Underfloor Insulation expol polysterene packs
Filed under Insulation, Under Floor Insulation.
May 25th, 2009
I have been advised by a well intensioned friend that I should not use expol underfloor sheets in an older house e.g 1930,s villa . Can you explain properly why if this the case and if I can still use borer bombs after expol has been installed if I do use this option of underfloor insulation.
Thank-you
17 Comments
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trying to retrofit my house, July 9th, 2009 on 7:24 am
An insulation industry expert recommended I use a polyester Warmfloor underfloor blanket R1.8 90mm as the wrong product can make electrical wiring brittle. Maybe the wiring could be brittle if in contact with Expol – I don’t know?
Sarah, July 14th, 2009 on 9:57 pm
Our advice is that polystyrene products must not come into direct contact with electrical wiring, as the risk is that the plasticizer in the PVC coating around the wiring can be absorbed into the polystyrene, leaving the PVC brittle. For this reason, when Expol is installed next to wiring an air gap of a cm or so needs to be left.
An alternative to this is to adjust the position of the wiring (best done by a qualified electrician). Some companies that install polystyrene products may also use a protective sheath that slips over the wiring and prevents it from coming in direct contact with the polystyrene.
Note that polyester and fibre glass products ( batts and blankets) do not react chemically with PVC.
Apart from issues with wiring, there is no particular reason why Expol or other polystyrene insulation should not be used in an older house such as a 1930s villa. However, older houses sometimes have a lot of variation in the distances between underfloor joists which may make the correct sizing of the polystyrene sheets more difficult.
As far as I know, (I checked with Poly Palace, a Wellington supplier of polyester underfloor insulation), there is no reason why you should not continue to use borer bombs after installing Expol or other polystyrene insulation. If you are concerned about borer you may wish to wait until the borer flying season ( September-November), borer bomb, and then have the sheets installed.
Sarah Free (energy adviser, Wellington HEAC)
Nick, March 28th, 2010 on 3:08 am
Nova floor insulation looks good, polyester ‘bricks’ look like they fit similar to polystyrene idea, but they expand when set in place abit so I figure this would allow for timber movement, and variance in an old house. (We are also looking at insulating an old house). I just came across this product today and am trying to find out more about Nova floor. They say they are sustainable and fibre free, no problems with allergy.
Sarah Free, Energy Advisor, March 29th, 2010 on 3:05 am
Hi Nick, Just wondered if you were aware that the Nova floor product is installed by some of the companies working in the government’s “Warm up New Zealand:Heat Smart” scheme (in case you were interested in getting a quote for installing it).
If you have a community services card, you would be entitled to a 60% subsidy (sometimes more) on the cost. If you do not have a community services card , there is a subsidy of 33% capped at $1300. For more details of the scheme and a list of companies in your area go to http://www.energywise.govt.nz/funding-available/insulation-and-clean-heating/step-one.
Note that to install underfloor insulation you usually need a clearance of at least 50-60 cms of space between the floorboards and ground.
Also, for more details on the Novefloor products (or other insulation products ) you can go to the BRANZ website and view the product appraisals, http://www.branz.co.nz/appraisals.
Regards, Sarah
Theresa Sharp, April 26th, 2010 on 12:59 am
Is there a company in Auckland thet fit Expol under the energy wise scheme
Wendy Philpott, May 3rd, 2010 on 3:26 am
I live in Mangonui in the Far North and require underfloor insulation for my 1998 built pole house. i lose a ot of heat through the floor. Do I qualify for a subsidy to fit expol under my floor? Is there a company/installer in my areaplease?
editor, May 4th, 2010 on 3:25 am
@ Wendy and Theresa,
If your house is built before the year 2000, you should be able to get underfloor insulation installed under the “Warm Up New Zealand: Heat Smart” scheme in Auckland and the far North; however a lot of companies are installing polyester insulation (either batts or blanket) rather than polyester. See http://www.energywise.govt.nz/funding-available/insulation-and-clean-heating/step-one
for a full list of companies you could contact to get a quote.According to information on the EECA site, there are 5 companies that install polystyrene products in the Auckland area (I am assuming this probably means Expol). They are:
Premier Insulation Ph 0800 467 855
Natural Insulation Ph 0800 628 222
J H Brewster Ltd Ph 09 238 8037
Love Construction Ph 0800 867 070
The Insulation Group Ltd Ph 09 845 5060The first two companies also install in the far North.
The funding available is either a 60% discount (if you have a community services card) or a 33% discount if you dont. The 33% discount is capped at a maximum of $1300.
Hope that helps,
Sarah Free, energy advisor, Wellington HEAC
roger taylor, October 2nd, 2010 on 9:42 am
Thinking of fitting expol to my pre 2000 house. Thanks for advice about keeping it away from electrical wiring. What should I do with the foil insulation at present draped over the floor joist, cut it out, squash it up to the underside of the floor or what? Many thanks
Sarah Free, Energy Advisor, October 11th, 2010 on 3:21 am
Hi Roger, If your house is pre 2000 you would be entitled to a subsidy for additional insulation if the foil is no longer intact or has corroded and is not doing its job. ( See the reply to Wendy and Theresa above).
If you want to install the polystyrene over the foil, I think that would be okay. However, I have rung some contacts in the industry to just check on that and will get back to you to confirm.
Cheers,
Sarah
Stu, January 29th, 2011 on 6:58 am
Hi Sarah,
I have the same question as Roger (Oct 2nd) re installing expol over old foil sheet – did you manage to get any further confirmation as to whether or not its ok to leave it in place?
Cheers,
Stueditor, February 2nd, 2011 on 8:48 pm
Hi Stu,
I ‘ve rung around a few of the suppliers of polystyrene underfloor insulation and the advice I received was that this should be fine from an insulation point of view.
However, be aware that with foil insulation you need to be very vigilant about keeping your fixings ( staples, screws, metal clips etc) well away from electrical wiring. One of the reasons foil insulation is not used any more in the government insulation programme is that there were some fatalities from installers stapling through electrical wiring and the foil becoming live.
I recommend doing a cautious visual inspection of where your electrical wiring is positioned and whether this is likely to be a risk before you even start. ( Consult with an electrician if there is even the slightest concern).
It is also important to find out where your wiring is for two further reasons:
Firstly the polystyrene must not come into direct contact with electrical wiring (a chemical reaction goes on which means the PVC sheathing around the electrical cables can become brittle). Leave a cm or two between the wiring and the edge of the polystyrene.
Secondly you do not want to put too much insulation directly over the wiring as it could potentially be at risk of overheating.
If you would like further advice, please do feel free to call me directly.
Cheers,
Sarah Free (energy advisor, Wellington HEAC)
Stu, February 7th, 2011 on 6:45 am
Hi Sarah,
Thanks for the reply – much appreciated.
Cheers,
StuDeborah, October 4th, 2011 on 3:47 pm
The nova floor appears to be the only product that doesnt require stapling in place and is therefore a safer installation option but the R Value is only 1.4.Polyester products from Greenstuff and/same stuff ? Coccoon by Autex are 1.5-2.6(various websites) can anyone suggest a no staple option with a higher R value than 1.4
Adam, October 18th, 2011 on 1:37 pm
This product claims friction fit – clips only needed if it’s a bit loose when put into place. R values are higher.
http://koolfoam.co.nz/products/underfloor-insulation/none, April 21st, 2012 on 11:10 am
Novafloor is the best underfloor insulation, period.
Stapled sheets and blankets lose half of their R value when stapled as the amount of air in the product is greatly reduced. A polyester blanket loses 19% efficiency under low winds and 40% of its efficiency underfloor when there is high wind, however novafloor loses nothing at low wind and only 6% with high winds.Don, May 13th, 2012 on 10:53 am
I would not recommend Expol at all for villas or bungalows or any home with gappy polished floors. Ive seen many such homes with expol destroyed when they recoat the floor with polyurethane.
I also dont recommend you DIY expol unless you know what you are doing. Ive seen many poor installs in my time as an assessor for a major insulation company.
Richard Moore, June 28th, 2009 on 12:00 pm
Hi, I would disagree, If your floors are at all gappy T&G then Polystyrene is better than a Batt because the air moves slower through Poly than it does through a batt. and when air moves through the product that portion of the product isnt insulating so when you need it in that cold Wellington Southerly it aint workin properly. Of coursae you could move off the minimum specification products at R1.3 – R1.4 to award winning Poly Palace thicker warmer R2 palace planks and get the 100% money back guarantee of a climate of Brisbane. Just dont get Richie More talking….