Replace underfloor metal foil?

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shanreagh, Jul 20, 8:09am
And Hunni Hunni I think the poster would have us believe these policy and procedure writers get up every morning and go to work determined to a bad job. (sarc)

Another point to also add to yours is 'experience from those using the product or procedure'.

As a writer of technical policy in a changing regulatory world it is a balancing act.
A very good reason why I totally respect the words of a former CEO that we were 'not to criticise* the work that had gone before in our sphere as our predecessors walked/worked to the beat of a different drum'. Provides cheap headlines but really does not get anyone anywhere to criticise the work of those who have gone before.

* Learn from it but do not criticise it.

fresiaa, Jul 20, 8:43am
Thank you all for your replies. So conclusion: even if it is properly installed it is passed its usefulness and better to be replaced.

tweake, Jul 20, 9:39am
i disagree a bit here.
if it was only the tech we are talking about, then your absolutely correct.
however in many cases its not about tech but rather the outside influences that play a major role in policy and procedure. for eg certain building supply companies who want the govt to change the rules so they could supply, for eg, untreated pine.
also the regulators got a lot of their information from the building industry who had a vested interest. that limited amount of information and failure to go to other sources, is one of the major causes of leaky homes. basically caused by the regulator(s) not doing their job correctly.

that you can most certainly criticise.

tweake, Jul 20, 9:40am
correct

zak410, Jul 20, 12:49pm
Yes, and replace with this :

https://www.expol.co.nz/

Trusted by Kiwis for more than 20 years, EXPOL Underfloor Insulation is easy-to-install and is available in 4 convenient joist widths 560, 470, 410, 360 (mm). It is the DIY solution that will keep your home warm, dry and healthy.

Suitable for use in both new and existing homes, EXPOL Underfloor Insulation comes with a 50 year product warranty and requires no maintenance."

** note the different sizes, made to fit under most wooden floors.

stevo2, Jul 20, 12:58pm
fresiaa. Personally I would be leaving it alone. It is perfectly safe as long as it doesn't come into contact with bare wiring. You are correct that it is no longer allowed to be used in new builds or renovations.
Cheers Stevo

stevo2, Jul 20, 1:01pm
Incorrect, the building code has NEVER REQUIRED Gib Board to have foil on the back. It has ALLOWED its use back in the old days as a cheaper ALTERNATIVE to soft insulation.

oh_hunnihunni, Jul 20, 1:29pm
Except to imagine any human endeavour can be free of politics is to be dreaming.

tweake, Jul 20, 2:00pm
i disagree.
its not the best insulation wise. its insulation density works against it. you really want something that can fill the joist cavity or be stung across the joists.
but the big issue is that it has low permeability. moisture does not go through it well, which means you can get moisture trapped between it and the floor. you can end up with condensation and have puddles of water on the insulation.

thats why i like polyester. its highly permeable, moisture goes right through it, so a floor can dry through it. and its size, its thickness for its insulation value, actually works well in this situation.

trade4us2, Jul 20, 2:57pm
https://www.building.govt.nz/about-building-performance/news-and-updates/all-news-and-updates/bc-update-188/

The Chief Executive of the Ministry of Business, Innovation and Employment (MBIE) has declared a ban, under section 26 of the Building Act 2004, on retrofitting or repairing foil insulation.
It is an offence under the Building Act to breach a ban and anyone who breaches the ban may be liable to a fine of up to $200,000.

nzshooter01, Jul 20, 3:50pm
Thats how it was suposed to be installed?
Not stretched tight but allowed to sag as said above

blueviking, Jul 21, 1:41am
Insulation installers have to remove it before installing any underfloor insulation by law.

martin11, Jul 21, 2:48am
Gib Foil was available before Batts here in Chch .

nzshooter01, Jul 21, 7:17am
yes but never compulsery

gabbysnana, Jul 21, 8:21am
not so, havent seen an underfloor installer remove it yet, just pushed up with polyester stapled over the top.

tweake, Jul 21, 8:48am
thats rough.
it should be removed just for insulation sake.

tho i left a lot of mine in because the new insulation went across the bottom of the joists and did not touch the old foil. (there is also no power cables there).

blueviking, Jul 22, 2:22am
I work for a property management co. and now we have to measure homes for heating and ventilation, so going back to check insulation statements and quotes, there was always a cost to remove the foil, followed by the wording of the law that pertains to it.From back to 2017.So if they just stapled over the foil, then that is illegal and you need to get them back to redo it.

tweake, Jul 22, 6:17am
and how exactly do you MEASURE homes for heating and ventilation?

wasgonna, Jul 23, 10:45am
I'm having the foil removed and proper insulation put under the floor under the updated Govt warmer homes scheme. If home built before 2008 the Govt pay for removal of foil and fully insulate under floor with 90% subsidy.

To give an idea what that means . . . my 100 sq m home will cost me just $212 total. This is floor only as roof up to regulation.

All signed up ready to go this morning, so hot off the press.

ryanm2, Jul 23, 3:56pm
That’s not true , the last poor soul that was killed was electrocuted as the incoming live and neutral were transposed. Both the electrician and inspector were prosecuted from memory.

blueviking, Jul 24, 1:54am
Every rental home in NZ has to have a fixed heating device that is thermostatically controlled.The law also requires the installation of a rangehood and bathroom extractor fan. This report must be completed by December 2020 otherwise there is a $5000 fine.If you go to "Tenancy services" all the info is there. How to measure your living area for what size heating device you require and how to measure for the ventilation standard.If you own a rental and throw in a smaller heatpump, you will have to replace this with the correct size as only items installed before July 2019 can be allowed if not compliant.

blueviking, Jul 24, 2:00am
And, it differs for which part of the country you live in, so for the same size house in Auckland or Southland,the KW required in Southland is 2-3kw more. It goes on the outside ambient temperature, to then heat your living area to 18*. Open fires do not count at all to heating.

blueviking, Jul 24, 2:01am
If you buy a house to turn into a rental, you have 90 days to install all of the above(including ceiling and underfloor insulation.

tweake, Jul 26, 10:54am
again, HOW are you measuring for ventilation etc?

my guess here is your not. your using the standard calc which doesn't take ventilation into account, because your not measuring ventilation.

hydroplane, Jul 26, 1:06pm
Venting is installing a range hood and an extractor fan in the bathrooms, no cal required, Any accessible area in a rental dwelling must be insulated to a R value and the best under floor product on the market for a piled house is a synthetic wool, (absolute requirement to remove any sisalation found), in excessively wet area's, some lay polythene on the ground as well for rising damp suppression. Problem with Xpol foam is that it falls out in high wind and is normally only installed with a compression fit.