Internal Wall Insulation Across The UK
The most effective solution for solid-wall properties. IWI dramatically reduces heat loss through walls, cutting energy bills and improving your home's EPC rating.
The Benefits of Internal Wall Insulation
Warmer Walls
IWI significantly reduces heat loss through solid walls, which can account for up to 35% of a home's total heat loss.
Lower Bills
Solid-wall properties are among the least energy-efficient in the UK. IWI can deliver substantial savings on heating costs year-round.
Improved EPC Rating
Insulating solid walls is one of the most impactful improvements you can make to your property's energy performance certificate rating.
Suitable for Solid Walls
IWI is the primary insulation solution for pre-1920s solid-wall properties that cannot have cavity wall insulation installed.
What's Included
Our IWI service follows PAS 2030 and PAS 2035 standards throughout. From initial assessment to final decoration, we manage the entire process.
- Pre-installation survey and moisture assessment
- Damp treatment if required prior to installation
- Insulation board or stud-wall system installation
- Vapour control layer and airtightness detailing
- Plasterboard, skim, and redecoration
- Electrical socket and skirting reinstatement
- Grant funding applications handled
- PAS 2030 completion certificate
Is My Property Suitable?
IWI is typically suitable for:
- Pre-1920s solid brick or stone properties
- Properties where external wall insulation is not possible
- Flats and apartments with shared external walls
- Properties in conservation areas or with planning restrictions
Not sure if your property is suitable? Our assessors will carry out a full survey and advise on the best approach.
Book a SurveyCommon Questions
What is internal wall insulation (IWI)?
IWI involves fixing insulation boards or a stud wall filled with insulation to the inside face of external walls. It is the main option for solid-wall properties that cannot have cavity wall insulation.
How much room does IWI take up?
Typically 60–100mm depending on the insulation system used. This reduces the internal floor area slightly, but the thermal improvement is significant. We'll discuss the options and trade-offs during the survey.
Does IWI require planning permission?
Internal wall insulation does not usually require planning permission as it is an internal alteration. However, listed buildings or properties in conservation areas may have restrictions — we can advise on your specific situation.
Is IWI eligible for grant funding?
Yes — IWI may be funded under the Great British Insulation Scheme (GBIS) or Energy Company Obligation (ECO4) for eligible households. We handle all grant applications on your behalf.
How long does IWI installation take?
Installation time depends on the size of the property and the number of rooms being insulated. A typical terraced house takes 3–5 days. We'll give you a clear timeline before work begins.
Will IWI cause condensation or damp problems?
When installed correctly with appropriate vapour control and ventilation, IWI should not cause condensation or damp. Our assessors follow PAS 2030 and PAS 2035 standards to ensure the installation is safe and effective.
Ready to Insulate Your Walls?
Get in touch to arrange a survey and find out if you qualify for grant funding towards your IWI installation.
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