The recommended UK standard for loft insulation is 270mm (10.5 inches). If you currently have less than 100mm, then you need to seriously look at getting it improved to this depth.
Why you should insulate your loft to current recommended standards
By having the recommended thickness of loft insulation, your home will be more comfortable and you should see a decrease in your energy bills. The cost of carrying out the work should pay for itself within 3 years. If you take advantage of some of the government grant subsidies currently available, then the payback period can be considerably less. After that the savings go right back into your pocket.
The basic equipment you need to do the job are:
Important note.... whenever you go in your loft, you must only walk on the wooden joists, do not tread on the ceiling, IT WILL NOT TAKE YOUR WEIGHT. Firstly measure the size of the loft in squared metres to determine the amount of material you need. You can do this by measuring the floor area downstairs, or by measuring the external area, as it is normally the same size as the loft. Measure the length in metres of any pipe insulation you may need.
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STEP 1: Insulate the tanks and pipework
Insulate all tanks in the roof space with cold water tank jackets. These can be purchased from most good DIY stores. If your tank is less than 300mm (12 inches) above the joist when laying the insulation don't lay any under the tanks. Warmth from the room below will keep the base of the tank warm enough to stop it from freezing in the winter. However, if your tank is more than 300mm above the joists then any heat rising from the room below would have dissipated before it can warm the bottom of the tank. In this case you insulate the floor of the loft as normal and then staple fix some insulation to the wooden base that the tank is sitting on. Use the bags that the loft insulation came in to staple fix it to the base.
These are the pipe insulation thickness that you need to provide adequate protection against pipes freezing in cold weather.
15mm pipe - needs 25mm thick insulation wall
22mm pipe - needs 19mm thick insulation wall
28mm pipe - needs 19mm thick insulation wall
Most good DIY stores will supply the pipe insulation with the correct size insulation wall. It is important that you fit the right size pipe insulation to give the maximum protection against freezing. When insulating pipes you must make sure that there are no gaps between the pipe joints. If the pipes are too close together or too close to a wall or floor, then wrap these in fibreglass and secure with duct tape. Also do this if your pipes are of a none standard size.
STEP 2: Insulating the loft
The easiest product to use in the loft is traditional fibreglass. The new fibreglass products are virtually itch free and are very comfortable to work with. Rockwool insulation can be used in lofts but is not as easy to use and can still be itchy. Fibreglass is lighter and you will need fewer rolls to complete the job. There are also encapsulated rolls which are targeted specifically for the DIY market but I would not recommend these, as they can sometimes trap condensation in the wrapping even though they are perforated.
When purchasing loft insulation rolls, try to purchase the 1200mm length combi rolls, as these rolls can fit both 400 mm width joists and 600 mm width joists. Most houses built before 1970 are typically 400 mm width joists most houses built after this are typically 600 mm width joists.
If your joist widths are a none standard size you simply cut the rolls by using a normal saw before unrolling at it from the wrapper to the size you want.
The loft insulation comes in commonly four thicknesses, 100 mm, 150 mm, 170 mm, and 200 mm. You need to select the thickness you need to bring it up to a minimum of 270 mm. To achieve the maximum insulation benefit the insulation needs to be crosslaid, one layer between the joists and a second layer across the joists. Some lofts may already have the first layer laid between the joists, in which case you simply need to lay the second layer.
This is the fitting method that you should use to lay the insulation:
Existing loft insulation nil - fit 270 mm (100mm between the joists and 170 across joists).
Existing insulation 25mm - fit 270mm (100mm between the joists and 170 across joists).
Existing insulation 50 -80mm - fit 200 mm across joists.
Existing insulation 100mm - fit 170mm across joists.
If you still need to store items in your loft, then you will only be able to have one layer up to the top of the joists which you can then board. Obviously, try to insulate as much of the loft as you can double laid.
There are certain items in the loft that must not be covered by insulation: Recessed ceiling lights and transformers. Any power cables serving immersion heaters, power showers, or electric cookers. These cables are very large cables around 3/4 inch in width.
When you have finished laying the loft insulation, you need to insulate the loft hatch. Use some of the existing loft insulation and staple fix it to the hatch with one of the bags that the loft insulation came in.
Ventilation
Ventilation in the loft roof space is very important. When laying the insulation, lay the insulation as close to the eaves as you can but ensure that there is still at least a 50mm gap above the insulation at the eaves. If you have a very low pitched lofts or a loft that is highly prone to condensation then you may have to provide additional ventilation. It is also a good idea to draughtproof the loft hatch if possible, as this is the easiest way that warm moisture gets into the loft. If you have to provide additional ventilation in the roof space. This can be done by any of the following methods:Â
Grants
Installing loft insulation yourself is perhaps not one of the most pleasant do it yourself jobs, but it can be done. However, you may wish to check out various grants for cavity wall and loft insulation that are available as this may save you time and money. Some people may even be entitled to free insulation. It's always worth checking the link below to see what government grants are available for insulation.
Why you should insulate your loft to current recommended standards
By having the recommended thickness of loft insulation, your home will be more comfortable and you should see a decrease in your energy bills. The cost of carrying out the work should pay for itself within 3 years. If you take advantage of some of the government grant subsidies currently available, then the payback period can be considerably less. After that the savings go right back into your pocket.
The basic equipment you need to do the job are:
- Face maskÂ
- Gloves Stanley knifeÂ
- SawÂ
- 50mm duct tapeÂ
- Knee pads (if your loft is large)Â
- Staple gun
Important note.... whenever you go in your loft, you must only walk on the wooden joists, do not tread on the ceiling, IT WILL NOT TAKE YOUR WEIGHT. Firstly measure the size of the loft in squared metres to determine the amount of material you need. You can do this by measuring the floor area downstairs, or by measuring the external area, as it is normally the same size as the loft. Measure the length in metres of any pipe insulation you may need.
 Â
STEP 1: Insulate the tanks and pipework
Insulate all tanks in the roof space with cold water tank jackets. These can be purchased from most good DIY stores. If your tank is less than 300mm (12 inches) above the joist when laying the insulation don't lay any under the tanks. Warmth from the room below will keep the base of the tank warm enough to stop it from freezing in the winter. However, if your tank is more than 300mm above the joists then any heat rising from the room below would have dissipated before it can warm the bottom of the tank. In this case you insulate the floor of the loft as normal and then staple fix some insulation to the wooden base that the tank is sitting on. Use the bags that the loft insulation came in to staple fix it to the base.
These are the pipe insulation thickness that you need to provide adequate protection against pipes freezing in cold weather.
15mm pipe - needs 25mm thick insulation wall
22mm pipe - needs 19mm thick insulation wall
28mm pipe - needs 19mm thick insulation wall
Most good DIY stores will supply the pipe insulation with the correct size insulation wall. It is important that you fit the right size pipe insulation to give the maximum protection against freezing. When insulating pipes you must make sure that there are no gaps between the pipe joints. If the pipes are too close together or too close to a wall or floor, then wrap these in fibreglass and secure with duct tape. Also do this if your pipes are of a none standard size.
STEP 2: Insulating the loft
The easiest product to use in the loft is traditional fibreglass. The new fibreglass products are virtually itch free and are very comfortable to work with. Rockwool insulation can be used in lofts but is not as easy to use and can still be itchy. Fibreglass is lighter and you will need fewer rolls to complete the job. There are also encapsulated rolls which are targeted specifically for the DIY market but I would not recommend these, as they can sometimes trap condensation in the wrapping even though they are perforated.
When purchasing loft insulation rolls, try to purchase the 1200mm length combi rolls, as these rolls can fit both 400 mm width joists and 600 mm width joists. Most houses built before 1970 are typically 400 mm width joists most houses built after this are typically 600 mm width joists.
If your joist widths are a none standard size you simply cut the rolls by using a normal saw before unrolling at it from the wrapper to the size you want.
The loft insulation comes in commonly four thicknesses, 100 mm, 150 mm, 170 mm, and 200 mm. You need to select the thickness you need to bring it up to a minimum of 270 mm. To achieve the maximum insulation benefit the insulation needs to be crosslaid, one layer between the joists and a second layer across the joists. Some lofts may already have the first layer laid between the joists, in which case you simply need to lay the second layer.
This is the fitting method that you should use to lay the insulation:
Existing loft insulation nil - fit 270 mm (100mm between the joists and 170 across joists).
Existing insulation 25mm - fit 270mm (100mm between the joists and 170 across joists).
Existing insulation 50 -80mm - fit 200 mm across joists.
Existing insulation 100mm - fit 170mm across joists.
If you still need to store items in your loft, then you will only be able to have one layer up to the top of the joists which you can then board. Obviously, try to insulate as much of the loft as you can double laid.
There are certain items in the loft that must not be covered by insulation: Recessed ceiling lights and transformers. Any power cables serving immersion heaters, power showers, or electric cookers. These cables are very large cables around 3/4 inch in width.
When you have finished laying the loft insulation, you need to insulate the loft hatch. Use some of the existing loft insulation and staple fix it to the hatch with one of the bags that the loft insulation came in.
Ventilation
Ventilation in the loft roof space is very important. When laying the insulation, lay the insulation as close to the eaves as you can but ensure that there is still at least a 50mm gap above the insulation at the eaves. If you have a very low pitched lofts or a loft that is highly prone to condensation then you may have to provide additional ventilation. It is also a good idea to draughtproof the loft hatch if possible, as this is the easiest way that warm moisture gets into the loft. If you have to provide additional ventilation in the roof space. This can be done by any of the following methods:Â
- Get a roofing company to provide roof tile vents tilesÂ
- Fit soffit vents to the soffits on both sides of the roofÂ
- Fit 9X9Â airbricks to both gable walls if your house has gable endsÂ
- Fit DIY easyvents. These are vents that are inserted between the felt on both sides of the loft to provide more ventilation. These are cheap and easy to fit.
Grants
Installing loft insulation yourself is perhaps not one of the most pleasant do it yourself jobs, but it can be done. However, you may wish to check out various grants for cavity wall and loft insulation that are available as this may save you time and money. Some people may even be entitled to free insulation. It's always worth checking the link below to see what government grants are available for insulation.
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