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A new roof does not automatically include insulation, but a full roof replacement gives you the ideal opportunity to improve or add it. Most modern reroofs use a breathable membrane under the tiles which allows for better ventilation, and many contractors will discuss loft insulation as part of the overall project. This post covers what you can expect, whether roofers handle insulation, how to check what you have already, and whether a new roof will actually make your home warmer.
Does a Roof Replacement Include Insulation?
Not by default, no. A standard roof replacement covers stripping the existing covering, laying new sarking felt or breathable membrane, relaying battens and tiles, and finishing all the ridges, hips, and flashings. Loft insulation sits below the roof structure on the loft floor or between the rafters and is a separate installation job. If your existing insulation is adequate, a standard reroof will not disturb it.
However, if your loft insulation is very thin, very old, or has been damaged by a long-term leak, a roof replacement is a good moment to address it. Some contractors will quote for both jobs together, which can save on logistics. It is also worth knowing that adding or upgrading loft insulation may attract government funding through schemes like the Warm Homes plan, potentially reducing the cost significantly.
Do Roofers Do Roof Insulation?
Many roofing contractors are happy to install or upgrade loft insulation as part of a broader roofing project, particularly if they are already working in the loft space. This is especially common where rafter insulation is involved, as it is sometimes installed between and below the rafters as part of a warm roof conversion. For straightforward loft floor insulation, some roofers include it and others subcontract it to an insulation specialist.
If you want cold roof insulation, which sits on the loft floor between and over the joists, this can be done by an insulation installer independently of any roofing work. The recommended minimum depth in the UK is 270mm of mineral wool on the loft floor. If your existing layer is less than that, or if it is the old loose-fill type that has settled and degraded, topping it up is a straightforward and relatively inexpensive job.
How Do I Know If My Roof Has Insulation?
The simplest way is to look in the loft. If you have a hatch, open it and look down at the floor of the loft space. You should see insulation material, usually mineral wool quilt in a grey or yellow colour, laid between and over the joists. The current recommendation is 270mm total depth. If you can see the tops of the joists clearly, your insulation is likely below the modern standard.
For between-rafter insulation, look at the sloping sections of the loft. Rigid insulation boards or sprayed foam between the rafters indicate this type has been installed. If the rafters are bare timber with just felt or membrane visible above them, there is no rafter insulation in place. An energy assessor can also tell you the current level if you are commissioning an EPC for the property.
Will a New Roof Make My House Warmer?
A new roof alone will not dramatically increase warmth if your insulation levels are already adequate. What it will do is eliminate draughts caused by gaps in an old failing roof covering, stop damp and moisture ingress that robs a home of heat, and replace old impermeable felt with a modern breathable membrane that manages moisture more effectively. Collectively these improvements can make a real difference to comfort levels.
If the new roof is combined with upgraded loft insulation, the impact on warmth and energy bills can be quite noticeable. The Energy Saving Trust estimates that a well-insulated loft can save a typical semi-detached home around £150 to £300 per year on heating bills. Combining a new roof with proper insulation is therefore a good investment in both comfort and running costs, particularly given current energy prices.
A new roof gives you the perfect window to review your insulation at the same time. Even if the roof replacement itself does not include insulation as standard, it is worth discussing it with your contractor and checking whether any grant funding is available. A warm, watertight roof is one of the best investments you can make in a UK home.
Frequently Asked Questions
Does a new roof come with insulation?
Not as standard. A roof replacement covers the outer covering and structure, not the loft insulation. However, a reroof is a good opportunity to upgrade insulation at the same time, and some contractors will quote for both together.
How much does it cost to reroof a 3-bedroom house?
Typically between £6,000 and £12,000 depending on materials, location, and roof complexity. London and South East prices tend to be higher. Natural slate sits at the top of the range, concrete tiles at the lower end.
Do roofers do roof insulation?
Many do, particularly rafter insulation as part of a warm roof conversion. Standard loft floor insulation can also be arranged through a roofing contractor or done separately by an insulation specialist.
How do I know if my roof has insulation?
Check the loft floor. You should see mineral wool quilt laid between and over the joists to a depth of 270mm. If you can see the tops of the joists, insulation is likely below the recommended level.
Will a new roof make my house warmer?
It can help, particularly by eliminating draughts and stopping moisture ingress. Combined with upgraded loft insulation, a new roof can contribute meaningfully to lower heating bills and improved comfort.
What is the minimum recommended loft insulation depth in the UK?
The current recommendation is 270mm total depth of mineral wool. Many older properties have only 100mm or less, which is well below modern standards.
Is loft insulation included in government grant schemes?
Yes. Loft insulation is one of the measures included in the Warm Homes: Local Grant and similar schemes. Eligibility depends on income and property EPC rating. Contact your local council to check.
What is a breathable roofing membrane?
A modern underlay that allows moisture vapour to pass through from inside the building rather than trapping it. It replaces older impermeable felt and helps manage condensation in the roof space, extending the life of the roof timbers.
Can I add insulation to an existing roof without replacing it?
Yes. Loft floor insulation can be added or topped up at any time without any roof work. Between-rafter insulation can also be installed from inside the loft without disturbing the roof covering above.
Does roof insulation reduce noise?
To some extent yes, particularly from rain and wind. Rafter insulation that fills between the rafters provides more acoustic benefit than loft floor insulation alone. It is not the primary reason to insulate, but it is a useful additional benefit.
How much does loft insulation cost in the UK?
Professional installation of mineral wool insulation on a loft floor typically costs between £300 and £600 for a standard three-bedroom house. Spray foam or rigid board rafter insulation costs considerably more, from £1,500 upwards.
Is spray foam insulation a problem for mortgages?
Yes, it can be. Some lenders refuse mortgages or remortgages on properties with spray foam in the loft, as it can make the roof timbers difficult to inspect and may cause moisture issues if installed incorrectly. Mineral wool insulation does not have this problem.
Does a new roof improve an EPC rating?
A new roof alone has limited impact on an EPC. Adding insulation alongside it has a more significant effect. A good EPC rating can improve mortgage options and increase property saleability.
How long does loft insulation last?
Mineral wool insulation has an indefinite lifespan if kept dry. Old insulation that has become damp, compressed, or contaminated from a roof leak should be replaced. Otherwise it continues to perform well for decades.