Solid Wall Construction for Insulating Properties
We are all encouraged to reduce heating in our homes, and there are several ways this can be achieved. Upgrading the insulation in a loft is fairly easy to do, and installing double glazed windows is very effective. Another popular and successful method is to fill the cavity walls with insulation material. This may be in the forms of polystyrene balls or recycled materials such as newspaper or fabric. But what if a property has a solid wall construction? Is there a way of insulating the walls without adversely affecting the property?
The fact is that solid walls allow twice as much heat to escape as cavity walls do. If your home was built before 1920 it’s entirely possible that it has solid walls. A cavity wall has two layers with a gap in between, and when they were first constructed building regulations did not require any form of insulation to be added to the cavity, so the benefits of having a cavity wall to the householder were minimal in terms of heating costs as this was not such a big consideration.
Solid wall properties can be insulated effectively and the cost savings can also be considerable.
A typical 3 bedroom semi can save between £400 – £500 per year. c 2013
The cost of carrying out the work varies enormously depending on several factors.
The energy saving trust estimates that insulating a property internally could cost between £5,500 and £8,500, whereas insulating externally could cost between £9,400 and £13,000. Costs can be reduced by carrying out some of the work yourself, and there are upsides and downsides to either method.
Internal wall insulation
Insulating a property internally can be cheaper to install than externally but the disruption can be major. On the other hand, it is possible to do each room individually. Skirting boards and architraves would need to be removed and replaced when completed. The walls would be fitted with timber or metal studwork and approximately 100mm of insulation is fixed between the studs. This is then covered with plasterboard and skimmed with a coat of plaster, or the joints are taped and filled with filler then sanded down to provide a finish ready for decorating.
Another method would be to use Plasterboards that are constructed with rigid factory bonded insulation directly to the walls by using fixings that go through them and directly into the wall behind. In some cases the boards can be ‘glued’ to the walls by using bonding adhesive.
The rigid insulation boards are usually about 60mm & can be as much as 100mm thick and are faced with plasterboard. This method will not reduce the size of the room as much, but if the walls are very uneven they would need to be levelled with a layer of plaster or render before the boards are fitted. For either method any problems such as penetrating or rising damp would also need to be dealt with beforehand.
External wall insulation
Applying the insulation to the external walls will mean less disruption to the household and it would not reduce the floor area of the house. Another benefit is that it can improve the appearance of the outer walls, along with making the house more weatherproof and soundproof. The insulation will also protect the brickwork and thus extend the life of the property. It will help to reduce the effects of penetrating damp, but it will not solve the problem of rising damp. You would need to ensure that the external walls are structurally sound and you may also need planning permission so it would be a good idea to check with your local council. Check also that there is good access to the external walls as scaffolding would need to be erected. The downside could be that you will be covering over very nice brickwork along with any features of the property.
The insulation boards are fixed to the external walls and a stainless steel mesh is fixed in place. This is then coated with a specialist render which contains silicone water repellents which also allow the render to breathe. Because of its ability to repel water it is also more resistant to the growth of algae and other microorganisms. The render is also blended with pigment colours which eliminate the need to ever paint the walls, and it is applied in either one or two coats.
It will also be necessary to remove all fascias and guttering from the property and to replace it once the rendering is completed.
Solid or cavity walls?
- If you are not sure what type of walls your property has there are a few checks you can make to determine this.
Age of the property
- Houses built after 1920 generally had cavity walls. If your property is nowhere near as old as that then you can be fairly sure that you have cavity walls.
Visually – Look at the walls to determine whether they have all of the bricks running long-ways. These are known as ‘stretchers’. If they do then it is most likely that you have cavity walls. If the walls have half or header bricks then it is possible that they are solid walls.
Measuring – A cavity wall is around 30cm which consists of two bricks and a cavity. A solid wall is around 23cm which is just one brick and no cavity. This can usually be measured in a doorway or window.
Drilling a hole – If you are still unsure then it may be worth drilling a hole through the wall. Make sure you do this in an area that will not show. You can then see inside the wall to determine whether it has a cavity.
Whichever method you use, the benefits are obvious but should also be viewed as a long term investment which will eventually pay you back and also improve the value of your property.