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Your guide to buying loft insulation

Buying guide to loft insulation

Find your ideal loft insulation

Homebase loft insulation visual

Insulate your loft and you'll slice a decent chunk off your heating bills. Without loft insulation you could be losing as much as 15% of your heating costs through your roof. Fitting insulation is simple and you can easily do it yourself.

How it works

Loft insulation basically acts as a blanket to stop hot air rising from rooms below escaping. For extra protection it's worth lagging your pipes and cold water tank too.

How much can you save?

A fair amount! If you don't have any loft insulation, you could save around £205 a year on your heating bills if you install the recommended 270mm depth of insulation. This would also stop the generation of about one tonne of carbon dioxide (CO2) a year. So you'd be helping the planet too. In fact, we could save around £710 million annually if everyone in the UK topped up their loft insulation to 270mm, says the Energy Saving Trust. This would cover the annual fuel bills of around 740,000 households!

The following table gives approximate costs, savings and paybacks for loft insulation:

Loft Insulation Loft Insulation
0-270mm 50-270mm
Anual saving per year Around £205 Around £60
DIY cost From £300 Around £200
DIY payback From 2 years Around 4 years
CO2 saving per year Around 1 tonne Around 300kg

Choosing your loft insulation

SPACE BLANKET

Space Blanket is a premium 'encapsulated' glass mineral wool product. Place between 400mm ceiling joists or on top of existing insulation. This is for the thermal insulation of pitched roofs at ceiling level and is usually put down in two layers - the first layer between the joists and the second at right angles to and over the joists.

This mineral wool insulation is lightweight and you can easily cut it to size. The sleeved encapsulation is a part-metallised polythene film that reflects heat and makes it simple and comfortable to install. Lay Space Blanket silver side up for the best results.

SPACE COMBI-ROLL

Space Combi-Roll is a flexible glass mineral wool quilt that's light, flexible, resilient and non-combustible. The rolls are 1140mm wide and partially perforated to produce either two rolls 570mm wide or three rolls 380mm wide. This makes it easy to use between 400mm or 600mm ceiling joists.

Space Combi-Roll is mainly for the thermal insulation of pitched roofs at ceiling level. But you can also use it to thermally insulate floors and partitions, or wherever a lightweight mineral wool quilt is needed. When you're insulating at ceiling level, you usually lay in two layers - the first layer between the joists and the second at right angles to and over the joists. Space Combi-Roll is simple to install, as it's lightweight and easily cut to size.

Both Space products are virtually itch-free and made from a non-combustible inorganic glass wool (called mineral wool). They don't contain CFCs, HCFCs or other material associated with ozone damage. They're odourless, rot-proof, non-hygroscopic (they don't absorb moisture), and don't support vermin or encourage fungi, mould or bacteria. They also have a vapour resistivity of 7.00 MN.s.g.m.

THERMAWRAP

Thermawrap Easy Fit General Purpose Insulation is light, flexible and CFC- and HCFC-free. It's also durable, 4mm thick, with high reflective foil facings to each side.Thermawrap insulation helps keep houses warmer in winter and cooler in summer. It will also help your home resist damp and reduce condensation. Installation is quick and easy.

ECOHOME

Talk about durable! Ecohome Non-Itch Recycled Fibre Insulation can last for 50 years or more. Ecohome is made from user-friendly non-irritant material that's free from floating fibres or dust. This prevents skin irritation and respiratory problems normally associated with other insulation.

Ecohome won't deteriorate over time and isn't affected by water, mould, mildew or rot. It's also resistant to vermin and insect attack. Ecohome insulation is totally safe, clean and easy to fit, and you don't need protective clothing. You may be interested to know it's totally recyclable and uses recycled plastic bottles in its production. And Ecohome's acoustic properties protect your home (or commercial premises) against noise pollution.

How to fit your loft insulation

When installing insulation, it's a good idea to wear gloves, goggles and a dust mask (simply pick up in store). Once you've cleared the roof space of clutter, lift all the insulation rolls into the loft. Starting at one end, unroll the first length so it fits between the ceiling joists over the floor of the loft. Take care not to insulate below the cold water tank. Make sure you don't block the eaves. Leave a gap of 25mm to allow ventilation to prevent condensation.

Don't squash the insulation down or compress it into tight corners or eaves. This reduces the insulation's depth and its effectiveness. Avoid contact between insulation and hot flues, chimneys and light fittings. Insulate your water tank and pipes: insulated roof spaces are colder as they get less heat from below. That means they need frost protection.

View our how-to guide on insulating your home.

How much does loft insulation cost?

That depends whether you have existing insulation in your loft - it may only need topping up. And also on the size of your loft of course. (A three bed semi-detached home costs £200 to £300 to insulate.) Your insulation can usually pay for itself in under two years if you didn't previously have it. This price is based on a DIY fitting (and it's easy to do!). Obviously costs could be higher if you bring in a professional.

How much loft insulation do I need?

Building regulations recommend a minimum depth of 270mm. Basically, thicker loft insulation significantly improves energy efficiency. The greater the thickness, the greater the energy and cost savings. Needless to say, you'll have to measure up your loft. The insulation roll's packaging will have a label that indicates the area it covers.

How do I find out how much loft insulation I already have?

Checking if you have the recommended depth of insulation is simple. Just slide a tape measure or ruler down the side of a piece of loft insulation until it hits the plasterboard ceiling. If the depth is below 270mm, you need to top up.

How long does it take to insulate a loft?

Building regulations recommend a minimum depth of 270mm. Basically, thicker loft insulation significantly improves energy efficiency. The greater the thickness, the greater the energy and cost savings. Needless to say, you'll have to measure up your loft. The insulation roll's packaging will have a label that indicates the area it covers.

What sort of clothing should I wear when installing loft insulation?

We suggest comfortable, loose-fitting clothes and protective gloves. Lofts can be dusty, so wearing a basic dust mask and plastic goggles is also a good idea (they can be picked up cheaply in store).

The benefits of loft insulation in a nutshell

There are many benefits including:

  • Lower energy bills and great savings each year.
  • It could upgrade your home's Energy Performance Certificate (buyers will find a more energy-efficient home a more appealing prospect).
  • You're doing your bit against global warming and climate change, as your heating system will emit less CO2.
  • Insulation offers sound absorption.
  • Your home will be warmer in cold weather.
  • Quick and easy installation.

How can insulating my home help the environment?

A well-insulated house uses less energy to keep it warm, so less CO2 is released. (CO2 is produced when fossil fuels are burnt to create energy.) Large amounts of CO2 and other greenhouse gases in the atmosphere have prompted global warming. This causes the earth's air and sea temperatures to increase and sea levels to rise. This in turn causes weather conditions to become increasingly severe - this is climate change. You can play your part in the campaign against it by insulating your home!

Useful accessories

Pipe insulation, fixing pipe tape, goggles, gloves, dust mask, ladders, measuring tape and a strong kneeling board.

Homebase buyer's tips

Don't forget the loft hatch! If you don't insulate your hatch, warm air can be drawn up through it. Cut insulation to fit the hatch but make sure the edges are well draught-proofed.

Keep insulation away from ceiling lights (such as halogen down lighters) to prevent overheating. Leave 150mm clearance around recessed ceiling lamps.

Lift electrical cables above loft insulation to avoid overheating. Don't cover high-load cables like those leading to cookers, electric showers and storage heaters.

An insulated loft is a colder loft so it's important to insulate water tanks and pipes to prevent bursts in freezing weather.

Find your ideal loft insulation