How to Insulate a Loft Roof

If you have a loft space, then you need to make sure it is properly insulated, even if you don’t use it. Here’s what you need to know about how to insulate a loft roof and why you should do it.

Why do you need loft insulation?

It’s essential that you have adequate insulation in your house, otherwise you will face consistently higher bills, problems with damp and condensation, and unstable temperatures.

Insulating walls is one thing, but a quarter of heat is lost through the roof in an uninsulated home. Insulating your loft or attic roof is an effective way to reduce heat loss, reduce your heating bills, and make your home a more comfortable place to live in.

Choosing the right type of insulation

Before you can begin installing anything, you need to choose the right type of insulation for your needs. If it will not be used as a living space or to store anything valuable or delicate, then you only need a ‘cold loft’ and you can just insulate the roof floor, to stop heat escaping from the main house into the loft.

If you want to make the loft a liveable space or store valuable items, then you will need a ‘warm loft’, which means you will need to insulate the rafters too.

How to insulate a loft roof floor

Loft floor insulation is usually made of either loft floor rolls or insulated loft floorboards. Loft floor rolls are usually made from fibreglass or mineral wool and provide blanket insulation between and over the ceiling joists.

Loose-fill insulation such as cellulose fibre can be used to top up blanket insulation or for insulating the harder to reach spaces. Blanket insulation can also be boarded over by using stilts to create a raised platform so that items can be stored on top.

Loft floorboards are made from a combination of rigid board and polystyrene insulation. Loft floor rolls still need to be installed first before boards can be laid on top. These boards are strong enough to store items on, but not enough to be the floor of a liveable loft space.

Insulation rolls first need to be fitted between the roof joists until the entire roof floor is covered. If storage is not required, a top layer of insulation roll is installed, with the rolls running perpendicular to the base layer.

If loft floorboards are being used to provide storage, they can be laid across the base layer rolls at right angles to the ceiling joists, provided the base layer is flush with the top of the joists. The boards are then fitted to the joists using screws.

How to insulate roof rafters

If you want a warm loft to store delicate or perishable items, or to convert it into a liveable space, then the roof rafters will need to be insulated. There are a few material options available here, such as spray foam insulation, rigid insulation boards, mineral wool or fibreglass batt insulation, loose-fill insulation and insulated panels.

To insulate roof rafters, the insulation material is applied between and over the rafters, preventing heat from escaping from the loft through the roof. If the loft is to become a living space, this insulation will first need to be covered with plasterboard before it is safe and aesthetically pleasing.

Can you insulate a loft roof yourself?

If your loft is easily accessible and does not have any problems with damp, rot, or any structural damage, then you may be able to install some types of loft insulation, such as roof floor insulation, yourself. In most cases, roof rafter insulation is a job that requires specialist materials and skills and is better left to a professional.

In cases where there are damp problems, damage to the roof or loft space, or a more complex insulation system is needed, a professional installer should definitely be used.

Loft insulation should be seen as a necessity – the only question that remains is how you want to use the space and whether you only need loft floor insulation, or you need roof rafter insulation as well.If you need an experienced professional to insulate your loft space, please get in touch – we’ll be happy to help.

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