Transcript drylining and plasterboards

DRY LINING
PLASTERBOARD TYPES AND USES
► Dry
lining is also known as :
► Direct Bond or Dot and Dab
► Most common form of plastering used in modern
construction.
► Involves securing sheets of plasterboard directly to
the background surface, leaving an air space
between the plasterboard and the background.
► Using the correct boards, fixing and finishing
materials is essential to ensure adhesion and
quality of finish.
ADVANTAGES
► Can
provide a much warmer house than
traditional plaster.
► Plasterboard is a much better insulator than
solid plaster.
► The air gap can form an extra insulating
layer.
► The speed of construction.
► Has a quicker drying time than solid
plastering.
DISADVANTAGES
► Can
produce a lot of waste plasterboard if not
measured and cut economically.
► Traditional plasterboard has a low impact
resistance so can not be suitable for some high
traffic areas.
► Plasterboard can disintegrate in wet environments.
► Can be difficult to fix things to eg radiators.
► If the wrong products are used sound insulation
can be a problem.
BACKGROUNDS
► Most
backgrounds are suitable for Direct
Bond eg Brick, Block and Concrete.
► Painted surfaces cannot be dabbed.
► Adhesive will not stick to a wet or damp
background.
► All backgrounds need to be free of dust,
grease and any large mortar snots.
Backgrounds
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Concrete might need
treating with Thistle Bond
It especially if the concrete
is very smooth or dense.
Ceilings should be boarded
before dabbing.
Dabs should not be placed
on structural columns, the
board and dabs should
bridge them.
BACKGROUNDS
► Dabs
of adhesive
should ideally be no
less than 10mm thick
and no more than
25mm thick (when
compressed).
► Dabs heavier than
25mm will sag and
give a less secure
fixing.
SERVICES
► Any
electrics or pipe
work should pass
behind the board in
the airspace.
► Pipes or wires thicker
than the airspace
should be chased into
the background.
SETTING OUT
► The
first thing to do is
identify the high spot
of the wall.
► This could be a bump,
a prominent brick or
anything that stands
out from the wall.
► Transfer the high spot
by plumbing it up to
the ceiling and down
to the floor.
SETTING OUT
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The first mark shows the
high point.
Add at least 10mm for the
thickness of the dab.
Add on the plasterboard
thickness eg. 12.5mm,
15mm.
Transfer the mark using a
chalk line along the ceiling
and wall.
This gives you a line for
the front edge of the
plasterboard.
Direct bond
► Building
regs. require a
continuous fillet of
adhesive around the
perimeter of the wall
to prevent the
movement of air.
► A solid line also aids in
the fixing of skirting
boards etc,.
► Any services , pipes,
sockets, mounting
points should be well
supported with dabs of
adhesive.
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Dabs of adhesive should
be positioned in three
vertical rows across the
width of the board.
Any boarding should be
started in internal angles.
Dabs should be placed
near any board joints.
Dabs should be no more
than 300mm apart.
Placing plasterboard
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Plasterboard packers
should be placed under the
board before fixing.
This helps prevent the
travel of moisture up the
board from the floor.
Helps to level boards up if
the floor is uneven.
Lifts the board tight up to
the ceiling.
► Place
board gently
against adhesive
compound dabs.
► White side of board
facing out.
► Rest board on
plasterboard packers.
► Tap
the board gently
but firmly with a
straight edge.
► Board should align
against the chalk lines
along floor and ceiling.
► Tolerance expected
along a 2m straight
edge is +/- 3mm.
Angles
► External
angles should
be well supported with
dabs.
► Dabs provide strength
and a fixing point for
angle beads.
► Board edges should
finish flush with each
other to provide a neat
angle.
Plasterboards
► Plasterboards
are available for a variety of
applications and specifications.
► Thicknesses available are 9.5mm, 12.5mm,
15mm and 19mm.
► Sizes are 1200mm x 900mm, 1800mm x
900mm, 2400mm x 1200mm and 3600mm
x 1200mm.
► Plasterboard can be used for fire control,
sound insulation and thermal insulation.
Fire resistant
► Produced
with glass
fibre and other
additives in the core.
► Used in partition, wall
lining and ceiling
systems for increased
fire protection.
► Used to protect
structural steel.
► Pink face paper.
Moisture resistant
► Has
water repellant
additives in the core
and paper liner.
► Can be used as a base
for tiling in wet areas.
► Green paper on face
and reverse.
Sound
► Has
a higher density
core.
► Used where greater
levels of sound
insulation are required.
► Pale blue face paper.
Thermal boards.
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Wallboard which is factory
bonded to an expanded
polystyrene insulant.
Optional with vapour check
to reduce risk of
condensation.
Used in refurb or new
build where a basic level of
additional thermal
insulation is required.
Impact resistant
Duraline has a higher
density core with glass
fibre and other
additives.
 Used to give a greater
impact resistance in
heavy use areas.
 Ivory face paper.

Fixing plasterboard
Centres and Spacings
► 9.5mm
plasterboard should be fixed to centres no
more than 400mm apart.
► 12.5mm and 15mm boards should be fixed to
centres no more than 600mm apart.
► Nails used for fixing should be galvanised and
approx. 3.5x the depth of the board.
► Screws should be zinc plated and no less than
2.5x the depth of the board.
► Nails are spaced at 150mm apart.
► Screws are spaced at 230mm apart.
► Plasterboards
should be staggered when
fixed to ceilings and studs.
► This helps to prevent long, ‘line through’
cracks.
► Methods of joint reinforcement are Hessian,
Fibre Tape and Paper Tape.
► Plasterboard joints should have a gap of no
more than 3mm apart.
► Always try to keep ‘factory’ edges together.
► Any cuts should be placed in internal angles
or behind beads.
Skimming to plasterboard
Joints between plasterboard
joints and all internal
angles between wall and
ceiling need reinforcing.
Use Cotton scrim, Hessian (
jute) or fibre tape.
If using hessian allow all
joints to set before
applying finish.
TAPE AND JOINTING
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Used in many dry lining
specifications.
Lots of products are ready
mixed.
Joint Cement, Joint filler
and Easi fill.
Joints are reinforced with
paper tape, angles use
beads or metal reinforced
corner tape.
TAPE AND JOINTING
► Tape
is bedded on with
material.
► Joints filled out into
tapered joint.
► All screws are filled.
► All joints will need
sanding down.
► Wall is then sealed
with dry wall sealer.
Beads for plasterboards.
► Skim
Bead.
► Used on external
angles for finishing
coat. These beads
cannot be plumbed or
levelled up, they are
governed by their
background.
► Nailed or screwed on.
SKIM STOP BEAD
► Used
to provide a neat
finish to an opening or
to form a panel.
► 3mm depth.
► Nailed or screwed on.
MOVEMENT BEADS
► Used
if there is an
expansion joint in the
background.
► The V in the bead will
slot into the slot left in
the plaster boarding.
► Flexible V insert
allows bead to move
without cracking finish.
► Nailed or screwed on.
PLASTERBOARD EDGING BEADS
► Slots
over the edge of
plasterboard.
► Provides neat, clean
finish.
► Protects edge of
plasterboard.
► Different widths to suit
thickness of
plasterboard.
RE CAP
► Using
the correct boards, fixing and
finishing materials is ………………… to ensure
adhesion and quality of finish.
► An advantage of dry lining is its ……………….
of construction.
► A disadvantage of dry lining is plasterboard
can……………………. in a wet environment.
► Dabs ……………………….. be placed on
structural steel columns.
RE CAP
► Dabs
of adhesive should ideally be no less
than ……………. thick when compressed.
► The first thing to do when dabbing is
to……………… the high spot.
► Any boarding / dabbing should be started
in………………… angles.
► A moisture resistant plasterboard has a
………………… coloured face paper.
RE CAP
► 12.5mm
plasterboards should be fixed to
centres no more than…………………… apart.
► Gaps between plasterboard joints should be
no more than………………… apart.
► Plasterboard thicknesses are 9.5mm,
12.5mm,………………… and 19mm.
► When fixing with screws the spacings
should be no more than…………….mm apart.