First, the installer should check that adequate underfloor
ventilation is provided as the waterproof system being placed above it will
prevent the migration of moisture. Floorboards
(2) should be secure and
rigidly fixed (BS 5268 Part 2 -1991) to the joists
(1).
For projects up to 20 sq metres:
Prime the floorboard surface with Ardion P51 applied as a thin coat
(3)
using a foam or short pile paint roller. Allow it to dry to a clear, tacky film.
The wedi Tilebacker
(5) board (minimum thickness 10mm) should be bedded
onto the primed boards using Ardex X7001 cement-based adhesive
(4). The adhesive should be trowelled out thoroughly
and combed through to give a ribbed bed.
The Tilebacker board should be laid with staggered joints, and bedded in so
no voids are present. Care must be taken not to overlap any movement joints.
When the adhesive has hardened, all board joints should be reinforced with jointing
tape (TT25 Glass Fibre Jointing Tape or WT50 Waterproof Joint Sealing Tape)
applied in a fresh layer of Ardex X7001
(10) with
a taping knife or similar tool. Immediately, a fresh layer of adhesive should
be applied to the top of the tape and feathered off to the board surface.
When the adhesive has set the boards should be given additional strength from
screw fixing
(9) at a rate of 5 per square metre, a minimum of 30mm from
the board edge. Proprietary washers (PW60) should be used, with the countersunk
screws being tightened until the head is flush with the board surface. In wet
areas it is worth putting silicone sealant into the holes before fixing.
For projects over 20 sq metres:
The installation follows the same steps up to and including the taping of the
joints. Before the mechanical fixings are used, a layer of glass fibre mesh
fabric TT60 should be placed over the boarded floor and tacked in place with
the screw/washer fixings.
Tiles
(7) can be fixed with a thin solid fixing bed technique
to ensure there are no voids left. Once the adhesive has
hardened, the tiles can be grouted
(8).
