top of page

Internal Wall Insulation

Internal Wall Insulation: Pros, Cons, and Installation Tips



If you're looking to improve the energy efficiency of your home and save on heating bills, internal wall insulation is worth considering. However, it's important to approach it with care, as poorly executed insulation can cause issues such as damp and condensation.


Internal wall insulation involves applying insulation to the interior face of external walls, usually in solid stone or brick homes built before the 20th century. This insulation method can be cheaper than external wall insulation, but it also reduces valuable floor space and can be disruptive during installation. So, it's important to make sure it's the best insulation solution for your home.



Type of installation


There are four main methods of installation, with building a new stud wall being the most common. However, it can be disruptive and require the removal and re-fixing of items such as switches, radiators, and kitchen units.


How much does it cost internal wall insulation?


The cost of internal wall insulation can range from £40 to £100 per square meter, depending on the type of insulation and the condition of the existing wall. Up to 60% of the cost will be labor, so skimping on insulation thickness to reduce costs is not recommended.




Building regulations stipulate requirements for airtightness and heat loss, with a maximum U value of 0.3W/m2 for solid walls. Achieving this requires installing at least 100mm of rigid insulation, such as Celotex or Kingspan.


Improving airtightness has a greater impact on heat loss than insulation, as gaps, cracks, and penetrations can be problematic. Insulation applied to the wall can form an airtight barrier, but the benefit will be reduced by up to 50% if the gaps, cracks, and penetrations are not also addressed.




Internal wall insulation can cause damp and condensation if not installed properly. A vapour control layer needs to be installed to prevent damp penetration, and cold bridges need to be covered with insulation to avoid the formation of condensation.

There are three basic methods of installing internal wall insulation, which involve checking the wall's condition, undertaking remedial work, and choosing the preferred installation method.




In summary, internal wall insulation can improve the thermal efficiency of your home and save on heating bills. However, it's important to approach it with care, as it can cause issues such as damp and condensation if not installed properly. By following the proper installation methods and addressing airtightness and heat loss, you can make the most of internal wall insulation and enjoy a more energy-efficient home.


If you're looking for a reliable contractor for your house extension, loft conversion, refurbishment, or renovation in London, be sure to check out the hashtags we've provided above. Don't hesitate to contact us if you have any questions or would like to discuss your project in more detail. We'd be happy to help you create your dream home

13 views

Recent Posts

See All
bottom of page