Loft Insulation

As much as a third of the heat you pay for could be escaping through your roof. Most loft insulation materials work by preventing the movement of heated air through the material. The Government say that you cut your energy bill by up to 20% through effectively insulating your loft.

  • Loft insulation is located between the joists on the loft floor of your property (Roof Insulation is located between the tiles and the rafters)
  • The main materials used by NIA installers are Blown Mineral Wool (Glass or Rock Wool), Blown Cellulose (Recycled Newspaper), Quilted Mineral Wool (Glass or Rock Wool)
  • The recommended depth for loft insulation is 270 millimetres for glass wool, 250 millimetres for rock wool or 220 millimetres for cellulose.
  • Loft Insulation can help lower your heating bills, lower wear and tear on your boiler and reduce global warming and climate change
  • There are a number of grants and schemes available to home owners which can substantially reduce the cost of installing these products.


BuildingPotential saving per yearInstallation cost *Carbon dioxide saving per year
Detached house £240 £395 990 kg
Semi detached house £140 £300 580 kg
Mid terrace house £135 £285 550 kg
Detached bungalow £200 £375 820 kg


* Average unsubsidised professional installation costs, although these will vary.


What is the recommended thickness for loft insulation?

The current regulations under the EEC programme states that a minimum 270mm of loft insulation is required.

I use my loft for storage but need to get it insulated, can I do this?

Once the loft has been insulated to a minimum 270mm thickness the ceiling joists will no longer be visible making the roof space hazardous to anyone attempting to enter. However it is possible to arrange for additional joists and floor boarding to be fixed via a local joiner to help maintain your storage area. If you already have a boarded area of no more than a third of the loft area the installers will work around it and leave it uncovered.

I have electrical cables in loft. Will these be a hazard in anyway?

Apart from any cables feeding a shower unit they will not. A cable, which feeds a shower unit, is usually a 30amp. The installers will identify this and make sure this cable is not covered by the insulation by either laying the cable on top if there is enough flex or leaving a gap in the insulation around the cable to ensure it does not overheat.

I have sloping areas and flat roof areas within my property. Can these be insulated?

It is not always possible to do these areas. The reason being is that the timbers within these areas need to breathe and if loft insulation is fitted in these areas it can block the airflow off altogether. Access to these areas is usually minimal if at all existent. However every property has to be treated on an individual basis and the surveyor will make an assessment when visiting the property and advise accordingly.

My roof space is not big enough for an installer to stand up in. Will this be a problem?

It is very common that roof spaces are not big enough for anyone to stand up in. This is not usually a problem as the installers are usually working in a kneeling position on walkboards. Many companies within the industry work to a 1.4m height minimum for installers to gain access. It is very rare that a roof space is less than this.

I already have some insulation in the loft but it is not very thick, will this have to be removed or can it be topped up?

Any existing insulation can be left in the loft and an additional layer added to it to bring it up to the required minimum thickness. It does not matter how long the existing insulation has been in the loft it still retains its insulant value.

Cavity Wall Insulation

Cavity Wall Insulation stores the heat within the inner walls, bouncing it back into the room and holding it for longer.

Solid Wall Insulation

If you live in a home with solid walls, 45% of your heat is escaping through the walls which is costing you money.

Draught Proofing

Draught proofing is one of the most inexpensive and effective energy efficiency measures for the home.