How to Insulate your Loft and Save Money on your Heating
With ever-rising energy prices for both gas and electricity, reducing heat loss from your home is a major part of saving costs and reducing waste.
On average a quarter of the heat lost from your home goes out through the roof, which means that reducing this lost energy should be top of your list when it comes to DIY jobs,
Whether you are in a new home or updating your old property, adding more insulation to your loft or roof space can be an easy way to reduce energy and save money.
I have recently increased the insulation levels in my roof space and researched the best ways to reduce heat loss. I have compiled all the information I found in the following post:
Access your loft space and lay down insulating materials between the joists, then add a second layer running over the first at right angles, cover any water tanks with insulating jackets and allow ventilation into the loft. The EEC minimum depth for loft insulation is 220mm (8 21/32”) for cellulose, 250mm (9 27/32”) for rock wool, & 270mm (10 ⅝”) for glass wool.
There are a few ways to make this job really simple and it can be done by anyone able enough to access the roof space and will save you money.
I have included things to avoid, which if you ignore them could end up causing more problems, check out the full details below:
Tools and Materials
There are a few tools and things you will need for the job:
Measuring Your Insulation and Preparing the Loft
The first step to improving your home’s insulation is to inspect the loft area and measure how much insulation is currently installed.
You may find that your roof space is already insulated to some degree but may not have as much as the current minimum required by government regulations.
Use a tape measure to confirm the depth of insulation, lift a small area of the insulating material near the loft access and ensure the tape is against the ceiling surface, then measure to the top surface of the insulation. Less than 250mm (9 27/32”) and you need to add more insulation.
Before changes in insulation and energy-saving regulations in 1995 the requirements for loft insulation was less than 100mm (4”), this was increased in the UK in 1995 to 200mm (8”) and again in 2003 to the current recommended minimum of 270mm (10 5/8”).
These figures are guidelines for minimum depth of insulation, however, adding more is a very good idea and will give you the best results and increase your energy savings.
It’s a good idea to check the roof timbers whilst you are working in your loft, look out for woodworm and signs of any wood rot use a wood treatment like this one from Sika which helps prevent woodworm and rot . Follow this link to use our guide to treating wood
Any exposed joists can then be treated with a good quality wood preserver and rot inhibitor before adding more insulation.
Any wiring or cables need to be lifted or clipped to the joists so that they are clear and allow for the insulation to be laid onto the ceiling surface without entanglement.
Check any junction boxes and joists are sound and where possible allow cables to be laid on top of the new layer of insulation.
Moving around and working in your loft space
When you move around your loft space remember that the ceiling is made of either plaster or plasterboard ceiling and is not designed to support your weight.
Take care when moving around your loft, use temporary floorboards or ¾” (18mm) thick chipboard to walk on, screw these across the joist to prevent them slipping, use cordless inspection lamps fixed to the rafters to add light to the roof space.
I use a few old floorboards or some ¾” (18mm) thick chipboard panels, which I lay across the joists. These will hold your weight and allow you to move around, just make sure that they are well supported at both ends on the joists, as they can move.
I often use a couple of screws just to temporarily hold them in place, this prevents any issues as you move around your loft.
To work more easily in your loft or roof space, you will need some lighting. If there is no permanent lighting in the loft, using a cordless inspection lamp that can be clipped to the rafters is an easy way to get light in the area,
Keep the lights as high as possible to flood a large area with light, I prefer to use cordless, battery-powered units. These are great as there are no tricky cables to step over.
If you need to run an extension lead to power your lights, make sure you keep the cables tidy and away from your feet.
Having a permanent set of lights fitted is the best option and doesn’t take very long, See our guide to installing lights in your loft here
For safety reasons let people know that you are working in the roof space and ensure you are able to research the access point if you need to.
Lofts and attics are very dusty places so I recommend you wear old clothes when working in these spaces and wear an appropriate face mask.
Always wear a face mask, eye protection, and protective gloves when handling insulation materials as they can irritate your skin. Check the manufacturer’s guidelines and read the labels on the product you choose before working with it.
Laying Blanket Insulation in Your Loft
Once you have prepared the loft space ready for the insulation, double-check pipe and vents and ensure any gaps are gaps sealed, you can use expanding foam or flexible mastic around wires and pipes that enter the loft space.
I recommend you transfer a few rolls of insulation at a time so that you don’t overcrowd your workspace, and always unwrap the packaging once you have the rolls in place in the loft.
The compressed materials will swell and expand once the packaging is removed, to have the rolls you are working with near to the position you are intending to lay it in.
Start by placing one end of the insulation roll onto the eaves, and between the joists, I find using an old dustpan fixed to a broom handle makes maneuvering the insulation around much easier than trying to do it by hand, this also means you don’t have to squeeze into tight spaces under the rafter.
Start at the furthest location from your loft access and work your way back to the access point, this means you should avoid stepping on any freshly laid insulation.
When you place the insulation, ensure you leave a gap under the eaves, to allow airflow and ventilation under the roof, you can trim the end of the blanket to follow the shape of the roof.
Then unroll the blanket so that it sits between the joists, and gently press it down to form a comfortable fit. Be careful not to compress the insulation, as this will reduce its performance and insulating ability.
If the spacing between your joists is narrower than the roll of insulation then simply allow the edges to curl up against the inside of the joists.
Work in one area at a time to fill the joist nearest you, to reduce the amount of movement you need to do, and reduce the risk of missing your footing.
Then move over to the opposite side of the loft and continue to lay the insulation toward the center, Cut the lengths so that they butt up against the previous roll.
Use a large pair of scissors or a bread knife to cut or trim blanket insulation, you will need to cut the ends to length and also around projections like light fittings or pipes.
Complete laying the insulation between the joist until you have fully insulated the roof space.
Insulating Around lights and Cables
When you lay down blanket insulation in your loft or roof space, make sure you allow space around any light fittings that protrude into the roof, spotlights are a good example of this as they are fitted flush with the ceiling and the housing sits up, inside the roof.
Cut the insulation so that it doesn’t cover the light fittings that protrude into the loft space and avoid covering electrical cables where there is a risk that they could overheat.
Lift cables when you lay the insulation and lay the cables back on top of the blanket or clip them to the sides of a joist so that the cable sits above the insulation
Insulating Storage Tanks
Water storage is used in many loft spaces for heating systems, cold water storage tanks need to be properly insulated to prevent any issues with freezing and to comply with current bylaws.
Insulating your cold water storage tank is straightforward and you can purchase insulation kits which include a tank jacket and all the other items required to cover and insulate your central heating expansion tank, this will help to reduce the need for using expensive electricity to reheat the water.
It’s a good idea to allow some heat to rise up below a cold water tank as this helps prevent freezing, so do not lay insulation in the area immediately below a cold water tank, it is better to put plastic catch try to prevent any leaks or drips during the winter.
Pipes for hot and cold water feeds often run over and along joists in the roof space. these need to be insulated properly to avoid any burst pipe or leaks from freezing water
Cover them with foam pipe insulation and tape any joints where you can or wrap them in foil insulation where the foam does not fit.
Before using loose-fill insulation, cover water pipes with a thin card cover to bridge the pipes, this allows heat from below to help prevent the pipes from freezing.
Laying Loose Fill Insulation
When using loose fill Insulation to insulate your loft or roof space make sure to cover and block any gaps that would allow it to leak out and take precautions against condensation in a similar way to those used for blanket insulation.
Allow plenty of space for ventilation and use rafter vents to cover the end of the ceiling where the roof angle meets the plasterboard.
You can avoid the vents becoming blocked with strips of plywood or fit cardboard between the joists as a guide before laying the loose-fill insulation.
The insulation can then be poured out between the joists and spread evenly using an old brush, once the material is distributed using a wooden batten to level the surface with the top of the joists.
This allows for overboarding or walkways to be used, if the insulation needs to be deeper than the joist add strips of wood to increase the joist depth.
Typically I like to leave at least 6” (150mm) between the top of the insulation and the underside of any boards, this allows for good airflow around your loft and means you can add more initiation if you choose or requirements change in the future.
Insulating The Loft Hatch
The one area the most people forget when insulating their loft is the access hatch
Creating a good seal and preventing any heat loss past the loft hatch is a good way to reduce energy bills.
Insulate your loft hatch with 4” (100mm) foil-backed insulation foam board. This is easy to trim with a knife and can be bonded to the hatch. Use a draft excluding strip around the edges of the hatch to prevent drafts and heat loss.
Cut a piece of insulation with a utility knife so that it fits inside the loft hatch opening and allows the hatch to open.
If you have a loft ladder fitted to gain access, ensure the insulation does not get in the way or prevent the ladder from extending or closing correctly.
If you use loose fill to insulate your loft hatch, use some wooden battens fixed around the edges of the hatch to create a box.
Fill this with the loose-fill insulation, then add a cover plate made of hardboard or plywood over the top to encapsulate the material and prevent it from falling out when the hatch is opened.
For more great DIY tips and ideas check out our blog post and Podcast with information to help everyone improve their home, follow the links below:
This article was written by: Richard Quinton – The DIY Help Desk Owner, Engineer & technical specialist.
Richard is one of the key partners in The DIY Help Desk team. He is a qualified Engineer, writer, and publisher, educated to Master’s level. He is a keen advocate of DIY and home improvements.
Richard enjoys helping others to learn new skills and reach their goals and believes that passing his knowledge and experience on through his writing is an effective way to positively impact the lifestyles and well-being of others on a larger scale.