Expert Loft Insulation Services in Cornwall

Loft insulation is a cost-effective way to boost energy efficiency, reduce heat loss, and lower energy bills. Properly insulating your attic or roof space keeps your home warmer in winter, cooler in summer, and more sustainable year-round. At Kernow Insulation, we offer tailored loft insulation solutions to suit Cornwall’s unique homes and climate, ensuring compliance with BS 5422 (building insulation) and BS 5250 (building ventilation) standards for optimal performance.

 

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Firstly, is it better to insulate above your ceilings or between your roof trusses?


Insulating between roof rafters includes the loft within the thermal envelope, significantly increasing the volume that needs heating and resulting in 20–60% higher energy use. This approach is particularly inefficient for bungalows, where the large roof area relative to the living space can add over £450 annually to heating costs for an 80m² home. Ceiling insulation, by contrast, keeps heat focused in the living areas, preventing energy waste and allowing loft spaces to remain naturally ventilated, which reduces moisture-related issues like condensation and mould. Rafter insulation can restrict airflow, trapping moisture and risking timber decay, while ineffective materials like spray foam and foil insulation exacerbate the problem, often causing long-term damage and higher costs.

Spray foam, for instance, can lock moisture against roof timbers and compromise future maintenance, while foil insulation provides minimal thermal resistance. Ceiling insulation, using trusted materials like mineral or sheep’s wool, is more cost-effective and efficient.

The most common types of loft insulation in Cornwall

Mineral Wool (Loft Roll)

  • Pros:

    • Affordable and widely available.

    • Excellent thermal performance.

    • Easy to install above ceiling joists.

    • Keeps the heat in living space below loft.  

    • Vapour open, allowing moisture to escape.

  • Cons:

    • Requires a thick layer (270mm) for optimal performance.

    • Can lose efficiency if compressed or dampened.

Rigid Foam Board (PIR insulation)

  • Pros:

    • High thermal resistance.

    • Lightweight and easy to cut to size.

    • Best option for loft conversions due to its rigidity.

  • Cons:

    • Not breathable, which can lead to condensation in certain roof types.

    • If placed between rafters it insulates loft space and not living space.
    • Although easy to cut, it’s very laborious to fit snugly / effectively. 

    • More expensive than other options.

Blown-In Cellulose

  • Pros:

    • Eco-friendly, made from recycled materials.

    • Excellent at filling hard-to-reach areas

  • Cons:

    • Susceptible to settling / slumping, which can reduce effectiveness.

    • Not suitable for areas prone to high humidity.

    • Hard to carry out repairs below insulation – a tradesperson’s nightmare! 

Sheep’s Wool

  • Pros:

    • Highly breathable and naturally regulates moisture.

    • Eco-friendly and sustainable.

    • Provides excellent thermal and acoustic insulation.

  • Cons:

    • Higher upfront cost.

Spray Foam Insulation (AVOID!!!)

  • Pros:

    • High thermal resistance 

    • Excellent for application to hard/metal surfaces such as shipping containers or boat hulls.

  • Cons:

    • Zero to extremely low vapour permeability, which can trap moisture and damage roof timbers.

    • Can cause mortgage and resale issues.

    • Expensive and difficult to remove.

Foil Blanket Insulation (AVOID!!)

  • Pros:

    • Reflects radiant heat, improving thermal performance.

    • Works very well in extreme heat (commercial) environments) 

  • Cons:

    • Limited effectiveness for conductive and convective heat loss.

    • Not breathable, which may lead to moisture issues in certain applications.

    • Can cause mortgage and resale issues.

Why Breathability Matters

In Cornwall’s heritage and stone-built homes, breathability is critical to managing moisture levels and preventing damp or rot.

The Moisture Vapour Transmission Rate (MVTR) indicates how much moisture can pass through a material over a given time. Higher MVTR values, like those found in materials such as mineral wool and sheep’s wool, allow moisture to escape, helping to regulate humidity levels and prevent condensation. Non-breathable materials with low MVTR values, such as spray foam and foil blankets, can trap moisture, leading to potential structural damage and unhealthy indoor environments. Selecting the right insulation for your property’s needs is vital to maintaining its integrity and comfort.

The Kernow Insulation Advantage

  • Tailored Solutions: Whether you have a traditional Cornish cottage or a modern property, we provide bespoke insulation options to meet your needs.
  • Expertise in Heritage Buildings: Our team understands the importance of preserving the character and integrity of older homes while improving energy efficiency.
  • Sustainability Focus: We prioritise eco-friendly materials and methods to ensure minimal environmental impact.

Contact Us for a Free Survey

Let our insulation specialists help you choose the best solution for your attic, roof, or loft space. Book a free, no-obligation survey today and take the first step towards a warmer, more energy-efficient home.

Why Choose Kernow Insulation?

At Kernow Insulation, we enhance your home’s comfort and efficiency with:

Loft Insulation in Cornwall:
We install breathable, high-performance loft insulation to improve energy efficiency in modern and older properties, following BS 5422 and BS 5250.

Sustainable Solutions:
We use eco-friendly materials to ensure performance while preserving your home’s integrity.

Preserving Heritage and Modern Homes:
We specialise in insulating both older and modern properties, ensuring proper ventilation and protection.

Contact Us Today
For loft insulation or energy efficiency advice, contact Kernow Insulation. Let us help improve comfort and preserve your property.

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