Cavity Wall Insulation
Avoid spiralling energy prices and help the environment by installing cavity wall insulation, find out more here.
Is your home insulated?
According to the National Insulation Association, the average home loses more than 40% of its heat through the loft space and walls. Of this heat, more is lost through the walls than
anything else – approximately 33% in an un-insulated home. Cavity wall Insulation is one of the most cost-effective and energy efficiency measures in the home - It can save
around £120 each year in a typical house.
A lot of older buildings, particularly those over 25 years old, will lose large amounts of heat because they had no insulation put in when the house was built. However, the Building Control legislation, which regulates newly constructed buildings, has become a lot stricter, so newly built homes should be well insulated. If you are concerned about heat loss in your home, a simple survey can be carried out by an insulation consultant who will ascertain where the heat is being lost.
What is cavity wall insulation?
A cavity wall is simply two walls separated by a space (a cavity). The cavity in the walls contains air, which is a good insulator and prevents the build up of condensation on the interior. Cavity walls have been used extensively within the UK since the 1920’s. However, the introduction of insulation into the cavity walls didn’t occur during construction in the UK until the 1970’s. Then, in 1989, building regulations made it compulsory to have insulation put into cavity walls. This means that a large proportion of houses pre-1970’s have poorer insulation, these are normally the types of property in which cavity wall insulation by injection is added.
Installing cavity wall insulation
Unless you are a trained professional, it can be difficult to assess whether you have a cavity wall and whether insulation is required or not. For this reason, Kevin Cooper,
from Cooper Insulations in Ireland, recommends that: ‘’The first step is to have a surveyor come out and do a quick survey, free of charge... a surveyor will tell you if you
need cavity injection insulation. The general standard of practice is that a surveyor will come out and check the weak points of the house, those places that likely need to insulation” says Cooper.
“Once the heat loss spots are examined, we might consider doing some cavity wall injection insulation so we need check things like what type of bricks are involved; is it a nine inch
tower block or a breeze block?”
Generally the site survey won’t last for longer than 30 minutes and then the insulation consultants will come back with a quote. They will evaluate things like the “U-value
” of the house, which is a measure of the overall ability of a wall/roof/floor to prevent heat loss and affects how much insulation must be used.
Adding cavity wall insulation by injection can usually be done in a half of a day. A series of holes will be drilled into the exterior walls of a property, based on a standard pattern that
is known to the installer. The holes are generally drilled along the top of the wall and then underneath any windows or obstructions. The holes created are only about one inch across and are
positioned around specific joints in the brick work so that when they are being rendered (filled up) there will be no obvious scars. Next the insulating material will be injected into the
wall through an air pressured hose.
What is cavity wall insulation made of?
There are several types of insulation an installer may use:
Blown mineral wool - the mineral wool used for cavity wall insulation consists of mechanically granulated spun glass or rock wool, treated with a binder or water repellent during manufacture. Once installed, this type of insulation will most likely last the properties lifetime.
U.F. foam - Urea Formaldehyde Foam is injected into the cavity in a wet foam state 90-95% pre expanded through 19mm holes. It completes its expansion by moulding itself to the unusual shapes within a cavity and sets to form a rigid insulant.
E.P.S beads - these small Polystyrene beads are produced to a specified size and density which remains unaltered during the installation process. They are combined with a binding agent at the time of injection, so that once injected they set to a water resistant, insulating mass.
All of the above insulating materials are effective and once injected the holes will be rendered to the closest shade of brick work possible. Some people are tempted to attempt to try a D.I.Y cavity insulation job themselves, however this can a very dangerous and costly mistake. In some cases it is very difficult to judge how much insulating foam needs to be injected and the most appropriate places in which to inject it. There are several known cases of DIY entrepreneurs over-filling walls, which have then ballooned and buckled under the pressure of the expanding materials.
Cost of cavity wall insulation
The cost of cavity wall insulation can vary depending on your property. Adam Smith from Home Care Insulation Ltd says: ‘’It depends on the size the house, how old it is, if it’s one story or two... an average 3 bedroom semi-detached house that is having cavity wall injection insulation put in, would cost from about £500 – to £700. ” Smith adds: “If the house is taller and scaffolding is required than that can push up the cost a bit more.”
There are however, government grants available for cavity wall insulations. So perhaps now, more than ever, it is a good time to consider your insulating requirements. The grants for cavity wall insulations are from 50% and above and are available for all home owners and private tenants regardless of your income. If you qualify under a certain criteria, such as receiving special benefits, 100% of the cost will be covered. Which is certainly an offer not to be taken for granted.
