Recently a customer for ecoMaster’s polyester underfloor insulation posed these two questions:
Termites Underfloor EcoMaster

1. Does Polyester Underfloor Insulation hide termite infestation?

Polyester underfloor insulation fits between the floor joists and if stapled as we suggest, it is held up firmly against the underside of the floor. 


Termites’ favourite food is timber and they eat it from the inside.  They prefer chunky timber-like floor bearers and joists.  Wall studs are also a favourite haunt.  Usually, you don’t see any damage from the outside of the timber, they somehow know when they are getting too close to the surface of the timber and veer away. 


Usually, the first indication that you have had termite infestation comes when there is some kind of structural problem such as sagging or you notice an extra springy floor.  Or part of your floor may just go “crack” as you step over a section that has been well eaten by the termites.


Having insulation fitted between the joists will not impede the detection of termites.  In fact, if they are already there then the stapling may actually discover their presence. In any case, if there is a subsequent termite infestation, you are just as likely to discover them by trying to pierce the bottom of the joists as you would from the side of the joists.  They will also be in the bearers which remain exposed.


The usual regime for inspecting termites in a timber floor with stumps is to look for the mud tunnels they built to travel from the soil up to the yummy timber.  These may be on an external wall, either inside or outside or they may be on one of the stumps.  The ant caps on the top of the stumps are there to make these tunnels even more visible.  None of this is affected by the inclusion of polyester underfloor insulation fitted between the joists.


Of course, if termites are detected in the floor timber, it will be necessary to remove the insulation in that area.  This can easily be done with polyester underfloor insulation by simply pulling firmly on the insulation at the staple fixings.  Keep the insulation because it will be able to be refitted after eradication and repairs have been affected.  Polyester insulation will not be impacted by termites and can be reused. 


By the way, if you have timber that is riddled with small holes, that’s caused by the larvae of the Borer beetle.  It’s not termites.  In severe cases, borer damage can also cause structural issues but that is reasonably rare and mostly it does not.  Professional spraying with insecticide usually prevents further damage.


Caption So whats wrong with next door EcoMaster

So what’s wrong with next door?

2. Does Polyester Underfloor Insulation encourage termite infestation?

As a potentially edible material, polyester underfloor insulation certainly does not encourage termites – it’s not their staple diet of cellulose. In our 20+ years of installing polyester insulation, we’ve had zero evidence of a sudden change in termite tastes.

Equally, there is no evidence that the other most common types of Australian underfloor insulation, such as fibreglass, glass wool or mineral wool, excite the average termite either.

Interestingly (or worryingly, if you’ve used it), there’s evidence from the US that termites can infest foam board insulation, although the jury is out as to whether this constitutes a change in diet or a willingness to chew through the foam as a means of accessing timber on the other side.

3. How can I discourage termites?

Termites are encouraged by damp conditions.  You can discourage termites by: 

  • Keeping the underfloor area well-ventilated
  • Keeping the area around your foundations (if you have a brick exterior wall) clear of brush and tree matter
  • Keeping your subfloor area clear of detritus.  This will make inspection easier and more likely to spot the telltale signs of termite activity.
  • If you live in a termite-prone area, a regular inspection by a qualified pest controller is prudent. 

People Also Ask: 

⇒  What insulation is best for discouraging termites?

Polyester insulation is one of the most effective forms of termite protection.  It is highly resistant to damage caused by termites. Polyester does not form part of a termite’s natural diet. It is lightweight and easy to install, making it an ideal choice for roof insulation, wall insulation and underfloor insulation.  As polyester insulation does not contain any glues holding the fibres together, it will hold its shape and format much longer and there is nothing to break down between the fibres.


⇒  How do I install subfloor insulation and reduce the risk of termites? 

If you have any concerns about termites in your floor or floor stumps: 

What’s next?

We hope this article has helped you learn how to use simple ways to save on your utility bill. This in turn will help you on your energy and thermal efficiency retrofit journey to make your home more comfortable all year round, and reduce your costs and carbon emissions.   

Next, explore what is R value and why is it important.

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