A detailed guide to installing loft insulation

So, I can insulate my own loft?

Yes you can! With the right tools, and the right guidance, you can find one of the cheapest ways to heat a house. See our previous three blogs on all things insulation, for even more detailed guidance on insulating other areas of the house.

Richard Bazley from Bradfords Ilminster   Richard Bazley from Bradfords Ilminster says

"The main reason to insulate your home is to save yourself some money, and it means you can do your bit to save the planet. The more insulation you put in, the better the results will be. Even though the product might be expensive, you will definitely see the benefit."

Your loft is one of the easiest places to insulate. Insulating your loft will have the biggest impact on heating and energy efficiency in your home. Once a house is built, it is very difficult to insulate wall cavities and piping. You will get the most benefit from insulation in the loft, and thanks to our expert Richard Bazley, you can now save money by doing it yourself! 

What should I do before I get started?


  • Wear the right protective equipment – so make sure you’re wearing eye protection and breathable masks as insulation materials can be irritants.
  • Be cautious when going into your loft – using your loft ladder safely is very important 
  • Be careless where you stand, always keep on the timbers 
Floor & Loft Insulation

Richard says,

"It’s sensible to do your homework first, find the right products for what you want, take the right safety advice and fit the materials to the manufacturer’s instructions"

Insulating the floor of your loft

1. Step one

Make sure that before you enter your loft, you take safety precautions. Tread only on the wooden joists, and use a ladder. If you’re unsure, or if it feels unsafe, then speak to a professional first. Once you’re in your loft, take measurements of the dimensions before you buy your insulation. You will need twice the surface area of your floor space, plus 10%. And remember, you can always speak to our advisors in store or online when choosing insulation for your loft. 

2. Step Two

Choose a lightweight product such as Superglass to insulate your loft floor. We recommend Superglass because it is made from recycled bottles and is affordable and lightweight. Superglass often comes in rolls 1200mm wide, and are ready perforated to fit common housing dimensions. The roll can be split in half (600mm) or into three (400mm). Make sure you measure carefully between your loft joists so you can section the insulation to the correct size.

3. Step three

You want to roll out your insulation in between ceiling joists. This first layer should then be followed with another layer put on top of the joists, in the opposite direction to avoid cold spots. The second layer stops any extra heat escaping. You need to insulate in both directions, as the timber of the roof joists will still not insulate the house fully. Once rolled out, you can secure the insulation using specially-made nails, remember always to be careful when doing this to avoid injury. 

How to insulate the walls of your loft

Insulating the walls of your loft is slightly more tricky than insulating the floor, but is very worthwhile if you want to save even more energy. 

1. Step one

Measure the dimensions of your loft walls first so you know how many metres you need to buy, remember to add 10% extra. We recommend you use Thinulex – this is a versatile multi-foil that you can simply roll out onto the underside of the roof walls. It’s easy to use a pair of scissors and a ruler to cut the Thinulex into shape. 
Roof Insulation

2. Step two

Nail the Thinulex in place along the roof joists, be careful – you may need help doing this. You can also use timber batten to secure it in place – the piece of timber goes across the roof timbers, but nails work just as well.

3. Step three

As with the floor insulation, remember to leave no gaps between your edges but make sure you don’t block up ventilation holes in your loft space – this can cause problems when there isn't any space for the air to circulate.  Always proceed with caution when doing this type of work yourself, and if in doubt, please seek advice from a professional.

If you need more guidance, see this video:

Richard’s final thoughts…

  • Wear the right protective equipment
  • Be cautious when going into your loft   
  • Make sure insulation is fitted, tight and as secure as possible
  • Allow space for an air vent - air needs to escape somewhere. 
If you have more questions on what types of insulation are available, our DIY specialists are ready in store for your questions. Whichever option is best for you, make sure you always seek advice before insulating your home. 

At Bradfords, we’re always happy to help and if you need to contact us simply call us on 0344 846 1133.