A Guide to Solid Wall Insulation

A Guide to Solid Wall Insulation
Posted in: Guides, Insulation

A Guide To Solid Wall Insulation


To improve the energy efficiency of your home, it can be very helpful to insulate the walls. It is important to know whether you have 'cavity' or 'solid' walls as this will affect the price and method of insulating your home. Read on for information on how to tell what type of walls you have and the various methods of insulating your home, as well as the advantages and costs involved.


Does My Home Have Solid Walls?

There are several ways to tell if you have solid walls. The first one is to go outside your home and have a look at the brickwork if it is visible. If your bricks are laid lengthways across the wall all the way down, then it is likely that you have a cavity wall. If your bricks are a mix of long length and shorter length bricks then you probably have a solid wall.

Another way is to measure your wall from a door or a window. If your walls are less than 30cm in thickness, then that’s a sign of a solid wall. Anything thicker than 30cm will usually indicate a cavity wall.

Another way is if you know the age of your home, you can make an educated guess. If your home was built before the 1930s then you are likely to have solid walls. After the 1930s many homes in Great Britain were built with cavity walls. If you’re not sure you can ask a cavity wall insulation company to carry out a drill test. They will make a small hole in your wall and from this, they can see whether or not your wall is solid or a cavity.


How Much Could Solid Wall Insulation Save Me?

It depends on where you live and the size of your home, but the Energy Savings Trust calculate you can make the following savings per year:

  • Detached House - £425
  • Semi Detached House - £255
  • Mid Terrace House - £160
  • Detached Bungalow - £175
  • Flat - £120


How Much Does Solid Wall Insulation Cost?

The cost of solid wall insulation depends on the price of insulation you choose. External insulation is more expensive than internal. This is because there is more work to do and decorative coatings need to be applied to bring the exterior of your home in line with the other houses in your area. This could be a necessity if you live in a listed building or a conservation area. Check with the local authority planning department to make sure you adhere to any current regulations.


What Are Cold Bridges?

Cold bridges are the gaps that might occur at the junction between the wall and the floor. As the cold air gets through to the gap it could cause condensation and eventually mould.


What is Internal Wall Insulation?

Like external wall insulation, you can use various materials for your internal insulation project. A wall in good condition can be insulated with:

  • Rigid Foam that has a coating to make it waterproof

If you intend to have a stud wall built, then you can use:

  • Rigid Boards such as PIR/PUR, Phenolic or Expanded Polystyrene

Internal wall insulation can be put onto an existing wall, or a stud wall can be built, and the insulation material placed in the gap between the original wall and the stud wall. If the wall is in good condition, then you can fix insulation boards to the wall and then plasterboard on top. If the walls aren’t in good condition, then it is advisable to build a stud wall.


Why Use Internal Wall Insulation?

It is an effective way to insulate your walls and it is cheaper than insulating the exterior. It is also a job that can be done if you have some experience of DIY. Walls that are in good condition can use board insulation which is quicker to install. If your walls aren’t in a suitable condition, then you can build a stud wall. The insulated stud wall is fixed to the original wall and after this is decorated it will have the added advantage of having a perfect finish.


Are There any Issues with Internal Wall Insulation?

You will lose an amount of internal space in the room due to the added insulation. Therefore, the size of your room will be smaller, especially if you build stud walls. You will also have to take into consideration things such as electrical sockets, door frames and light switches as they will need to be re-positioned. Allow for these possible extra costs when you are budgeting for the work to be carried out.


Are there Building Regulations for Solid Wall Insulation?

You don’t normally need planning permission to install interior insulation, but there are building recommendations that should be followed. For external wall insulation, there may well be regulations that must be followed. A reputable insulation company should be able to advise you on any regulations and recommendations. It is also advisable to check with your local authority planning department before undertaking any such work on your property.


What Are The Benefits of Solid Wall Insulation?

  • Internal Wall Insulation tends to be a cheaper option than external insulation, allowing you to save money on the entire process.
  • It also is usually easier to install and is less of a process, with no need for scaffolding.
  • You won’t need to alter the appearance of your home from the outside.
  • It’s often the only option for those that live in a block of flats, for example.
  • It’s also ideal if you are unable to do any work on the outside of your home, for any reason.


Are There Any Disadvantages To Solid Wall Insulation?

Though there are plenty of advantages, some may consider other options for a few reasons. 

  • The size of the room will be reduced after the insulation is installed, as the wall will need to be brought in slightly.
  • Disruption will occur when the insulation is being installed in each room.
  • If the wall’s surface is uneven, it’ll need to be levelled off with plaster or render before fitting rigid insulation boards. 
2 months ago
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