Product & Installation Information


  • Ensure a clear working environment - eliminate hazards such as sharp objects and obstructions.
  • Identify all potential electrical hazards. Power cables must be identified to prevent staples piercing them during installation.
  • Ensure a safe working clearance under the floor. At least 400mm clearance is required below the bottom of any bearer.



You will need:

  • Overalls, dust mask and safety goggles for working in a dusty environment.
  • An LED headlight is a much better option than mains power work lights.
  • A quality staplegun or hammer tacker and 10-12mm staples. Use stainless steel staples in coastal areas.



PolyKing Underfloor Insulation is a polyester laminate specifically designed for the underfloor insulation of new and existing suspended floors. For new buildings the insulation is installed after the flooring has been laid. PolyKing Underfloor Insulation has two carefully engineered performance layers:

  • A high loft polyester upper layer provides thermal insulation.
  • A tough, bonded polyester outer layer provides resistance against sagging and staple tear-through as well as mitigating against wind wash.

The two layers are permanently fused together through the thermal bonding process. This unique construction fully utilises the benefits of the individual components, to create a high performance underfloor insulation.

PolyKing® is designed to be stapled between floor joists in old or new houses to meet the requirements of the New Zealand building code.



  • PolyKing underfloor product is designed for all underfloor ground conditions. However the insulation will not prevent ground vapour rising and potentially causing damage to your home. If the ground is wet, a vapour barrier (250µm polythene) should be installed directly over the earth.
  • Distribute the bags of PolyKing product to the areas to be insulated. The underfloor bales are designed to be easily maneuvered under a home. Leave them bagged until you are ready to install each section.
  • Split the bags, or pull the PolyKing from the bag. Run the PolyKing in a continuous length between the floor joists and over the main bearers.


  • PolyKing is designed to friction fit most joist spacings. Push the PolyKing lightly up to the bottom of the floorboards, while still retaining its loft. Staple through the bottom layer between 50mm and 80mm from the top of the joist. The idea is to allow the insulation enough space to loft to its designed thickness but still have the insulation in contact with the underside of the floor. At the end of the joists the stapling height should be closer to 50mm below the top of the joist to ensure no air can circulate above the insulation.
  • Staples should be placed every 10cm or less, while keeping the PolyKing firm and tensioned. Do not staple directly to the underside of the floor - this will compress PolyKing and reduce its insulating properties.
  • Two lengths of insulation can be butt jointed mid-section by pressing the ends together firmly before stapling the new length.
  • The insulation can be torn across the width of the roll to trim the length to fit firmly against the bottom plate and joist noggings. It is good practice to also staple the ends of the rolls to the bottom plate and joist noggings.
  • Where the floor joist spacings vary, measure the gap by holding PolyKing up to the joist and simply rip across the roll to size, push into place and staple. Repeat until the joist row is complete.


  • Clearances: Leave a 100mm gap between insulation and waste pipes that penetrate through the floor, and a 200mm gap between insulation and underfloor lighting and heat sources
  • On completion, remove all plastic bags and leftover material from the underfloor space. • Staple a Product Information and Identification Certificate adjacent to the underfloor access for future reference.



Having the right insulation product is one part of the story. The other is how it is installed – it is vital to the performance of any underfloor insulation that it is installed properly, as this can drastically affect the performance and longevity of your underfloor insulation.

PolyKing advises you use trusted, experienced and qualified installers for your underfloor insulation. We use and highly recommend EnergySmart – who have been doing a great job nationwide since the 90's!

The cost effective option underlying a warmer, healthier home

Millions of tiny pure polyester fibres are bonded together to create a thick thermal barrier

PolyKing® is manufactured by trusted parent company Terra Lana Products, as an economical alternative to the Terra Lana wool insulation range.