Complete Manual for Internal Wall Insulation

Since many year, solid wall insulation has been a viable option for improving energy efficiency, but implementation is still very low. In Great Britain, 7.7 million homes have solid, uninsulated walls, thus installing internal or external wall insulation is theoretically possible.

However, only about 3% of those properties have wall insulation installed till now, which is combined internal and external insulation.

Your home could become more pleasant and your heating expenses could be significantly reduced by insulating your solid walls.

Your home’s external walls are presumably solid walls rather than cavity walls if it was constructed before the 1920s.

Solid walls cannot be filled with cavity wall insulation since they have no gaps. A small space, or “cavity,” separates the two layers that make up cavity walls.

However, solid walls can be shielded and insulated from the inside as well as the exterior. This will cost so much to insulate than a typical cavity wall, but you’ll also save more on heating costs. You can freely contact the surveyors of Spray Foam Quotes to derive at least three Quotes by comparing it from different suppliers.


●     Prevent heat loss in your house

●     Reduce your heating costs.

●     Cut back on your carbon footprint

How does it function?

Although there are some variances, the fundamental idea is the same for insulating internal and external walls.

To guarantee that the exterior of the wall that is visible to the outside world is not compromised, your installer will apply insulation material to it before covering it.

Types of Solid Wall Insulation

The first point you must determine is what kind of walls you possess. If you’ve got solid walls, they are almost probably not insulated. If the exterior of the house includes brickwork, take a close look at the brick pattern to determine how the wall was constructed.

Insulation comes in a wide variety of forms, both in terms of the components and procedures used. Let’s get over all the most common choices.

Material Types

Insulating materials are typically made of wool varieties like fibreglass and mineral wool or foam polymers like polyurethane, icynene, polyisocyanurate, and polystyrene. Foam plastics are lightweight, strong, and moisture-resistant, but they are also combustible and release poisonous gases when they burn. Wool kinds are non-flammable, typically less expensive, and frequently include an integrated vapour barrier that helps keep dampness at bay.

Rigid insulation Boards

An installer will mount these sturdy, light-weight rectangles on your wall before plasterboard is applied. Some even have the plasterboard already fastened. Rigid insulation boards offer the maximum level of energy efficiency while often costing more than other types of solid wall insulation. They can also get thinner as a result, taking up less room. They’ll increase the heat insulation and soundproofing in your house. Additionally, your installer may include a vapour barrier in them to shield your home from moisture. Although they are usually flammable and will release harmful vapours if they burn, they won’t decay.

Flexible Thermal Lining

Rolls of flexible thermal lining are available, and they can be attached to walls using a specialized adhesive. Although it is frequently less expensive, it is normally less effective at protecting against anything than its two interior counterparts. Additionally, it is only about 10mm thick and simple enough for a DIY installation. This is an excellent option if you’re searching for an inexpensive solution to somewhat improve your insulation levels.


After the insulating material has been completed, plasterwork, also known as render, is applied to the exterior of your home to give it a polished texture. It typically costs less than cladding and gives you the freedom to paint the wall any colour you desire, something that cladding typically does not. As an alternative, you might alter the appearance of your home and increase its durability and wear resistance by adding pebbledash, occasionally pebbles to the plasterwork.

Cost of Solid Wall Insulation

According to the Energy Saving Trust, solid wall insulation costs in the UK are approximately £12,000 for external walls and £8,500 for interior walls.

In order to save money, we advise integrating insulation work to other home renovation tasks like window replacement or solar panel installation. You can spread out the costs in this manner.

For solid wall insulation, you’ll normally need to pay £100/m2, so you may measure your house and determine an approximation of the cost. Here is a ballpark cost for various types of homes, but we still advise getting quotes from at least three experts.

Internal Wall Insulation

Insulating internal walls can be accomplished in two ways: by attaching rigid insulation boards to the wall or by erecting a stud wall with insulation material like mineral wool fibre within. Internal Insulation is spray foam insulation cost

  • It is typically less expensive to install than insulation for exterior walls.
  • The floor space of any rooms in which it is applied will be marginally decreased.
  • Although it can be done room by room, it can be rather disruptive.
  • It requires the removal and reattachment of skirting boards, door frames, and outside fixtures.
  • It can make it difficult to attach large objects to inside walls, even though specialized fasteners are available.
  • It cannot be done prior to addressing any issues with rising or penetrating moisture.

External Wall Insulation

For external wall insulation, a layer of insulating material is fixed to the wall before being covered with a particular kind of render or cladding. The finish can be painted, tiled, paneled, pebble-dashed, smooth, textured, painted again, or finished with brick slips.

Savings from Solid Wall Insulation

According to the EST, solid wall insulation can reduce your annual energy costs by up to £540 and spare the environment up to 0.9 tonnes of CO2.

According to the most recent government statistics, the UK is liable for more than 400 million tonnes of CO2e* each year. This amounts to 6.2 tonnes per individual.

Therefore, the thought of saving up to 24% of that sum and improving your family’s winter comfort sounds fantastic.

Also, having an extra £540 in the bank each year isn’t bad.

 As a result of the ongoing energy crisis, which is causing expenses to keep rising, proper house insulation is becoming even more crucial.


To avoid causing additional damp issues in the future, water vapour must be taken into consideration whenever solid wall insulation is installed in a structure. This can need employing “breathable” insulation materials to keep the vapour from leaving the walls, or it might entail constructing a constant vapour barrier to prevent any vapour from entering the walls from the inside. To create a moisture management strategy unique to your building, you will want the insulation with spray foam from a skilled specialist installer.

Your home may become more resilient to cold, wetness, and noise by adding solid wall insulation. You might reduce your annual energy costs by several hundred pounds. Using less energy to warm your home can potentially aid in the fight against climate change.