Internal Timber Frame Wall Insulation

SYSTEM OVERVIEW – Timber Frame Internal

Application Type:
Internal insulation to timber frame (stud) wall constructions

System Classification:
Internal Multifoil Insulation System – Timber Frame

Primary Function:
Thermal insulation + Vapour Control Layer (when fully sealed) + Radiant barrier

Installation Orientation:
Horizontal or vertical application directly to timber studs

Minimum Overlap:
50 mm

Staple Fixing:
Typically 50–100 mm intervals (maximum 300 mm centres)

Airspace Requirement:
Secondary counter battens create required internal air gap

Vapour Resistance:
1200 MNs/g (acts as VCL when joints are sealed)

Internal Finish:
Plasterboard or internal lining fixed to counter battens

Storage & Exposure:
Store indoors prior to installation. All SuperFOIL products must be covered within 48 hours after installation.

Timber frame wall constructions are particularly sensitive to vapour movement and moisture accumulation.

Inadequate vapour protection may lead to:

• Interstitial condensation
• Timber rot
• Structural deterioration
• Reduced thermal efficiency

SuperFOIL multifoil insulation provides:

• Built-in vapour resistance (1200 MNs/g)
• Continuous internal insulation layer
• Airtightness when properly sealed
• Reduced thermal bridging
• Space-efficient build-up

Due to the limited thickness of timber frame walls, multifoil systems offer an effective solution without significantly increasing wall depth.

For detailed step-by-step visual guidance on working with SuperFOIL insulation, please refer to the “Internal Wall Insulation” section in the main menu.

Pre-Installation Assessment

Before installation begins:

• Inspect timber frame structure for integrity and dryness
• Confirm sheathing boards are sound
• Ensure no active moisture issues are present
• Verify external weather protection is intact
• Plan service routes (electrics, pipework, ventilation)
• Ensure overall building ventilation strategy remains adequate

All electrical and plumbing works must comply with relevant regulations and be undertaken by suitably qualified persons.

Copper pipes must be wrapped in non-metallic insulation before contact with aluminium foil surfaces.

HOW THE INTERNAL TIMBER FRAME SYSTEM WORKS

Step 1 – Stud Preparation

SuperFOIL is applied directly to timber studs.

Ensure:

• Studs are aligned and secure
• Stud centres are typically not exceeding 600 mm
• Openings around windows and doors provide secure fixing points

Perimeter battens may be installed at floor and ceiling level to assist with sealing and fixing.

Step 2 – Installing SuperFOIL

SuperFOIL may be installed:

• Horizontally (starting at the bottom and working upwards)
• Vertically (starting at the top and rolling downwards)

For horizontal installation:

• Begin at the base of the wall
• Maintain a minimum 50 mm overlap between layers

For vertical installation:

• Begin at the top
• Maintain minimum 50 mm overlap at vertical joints

Fixing method:

• Keep product taut during installation
• Staple securely into studs
• Typical staple intervals 50–100 mm
• Maximum spacing not exceeding 300 mm

At floor, ceiling, window and door junctions:

• Leave sufficient overlap for sealing
• Ensure overlaps are fully taped before closing with battens

Recommended Batten & Staple Sizes

To prevent compression and maintain reflective performance:

SF19+ → 38 mm battens → 14 mm staples
SF40 → 50 mm battens → 20 mm staples
SF60 → 63 mm battens → 25 mm staples

Batten depth should correspond to selected product thickness.

Sealing & Airtightness

Airtight installation is essential for vapour control performance.

Ensure:

• All overlaps are sealed using SuperFOIL foil tape
• All tears and cuts are sealed
• Service penetrations are minimised and taped
• Junctions at floor and ceiling are sealed before internal lining

Double-sided tape or compatible sealant may be used where required.

Secondary Counter Battens

Once insulation is fully installed and sealed:

• Install secondary counter battens through SuperFOIL into studs
• Maximum 600 mm centres
• Create a continuous internal air gap (typically minimum 20 mm)

This layer:

• Maintains reflective airspace
• Provides a service void
• Supports plasterboard installation

Junction Detailing

Ceiling Junction

• Maintain continuous insulation to ceiling line
• Seal overlaps before fixing battens
• Avoid gaps at head plate

Floor Junction

• Trim insulation neatly at floor level
• Seal junction to maintain airtight continuity
• Avoid gaps behind skirting zone

Window & Door Reveals

• Cut and fold insulation neatly into reveal areas
• Seal all cut edges
• Maintain airtight perimeter before finishing

Moisture & Condensation Considerations

With vapour resistance of 1200 MNs/g, SuperFOIL can function as a Vapour Control Layer when fully sealed.

However:

• Overall wall build-up must be considered
• Additional insulation layers must be assessed
• Hybrid constructions should be evaluated for condensation risk

Project-specific assessment is recommended where build-ups are complex.

Cutting & Handling

Recommended tools:

• Utility knife (compress before cutting)
• Rotary cutter
• Heavy-duty shears

Seal all cut edges after trimming.

Installation Checklist

Before completion ensure:

• Timber frame inspected and dry
• Minimum 50 mm overlaps maintained
• Staples ≤ 300 mm centres
• All overlaps and penetrations sealed
• Counter battens ≤ 600 mm centres
• Air gap maintained
• Internal lining correctly installed
• Installation stages documented