InsulMax or similar retrofit wall insulation - Anyone here with experience?

[SimonW]

Hi All,

I have a 1960's brick veneer house which has already been double glazed throughout and has decent ceiling insulation, but the house fails to hold heat due to the walls having zero insulation.
The house was extensively renovated throughout courtesy of EQC not long before I purchased it. I have installed a log burner as the heatpump totally failed to provide enough warmth last winter. I now have plenty of heat while the fire is running which is great, but after the fire burns out, the heat is gone within an hour or two. This makes for very cold mornings still.

I got InsulMax to come and give me a quote to insulate the walls last week. Their insulation consists of the following:
Insulmax® is a soft, white blown mineral fibre. It is a thermal and acoustic insulation made by melting and spinning inert materials, treated with inert water repellent. It is non-hygroscopic (non-wicking), will not rot, degrade or sustain vermin and will not encourage the growth of mould, bacteria or fungi.

InsulMax is installed via drill holes in the external cladding, under pressure so that all voids are filled. The holes are then sealed up and mortar is applied prior to the holes being repainted. Because InsulMax material is water resistant, it can fill the entire space between the internal wall lining and the brick cladding - not just the space within the timber framing. This means that a significantly higher R value can be achieved when compared to standard batt insulation which requires an air gap to be maintained between itself and the cladding.

While I am generally sold on the product and an estimated wall insulation R value of 4+ at the conclusion of the work, I am concerned as to what standard the holes are drilled and patched up afterwards. My brick cladding was repointed and painted white after EQC works were completed, and the result is some pretty nice looking exterior walls. I'd hate for this to be ruined in the event that they can't match the pointing, meaning that the drill hole patches could be very noticeable on the cladding.

While installing via holes in the interior wall lining is an option, I really don't want to have to patch and repaint the whole interior of my house. At least the white paint on the bricks is easy to colour match and spot paint.

My house is around 105 square metres and the quoted price is a tad over $5.5k. Yes it's probably more expensive than ripping the internal wall linings off and insulating/relining/painting myself, but the mess, time and hassle of that just doesn't stack up in my busy household. Not to mention that to do it properly I'd have to rip the kitchen and bathroom out which is never going to happen!

Has anyone here had a similar retrofit wall installation done on a brick house? If so, how noticeable were the installation holes after they had been mortared up? I am also keen to know how much of a difference the insulation made to the warmth and heat retaining characteristics of the home. While there are plenty of testimonials on their website, I always prefer unbiased opinions from other sources.

[John the builder]

brick veneer incorporates a cavity for drainage and drying The concern with filling this gap is that this is lost and the insulation forms a possible bridge for water to transfer.
Bricks are naturally absorbent and water will run down the inside face when wet. There is good evaporation back the other way when the rain stops and sun is out again.
In your case painting the bricks has likely stopped water absorption into the bricks (but stops evaporation as well) but the window weathering details in bricks are crude (if not non existent)t and also rely on the cavity and they may be leaking regularly at present

Can you be sure that water isnt stil being drained from the cavity fro openings? This could be compromised by insulation?

This needs a consent because it isnt exempted for this reason that at least a cases by case assessment is done by the council.

Are you certain there is no building paper? (common in older veneers) but this would allow only the wall framing to be treated with insulation from the inside.

Does the quote include a building consent?

[hawkeye]

Has you had your brick veneer been asbestos tested? Some of those cladding that look like brick have asbestos backings. In that case I wouldn't be drilling through it.

We had a product pumped into the walls from the inside years ago in Wellington. It wasn't too bad but it was an old house with no dwangs so they didn't need to put a hole in each section. If you have dwangs you will need to make a hole in each section. I would think it would be safer to do it from the inside despite the mess as I would be worried about making lots of holes in the outside in case they fail and leak later on. Plasterers can patch holes very quickly and neatly. Or is there some reason you would have to rip all the linings off?

LAJ

[John the builder]

Brick veneer mean a solid brick wall outside a timber frams the system you refer to is venners and crick glued to a steet material and yes it could vhave contyined asbestos but not in this case,.

I dont think drilling the joints is a biggy

if the cavity is open the 40mm cavity space will spread the insulation. but how do they know they have filled enough?

You could ask for a thermal image to confirm insulation is consistent and filled all the voids

but the real question is is it a good idea? (despite the obvious thermal advantage)

[Dunning]

Do you have underfloor insulation and a moisture barrier? Together these make a huge difference. I've heard that there can be issues with settling/ voids with blown insulation into walls. John's thermal image to confirm insulation idea sounds like a must for any wall installation.

[ripeka]

You haven't actually said but I am presuming the ceiling insulation is up to scratch (newish with good depth) and that the underfloor was thoroughly checked with no old liquifeaction under there and is also well insulated.

also, i don't know the product but once installed, does its use in the wall stop you from ever again running new wiring and cables through the walls?

[SimonW]

brick veneer incorporates a cavity for drainage and drying The concern with filling this gap is that this is lost and the insulation forms a possible bridge for water to transfer.
Bricks are naturally absorbent and water will run down the inside face when wet. There is good evaporation back the other way when the rain stops and sun is out again.
In your case painting the bricks has likely stopped water absorption into the bricks (but stops evaporation as well) but the window weathering details in bricks are crude (if not non existent)t and also rely on the cavity and they may be leaking regularly at present

Can you be sure that water isnt stil being drained from the cavity fro openings? This could be compromised by insulation?

This needs a consent because it isnt exempted for this reason that at least a cases by case assessment is done by the council.

Are you certain there is no building paper? (common in older veneers) but this would allow only the wall framing to be treated with insulation from the inside.

Does the quote include a building consent?

Hi John,

Insulmax advise that their product is Codemark approved, and this certification means it is compliant with the NZ Building Code when installed correctly by an approved practitioner. Apparently this also means it meets certain standards relating to moisture and performance during fires etc. The below is taken direct from the Insulmax website:

Water resistant: Insulmax® is treated with an inert water repellent making it non hydroscopic and has a negligible ability to absorb or wick water. Tested according to EN 1609
Does not settle or shrink: Settling rated according to to EN 14064-1 :2010 as “S1” (settling of less than 1% or too negligible to be measured) at installed densities.


Inert: Insulmax® has no detrimental effect on existing building elements and does not react with TPS wiring.


Negligible resistance to the movement of water vapour: Classified according to EN14064, as possessing negligible resistance to the movement of water vapour. This means the product is breathable.

Dry and safe: Installed dry with no binders, glues, formaldehyde or other additives
Non-combustible: Achieves the highest standard of A1 – Non Combustible. Tested according to EN ISO 1182 & 1716




In regards to water from the windows, this is something I am unsure of. I do have reasonably new (ie less than 5 years old) aluminium double glazing in all windows in the house. These all have the external drain holes that all modern aluminium frames have. Do you think this means that there is negligible chance of water ingress from the windows?Yes I have been advised that building consent is required, and this cost is included in the quote I received.

I am certain there is no building paper in my house - last year I removed the GIB on part of one wall in order to run new antenna and power cabling to mount my TV on the wall. There was no building paper.

[SimonW]

Has you had your brick veneer been asbestos tested? Some of those cladding that look like brick have asbestos backings. In that case I wouldn't be drilling through it.

We had a product pumped into the walls from the inside years ago in Wellington. It wasn't too bad but it was an old house with no dwangs so they didn't need to put a hole in each section. If you have dwangs you will need to make a hole in each section. I would think it would be safer to do it from the inside despite the mess as I would be worried about making lots of holes in the outside in case they fail and leak later on. Plasterers can patch holes very quickly and neatly. Or is there some reason you would have to rip all the linings off?

LAJ

Hi Hawkeye,

No my bricks are indeed just good old fashioned masonry bricks so will not contain asbestos. I don't want to install the insulation though the GIB - I couldn't face the task of repainting the whole interior of the house, mostly because it was only just painted by EQC not too long ago.

The outside of my house was painted a matte white colour just over 2 years ago. The paint is elastomeric meaning it is non-permeable. Spot painting over each individual hole is very easy and I still have the paint for this. Insulmax have said they will do this and it's part of the quoted price. It is unlikely that the paint touch ups will be visible given the matte finish. In the unlikely event that they are, then I will go down the route of repainting the entire front wall as that's the one I look at every day when I get home from work. The others can wait for their 10 year recoat.

[SimonW]

Brick veneer mean a solid brick wall outside a timber frams the system you refer to is venners and crick glued to a steet material and yes it could vhave contyined asbestos but not in this case,.

I dont think drilling the joints is a biggy

if the cavity is open the 40mm cavity space will spread the insulation. but how do they know they have filled enough?

You could ask for a thermal image to confirm insulation is consistent and filled all the voids

but the real question is is it a good idea? (despite the obvious thermal advantage)

Hi John,

Insulmax say they use their thermal camera constantly during the installation to ensure that every void has been filled. They even brought it to the quote meeting at my house. I had a play with it and was able to ascertain that I had insulated my skillion lounge ceiling very effectively last year (no gaps anywhere). It was very interesting to see the difference (thermally speaking) between my insulated ceiling and the uninsulated walls....

[SimonW]

Do you have underfloor insulation and a moisture barrier? Together these make a huge difference. I've heard that there can be issues with settling/ voids with blown insulation into walls. John's thermal image to confirm insulation idea sounds like a must for any wall installation.

I have that foil insulation stuff stapled to my floor joists - I am not really sure how good this is to be honest (it was there when I bought it). If it's any indication, my bathroom and kitchen fllors are freezing underfoot in winter. There is also no vapour barrier but the ground underneath my house gets very good ventilation - there are venting grilles about every 1.5 metres around the entire circumference of my house. Improving the underfloor insulation and adding a moisture barrier are both on the agenda at some point.

Insulmax claim that their product is blown in "under slight pressure" so it ends up tightly packed. In a demonstration video on their website, they removed a perspex screen which simulated removing GIB from framing, and the tightly packed insulation stayed in place. They also claim their product has negligible settling characteristics (up to a maximum of 1%)

[SimonW]

You haven't actually said but I am presuming the ceiling insulation is up to scratch (newish with good depth) and that the underfloor was thoroughly checked with no old liquifeaction under there and is also well insulated.

also, i don't know the product but once installed, does its use in the wall stop you from ever again running new wiring and cables through the walls?

Yes my house now has very good ceiling insulation. When I bought it, the skillion ceilings with exposed rafters in the lounge area had none at all. I ended up installing R3.6 between the rafters and then lined it with GIB. This made a massive improvement to heat retention in the lounge. The rest of the house has standard ceilings and very good insulation.

My house in in the north west of Christchurch and there was very little liquefaction in this area, and no evidence of any liquefaction at this particular property.

In regards to running new wall cabling in future, Insulmax claims that their product is so tightly packed during installation that you can remove the GIB and it stays in place. They have a video demonstrating this on their website. The proof is in the pudding though. Fortunately I have pretty much run all the cabling I will ever need already (I have recently had fibre broadband installed as well as wall mounting my TV. All the cabling for these is already hidden behind the GIB or under the floors.