weber.thermFT

weber.therm FT is a range of components for use with External Wall Insulation on single skin or frame construction. It consists of the weatherseal unit for positive detailing around openings and the standoff rail to provide the weather defence cavity recommended by the NHBC when using External Wall Insulation with metal frame construction.

• Multilevel defence provides positive, robust detailing
• Components can be used together or independently
• Weatherseal unit fabricated offsite from window schedule and delivered ready assembled with fixing kit
• UKAS tested and certified to the standards expected of double glazed units
• Corrosion resistant components
• Powder-coated weatherseal unit can be coloured to complement or contrast with window/wall area colour
• Fire breaks easily incorporated
• Jointing tongue for rails ensures horizontal alignment, including corners, minimises cutting and reduces waste.

Weatherseal unit: a powder coated aluminium assembly which closely surrounds window or door frame, incorporating cill, head, reveals and closure units with multi-level hydrophobic expanding foam seals and wedge gaskets.

Standoff rail: substantial horizontal aluminium rail fixed independently of the sheathing board and spanning the studs in the frame. Insulation boards are fixed to the standoff rails along their horizontal edges.

Project-specific technical and design support is available on request from weber's technical staff.

Weatherseal units are bespoke outer frames for windows and doors. The agreed window schedule should be made available in good time, to enable the manufacture of the weatherseal units, normally 6 - 8 weeks.

The face of the window frame should be fixed 30 - 40 mm proud of the outer face of the facade. When secured in this position, there should be a corresponding groove or rebate in the bottom edge of the window frame to locate the water bar on the weatherseal unit.

The gap between the frame and structural opening should be sealed as normal, prior the application of the weatherseal units.

Weatherseal units should be fitted prior to the fixing of the standoff rails.

Weatherseal units
Fit expanding foam strip supplied in accordance with the installation instructions and offer unit to widow. Engaging the sill upstand in the rebate in the underside of the window, rest the unit on the top of the projecting window.

Using the spacers provided ensure there is a 3 mm gap between widow and head of weatherseal unit. Fix sides of unit to substrate. Remove spacers and fit wedge gasket.

Compressing the foam strip, slide closure trims to within 3 mm of window frame and tighten fixing screws. Fit wedge gaskets and snap in cover plates.

Base closure trim
Fix the base closure trim on the top edge of the DPC or as directed. Ensure trim is level.

Standoff rails
Note: Rails are fixed through the sheathing board into the lightweight steel studs with the spacer located in the recess at the back of the rail. Mark off the steel stud centres on the standoff rail and drill 8 mm clearance holes along the screw groove on the rail. Do not attempt to fix to the sheathing board only.

Maximum spanning distance 600 mm.

Starter rail
Using the specified fixings and 30 mm plastic spacers, fix the starter rail with the lower edge touching the base closure trim. Leave a 10 - 15 mm gap between the rail joints for drainage.

Main wall rail
Sit insulation boards into the base bead, one at either end of the standoff rail, and rest the main wall standoff rail on top. Secure the rail with the fixings and spacers supplied. Insulation is always fixed with its long axis horizontal. Continue fixing rails, always ensuring that the vertical centres of the rails correspond to the height of the insulation.

Butt-join rails using aluminium joint straps. Alignment is maintained at internal and external corners by bending the joint straps.

Where required, fix trimmers (starter rail) above and below openings to support the insulation.

Horizontal firebreaks should be fitted where specified, using the self-adhesive intumescent tape fitted to the reverse face of the rail. Care must be taken to ensure that the tape is aligned within the fire-break zone.

Insulation can be fitted after 2 or more rails have been secured. The insulation is fixed to the rails along the top and bottom edges of the boards. Fixing kits are supplied based on the insulation thickness. Please refer to the relevant data sheet for system installation and fixing pattern.

Weatherseal units are finished units and should be stored where they will not be subject to accidental damage.

Standoff rails should be stored where they will remain straight to allow for true alignment when fixed.

Care should be taken when handling rails cut to length on site - edges may be sharp.

weber's Customer Services Department has a team of experienced advisors available to provide on-site advice both at the specification stage and during application. Detailed specifications can be provided for specific projects or more general works. Site visits and on-site demonstrations can be arranged on request.

Technical helpline
Tel: (01525) 722110
Fax: (01525) 718988

Sales, England and Wales
Tel: (01525) 722100
Fax: (01525) 718988

Sales, Scotland
Tel: (0141) 445 0121
Fax: (0141) 445 0122

Sales, Ireland
Tel: (028) 9335 2999
Fax: (028) 9332 3232