Roof Insulation

Why insulate your loft?

In an uninsulated home a quarter of your heat is lost through the roof. Insulating your loft is a simple and effective way to reduce your heating bills. Loft insulation - what's it all about? Without proper insulation a lot of the valuable, expensive energy you use to heat your home will be lost through the loft. The recommended depth for mineral wool insulation is 270mm however there are other materials which require different depths. In fact, by not insulating your loft you could be wasting as much as 15% of your heating costs. Loft insulation is an effective way to save energy and money at home. A well insulated house keeps warmth exactly where you need it - indoors. So, insulating your loft - or topping up any insulation you have already - will help to heat your home more efficiently. Using less energy reduces carbon dioxide emissions (CO2): one of the biggest causes of climate change. You will also save money on your bills too.

What could you save?

	Loft insulation (0 - 270mm)	Loft insulation (50 - 270mm)
Annual saving per year (£)	Around £205	Around £60
Installed cost (£)	Around £250	Around £250
Installed payback	Around 1 year	Around 4 years
DIY cost	Around £300	Around £200
DIY payback	Around 2 years	Around 4 years
CO 2 saving per year	Around 1 tonne	Around 300kg

These are estimated figures based on insulating a gas-heated, semi-detached home with three bedrooms.
Loft insulation is effective for at least 40 years,. The better insulated your home, the less energy you need to keep it warm - the more money you'll save in the long run. By saving energy, your household will produce less CO2. There are grants and offers available to help pay for loft insulation.

Could loft insulation work for your home?

Generally speaking, your home will be a perfect candidate for loft insulation if it has an accessible loft with no damp or condensation problems. For lofts with difficult access, blown insulation can be used however this must be installed by an installer. If you'd like to use your loft for living space, then you could look at insulating the roof of the loft instead. This is usually done by insulating between the roof rafters using rigid insulation boards.

Heat will always flow from a warm area to a cold one. The colder it is outside, the faster heat from your home will escape into the surrounding air. Insulation makes it much more difficult for heat to pass up through your roof by providing a layer of material which has lots of air pockets in it. These pockets trap heat, cutting what is known as the U value of the loft.

The U value measures how quickly it loses heat so the lower the U value, the less energy you need to keep your home warm. Loft insulation cuts your loft's U value from around 95%. Loft insulation is suitable for most houses that have an accessible loft.

As insulation stops heat from escaping from the living spaces, it will actually make your loft space cooler, which could make existing damp/condensation problems worse. You should get professional advice before installation takes place as this will need to be fixed before insulating.

Can you insulate a flat roof?

You can - from the outside and the inside.
The best time to think about insulating a flat roof externally is when you come to renew its waterproof covering with a single ply membrane e.g. Rhepanol FK (or decorating the room). Renewing the flat roof covering should be done every 15 to 20 years. Insulating the outside of your roof involves laying boarding backed with insulation material either on top of or under the waterproof layer. Insulating the inside of a flat roof is also achieved using insulation backed boards and is very similar to internal solid wall insulation.

What insulation materials do you need?

There are three main types of loft insulation:

Quilts:

• Sold in flexible blankets of different thicknesses.
• Man made from glass or rock fibre, some of which will have been recycled.
• Mineral wool is the most common form of loft insulation quilt in the UK.
• You should always wear a protective mask and gloves when insulating your loft with mineral wool.
• Natural wool insulation is another form of quilt that's very environmentally friendly.

Blown insulation:

• Blown loose into the specific, sectioned-off area to the required depth.
• Blown cellulose fibre or mineral wool should only be installed by installers
• Cellulose is man-made from newspapers.
• Fire resistant

Boards:

• Boards are made from expanded / extruded polystyrene - for roof insulation only
• Expanded polystyrene (EPS) is polystyrene that's been expanded into foam.
• Extruded polystyrene (XPS) is similar but an even better insulator.