Uninsulated loft space or attic
An uninsulated loft allows a huge amount of heat from your home to be lost, unnecessarily increasing your fuel bills.
Even if you already have some insulation, check to see that it is adequate. The current thickness recommendation for mineral wool is 270mm. For other materials, the thickness may be different.
To insulate the area is a relatively cheap and easy job to do.
Measuring for insulation
Measure the overall area of your loft in square metres.
Clear the area to make the work as easy as possible. You will need a couple of boards to lay across the joists giving you a platform on which to work.
Remember the ‘floor’ is actually the ceiling of the room below and will not support any weight.
Your boards should be large enough to span the joists but be careful not to allow them to overhang and tip when stood on.
Equip yourself with a suitable mask as the insulating material will emit a large amount of dust while being installed.
You should also wear protective clothing and gloves, particularly when handling glass fibre insulating material as this may irritate the skin.
Wear safety goggles to protect your eyes.
Lighting in the loft or attic
If you have no lighting in the loft, you will need an inspection lamp hung from the rafters and connected to a power supply socket on the floor below. Alternatively, you could consider installing a permanently fixed light with a switch near the access hatch – refer to the lighting section.
Loft insulation – blanket or wool
Types of blanket loft insulation
This may be glass, mineral or rock fibre and comes in rolls for easy handling.
You will need to look at the information on the packs to decide how many rolls you need. The details will tell you how many square metres can be covered for a given thickness. If your loft is uninsulated, choose 250mm thickness. If you are topping up the thickness of existing insulation, choose one which provides the additional thickness required. Check carefully, as some rolls come pre-split offering two possible thicknesses.
Also, check the width between your joists. The standard rolls are about 400mm wide to suit most joists, but wider gaps can be accommodated by trimming.
Laying the blanket insulation
Take the rolls up to the loft while still wrapped. They are very compressed and expand when unwrapped.
When laying the material, lift any electrical cables and clip to the joists. Insulation laid over cables may cause them to overheat.
Do not lay insulation over light fittings from the ceiling below.
Also, do not lay insulation beneath the water tank as the heat rising from below will help to avoid freezing.
Start at one end of the loft. Unwrap the first roll. Trim the end to an angle and place it towards the eaves. But, be careful not to block the airflow at the eaves as this is designed to provide necessary ventilation to the loft space. Unroll and position the blanket between the joists. If the roll is a little wider than the gap between joists, allow it to fold up at the edges. Take care not to compress the material, as its insulation qualities depend in part on the air trapped within it.
Continue unrolling the blanket. Butt join new rolls and continue working your way across the loft trimming at the eaves as before.
Trim the material to fit any odd areas as you go.
At the loft access, cut the blanket to fit the back of the hatch. Cover this with an old piece of sheet and fasten with drawing pins or staples. You may also fit draught excluder, like that used for doors, to prevent unnecessary heat loss around the opening.
Loft insulation – loose granules
Advantage of loose insulation
The advantage of this type is that no cutting is required, making it easy to lay in a loft where the joists are irregularly spaced.
Laying the loose insulation
It is supplied as granules which are poured from a sack and spread across the floor area between the joists. To gain the required depth of cover, unless you have particularly deep joists, will result in the joists being covered. You will, therefore, need to build up the level of the joists in some areas to support some form of boarding to provide a means of access to the various areas for maintenance – i.e. water tanks.
Without such access, you won’t be able to see where it is safe to stand, as the joists won’t be visible.
As with the blanket material, you will need to keep the insulation clear of eaves ventilation, cables, light fittings, and beneath the water tanks. To do this, use lengths of wood or hardboard to hold it in place.
If you have water pipes running along the floor, you can lay lengths of wood or hardboard along the sides to prevent the granules flowing underneath. This way, the heat rising through the ceiling will help to keep the pipes warm and prevent freezing.
Pour the granules from the pack, starting at one end of the loft, and use a batten or broom to spread them to the required depth.
Nail battens around the edge of the loft access panel to form a recess for the material. Once this has been filled, cover with a piece of an old sheet and fasten with drawing pins or staples. If you don’t, the granules will tip out easily. You may also fit draught excluder, like that used for doors, to prevent unnecessary heat loss around the opening.
Loft insulation – tanks and pipes
Protecting the tanks and pipes
When insulating the loft, take the opportunity to protect the water tanks and pipes as well. In fact, the water bylaws now require that tanks are insulated.
Insulating the water tanks
The cold water storage tank and the expansion tank for the central heating should be insulated, as should the hot water cylinder (in the airing cupboard). Purpose made jackets are available which make the job simple and effective. They consist of an insulating blanket wrapped in a plastic cover. These are positioned over and around the tanks and held in place with ties.
Remember, to take a note of the tank sizes so you can get the correct size jacket for the job.
Insulating the pipes
All exposed water pipes can be readily protected by sleeving with pipe insulation.
This is sold in lengths of various materials. The lengths are slit so that they can be fed onto the pipes. Check the size of pipes before buying the insulation as it comes in varying diameters.
At pipe joints and junctions, the insulation can be spliced with a craft knife to accommodate the fittings. Use pvc tape to hold the insulation in place at joins between lengths and at fittings. This will prevent gaps appearing.