance but also provide outstanding resistance to acoustic transfer.
As a rule of thumb you start at the top and work your way down, however there are a couple of exceptions to that rule, one, in the event that you have some ceiling insulation, but it may not necessarily be great, but no, wall insulation, it’s sometimes worthwhile attacking walls first. Second, on other occasions you may tackle the floor first to prevent draughts or air infiltration.
Yes you can, polyurethane spray foam is incredibly versatile and will stick to most surfaces.

All insulation installations require a two pronged electrical safety check, the first component is ensuring that we have safe plan for recessed lighting and the second component is ensuring that the circuit protection is suitable for the type of insulation that surrounds the cables.

A board upgrade is an update of the electrical fuses in the home to the latest circuit protection with integrated earth leakage protection all mounted in a new enclosure within the existing fuse box.

Please ask any questions we have not answered here.