Skip to content

Loft insulation

Installing loft insulation into your home could save you up to £215 for detached houses.

You lose up to a quarter of your heat through an uninsulated roof

Having your loft space insulated is the best and easiest way to save on your heating bills.​

Loft insulation should last for up to forty years once installed and will save you money on your heating bills for years to come. As lofts are sometimes not the nicest places to enter it makes sense to get your insulation installed by a professional. Let our experienced surveyor carry out a full loft survey to see what we can do for you and start saving as soon as the work is carried out. While we insulate your loft our experienced installers will also insulate any cold water tanks and pipes that are in there, as well as install a walkway to them in case your plumber or heating engineer needs to get to them.

How does getting your loft insulated help?

We usually install loft insulation up to a depth between 270mm and 300mm. The mineral fibre is laid between the joists and then we cross lay another layer over that to ensure there are no gaps. The insulation acts like a large duvet covering your house stopping the heat from escaping into your loft space and then exiting the roof.

How much could I save with loft insulation?

The Energy Saving Trust estimates that you could save up to £215 a year by adding loft insulation.

If you consider that loft insulation can last up least 40 years, those savings could really add up.

Here are the estimated savings if you add the recommended 270mm of mineral wool loft insulation to a loft with no insulation in a gas-heated home:

Detached House
Semi-Detached House
Mid-Terrace House
Detached Bungalow
Estimated saving on fuel bill (per year)

Figures are based on fuel prices as of April 2018. Source: Energy Saving Trust.

For more details on the costs and benefits of loft and roof insulation, visit the Energy Saving Trust.

Properties of Mineral Wool

Thermal Conductivity

For the purpose of U Value calculations to determine if the requirements of the building (or other statutory) regulations are met, the thermal conductivity of the insulation may be taken as 0.040 W/MºC.


Typical installed densities range from 18kg/m3 for glass wools to 40kg/m3 for rock wools (depending on individual BBA certificates).


Blown Mineral Wools are non – combustible, tested to BS 476 : Part 4 : 1970.


Mineral Wool is resistant to water penetration and will not transmit water across the cavity or from below DPC level by capillary action. It does not, however, act as a water vapour barrier.


A pre-installation survey is carried out to assess the suitability of the property for the installation of cavity wall insulation.

Site Preparation

Essential ventilation openings such as those providing combustion air or underfloor ventilation, and all flues in the cavity wall must be checked. If adequate sleeving or other cavity closures are not present, installation must not proceed until these openings have been sleeved or otherwise modified to prevent blockage by the insulant.

Installation Procedures

Where a semi-detached or terraced property is to be treated, the insulation is contained by inserting a cavity barrier at the line dividing the properties. This consists of a nylon brush which is retained in the cavity.

• Injection holes of 22mm or 25mm diameter are drilled at a predetermined pattern/distance (depending on individual BBA certificate).
• Wool is blown into the cavity via a flexible hose fitted with an injection nozzle, using an approved blowing machine. Filling proceeds from the bottom to the top of the wall and from one end of the elevation to the other.
• After injection of the insulant, the holes are made good to match the existing finish as closely as possible.

Post Installation Checks

All necessary air vents are checked e.g. those providing underfloor ventilation and combustion air. In all cases, flues are carefully checked on completion of the installation by means of an appropriate test to ensure they are not obstructed by the insulant.

A technologically advanced insulation system

The product has been developed and refined over many years to satisfy the ever-increasing demand for better, warmer, more energy-efficient housing. It outperforms all other methods of insulating cavity walls.

Fast installation

Less time at your home compared to blown mineral wool BBA approved provides a unique solution: can be used in ‘hard-to-treat’ cavities that could not be filled in the past cost-effective clean installation fewer drilling holes instant effect.

Read the wool datasheet

We use cookies to ensure that we give you the best experience on our website.