Loft insulation is one of the most effective ways to improve your home’s energy efficiency, keeping it warm in winter and cool in summer. With several insulation materials to choose from, it can be challenging to know which is best for your loft. Each material offers unique benefits, making it suited to different needs and budgets. In this guide, we’ll break down the top materials for loft insulation, including their pros, cons, and ideal applications to help you make an informed choice.
Fibreglass insulation is one of the most popular choices for lofts due to its affordability, availability, and ease of installation. Made from fine glass fibres woven together, fibreglass is commonly sold in rolls or batts.
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Best for: Loft floors and walls, especially if you’re looking for a cost-effective, DIY-friendly solution.
Mineral wool, also known as rock wool or stone wool, is made from volcanic rock or industrial byproducts. Its dense structure makes it effective for both thermal and sound insulation.
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Best for: Loft walls, ceilings, and floors, particularly if you want added soundproofing and fire resistance.
Spray foam insulation comes in two types: open-cell and closed-cell. Closed-cell spray foam offers a high R-value and provides both insulation and air sealing, while open-cell foam is lighter and more affordable.
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Best for: Lofts with complex shapes or hard-to-reach areas, and for homeowners who want maximum thermal efficiency and air sealing.
An IMPORTANT NOTE about spray foam insulation: many homeowners with timber framed homes are having issues with mortgages as poorly installed foam insulation can damage the timber frame by allowing condensation and damp to seep in and rot the wood. For more information please start here: https://commonslibrary.parliament.uk/spray-foam-insulation-and-mortgages/
Thermedge Ltd appreciates both the ease and efficiency of spray foam insulation, but we do not and will not insulate homes with it.
Rigid foam board insulation is made from materials like polystyrene or polyisocyanurate. These boards offer a high R-value and good moisture resistance, making them a durable choice for lofts.
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Best for: Loft floors and walls, particularly in areas prone to moisture or where a high R-value is required.
Loose-fill insulation, often made from cellulose, fibreglass, or mineral wool, is blown into place, making it ideal for covering irregularly shaped areas or filling gaps. It’s commonly used in older homes or lofts with difficult access.
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Best for: Lofts with irregular spaces or existing insulation that needs a top-up. Professional installation is recommended for even coverage.
Radiant barrier insulation is a reflective material, usually made of foil, that reduces heat transfer by reflecting radiant heat away from the home. It’s commonly used in lofts in hot climates to keep homes cooler.
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Best for: Lofts in hot climates or as an additional layer with other insulation types to improve energy efficiency.
Each insulation material has unique properties that make it suitable for different situations. Here’s a quick comparison to help you decide:
| Material | R-Value | Moisture Resistance | Soundproofing | Fire Resistance | Installation |
|---|---|---|---|---|---|
| Fibreglass | Moderate | Low | Moderate | High | DIY-friendly |
| Mineral Wool | High | Moderate | High | High | Professional |
| Spray Foam | Very High | High | Moderate | High (closed-cell) | Professional |
| Foam Board | High | High | Moderate | Moderate | DIY/professional |
| Loose-Fill | Moderate | Low | Moderate | Moderate | Professional |
| Radiant Barrier | Low (reflective) | Low | Low | Moderate | DIY-friendly |
Choosing the best loft insulation material depends on your budget, climate, and specific insulation needs. For general use, fibreglass and mineral wool are popular options that provide solid performance and value. Spray foam and rigid foam boards offer high R-values and moisture resistance, making them ideal for homes with extreme weather conditions or damp-prone areas. Radiant barriers work well in hot climates by reflecting heat away, while loose-fill insulation is perfect for covering irregular spaces. By selecting the right material for your loft, you can enjoy a more energy-efficient, comfortable home year-round.
Uninsulated roofs and loft spaces can lead to significant heat loss, increasing energy bills and leaving your home feeling cold and uncomfortable. Loft insulation is one of the most effective ways to boost energy efficiency and create a cosy, consistent indoor environment. Plus, well-insulated loft spaces help prevent damp issues, which can lead to costly repairs and even impact your health.
With over 25 years of experience in home insulation, we understand the benefits of a properly insulated home. Now that you know the benefits of loft insulation, you may have an idea of the difference it could make. If you’d like our help, we’re here to provide an expert inspection, confirm your insulation status, and offer a quote for adding or upgrading insulation to suit your needs. Simply tap the button below to get in touch with us!
Fibreglass is one of the most affordable and widely available options for loft insulation, offering good thermal performance at a lower cost.
Mineral wool provides excellent soundproofing properties due to its dense structure, making it a good choice for lofts in noisy areas.
Some types, like fibreglass and foam board, are DIY-friendly, while others, such as spray foam and loose-fill, require professional installation for best results.
Generally, loft insulation should be at least 270mm thick for optimal energy efficiency, though this can vary based on climate and insulation type.
Loose-fill or blown-in insulation is ideal for irregular spaces, as it can cover hard-to-reach areas and provide consistent coverage.
Spray foam has a high R-value and seals air gaps, providing excellent thermal efficiency and moisture resistance. Although it’s more expensive, the energy savings can offset the initial cost over time.
Moisture-resistant materials like closed-cell spray foam and rigid foam boards can help reduce the risk of damp by creating a moisture barrier.
Quality insulation can last over 40 years, but it’s recommended to inspect it every 10–15 years to check for signs of settling, moisture damage, or wear.
Radiant barriers are most effective in warm climates where they reflect heat away. In cold climates, they are less effective as standalone insulation.
Yes, mineral wool is safe, fire-resistant, and provides excellent thermal and sound insulation. However, proper installation is recommended to avoid exposure to airborne particles.
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Jonathan Mudd has over 26 years of experience in the insulation industry, having worked with both government contracts and several of the UK’s leading energy suppliers. Throughout his career, Jon has earned a reputation for his meticulous attention to detail and commitment to maintaining the highest standards in every project.
Driven by his wealth of experience and a passion for innovation, Jon now leads the way in loft insulation with his patented products and advanced methodologies, setting new benchmarks for efficiency and quality in the industry. His dedication to staying at the forefront of technological advancements has solidified his position as a trusted expert in the field.
When he’s not overseeing operations as Managing Director, Jon enjoys exploring the scenic landscapes of the North Yorkshire Moors with his dog, Harry.