How to check your underfloor insulation

Insulation

Not sure if you’ve got enough underfloor insulation? Here's a handy checklist to see if your underfloor insulation is up to scratch.

Book a FREE Home Energy Assessment and we'll come and tell you. 

If you'd like to have a look yourself before we get there, here is a handy underfloor insulation checklist:

For underfloor foil insulation - if it's fixed with staples, avoid touching the foil unless you've had it checked by a registered electrician (if an electrical cable was accidentally stapled when it was installed, there's a risk the foil could electrocute you). Check:

  • that it is either stapled to the underside of the floor joists, or draped over the floor joists with a sag of 100mm or more
  • that the foil is still in good condition, i.e. not tarnished, very dirty, torn, delaminated or otherwise deteriorated
  • that, if attached to the underside of the floor joists, the foil is still well-supported by staples which should be punched flush to the foil surface
  • that all joins between foil runs are overlapped and sealed with adhesive foil tape
  • that the airspace between the floor and the foil is properly sealed, including along the floor perimeter and at the points of pipe penetrations
  • that, for houses with brick-veneer cladding, the airspace between the floor and the foil is properly sealed off from the brick-veneer cavity
  • that it covers at least all parts of the suspended floor which are accessible.

For underfloor bulk insulation check:

  • that it is at least 50mm thick
  • that there are no visible gaps between the insulation and the floor joists or at joins of insulation pieces
  • that the insulation is dry and not infested with vermin (e.g. birds or rodents nesting)
  • that the insulation is securely installed flush against the underside of the flooring (e.g. floorboards)
  • that it covers at least all parts of the suspended floor which are accessible.

For underfloor polystyrene insulation check:

  • that it is at least 50mm thick
  • that there are no visible gaps between the insulation and the floor joists or at joins of insulation pieces
  • that the insulation is securely installed flush against the underside of the flooring (e.g. floorboards)
  • that it covers at least all parts of the suspended floor which are accessible.

Your underfloor must be accessible (i.e. more than half a metre off the ground) to be able to put in new insulation. If you are unsure about how effective your underfloor insulation is, talk to Smart Energy Solutions or a qualified builder.

 

Learn more about underfloor insulation types, brands and installation.

Information reproduced here from the EECA Energywise website Is Your Insulation Adequate? page.