Page 1
CHAPTER – 12
FLOORS
In order to sub-divide the portion between the plinth level or basement
level and roof level, solid constructions are Carrie out. These
constructions are known as floors and exposed top surface of floors are
termed as floorings. Ground floors or basement floors, which directly
rest on the ground, do not require the provision of a floor. But they are
provided with suitable type of flooring.
12.1 Types of Floors:
Floors are classified into two categories
1. Timber Floors
2. Composite Floors
1. Timber Floors: In this floor, only timber is used as a material.
Timber floors are further divided into four types.
a. Basement or Ground floor of timber
b. Single Joist timber beam
c. Double Joist timber beam
d. Framed triple joist timber floor.
Features of Timber Floors:
(i) Floor Boards: These boards are provided at the top of bridging joists
and they form the wearing surface of the floor. The width varies from
100mm to 200mm and thickness varies from 20mm to 40mm. the
Page 2
CHAPTER – 12
FLOORS
In order to sub-divide the portion between the plinth level or basement
level and roof level, solid constructions are Carrie out. These
constructions are known as floors and exposed top surface of floors are
termed as floorings. Ground floors or basement floors, which directly
rest on the ground, do not require the provision of a floor. But they are
provided with suitable type of flooring.
12.1 Types of Floors:
Floors are classified into two categories
1. Timber Floors
2. Composite Floors
1. Timber Floors: In this floor, only timber is used as a material.
Timber floors are further divided into four types.
a. Basement or Ground floor of timber
b. Single Joist timber beam
c. Double Joist timber beam
d. Framed triple joist timber floor.
Features of Timber Floors:
(i) Floor Boards: These boards are provided at the top of bridging joists
and they form the wearing surface of the floor. The width varies from
100mm to 200mm and thickness varies from 20mm to 40mm. the
Floors
thickness may be changes when a floor subject to heavy traffic from 60
to 80mm. The floor boards are joined and widened by any suitable joint
as shown in the figure.12.1
Fig 12.1 Pugging
(ii) Floor Ceilings: To make the underside of the floor flat and to
improve the appearance as a whole, ceilings may be provided rest on
bridging joists or binders. The ceilings may consists of plaster boards or
sheets of asbestors cement or some suitable material. In order to make
ceilings strong and durable, ceiling joists may be provided at right angles
to the bridging joists or the binders.
(i) Pugging: In order to make the timber floor sound proof,
pugging may be resorted. Pugging plaster is a mixture of
chopped straw and mortar. Insulating boards supporting on
fillets are provided and hallows space between the
floorboards and the insulating boards is filled up with the
pugging plaster.
(ii) Trimming: When openings are to be provided in wooden
floors, it is clear that bridging joists will not rest on the walls.
In such cases, the process of trimming is required. Trimming
joists support one or two trimmer joists to which trimmed
joists are fixed. The trimming joists and trimmer joists have
Page 3
CHAPTER – 12
FLOORS
In order to sub-divide the portion between the plinth level or basement
level and roof level, solid constructions are Carrie out. These
constructions are known as floors and exposed top surface of floors are
termed as floorings. Ground floors or basement floors, which directly
rest on the ground, do not require the provision of a floor. But they are
provided with suitable type of flooring.
12.1 Types of Floors:
Floors are classified into two categories
1. Timber Floors
2. Composite Floors
1. Timber Floors: In this floor, only timber is used as a material.
Timber floors are further divided into four types.
a. Basement or Ground floor of timber
b. Single Joist timber beam
c. Double Joist timber beam
d. Framed triple joist timber floor.
Features of Timber Floors:
(i) Floor Boards: These boards are provided at the top of bridging joists
and they form the wearing surface of the floor. The width varies from
100mm to 200mm and thickness varies from 20mm to 40mm. the
Floors
thickness may be changes when a floor subject to heavy traffic from 60
to 80mm. The floor boards are joined and widened by any suitable joint
as shown in the figure.12.1
Fig 12.1 Pugging
(ii) Floor Ceilings: To make the underside of the floor flat and to
improve the appearance as a whole, ceilings may be provided rest on
bridging joists or binders. The ceilings may consists of plaster boards or
sheets of asbestors cement or some suitable material. In order to make
ceilings strong and durable, ceiling joists may be provided at right angles
to the bridging joists or the binders.
(i) Pugging: In order to make the timber floor sound proof,
pugging may be resorted. Pugging plaster is a mixture of
chopped straw and mortar. Insulating boards supporting on
fillets are provided and hallows space between the
floorboards and the insulating boards is filled up with the
pugging plaster.
(ii) Trimming: When openings are to be provided in wooden
floors, it is clear that bridging joists will not rest on the walls.
In such cases, the process of trimming is required. Trimming
joists support one or two trimmer joists to which trimmed
joists are fixed. The trimming joists and trimmer joists have
slightly greater section than bridging joists Fig. 12.2 shows a
wooden floor with stair well.
(iii) Use of stell sections: Binders and girders of wooden floor can
be replaced by mild rolled steel joists. The only precaution to
be taken in this case would be to encase the R.S.J. by
concrete so as to prevent rusting of R.S.J. The use of steel
section makes the floor light and economical.
a) Basement or ground floor of timber:
In auditorium, to carry out dances or dramas timber floors are
constructed on ground floor. Sleeper walls, which may be of
one-half brick or one brick thickness, are constructed at
centre to centre distance of 1.20m to 1.80m. Wall-plates are
provided along the wall as well as along the sleeper walls and
they reduce the spans of the building joists and serve as end
supports for the bridging joists. On wall-plates rest the ends
of bridging joists, which are usually provided at a centre to
centre distance of about 30 cm. Finally, floor boards are
provided to finish up the floor. The details are as shown in fig
12.2.
Page 4
CHAPTER – 12
FLOORS
In order to sub-divide the portion between the plinth level or basement
level and roof level, solid constructions are Carrie out. These
constructions are known as floors and exposed top surface of floors are
termed as floorings. Ground floors or basement floors, which directly
rest on the ground, do not require the provision of a floor. But they are
provided with suitable type of flooring.
12.1 Types of Floors:
Floors are classified into two categories
1. Timber Floors
2. Composite Floors
1. Timber Floors: In this floor, only timber is used as a material.
Timber floors are further divided into four types.
a. Basement or Ground floor of timber
b. Single Joist timber beam
c. Double Joist timber beam
d. Framed triple joist timber floor.
Features of Timber Floors:
(i) Floor Boards: These boards are provided at the top of bridging joists
and they form the wearing surface of the floor. The width varies from
100mm to 200mm and thickness varies from 20mm to 40mm. the
Floors
thickness may be changes when a floor subject to heavy traffic from 60
to 80mm. The floor boards are joined and widened by any suitable joint
as shown in the figure.12.1
Fig 12.1 Pugging
(ii) Floor Ceilings: To make the underside of the floor flat and to
improve the appearance as a whole, ceilings may be provided rest on
bridging joists or binders. The ceilings may consists of plaster boards or
sheets of asbestors cement or some suitable material. In order to make
ceilings strong and durable, ceiling joists may be provided at right angles
to the bridging joists or the binders.
(i) Pugging: In order to make the timber floor sound proof,
pugging may be resorted. Pugging plaster is a mixture of
chopped straw and mortar. Insulating boards supporting on
fillets are provided and hallows space between the
floorboards and the insulating boards is filled up with the
pugging plaster.
(ii) Trimming: When openings are to be provided in wooden
floors, it is clear that bridging joists will not rest on the walls.
In such cases, the process of trimming is required. Trimming
joists support one or two trimmer joists to which trimmed
joists are fixed. The trimming joists and trimmer joists have
slightly greater section than bridging joists Fig. 12.2 shows a
wooden floor with stair well.
(iii) Use of stell sections: Binders and girders of wooden floor can
be replaced by mild rolled steel joists. The only precaution to
be taken in this case would be to encase the R.S.J. by
concrete so as to prevent rusting of R.S.J. The use of steel
section makes the floor light and economical.
a) Basement or ground floor of timber:
In auditorium, to carry out dances or dramas timber floors are
constructed on ground floor. Sleeper walls, which may be of
one-half brick or one brick thickness, are constructed at
centre to centre distance of 1.20m to 1.80m. Wall-plates are
provided along the wall as well as along the sleeper walls and
they reduce the spans of the building joists and serve as end
supports for the bridging joists. On wall-plates rest the ends
of bridging joists, which are usually provided at a centre to
centre distance of about 30 cm. Finally, floor boards are
provided to finish up the floor. The details are as shown in fig
12.2.
Floors
Fig 12.2. Basement or ground floor of timber
b) Single Joist timber floor:
These floors consist of single joist, which are placed below
the floorboards. The joists are usually placed at a centre to
centre distance of 30cm to 45cm. The joists are supported on
wall-plates at their ends. A space of about 50mm is kept for
the circulation of air as shown in fig 12.3. Single joist timber
floor can be adopted for a maximum span of about 3.6m.
When the span of joist exceeds 2.4m, it becomes necessary to
strengthen the joist by providing bearing bone strutting. In
this arrangement, inclined timber pieces are firmly fixed
between the joists and the ends of these struts are nailed to the
joist. At the end, wedges are provided between the wall and
the joists.
Page 5
CHAPTER – 12
FLOORS
In order to sub-divide the portion between the plinth level or basement
level and roof level, solid constructions are Carrie out. These
constructions are known as floors and exposed top surface of floors are
termed as floorings. Ground floors or basement floors, which directly
rest on the ground, do not require the provision of a floor. But they are
provided with suitable type of flooring.
12.1 Types of Floors:
Floors are classified into two categories
1. Timber Floors
2. Composite Floors
1. Timber Floors: In this floor, only timber is used as a material.
Timber floors are further divided into four types.
a. Basement or Ground floor of timber
b. Single Joist timber beam
c. Double Joist timber beam
d. Framed triple joist timber floor.
Features of Timber Floors:
(i) Floor Boards: These boards are provided at the top of bridging joists
and they form the wearing surface of the floor. The width varies from
100mm to 200mm and thickness varies from 20mm to 40mm. the
Floors
thickness may be changes when a floor subject to heavy traffic from 60
to 80mm. The floor boards are joined and widened by any suitable joint
as shown in the figure.12.1
Fig 12.1 Pugging
(ii) Floor Ceilings: To make the underside of the floor flat and to
improve the appearance as a whole, ceilings may be provided rest on
bridging joists or binders. The ceilings may consists of plaster boards or
sheets of asbestors cement or some suitable material. In order to make
ceilings strong and durable, ceiling joists may be provided at right angles
to the bridging joists or the binders.
(i) Pugging: In order to make the timber floor sound proof,
pugging may be resorted. Pugging plaster is a mixture of
chopped straw and mortar. Insulating boards supporting on
fillets are provided and hallows space between the
floorboards and the insulating boards is filled up with the
pugging plaster.
(ii) Trimming: When openings are to be provided in wooden
floors, it is clear that bridging joists will not rest on the walls.
In such cases, the process of trimming is required. Trimming
joists support one or two trimmer joists to which trimmed
joists are fixed. The trimming joists and trimmer joists have
slightly greater section than bridging joists Fig. 12.2 shows a
wooden floor with stair well.
(iii) Use of stell sections: Binders and girders of wooden floor can
be replaced by mild rolled steel joists. The only precaution to
be taken in this case would be to encase the R.S.J. by
concrete so as to prevent rusting of R.S.J. The use of steel
section makes the floor light and economical.
a) Basement or ground floor of timber:
In auditorium, to carry out dances or dramas timber floors are
constructed on ground floor. Sleeper walls, which may be of
one-half brick or one brick thickness, are constructed at
centre to centre distance of 1.20m to 1.80m. Wall-plates are
provided along the wall as well as along the sleeper walls and
they reduce the spans of the building joists and serve as end
supports for the bridging joists. On wall-plates rest the ends
of bridging joists, which are usually provided at a centre to
centre distance of about 30 cm. Finally, floor boards are
provided to finish up the floor. The details are as shown in fig
12.2.
Floors
Fig 12.2. Basement or ground floor of timber
b) Single Joist timber floor:
These floors consist of single joist, which are placed below
the floorboards. The joists are usually placed at a centre to
centre distance of 30cm to 45cm. The joists are supported on
wall-plates at their ends. A space of about 50mm is kept for
the circulation of air as shown in fig 12.3. Single joist timber
floor can be adopted for a maximum span of about 3.6m.
When the span of joist exceeds 2.4m, it becomes necessary to
strengthen the joist by providing bearing bone strutting. In
this arrangement, inclined timber pieces are firmly fixed
between the joists and the ends of these struts are nailed to the
joist. At the end, wedges are provided between the wall and
the joists.
Fig 12.3 Details of single joist timber floor
c) Double joist timber floors:
In this type of floors, intermediate supports known as binders,
are provided for bridging joists. Binders are generally placed
at a centre to centre distance of 1.80m to 2.40m as shown in
fig 12.4. The ends of binders rest on wooden or stone blocks.
Double joist timber floors are stronger than the single joist
timber floors. They prevent the passage of sound in better
way and they are suitable for spans of 3.60 to 7.50m. This
type of floors has following disadvantages.
(i) The weight of floor is thrown on few points in a wall.
(ii) Depth of floor is increased by the use of binders and
accordingly height of the room is decreased.
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