Internal Wall Insulation In Scotland

Scotland’s distinct climate often demands solutions that not only combat the cold but also address energy efficiency. Enter internal wall insulation: A solution that’s both economical and efficient.

The benefits of internal wall insulation are clear. It’s not just about energy efficiency; it’s also about creating a more comfortable living space and reducing noise. Additionally, with the potential to save money on heating bills, it’s a win-win for Scottish homeowners.

If you’re considering internal wall insulation as an energy-saving solution, you’re already taking the first step to a warmer, smarter way of living.

With this comprehensive guide, you’ll learn everything you need to know about internal wall insulation, why it’s necessary, the types available, and the installation process.


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What is Internal Wall Insulation?

Internal wall insulation involves adding layers of insulation material to the inside walls of a building. The materials used not only prevent heat from escaping but also boost overall energy efficiency and offer the added perk of soundproofing.

Oftentimes, the process involves attaching rigid insulation boards to your walls or setting up metal frames (called “stud walls”), which are then packed with materials like mineral wool.

These insulating materials work by bouncing heat back into the room, keeping the indoors warm. This means homeowners can enjoy a steady, comfortable temperature without frequently fiddling with the heater, which can lower energy bills.

Plus, these insulating layers can also make things quieter, lowering those loud street noises by up to 40%.

Why Insulate Internal Walls?

Around 35% of a home’s heat escapes through its walls, windows, and doors. For newer homes, cavity wall insulation is common, but for older buildings with solid walls, internal wall insulation is your best insulation option. Even if you have external wall insulation, adding insulation inside can still offer plenty of advantages.

Cost savings

One of the most significant benefits of insulating your internal walls is cost savings. Homes with this insulation use roughly 32% less energy than uninsulated ones. This means lower monthly utility bills, particularly with the recent surge in energy prices. Plus, it’s usually about half the price of external insulation.

Energy efficiency

If external wall insulation isn’t an option due to building codes or historical preservation, internal wall insulation is your go-to solution. While external insulation may be better at regulating temperatures, internal insulation is great for keeping indoor temperatures steady. This negates the need to consistently increase your heating indoors, which reduces your demand for energy.


Regardless of the time of day or season, homeowners will enjoy steady temperatures inside their homes with internal insulation. This means heaters or air conditioners work less, keeping homes cosy without high energy bills.

Additionally, internal wall insulation can help reduce noise, lessen condensation and improve air quality. Overall, you get optimal comfort in your living space.

internal insulation

Who Needs Internal Wall Insulation?

If you have solid walls or if cavity wall insulation isn’t enough, internal wall insulation might be your next best bet, especially if external wall insulation is beyond your budget.

Internal wall insulation can be especially beneficial for specific types of homes and situations.

  • Older homes: Many older homes, especially those built before the 1920s, have solid walls without a cavity that can be filled with insulation. These structures often lose a lot of heat, making them prime candidates for internal wall insulation to help maintain warmth and energy efficiency.
  • Historical buildings: When buildings are historically important, external insulation is often restricted. Internal insulation is an option that allows owners to improve energy efficiency without altering the building’s exterior appearance.
  • Homes with external limits: In some cases, properties can’t be changed on the outside because of space issues or local rules. Internal insulation offers all the insulation perks without any outside changes.
  • Noise-affected homes: Homes in noisy environments, such as urban centres or near busy roads, can benefit from internal insulation. The insulation can help dampen sound to create a quieter interior space.
  • Homes in extreme climates: In areas with severe winters or hot summers, internal insulation can help maintain a comfortable temperature. It eases the strain on heating and cooling systems, saving homeowners money on energy bills.
cavity wall insulation

How Does Internal Wall Insulation Work?

Internal wall insulation is applied directly to the interior walls of your home, acting as a heat shield to prevent warmth from escaping through the walls. Other than just trapping heat; it sets up a protective layer between you and the underlying brickwork.

External insulation might enhance your wall’s thermal performance, but it doesn’t instantly boost the cosiness you feel indoors. That’s where internal insulation shines.

Your comfort in your home relies on two main factors. First, there’s the room’s actual temperature. Secondly, is the feedback you get from the room itself, which comes down to the infrared radiation emitted by the surfaces surrounding you. This radiation isn’t something you see, but rather something you feel on your skin.

Even with external wall insulation, if you have thick, dense solid walls, it might not feel warm when you’re inside. This is because the wall is soaking up the infrared radiation that your body emits, instead of reflecting it back to you.

If you install internal wall insulation, you’re introducing a surface that heats up much quicker and starts to send that infrared radiation back in your direction. That means the room doesn’t just trap heat; it reciprocates the warmth.

Types Of Internal Wall Insulation

The insulation material you choose matters. Which material you choose will depend on your walls, how much space you have, and your budget.

Some of the most popular options for internal wall insulation include:

  1. Mineral wool: Made from fibres of molten glass or rock, mineral wool is popular for its thermal and sound insulation. This insulation is available in rolls or batts, which is versatile for fitting between studs or onto walls.
  2. Rigid foam: Boards, like expanded or extruded polystyrene, offer strong heat resistance in various thicknesses and typically come with a waterproof coating to prevent dampness. These boards are fitted to walls using adhesive or mechanical fastenings to form an unbroken insulating layer.
  3. Natural fibre: Eco-conscious homeowners might prefer natural fibres like sheep’s wool, hemp, or wood fibre. Besides robust thermal performance, they regulate moisture well and are available in rolls or batts for various applications.
  4. Rigid insulation boards: Polyisocyanurate (PIR) and polyurethane (PUR) boards deliver top-tier thermal insulation with slim panels. They are light and attachable with adhesive or mechanical fastenings.

Choosing the right insulation material means weighing up thermal performance, moisture and fire resistance, and environmental impact. It’s wise to consult a professional to ensure your choice fits your home’s needs and complies with building regulations.

Installing Internal Wall Insulation

Installing internal wall insulation is a detailed job that can significantly improve your home’s energy efficiency. But it’s a job best done by professionals due to the complexity and expertise required.

Professionals will know how to handle potential issues, such as moisture control and maintaining the building’s structural integrity.

The most common methods for installing internal wall insulation are:

  1. Installing insulation directly onto the wall

Insulation boards, which often have a built-in vapour barrier, are attached directly to the wall using special adhesive or mechanical fastenings.

A professional will make sure there are no breaks in the moisture barrier to prevent any potential moisture problems.

This method is fast, but reattaching heavy items to the insulated wall can be challenging.

  1. Battening the wall

This installation method involves attaching wood (battens) to the wall and then fixing insulation to these battens or placing the battens over the insulation (known as the ‘warm batten’ method).

The warm batten method is less common, but it does offer perks like keeping the battens from rotting due to warmth from the insulation and providing direct access to the battens for fixing or hanging items to the wall.

  1. Constructing a new stud wall

A more complex and expensive option, this method involves building a new, usually about 100 mm thick, stud wall alongside the existing wall, with a small 40 mm space in between for ventilation.

The cavity allows for any moisture to escape, but it can also affect the room’s airtightness, so this method is only suitable for very damp walls.

The Cost of Internal Wall Insulation

The cost to install internal wall insulation can vary, influenced by factors like the type of insulation materials used, the complexity of the installation, the area size, and the labour costs.

Generally, internal wall insulation services cost between £40 and £100 per square metre, covering both materials and installation. For a standard home, this could be anywhere from £5,000 to £12,000. This is often less expensive than external and solid wall insulation.

It’s always best to get detailed quotes from professional installers to understand the exact costs for your specific needs and property features.

Internal Wall Insulation & Government Regulations

In Scotland, it’s important to talk to your local building office if you’re planning to add internal wall insulation to your home. This step ensures your insulation project aligns with the necessary building regulations, avoiding potential legal complications or fines.

According to Scotland’s Building Regulations technical handbook, the sections most relevant to insulation are Section 2 (Fire), Section 3 (Environment), and Section 6 (Energy).

In Scotland, the building rules focus on something called “U-Values”, a term used to describe how well parts of a building, like walls or roofs, can keep heat in. The idea is simple: The lower the U-value, the better the building retains heat.

This is crucial in Scotland due to its generally colder climate compared to places like England. Therefore, buildings in Scotland require better insulation to maintain warmth. For example, the minimum U-value for wall insulation is 0.15 W/m²K in Scotland.


In Scotland, you can take advantage of the UK Government’s Energy Companies Obligation (ECO4) scheme, which provides grants to eligible households for insulating internal walls.

Absolutely, internal wall insulation can save you money. It not only makes your home warmer but it is also more affordable than external insulation. In fact, the Energy Saving Trust suggests that internal wall insulation could save around £460 a year for a typical three-bedroom, semi-detached house.

Yes, you can add insulation to a pre-existing wall. This is done by either fixing insulation boards to the wall (best for solid walls) or cutting holes in the wall’s interior or exterior and spraying insulation materials, such as mineral wool, cellulose, or fibreglass, into the spaces between the studs (best for cavity walls).

Definitely! Internal wall insulation can help cut down on heat loss, boost energy efficiency, and make your home more comfortable. While it’s not as effective as external wall insulation, it’s a more affordable and smart option if you’re unable to insulate your external walls.

Internal wall insulation can cause condensation if it’s not installed correctly with adequate ventilation and airtightness. This can trap moisture, resulting in mould. To avoid this, a vapour barrier is needed to prevent dampness while keeping your walls warm and less prone to condensation.


To sum it up, installing insulation in your home’s internal walls is a smart choice if you want to make your home cosier and cut down on energy expenses.

The upfront cost will depend on how big the space is and the materials you pick, but in the long run, most people see valuable savings in lower energy bills. Plus, it’s more wallet-friendly compared to external, cavity, and solid wall insulation.

Though installation of internal insulation needs the skilled hands of experts, it’s a wise move for homeowners seeking long-term benefits of energy savings as well as a cosier home.