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IWI – Refurbishment


EpsiLine – when insulating on the outside is not an option!

Wetherby’s R&D department are always on the look out for new opportunities to help expand their system portfolio and it seemed a natural progression for Internal Wall Insulation to be the next step.

Along with external wall insulation, Wetherby are now in a position to offer a ‘whole house approach’ when it comes to thermally insulating solid walled properties.

Specifically developed to meet an increasing demand to improving the energy efficiency of homes in the UK that need to maintain their external appearance, Wetherby’s new EpsiLine Internal Wall Insulation System is one of the most flexible and cost effective IWI solutions on the market.

The EpsiLine System comprise a high performance rigid PIR insulation board – featuring a bi-laminate foil/kraft paper-facing – bonded to a tapered edge standard plasterboard. This pre-bonded solution means that the insulation and plasterboard is installed in one operation, significantly reducing installation times when compared to alternative systems where each component is individually fixed.

Epsiline-BBAOffering installers and contractors complete flexibility during installation, the EpsiLine system is BBA approved (certificate number 15/5193) for use with the most diverse range of fixing techniques including:


Fixing Method Wetherby System
Dot & Dab EpsiLine DD
Direct Fix EpsiLine DF
Timber Batten EpsiLine TB
Metal Furring EpsiLine MF

Each fixing method provides a reliable long term energy saving benefit, especially on domestic refurbishment projects and they’re absolutely ideal for properties where no cavity exists (solid wall).

The EpsiLine IWI System is available in a wide variety of thicknesses, with a 15mm reveal board being the ideal solution for window and door reveals.


The benefits of insulating internally

  • Generally cheaper to install than external wall insulation.epsiline-iwi-internal-wall
  • Quicker to install than EWI – in fact EpsiLine is one of the quickest solutions on the market!
  • Doesn’t affect the external appearance of a property – architectural features can remain intact.
  • Delivers better U-values and thinner solutions compared to alternative systems.
  • Offers the installer maximum flexibility and installation speed due to the tapered edge insulated plasterboard.
  • Provides reliable long term energy savings.


Anticipated Cost Savings

Type of property Installation cost Savings per year CO2 savings per year (kg)
Detached house
(four bedrooms)
Est. between £4,500 and £15,000 £460.00 1,040
Semi-detached house
(three bedrooms)
Est. between £4,500 and £15,000 £270.00 600
Mid-terrace house
(three bedrooms)
 Est. between £4,500 and £15,000 £180.00 395
Detached bungalow
(two bedrooms)
Est. between £4,500 and £15,000 £180.00 410
Mid-floor flat
(two bedrooms)
Est. between £4,500 and £15,000 £150.00 345



For further information on the EpsiLine system, contact our technical support department on 0800 107 32 99.