Safe Alternatives to Spray Foam Insulation
Discover mortgage-friendly, breathable insulation options that won't trap moisture, damage timber, or reduce property value. Get the thermal performance you need without the risks of spray foam.
Why Choose Alternatives to Spray Foam?
After removing spray foam or if you're looking to insulate without spray foam's problems, these alternatives provide excellent thermal performance while maintaining roof health and mortgage eligibility.
Sheep's Wool
Cost: £20-£35/m²
Best for: Eco-conscious homeowners
Mortgage-friendly ✓
Mineral Wool
Cost: £8-£15/m²
Best for: Budget-conscious
Mortgage-friendly ✓
Multifoil
Cost: £18-£30/m²
Best for: Limited headroom
Mortgage-friendly ✓
Alternative 1: Sheep's Wool Insulation
Natural & Breathable
£800 - £1,800Advantages
- • Naturally moisture-regulating
- • No VOCs or harmful chemicals
- • Excellent thermal performance (0.038 W/mK)
- • Sound insulation benefits
- • Sustainable and renewable
- • Easy to handle and install
Considerations
- • Higher cost than mineral wool
- • Requires treatment for fire resistance
- • Can settle slightly over time
- • May attract moths if untreated
Best Applications
Loft insulation, between-rafter insulation, timber frame walls. Particularly good for period properties and eco-builds. Popular brands: Thermafleece, Black Mountain.
Alternative 2: Mineral Wool (Glass/Rock Wool)
Cost-Effective Standard
£400 - £1,000Advantages
- • Most affordable option
- • Widely available
- • Non-combustible (fire-safe)
- • Won't settle or degrade
- • Easy DIY installation
- • Proven 50+ year track record
Considerations
- • Can irritate skin during installation
- • Loses effectiveness if compressed
- • Bulkier than some alternatives
- • Not ideal if loft used for storage
Best Applications
Loft insulation (270mm standard), cavity walls, timber frame. Industry standard for most UK homes. Brands: Knauf, ROCKWOOL, Superglass.
Alternative 3: Multifoil Reflective Insulation
Thin & High-Performance
£600 - £1,500Advantages
- • Very thin (typically 20-40mm)
- • Reflects radiant heat
- • Breathable versions available
- • Lightweight and flexible
- • Good for limited headroom
- • Vapor permeable options
Considerations
- • Requires air gaps to work properly
- • Performance debated by some experts
- • Must use breathable types
- • More complex installation
Best Applications
Between rafters where space is limited, wall insulation, conversion projects. Use breathable types only. Brands: Actis, TLX, SuperQuilt.
Alternative 4: Rigid PIR/PUR Boards
High Performance Boards
£900 - £2,000Advantages
- • Excellent thermal performance (0.022 W/mK)
- • Thin but effective
- • Rigid and easy to cut
- • Moisture resistant
- • Won't sag or settle
Considerations
- • More expensive than mineral wool
- • Requires careful ventilation design
- • Not as breathable as natural materials
- • Needs professional installation
Best Applications
Between rafters, flat roofs, wall insulation. Provides high R-value in minimal thickness. Brands: Celotex, Kingspan, Recticel.
Comparison Table: All Alternatives
| Material | Cost/m² | Thickness | Breathability | Eco Rating |
|---|---|---|---|---|
| Sheep's Wool | £20-£35 | 270mm typical | Excellent | ★★★★★ |
| Mineral Wool | £8-£15 | 270mm typical | Good | ★★★☆☆ |
| Multifoil | £18-£30 | 20-40mm | Good (breathable types) | ★★★☆☆ |
| PIR/PUR Boards | £25-£45 | 100-150mm | Moderate | ★★☆☆☆ |
| Spray Foam | £30-£50 | 100-150mm | Poor/None | ⚠️ Not Recommended |
Get Expert Insulation Advice
Not sure which alternative is right for your property? We can connect you with insulation specialists who will assess your needs and recommend the best mortgage-friendly, breathable solution.
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