ISO EPS is a cost efficient, thermally efficient and easy way to pour foundations and floors. Possible savings are three-fold; save on materials, labour and time!

The system works by using Expanded Polystyrene (EPS for short) in sheet form, which is cut in profile to suit the perimeter of your build.

Known as ‘formwork’ these precision-cut pieces fit together to provide an insulated ‘box’ for you to add concrete to.

Essentially, the insulated foundation solution provides the ‘slab’ which you build upwards from. Take a look at our step-by-step guide and discover the ease and convenience, making your foundation journey one that saves you money on materials, labour and time!

ISO EPS offers a complete, thermally-insulated foundation envelope at a considerable saving to the customer, when compared with traditional methods. Just imagine the scenario:

You’re looking to create an energy efficient and cost-effective construction for your foundations but every quote you receive is unclear, timely and expensive? Yep, we’ve been here too and as today’s market becomes, ‘energy-conscious’, insulated foundation options like ISO EPS come into their own as they provide a quick build with added thermal benefits – your feet will thank you for it.

How much different can it be, we hear you ask? Our answer is; impressively different!


With ISO EPS, you get many benefits:

Benefits at a Glance

  • Is suitable for all ground conditions.
  • Is suitable for all building types.
  • Offers low U-Values
  • Eliminates wall-to-floor cold bridge
  • System will not diminish over time – EPS lasts
  • Unaffected by water
  • Passive slab approved.

Frequently Asked Questions

ISO EPS is an innovative and passive-approved system to achieve an insulated foundation without the use of trenches.

This trenchless-system uses a rigid EPS which is precision-manufactured and fully tested to be used as formwork in a wide variety of foundation conditions.

ISO EPS is a cinch to install and is based around EPS formwork that is installed in the ground and remains in situ. An insulated foundation is constructed using the insulation profiles before applying steel / concrete.

This is specified by your Structural Engineer who will design your slab and provide a construction-issue drawing which will itemise the depth of the slab (in mm) and also the steel requirements. Generally the system uses much less than traditional methods so results in a cost-saving.

ISO EPS is a breeze to install, arriving in sheet form as a kit, ready to install straight away according to the drawings provided. ISO EPS reduces build times drastically, with feedback of 3 days and below commonplace.

Important Note: There are steps you can take to ensure this happens. Preparations made before the system arrives are absolutely key. For further information on preparation of your site, see the installation notes below.

Often it’s a case of your budget and ground type but ISO EPS ensures you build to a high thermal standard using the EPS insulation. It’s a simple formula, excellent insulation = significantly lower energy consumption = lower bills and short-term return on investment (ROI).

For a more detailed discussion on pricing, please send your plans to us or get in touch and we’d be happy to look over your build and provide more details.

ISO EPS arrives in EPS 'L' profile form and requires amendment on-site to your design and with this in mind, end-to-end only takes around 4 weeks. This is especially competitive when you consider other build systems taking 12-16 weeks.

How does it work?

With ISO EPS the principle is simple and can be split into two distinct phases:


  • Prepare ground according to details specified by your appointed Structural Engineer. You may also be required to provide a Soil Investigation (SI) report to help your engineer make the correct calculations. This takes the form of a 'pack' that's essential before you commence with any groundworks.


On delivery of the system, offload all the sheets of insulation and begin to lay out the formwork pieces according to your build drawing, supplied by us. Place each 'L' element in line that correspond with the drawing to the perimeter of the build. Following this you need to:

  • Continue placement of 'L' profiles. Trim profiles as necessary to achieve a tight fit.
  • Check drawings for trimmed high-density sheet.
  • Place three layers of ISO EPS insulation sheets over the remaining foundation. Overlap the sheets to achieve continuity of insulation and secure with pins provided.
  • Include DPM, steel and concrete as advised by your structural engineering pack. ISO EPS is now ready to take concrete.
  • Fill the system with concrete, power floating the slab and leave to cure for at least 48 hours before building.

You’ve now successfully built with ISO EPS, the quick and easy choice of trench-less, insulated foundation solutions.

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