Wedi Board info

[TF Ed]

heres some info on Wedi board.
theres a web link and technical helpline number too



WEDI BOARD

Call Technical Services on 01706 647 333 Wwww.wedi.co.uk

. German pioneered ‘tile backer board’ developed in Northern Germany by Helmet Wedi in 1983.
. Water proof, dimensionally stable and very high thermal values. Weight ratio = 60kg/m2
. Wedi boards consist of a ‘dow styrofoam’ core, while the outer layer of the boards have a laminated glass fibre impregnated into a polymer cement coating for strength . +/- 1mm per sheet.
. The boards also have ‘indentations’ pressed into the surface, designed to give a mechanical key.
. Wedi boards come in many thickness’s – 4mm, 6mm, 10mm, 12.5mm, 20mm, 30mm, 40mm, 50mm. Specialist sizes are also available in 60mm, 70mm and 80mm
. Boards sizes are normally between 1250mm x 600mm and (2500mm x 600mm & 900mm)
. Specialist sizes are available at 2500mm x 1200mm.
. Wedi also manufacture, curved boards, partitioning,wet rooms, seating and right angled boxing- in sections in 2.4 meter long sections in various widths ie 200mm, 300mm, 400m etc.

Installation...

There are 3 methods of installing Wedi boards:

1. The ‘Direct Fix’- using a notched trowel, spread SPF adhesive onto the substrate and bed the wedi board onto the adhesive. Allow to dry and then mechanically fix using wedi screws and washers at 5 per m2 for ceramic tiles and 8 per m2 for stone tiles.
Note: Wedi technical dept claim you can direct fix any thickness of board using this method.
They also claim that they only specify a spf adhesive and a thin bed trowel for application. If you feel you would rather use a larger notched trowel for thicker boards, then that’s your prerogative.

2. ‘Dab & Dowel’ – Make 8 holes per board and dab spf adhesive onto the rear of the boards covering the holes. Place the boards against the wall and press the boards firmly till the dabs are compressed to around 10mm deep and ensure that the boards are level and straight. Allow the adhesive to dry, then using an 8mm bit, drill into the pre-formed holes and tap in wedi plastic dowels and washers to mechanically hold the boards to the dabs. Note: - 5 per m2 for ceramic tiles & 8 per m2 for stone tiles.
Note: The minimum board thickness for this fixing method is 10mm

3. Fixing To Frame Work – simply screw the boards to the timber/metal framework using 8mm galvanised screws and wedi washers at 5 per m2 for ceramic tiles & 8 per m2 for stone tiles.

Wet areas: - All boards must have wedi WT50 waterproof sealing joint tape)’ fitted down the joints of the boards. They must overlap by 50mm either side of the board joint and SPF adhesive must be spread over the tape and feathered off to ensure a fully waterproof seal. Waterproof ‘internal & external’ corner seals should also be installed too.
Dry areas:- For dry areas, wedi provide a TT25 glass fibre joint tape that is stronger than conventional fibre tape/mesh. This is not water proof and not flexible and should only be used in dry areas. Spread SPF adhesive over the tape and feather off.

Fixing to concrete floors – Ensure the concrete is dust and debris free, then using a suitable spf adhesive with notched trowel, fix the boards in a staggered pattern ensuring all voids are filled. Allow to dry and then tape joints with either WT50 or TT25 tape. Smooth over with spf adhesive and feather out. If ‘Fixing to timber floors’ - Prime the timber floor using a suitable acrylic primer, then complete the same process as fixing to concrete. When dry, mechanically fix using wedi screws and washers at 5 per meter. Do not fix boards over existing expansion joints!
For projects over 20m2 – Apply TT60 MESH over the floor prior to fixing with wedi screws &washers.