A Beginner’s Guide to Loft Insulation

Improving the level and quality of insulation is the most effective way you can improve your home’s energy efficiency. By improving the insulation in your home, you can reduce your carbon footprint and make significant savings on your energy bills.

A poorly insulated roof can result in around a 25% loss of the heat generated in your home. By correctly insulating your roof, you can retain more heat in your property and enjoy a cosy home throughout the whole year.

Investing in insulating your roof will improve the energy efficiency of your home for years to come. You will soon recoup your investment quickly, and you will be able to enjoy the benefits of your insulation for a long time.

This short guide will help you understand the basics of installing insulation, how insulation works, what different types of insulation are available, and what things you need to consider before you start. For tips and tricks on how to insulate your roof, carry on reading.

Why Should You Insulate Your Loft?

You can enjoy the benefits of insulating your loft throughout all seasons. Quality insulation which has been correctly installed will retain heat during the winter months, keeping your home nice and cosy. By choosing the suitable insulation material, you can reduce solar gain and maintain a cool home during the summer months. Overall, this leads to significant savings on your energy bills.

Pitched roof insulation between rafters can be installed either on the sloping roof, between and over rafters, or at ceiling level between or over ceiling joists. Deciding how and where to insulate your roof depends on how your space is going to be used. Throughout this guide, we will explore the advantages and disadvantages of different types of roof insulation.

The best roof insulation type for your property will become more apparent as we discuss the options available.

What are the benefits of insulating your loft?

There are many benefits to insulating your loft, these benefits include:

  • Improving energy efficiency
  • Reducing your carbon footprint contributing to the fight against climate change
  • Reducing your heating/cooling bills
  • Improving your home’s value
  • Reducing the transmission of external noise

We all know how crucial it is to reduce our carbon footprint and live a more sustainable life. If you care about the environment and want to do your bit to help fight climate change, then insulating your loft is a sensible first step to take. You will also save a considerable amount on your energy bills.

How much money will insulating my loft save me?

Insulating your loft correctly will save you a significant amount of money per year by reducing your energy bills. Take a look at these examples (figures from the Energy Saving Trust). 

Type of homeDetachedSemi detachedMid terraceBungalow
Typical cost of loft insulation installation£395£300£285£375
Fuel bill savings per year£240£140£135£200
Carbon dioxide savings per year990 kg580 kg550 kg820 kg

*Typical costs based on average home installation

**Fuel bills based on gas central heating

Energy-efficiency grants might also be available in your area to help reduce the cost. For more information visit the government-endorsed website Simple Energy Advice.

What Are The Different Types of Roof Insulation?

Wondering how to insulate your roof for the best results? There are many different types of loft insulation, varying in cost, durability, and insulating performance. The choice includes traditional insulations such as glass and mineral wool insulation, Earthwool and other eco-friendly materials, high-density foam board insulations, and blown (loose-fill) insulation.

Multifoil insulation is fast becoming the first choice for many commercial and domestic projects. Developed for commercial use following its success in the NASA space programme multifoil insulation is made using multiple layers of aluminium foil alternated with foam wadding.

SuperFoil multilayer foil insulation uses sustainable and recycled materials and is available in a range of thicknesses to enable you to select the most appropriate solution for your project. For use in lofts, walls and floors SuperFoil provides you with a solution that is both affordable and effective. Plus, you can be confident in knowing that SuperFoil products have gained the approval of all the major Accreditation bodies and Warranty Approval schemes in both the UK and Europe.

The SuperFoil range now includes SuperFOIL SF19BB and SF40BB, both are fully breathable and combine insulation and breather membranes in one so you won’t need to take additional steps when installing your multifoil insulation in your roof.

Are you confused by R- Values & U-Values?

Both measures are very important and should be considered when you are selecting an insulation material and to assess the performance of the finished floor, roof or wall structure.

Now to clear up the confusion, the R-value is the assessment of the thermal resistance of the material. All materials included in the structure have an R-value. Individual materials do not have a U-Value.

To calculate the U- Value you add together all the R- Values and then divide 1 by the total to get the U-value. The U -Value therefore is the reciprocal of the sum of the R values.

So, the higher the sum of the R-Values the lower the U- Value. Building Regulations determine the U- Values which we are aiming to achieve with our building.

This is where we come in, you don’t need to calculate these values yourself- simply contact our technical helpline and we will do it for you!! .

What is radiant heat transfer and why does it matter?

Most forms of loft insulation such as glass wool and chemical foam insulation work by slowing both conductive and convective heat flow to trap warmer air inside your home.

However, what about that heat loss through radiation? Radiant heat transfer happens when heat hits a flat surface and warms that surface. You might have noticed this effect when you touch the bonnet of your car on a hot, sunny day.

Around 75% of the total heat loss that occurs from your home can occur in this way. That’s why it’s so important to include a radiant heat barrier to improve overall insulation performance, improves comfort in your home and reduce your energy costs.

Multifoil insulations such as SuperFOIL address all three elements, Don’t forget, this is also one of the reasons why NASA chose advanced multifoil technology for their space missions.

More traditional forms of loft insulation such as glass wool and even natural insulation products slow down heat loss, but they have some disadvantages. They often have low reflective ratings, high emissivity ratings and don’t offer all the same benefits as multifoil insulations.

What to consider before insulating your loft:

You should bear in mind several factors before you insulate your loft so that you can find the optimal solution for your space. How to insulate your roof depends on your property’s requirements; keep reading to find out the best solution for your loft.

1. Do you want your loft to be a cold or warm space?

When it comes to loft insulation, you can either focus on keeping your living spaces warm and leave the loft cooler, or you can insulate the entire space. This is especially useful if you’d like to use the loft as a living space or would like to use the loft for storage.

To create a warm loft, you need to insulate pitched roof insulation between the rafters. To create a cold space, you can insulate between and over the ceiling joists at ceiling level.

Insulating at rafter level can be a more complex task, but by taking this route you’ll be able to use this extra space as you wish; simple storage or as many people are doing today, expanding the accommodation in their current homes rather than choosing to move.

It is also important to insulate party walls and gable walls as well as any other uninsulated parts of the room to minimise heat loss.

If you’d prefer to focus on your existing home and living space, you can insulate at ceiling level, between and over joists which will improve the comfort of the rooms below and leave your loft cooler.

You can use SuperFoil Insulation whichever option you choose, speak to our team who will be pleased to go through the options available to you.

2. Is the loft already insulated?

Many homes already have some insulation but this most probably doesn’t reach current building standards or no longer offers the optimal level of insulation for your needs.

If this is the case, you can ‘top up’ your existing roof insulation relatively simply. This can save you time and money but still provide optimal insulation solutions.

Take the opportunity to upgrade to a high-performance loft insulation material such as SuperFOIL. Call the SuperFoil ‘Technical helpline’ to discuss your project further or submit an enquiry online at www.superfoil.co.uk..

3. Do you have a flat roof?

Flat roofs (those with a pitch of less than 18″) demand a different approach than compared with pitched roofs. You can choose to have a warm roof, which is when the insulation material is placed on top of the roof.

Alternatively, you can choose to have a cold roof when the insulation is placed between and under the ceiling joists. Seek the assistance of our technical team to plan the best approach for your project.

4. Does your home suffer from damp?

Condensation can be an issue, and it is crucial to ensure that your insulation is installed correctly following the manufacturer’s guidelines to avoid any problems. Maintaining airflow and ensuring that you have sealed all necessary cuts and overlaps is an integral part of installing roof insulation.

At SuperFOIL, we always advise you to ensure adequate ventilation and that you deal with any damp problems beforehand. It’s always worth asking a builder or damp expert for professional advice.

5. Where are your pipes and water tank?

If your pipework and water tank are in the loft, and you have insulated at ceiling level it is essential to ensure that they are insulated both to prevent burst pipes, damage from the cold and other costly repairs.

If you’re insulating the rafters to create a warm room, there’s no need to worry.

6. Have you insulated your loft hatch?

When you’re insulating the ceiling joists without insulating your loft hatch, you might be surprised at the amount of heat that can escape. That’s why it’s a good idea to fit an insulated loft hatch and place strips of draught-excluding material around the edges to help your home better retain heat.

7. Do you have recessed halogen lights in a room below the loft?

If you’re laying your loft insulation over the joists and you have recessed halogen lights in the room below, you will need to take extra precautions to reduce your fire risk.

Simply invest in loft caps/loft covers (fire protectors) and you can protect yourself whilst still enjoying the full benefits of insulation.

If you’d like more information on SuperFOIL insulation products and how to insulate your roof, please get in touch with us today to directly find out more. We also offer no-obligation quotes; if you’d like to save money on your energy bills and reduce your carbon footprint, please don’t hesitate to send us an email or give us a call on 01636 556779.


Our FREE guide gives you all the information on saving time and money when insulating your home, and how to really make a difference to the comfort of your rooms.

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SuperFOIL Insulation Guide