Knauf Earthwool FrameTherm Roll (Ready-Cut)

FrameTherm 32 is a glass mineral wool roll designed for standard timber-frame and stud wall cavities. It provides dependable thermal insulation and basic acoustic reduction for everyday external and internal walls. Its soft-handling structure friction-fits securely between studs and reduces heat loss across the thermal envelope. It suits buyers needing reliable, cost-efficient insulation for typical residential builds.

FrameTherm 35 offers improved thermal resistance and stronger acoustic absorption than 32. It supports better U-value targets in new-build and retrofit homes and adapts easily around service penetrations. The roll helps limit cold bridging in timber and steel frame systems and improves comfort in occupied rooms. It suits buyers wanting balanced performance without moving to premium-grade insulation.

FrameTherm 40 delivers the highest insulation and acoustic performance in the FrameTherm range. It enhances thermal envelope efficiency in low-energy and high-spec homes and provides dense acoustic cavity fill for quieter interiors. The roll reduces airborne noise transfer and supports compliance with enhanced building regulations. It suits buyers seeking maximum energy efficiency, noise control and long-term performance.

Installation Guide:

• Unpack and unroll the insulation roll inside the wall or floor cavity, aligning with framing studs or joists
• Press gently so the insulation fills the cavity without compression, avoid squashing or gaps
• For external walls, ensure vapour barrier / membrane is installed per building regulations before internal lining
• Trim excess with insulation knife for a neat fit around services or irregular spaces
• Use appropriate protective gloves, mask and eye protection when handling mineral wool

Which One to Choose and Why?

FrameTherm 32 is ideal for budget-focused projects needing standard cavity insulation with good baseline performance. FrameTherm 35 offers a middle-ground upgrade for buyers who want better thermal and acoustic comfort at a modest extra cost. FrameTherm 40 is the premium choice for high-performance walls, low-energy builds, deep retrofits and projects where maximum comfort and regulatory alignment matter. All three install the same, but thermal and acoustic gains increase with each grade.

Why are they called FrameTherm 32, 35 and 40?

FrameTherm 32, 35 and 40 are named after their thermal conductivity values (λ-values), which indicate how well each roll resists heat transfer. A lower number means better insulation performance.

• FrameTherm 32 has the lowest λ-value, so it offers the strongest thermal efficiency.
• FrameTherm 35 provides mid-range performance suitable for most homes and standard building regulations.
• FrameTherm 40 has the highest λ-value of the three, making it the entry-level option for projects needing reliable but less demanding insulation.

These numbers help buyers compare energy efficiency quickly and select the right product based on performance targets, wall build-up and budget.

Which FrameTherm 32, 35 and 40 are used for which purpose?

• FrameTherm 32 suits projects that need the best thermal performance in the range. It is ideal for external timber-frame walls, energy-efficient homes and builds aiming for lower U-values. It works well in new-build houses targeting improved insulation levels and reduced heat loss.
• FrameTherm 35 fits most standard residential applications. It gives balanced thermal and acoustic performance for internal and external stud walls. It suits buyers who want better comfort than entry-grade insulation without moving into premium-level specification.
• FrameTherm 40 is used for basic cavity insulation where insulation demands are modest. It works in internal partitions, simple refurbishments and areas where acoustic control matters more than high thermal performance. It suits budget-led projects that still need reliable mineral wool insulation.