How to effectively install roof insulation
Touted as one of the easiest ways to shave hundreds of pounds off your annual energy bill, insulating your roof space is well regarded as one of the best ways to save money. Keeping warm air in during winter and hot air out in summer months, roof and loft insulation is a relatively straightforward job. Once completed, it can last for up to 40 years or more – sometimes longer if you use sheep’s wool.
Yet when it comes to roof insulation, it really pays to know what you’re doing. Although a relatively straightforward DIY task, installing roof and ceiling insulation can pose a number of challenges. Whether that’s knowing what the right tools for the job are or the steps to take, we’re here to offer a helping hand.
If you’re not sure where to start, help is at hand. In this guide, we’ll talk you through some common pitfalls of roof insulation and how you can effectively install roof insulation on all manner of different roofs.
What material do I need to insulate my loft?
What you use to install roof insulation will depend on whether you have a cold or warm roof.
You have a ‘cold’ roof if you do not use your loft space as a room but may use it as storage for example. It’s called a cold roof as insulation is placed above the ceiling, which keeps the house warm, but your attic cold.
In a ‘warm’ roof, the opposite is true. If you use your attic as a living space, such as an office, bedroom or living room, you’ll have what’s known as a warm roof. This is where insulation is placed between the roof rafters to keep the whole house (including the roof space!) warm.
Cold roof insulation materials
If you plan on having a cold roof, you have a greater degree of choice when it comes to materials. Whether you choose sheep’s wool, mineral wool, loose-fill or glass wool loft insulation is up to you.
If your loft is prone to damp, then slab insulation is a great option as it’s water-repellent and breathable. The increased ventilation will mean your roof won’t be damaged by rot or mould. Rigid installation boards are great when it comes to maximising storage too, as they have a similar level of insulation to wool but are typically much thinner.
The best materials for ceiling insulation
Soft to the touch and safe for sensitive skin, sheep’s wool loft insulation is a great option if you’re opting for DIY but struggle to work with artificial wool.
As well as being easier to work with, sheep’s wool is easy to install and breathable, meaning it’s brilliant for preventing mould in joists and rafters.
If you want to keep the costs down on your loft roof insulation, fibreglass is a popular option. Much cheaper than sheep’s wool loft insulation, fibreglass insulation is available in rolls and acts just like sheep’s wool. As well as being cheaper, it’s also fire and insect-resistant, as well as eco-friendly.
Another affordable insulation type, mineral wool is made from volcanic rock which is heated until it melts. Then, it’s spun together to form a roll, much like the other types of insulation. One of the easiest types of roof insulation to install, it’s perfect for DIY projects and fire-resistant too.
Warm roof insulation materials
If you have a warm roof, you’ll need to insulate the rafters. Although your options are more limited, you’ve still got plenty of options.
Warm roof insulation requires denser, more rigid forms of insulation. For example, insulation boards are a great option as they can be cut to size and neatly slotted in between the rafters.
Once you’ve taken this step, simply pop some insulated plasterboard over the top and you’ll be good to go.
Warm roof insulation boards
For warm roof insulation, loft insulation boards are a great choice. Rigid and half the thickness of rolls, rigid boards can be used for both cold and warm lofts. They can also withstand pressure, so you can easily walk across them to get from one side of the loft to another.
Insulation slabs are similar to rolls, except the materials are formed into rigid slabs. This makes them easy to install. As they are easy to cut to size, they neatly fit between joists, battens and walls.
Thanks to their versatility, they can be installed virtually anywhere that requires thermal or noise insulation.
Foil board insulation
For insulating a warm roof in particular, foil insulation is a great choice. Made up of layers of insulating materials and foils, the reflective nature of the insulation allows heat to bounce back into the room.
To install, simply staple the foil to the rafters and tape the joins. Job done!
What depth of insulation will I need?
According to the UK government, insulation should be a minimum of 27cm thick. Yet if you own a newbuild property, the chances are you could have even more insulation than this as standard.
If you already have loft insulation but your house feels chilly, then it could be time to top it up. Over the years, the recommended insulation levels increase, so if your house hasn’t been freshly insulated for 30 years or so, it could be time to add some more to keep your house toasty.
What you’ll need
Before you begin, make sure you have all the insulation accessories required to complete the job.
You will need:
- A tape measure
- A knife or saw
- An Actis cutter if you’re using Actis Insulation
- A ruler or straight edge
- A drill
- A staple gun
- A nail gun
- Your insulation of choice
- Safety goggles and gloves
H2: How to insulate roof rafters?
If you’re planning to use your loft as a living space, you’ll need to insulate your roof rafters. To make life simple, we’ve put together an easy-to-follow guide for DIY enthusiasts.
- Step one: prepare the space
Make sure that you can see what you’re doing by installing a light fitting. Then, if you don’t have floorboards, place down some crawling boards so you can safely move from one side of the loft to the other.
Make sure to check for signs of damp too!
- Step two: measure up
To work out how much roof insulation roll you’ll need, measure from the apex of the roof down to the top of the joists and multiply this by the breadth. It’s good practice to measure between the rafters too.
- Step three: insulating beneath the rafters
The easiest way to insulate your roof is beneath (rather than between) the rafters as you don’t need to leave gaps for ventilation.
If you’re using insulation boards, lay out an outline of where each board is going to go, and if required, cut them down to size. Then, simply attach the insulation boards to the rafters using a nail gun.
Once that step is complete, they can be left covered with plasterboard.
If you’re using multifoils, it’s even simpler. All you need to do is staple the foils to the rafters. Unroll the foil as you go, and once you’ve reached the other side, simply go back and forth until the whole area is covered.
You can finish up with some tape too – but this step is optional.
Step four: insulating between the rafters
If you’re insulating between the rafters, this is slightly trickier than insulating beneath the rafters, so should only be carried out by a competent DIY expert.
To avoid mould and rot, you’ll need to leave a gap of 50mm between the insulation and the roof membrane.
To make sure you have left an adequate gap, it’s a good idea to fix wooden battens to the rafters. If your rafters aren’t deep enough for the required level of insulation, you can always attach wooden extensions until your rafters are deep enough for the insulation.
If you’re using a roll, follow steps one to three. If you’re using boards, it’s important to measure your boards precisely so they fit properly. Once you’ve measured out the distance between your rafters, cut the boards to fit the gaps and secure them using a staple gun.
If you’re unsure, it’s best to get professional help.
How to install cold loft roof insulation
Luckily for DIY enthusiasts, installing cold loft insulation is relatively straightforward.
Make sure you prepare your loft and then it’s time to measure up. Measure the width and length of the floor and multiply these together to get the area of your loft. Then make note of the space between the joists and the height of the joists too.
When you’re buying your insulation, you’ll need to choose insulation that is the same thickness as your joists. If you’d like further insulation, you can add a layer of insulation over the top of the joists.
When it comes to laying your loft insulation, follow 3 simple steps.
- Step one: Insulate between the joists
To insulate between the joists, start as far from the loft hatch as possible and begin slowly unfolding the roll. Using an insulation cutter, scissors or sharp knife, cut the insulation to size.
Make sure to wear protective goggles if you’re using fibreglass or mineral insulation.
- Step two: Insulate over the joists
Once you’ve filled between the joists with insulation of your choice, you can begin to layer more insulation on top. You can add as much or little as you like, but make sure it totals at least 27cm deep.
When laying your insulation over the joists, it’s best to work at a 90-degree angle to the joists, running in the opposite direction.
- Step three: Insulate and draught-proof the loft hatch
If you’ve insulated your loft carefully, don’t let the project down with a hatch that lets out all the warmth! To properly finish the job to a professional standard, staple some insulating materials to the loft hatch and finish off with some draught-proof strips.
This should be enough to stop any heat from escaping.
Get your loft and roof insulation from Burton, the specialist Roofing Merchants
With over 35 years in the trade as specialist roofing merchants, we know a thing or two about getting the right roof insulation for the job at hand.
As a result of our customer-oriented approach and reputation for stocking some of the world’s leading brands, we’re proud to have earned an ‘Excellent’ Trustpilot rating from our customers.
For more information about our roof insulation, visit your nearest branch today. Alternatively, if you’re in need of a helping hand please, contact our friendly sales team on 0800 124 4431 or email us at firstname.lastname@example.org.