Compare FREE Quotes on Loft Insulation!
See if you are eligible for the Great British Insulation Scheme
Save Time
Save Time

Get Free quotes from insulation specialists near you

Save Money
Save Money

Save money by comparing quotes and choosing the most competitive offer

Free and No Obligation
Free and No Obligation

The service is 100% free and with no obligation

Mentioned in
The Guardian logoHarvard University logoIndependent logoSPACE.com logoForbes logo
Last updated: 27 September 2024

Loft Conversion Insulation in the UK: A Complete Guide (2024)

loft-conversion-hero
  • Insulation in loft conversion works by insulating an existing unused loft area of a home. This allows the creation of new living spaces without paying for a costly extension.
  • Proper loft insulation can reduce home heat loss by more than a quarter, save you up to £340 in annual bills, and even cut your CO2 footprint by 1 ton a year.
  • There are several important regulations to follow with loft conversions, including roof height, reach, loft volume and more.

Loft conversions are a perfect way to create new living space in your home without extending its blueprints. You can drastically grow your home by using your loft area smartly, often saving much more money than a traditional extension. 

However, a key step in making your loft conversion worthwhile is making sure that it’s properly insulated. Complete loft insulation can reduce your home’s heat loss by up to 26%, bringing a detached UK home up to £340 in annual savings on your energy bills. In addition, it’ll improve your living comfort and even up the value of your home! 

This ultimate guide by GreenMatch UK will walk you through everything you need to know about retrofit insulation loft conversion, including the process, regulations, best materials and more.

Ready to insulate your loft? Free yourself from the burden of endless research and vetting by letting GreenMatch UK handle it for you. Simply fill out our 30-second form and we’ll send you up to 3 free home-tailored quotes directly from our nationwide network of trusted installers. Click the button below to begin!

Get your best deal
Quickly compare FREE quotes
  • Describe your needs
  • Get free quotes
  • Choose the best offer

It only takes 30 seconds

Earth globe icon
Optimise your home and save the planet
Earth globe icon

Why should you insulate your loft conversion?

Put simply, a loft conversion helps you to maximise the use of space in your home. Many homes have existing loft spaces that are left unused, only to store a boiler or some old boxes, but this space can be transformed into a wonderful living area.

When converting your loft, you’ll need to insulate it as well to ensure it’s comfortable, liveable, and does not become a financial burden in the long run. In addition to significant savings on your energy bills, loft conversion insulation will also cut your domestic carbon footprint by a staggering 1 ton a year, benefitting you and the planet at large.

How to insulate a loft conversion?

loft-conversion-steps

If you’re wondering how to insulate a loft conversion, you’ve come to the right place.

Insulation for loft conversion may seem daunting but is relatively straightforward in most cases. Factors such as your roof type, loft condition, chosen material and even location can all affect your investment and labour needs. 

The cost of how much to insulate a loft varies depending on your choices and conditions, but in general, a detached UK home can expect to pay around £1,200 for full loft insulation. Some homes can qualify for a loft insulation grant to cover this cost.

In any case, it’s highly recommended to work with a professional installer instead of tackling the job DIY, as poor craftsmanship can quickly turn your loft into a financial nightmare of repair and replacement costs.

Here are the key steps you can expect in a loft conversion insulation:

  • Identify your roof type: In most cases, you’ll have a traditional pitched roof which can be converted and insulated in a standard manner. In some cases, you may have a trussed roof, or a shared pitched roof, which a professional installer may need to adjust their plans to properly insulate.
  • Decide on insulation material: The type of material you opt for will determine how your loft conversion can be used. For living spaces, it’s recommended to work with rigid insulation boards such as PIR, PUR or cork, as they do not have airborne particles like mineral wool and fibreglass. 
  • Prepare loft area: This pertains to the loft conversion and will require a thorough assessment by a professional. Any unattended repairs will need completing, electrical wiring may need relocating for safety, and any debris needs to be removed. 
  • Begin loft insulation: Depending on your circumstance, an installer may do cold roof insulation, which is when insulation material is placed between and under the roof rafters. Alternatively, they may do warm roof insulation, which is insulation between rafters as well as above. The main advantage of the latter is that there’s more headspace in the loft area.

At the end of the day, working with a professional installer will allow you the comfort of knowing that the best choice will be made tailored to the conditions of your property. 

Loft conversion insulation regs

There are several loft conversion insulation regs in place to ensure thermal efficiency and building conduct. Most of the time, planning permission is not needed to convert a loft or insulate it, but that’s only if certain key requirements continue to be met. Some main ones are:

  • Your property must have Permitted Development rights to add an additional storey.
  • A loft conversion cannot exceed the existing height or roof slope of your current roof structure.
  • Your loft conversion can’t exceed more than 40 cubic metres of volume (terraced house), or more than 50 cubic metres of additional volume for other home types.

While these may highlight some of the more important regulations, every loft conversion job will likely have its unique legal conditions to abide by, which is why working with a professional installer is so necessary. With a professional at hand, you can be ensured that all the necessary legal regulations will be met as expected, giving you peace of mind and a swift loft conversion insulation job. 

Finding the right installer can sometimes feel like looking for a needle in a haystack, but luckily, GreenMatch UK can simplify the process for you.

Instead of spending countless hours on websites and phone calls, spend just 30 seconds filling out our simple form and get up to 3 free home-tailored quotes from our trusted installers. Click the button below to begin!

Fill in the form in just 1 minute

What materials are best for loft room insulation?

loft-conversion-materials

If you’re wondering how to insulate an existing loft room, we’ve got you covered. While there is no best insulation for loft purposes, there is no shortage of various insulation materials available on the market for loft room insulation, all suited for different budgets and applications. 

To save you time, we’ve compiled the top 3 most popular loft room insulation materials based on their best qualities:

  • Mineral wool: One of the most popular insulation materials, and for good reason, mineral wool is budget-friendly, versatile in application and an effective thermal insulator. Made from rock or glass, mineral wool costs around £13 - £17.5 per m2, and boasts an impressive r-value range of 2.5 - 3.3 m²K/W. The only downside is that mineral wool will need to be secured in place with plasterboard to avoid airborne particles from causing respiratory irritation.  
  • PIR Board: Polyisocyanurate (PIR) is a synthetic polymer with incredibly effective thermal insulation and high durability. Costing around £5 – £15 per m2 on average, PIR boasts an impressive r-value range of 3.6 - 4.5 m²K/W. These are also some of the thinnest insulation for loft conversion, due to their impressive thermal capabilities.
  • Cork Board: This sustainable and fully recyclable alternative to synthetic rigid insulation boards is a great material for loft conversion insulation. Although it may cost a higher margin of £17 - £22 per m2, it still exhibits an incredible r-value range of 3.6 - 4.0 m²K/W, making it a worthy contender on the insulation market.

If you’re looking for a budget-friendly loft room insulation material that still packs a punch, mineral wool is a great option for you. If you prefer thermal efficiency over everything, PIR insulation boards are hard to beat. Finally, if you care for sustainability and the well-being of our planet, cork boards stand out as your best choice.

What to keep in mind when getting roof insulation for loft conversion

loft-conversion-problems

To successfully insulate a loft conversion, like any insulation job, it’s important to be mindful of certain conditions before any job takes place. Proper monitoring can help avoid unnecessary damage and identify issues before they become full-blown repair jobs.

Keep an eye out for these emerging conditions, before or after insulation, to solve them before they get out of hand:

  • Cold spots: This is when you notice areas of coldness on your walls, floors, or roof rafters, despite being in an insulated space. This might indicate the clumping of insulation material, most common with materials such as mineral wool, fibreglass, and cellulose. 
  • Condensation: If you notice condensation forming on your walls, roof, or windows, it’s clear that there is a lack of proper sealing. This may have to do with your insulation, but also gaps, cracks, and openings in your loft space that need to be sealed. 
  • Mould growth: If you notice the growth of mould, rot and mildew, this indicates a clear dampness problem in your loft space. A professional installer will need to address these issues before any insulation job can take place.

By keeping an eye out for these telltale signs, you can ensure that you resolve outstanding issues before or after your loft conversion roof insulation, for peace of mind and comfort.

Should I get loft conversion insulation?

Getting a loft conversion insulation job is an upgrade with a wealth of benefits. Apart from extending your home’s livable space, you achieve more thermal comfort, save significantly on energy bills, and even reduce your domestic carbon footprint. It’s an upgrade that benefits you, your home, and the planet all at once.

However, this is just the first step. The next requires finding the right accredited professional installer for the job. We recommend getting multiple quote prices from a range of loft insulation installers to land the best bargain, which can be hard. Most people don't have endless hours of spare time to spend surfing the internet and waiting on phone calls. That's where GreenMatch UK comes in. 

Simply fill out our 30-second form and we’ll send you up to 3 free home-tailored quotes from our nationwide network of pre-vetted installers. The best part? Our services are completely free of charge and obligations. Click the button below to begin!

Get your best deal
Quickly compare FREE quotes
  • Describe your needs
  • Get free quotes
  • Choose the best offer

It only takes 30 seconds

Earth globe icon
Optimise your home and save the planet
Earth globe icon

FAQ