The document discusses the materials and process used for installing lath and plaster ceilings. Lath and plaster involves attaching thin wood laths to ceiling joists, with gaps between, then applying plaster in three layers to form a smooth, fire-resistant ceiling surface. This traditional method was time-consuming and required skilled labor, so it was largely replaced in the mid-20th century by pre-manufactured drywall which was less expensive and easier to install. The restaurant ceiling being described was installed using the traditional lath and plaster method due to its superior soundproofing and fire prevention qualities.

1. RESTAURANT DESIGN
THE
CEILING
backofen PLASTER AND LATHE
MATERIALS USED
PLASTER & LATH
LATH AND PLASTER IS A BUILDING PROCESS USED TO FINISH MAINLY
INTERIOR WALLS AND CEILINGS.
AN ADVANTAGE OF USING LATH IS FOR OR NAME NT AL OR UNUSUAL SHAPE S.
FOR INSTANCE, BUILDING A ROUNDED WALL WOULD BE DIFFICULT IF DRYWALL WERE
USED EXCLUSIVELY, AS DRYWALL IS NOT FLEXIBLE ENOUGH TO ALLOW TIGHT RADII.
BACKOFEN 'S CEILING HAS BEEN INSTALLED THE TRADITIONAL LATH AND PLASTER.
THESE MATERIALS HAVE SUPE R IOR SOUND-PR OOF ING QUALITIES WHEN USED WITH
LIME PLASTER WHICH IS DENSER THAN MODERN GYPSUM BOARD.
PLASTER & LATHE CEILING HAVE A MAJOR ROLE FOR THE PR E VE NT ION OF F IR E SPR E AD.
" THEY ARE CRITICAL TO THE PROTECTION OF HORIZONTAL ELEMENTS SUCH AS TIMBER JOISTED
FLOOR, INCLUDING THE FLOORING ON TOP, WHICH IN TERMS OF THE FIRE PERFORMANCE IS OFTEN IN A
POOR CONDITION DUE TO THE PRESENCE OF GAPS "
Ceilings were usually made using the lath and plaster attached to
wooden joists.
The laths are thin strips of wood (typically about 25mm by 6mm (1 by 1/4
inch) nailed to the underside of the timber joists with a gap of about
6mm (1/4 inch) between each lath.
The plaster was traditionally applied to the laths in thre e lime putty
laye rs:
The first layer (aka the render layer) was forced into the gaps between the laths to obtain a
strong bond to the laths, this layer was typically about 6mm (1/4 inch) thick.
The second layer (aka the floating coating) to be applied provided the relatively smooth finish
for
the third layer, this layer was typically about 6mm (1/4 inch) thick.
The third and final layer (aka the setting layer) provided smooth finish suitable for decoration
(typically the finish was whitewash or distemper), this layer was typically about 3mm
(1/8 inch) thick.
HOWEVER, Installing lath and plaster ceilings required skilled workers
and was time consuming; they were largely replaced by the use of pre-manufactured
plasterboard when it became widely available in the
middle
of the twentieth century.
LATH
Gypsum lath is commonly
used in place of wood since
it is non-combustible, easy
to use, and gives better
results. The popularity of
the lath and plaster method
declined in the 1950s, as it
was replaced by the less
expensive drywall method.
Gypsum lath is available with
a foil facing which acts as
a vapor barrier and heat
reflector, and as a veneer
base for plaster veneer.
PLASTER
Plaster is a building
material used for
coating walls and
ceilings. Plaster is
manufactured as a
dry powder and is
mixed with water to
form a paste when
used. The reaction
with water liberates
heat through
crystallization and the
hydrated plaster then
hardens.