[0001] The invention relates to a method for constructing a building, which building has
at least two floors, in which method a frame of the building is erected, which frame
comprises at least one intermediate floor and load-bearing structural elements, such
as load-bearing walls and/or pillars, supporting the intermediate floors, an opening
is formed to at least one intermediate floor in connection with the construction of
the intermediate floor and a modular unit is lowered to at least one floor under the
intermediate floor through said opening. The invention also relates to a building
constructed with the method.
[0002] The concentration of the population in cities and growth centres creates the demand
to build new apartments, especially in blocks of flats. The constant price increase
of new apartments has led to the situation, in which many of those in need of apartments
can't afford their own apartment. The rise of the construction costs also inevitably
leads to the rise of the rent level, which also makes it harder to get a rental apartment
for a reasonable price. There is thus a clear need for solutions reducing the construction
costs of blocks of flats.
[0003] One known way for reducing the construction costs is to increase the use of prefabricated
structural elements, i.e. units. The prefabricated structural elements can be manufactured
in plant conditions faster and more efficiently than on the construction site, whereby
the construction time of a block of flats shortens bringing savings to the construction
costs. The prefabricated structural elements typically used in the construction of
blocks of flats are hollow-core slabs, partition elements and façade elements. Also
prefabricated sanitary box elements, i.e. bathroom elements, are known, in which elements
the entire bathroom is manufactured as one modular unit ready for installation. The
finished modular units are typically installed in their places after the construction
of the load-bearing frame of the building, i.e. after the construction of load-bearing
vertical structures and intermediate floors. Transferring and installing of the modular
units between the closed intermediate floors is hard and slow. Furthermore, the floor
surface of the modular unit to be placed on the intermediate floor remains higher
than the floor surface of the other spaces of the apartment, which makes the use of
the space harder and weakens the aesthetic look of the apartment.
[0004] Publications
FR 2025953 and
US 2005/0108957 describe installation methods of modular units, in which methods the modular units
are lowered in their places inside the frame of the building from above through the
openings in the intermediate floors of the building. The modular units are installed
in their places simultaneously with the progress of the construction work or immediately
after the frame is finished. Publication
WO 2007/085687 describes a repair method for sanitary cabins of a block of flats, in which method
the old sanitary cabins and the parts of the intermediate floors of the building limited
to them are demolished. New sanitary cabinet elements are lowered inside the building
through openings formed in the intermediate floors in connection with the demolishing
work.
[0005] The object of the invention is to provide a method for constructing a building, especially
a block of flats, and a building constructed with the method, with which method and
building the disadvantages relating to the prior art can be reduced.
[0006] The objects of the invention are obtained with a method and a building, which are
characterized by what is presented in the independent claims. Some advantageous embodiments
of the invention are presented in the dependent claims.
[0007] The invention relates to a method for constructing a building, which has at least
two floors. In the method, a frame of the building is erected, which frame comprises
at least one intermediate floor and structural elements, such as load-bearing walls
and/or pillars, supporting the intermediate floors. The frame of the building can
be constructed on the site or entirely or partly as prefabricated structure elements.
In the method, an opening is formed to at least one intermediate floor in connection
with the construction of the intermediate floor and a modular unit is lowered to at
least one floor under the intermediate floor through said opening. Through the opening
in the intermediate floor the modular unit can be lowered from above directly in its
correct place in the floor, whereby it is not necessary to transfer the modular unit
anymore in the floor level. In the method, a roof covering is substantially ready
installed to the building before lowering the modular units to the floors. A substantially
ready-made roof covering refers to the fact that the roof covering of the building
prevents the rain water to get inside the building through the roof covering. A substantially
ready-made roof covering thus comprises at least water-proof underlay and it can also
comprise a surface layer of the actual roof covering. An opening is formed to the
roof covering, which opening is in alignment with the openings of the intermediate
floor, and the modular units are lowered to the floors through the opening of the
roof covering. Before lowering the modular units in their places the opening formed
in the roof covering can be covered by a temporary cover. After lowering the modular
units in their places, the opening of the roof covering is constructed so as to be
closed, i.e. covered with the roofing used in the roof covering, whereby the roof
covering becomes entirely waterproof and uniform in its appearance.
[0008] In a preferred embodiment of the method according to the invention, a frame is erected,
which frame has several intermediate floors, and at least one opening is formed to
substantially each intermediate floor of the frame so that the openings are in alignment
with the same vertical line and at least one modular unit is lowered through the openings
to substantially each floor. In this embodiment the building to be constructed is
thus clearly a block of flats, which has several floors on top of each other, which
floors have one or several apartments. The number of the floors is not limited in
any way. In typical blocks of flats, the number of the floors can be from three to
twelve, but the number of the floors can also be bigger than mentioned above. The
number of the intermediate floors depends naturally on the number of the floors of
the building. The number of the intermediate floors can be for example 2, 3, 4, 5,
6 or more than 6.
[0009] The blocks of flats are constructed so that the room spaces in different floors to
be constructed from the modular units have substantially the same size and they set
exactly on top of each other, i.e. they are in the same place of the intermediate
floor in every floor. One floor can have several apartments, wherein each apartment
has typically at least one room space to be constructed from the modular unit. The
modular units are lowered to the floors from above through the openings of the intermediate
floors and the roof covering so that the modular unit of the lowest floor is lowered
in its place first. After this the modular unit of the second lowest floor is lowered
in its place, and this is continued until the modular units are lowered in their places
in all floors. Naturally, the modular unit of the uppermost floor does not need to
be lowered through the intermediate floor between the floors.
[0010] In another preferred embodiment of the method according to the invention outer walls
and roof are constructed to the building. A thermal insulation is installed to the
outer walls and roof before lowering the modular units to the floors. In this way,
a thermally insulated, weatherproof continuous outer coating is provided to the building.
Due to the thermally insulated outer coating the inner temperature of the building
can be increased with the heating devices to the level of the normal residential temperature,
whereby the frame structures start to dry and the humidity and the temperature of
the interiors can be kept substantially constant. At least a part of the outer walls
of the building can be built substantially ready before lowering the modular units
to the floors. This means that the construction of the cladding of the outer walls
can be started immediately after installing the thermal insulation layer of the outer
walls.
[0011] In yet another preferred embodiment of the method of the invention the modular units
have a floor slab and they are supported from the floor slab to the edges of the opening
of the intermediate floor so as to bear the vertical loads after they have been lowered
in their places to the right floor inside the block of flats. The dead weight of the
modular units and the loads of the modular unit during their use, such as person loads,
are transferred through the edges of the floor slab to the edges of the opening of
the intermediate floor, wherefrom they transfer through the load-bearing frame of
the building to the ground. Vertical loads are thus not at least remarkably transferred
from the modular unit located higher in the building to the modular unit underneath
it. The openings of the intermediate floors are dimensioned so that they are only
slightly bigger in their size than the floor slabs of the modular unit, so that only
a clearance which is as small as possible and enables the through passage of the modular
units remains between the edges of the floor slab and the edges of the opening. In
this case, the floor slab is easy to attach from its edges to the edges of the opening
without big supporting elements. Preferably the modular units are supported in their
places so that the upper surface of the floor slab and the upper surface of the intermediate
floor set to a substantially same level. In the apartments of the building all floor
surfaces of the room spaces are thus substantially on the same level, whereby they
fulfil the requirements of unrestricted living.
[0012] In yet another preferred embodiment of the method according to the invention, a modular
unit comprising a floor slab, ceiling and walls, is lowered to the floor with the
method. The walls have a first surface and a second surface, and the first surfaces
of the walls define a bathroom inside them. The bathroom has fixed equipment and/or
furniture for use in the bathroom. At least a WC seat, hand basin with accessories,
shower wall or curtain, shower faucet, bathroom cabinet, lamp, heat distribution system,
floor drain and washing machine connections belong typically to the equipment of such
modular unit.
[0013] In yet another preferred embodiment of the method according to the invention, a modular
unit, in which a part of said floor slab extends along the length of at least one
wall outside the area defined by the second surfaces of said walls, is lowered to
the floor with the method. This part of the floor slab and/or the second surface of
said at least one wall have second fixed equipment and/or furniture for use in the
second room space. The essential fact in this embodiment of the invention is thus,
that there are first fixed equipment and/or furniture inside of it, which equipment
and/or furniture are designed for use in the bathroom inside the modular unit, and
that there are second fixed equipment outside the modular unit, which equipment are
designed for use in the space outside the modular unit. The second room space outside
the modular unit can be a kitchen, whereby the above-mentioned second equipment and/or
furniture are fixed kitchen equipment and/or furniture. Such equipment that typically
belong to every kitchen are among others kitchen cupboards, kitchen sink with accessories
as well as connections for installing dish washer, stove and refrigeration equipment.
The second equipment and/or furniture can also be fixed hall equipment and/or furniture,
such as closets.
[0014] A building according to the invention has at least two floors, a frame comprising
at least one intermediate floor and load-bearing structural elements, such as load-bearing
walls and/or pillars, supporting the intermediate floors. The building comprises further
at least one modular unit in the floor under at least one intermediate floor. The
modular unit has been lowered through the opening in the intermediate floor formed
in connection with the construction of the intermediate floor. The building is characterized
by having a roof covering, which is substantially ready built before lowering the
modular units to the floors. An opening which is in alignment with the openings of
the intermediate floor is formed to the roof covering, and the modular units have
been lowered to the floors through the opening in the roof covering. A preferred embodiment
of the building according to the invention has outer walls and a roof, to which a
thermal insulation has been installed before lowering the modular units to the floors.
[0015] In yet another preferred embodiment of the building according to the invention the
modular units comprise a floor slab and the modular units are supported from the floor
slab to the edges of the opening of the intermediate floor in a manner so as to bear
the vertical loads.
[0016] An advantage of the method according to the invention is that it enables a remarkable
increase of the prefabrication degree in the construction of block of flats, what
shortens the construction time and brings savings to the construction costs.
[0017] Further, an advantage of the invention is that it accelerates the installation of
the modular units to the building. Before installing the modular units in their places,
the openings in the intermediate floors formed for the modular units serve as "channels",
which make it easier and faster to heat and dry the building during the construction
work. The invention thus shortens the construction time also in this way. Further,
an advantage of the invention is that it improves the construction quality, since
the major part of the construction-technically demanding construction works is transferred
from the construction site to be made in plant conditions.
[0018] In the following, the invention will be described in detail. In the description,
reference is made to the enclosed drawings, in which
Figs. 1a to 1d show by way of an example a construction method of a building according
to the invention with the aid of a series of pictures and
Figure 2 shows a cross-sectional view of the modular unit in a building constructed
with the method.
Figures 1a-1d show by way of an example a construction method of a building according
to the invention with the aid of a series of pictures.
[0019] The building to be constructed with the method presented in Figures 1a-1d is a six-storey
block of flats. In the method, the foundation 28 is constructed first, on which foundation
the frame 10 of the block of flats is erected (Fig. 1 a). The foundation can be a
footing foundation or a pile foundation or any other known foundation. The block of
flats has several floors 26 on top of each other, which floors can have one or more
apartments. The block of flats presented in Figures 1a-1d has six floors, but it can
also have another number of floors. Between each floor there is an intermediate floor
12, which forms the ceiling of the lower floor and the floor of the upper floor. The
upper surface of the uppermost floor has a roof 14, which has a substantially same
structure as the intermediate floors. The lower surface of the lowest floor has a
base floor 16, which in Figure 1a is a ground slab. Between the intermediate floors
12 and the uppermost intermediate floor and the roof 14 there are vertical load-bearing
walls 20 and pillars 22, which bear the loads of the roofs and intermediate floors
and transfer them into the foundation. The frame of the block of flats is constructed
from reinforced concrete, i.e. its load-bearing structures are reinforced concrete
structures. The frame can be constructed on the site or entirely or partly as prefabricated
structure elements. The construction of the frame of the block of flats is conventional
known construction technique, which is not described in more detail in this connection.
[0020] In the method, openings 30 are formed in each intermediate floor 12 so that the openings
in the superimposed intermediate floors have substantially the same size and form
and they are in alignment with the same vertical line. Openings 30 corresponding to
the openings in the intermediate floors are formed to the roof 14. The openings are
formed so many, that there is one opening in the place of an apartment to be built
in each floor. The openings are dimensioned so that their outer dimensions are slightly
bigger than the outer dimensions of the modular unit to be placed in the opening.
[0021] The thermal insulation layer of the roof 14 and the roof covering 18 as well as the
outer walls 24 of the building are constructed after the frame of the building has
been finished. The roof covering is constructed to a degree of readiness, where the
roof covering becomes rain water proof. This means that at least waterproof underlay
is installed to the roof covering. The roof covering can also be substantially ready
built in its entirety, i.e. also a final surface layer of the roof covering can be
installed therein. Lead-through openings 30a are left in the roof covering in the
places of the openings in the roof. The openings of the roof covering are covered
by opening covers (the covers are not presented in the Figures), so that the roof
covering becomes waterproof.
[0022] The outer walls can be constructed on site or as prefabricated structure elements.
The outer walls are constructed at least to a degree of readiness, where they have
a finished thermal insulation and an external wind shield layer covering the thermal
insulation from weather. After the construction of the outer walls and roof covering
the interiors of the building are protected from the weather and the outer covering
of the building is thermally insulated. After this the inner temperature of the building
is increased to normal residential temperature with the heating devices, whereby the
structures begin to dry. The drying of the structures can be accelerated with separate
dryers. Decoration works of the building are made simultaneously with the drying of
the structures.
[0023] After having obtained a sufficiently low relative air humidity concerning the durability
of the surface materials the modular units 50 (Figure 1 c) are transferred inside
the building. The modular units are prefabricated structural elements, which have
a floor slab, walls and a ceiling. The structure of the modular units is disclosed
in more detail in the description of Figure 2. The modular units are ready built and
equipped at the element factory and delivered to the construction site as parts ready
to be installed. In order to transfer the modular units, the openings 30a in the roof
covering are opened and the modular units are lowered by a crane 100 through the openings
in the roof covering 18, roof 14 and in the intermediate floors 12 to the floors 26.
The openings of the roof covering, roof and intermediate floors are dimensioned so
that the side dimensions of the openings are slightly bigger than the outer dimensions
of the modular unit. The side dimensions of the opening can be for example in both
directions 50 mm bigger than the side dimensions of the modular unit. Thus, a sufficient
clearance, which enables a lead-through, remains between the outer surfaces of the
walls of the modular unit and the edges of the opening.
[0024] The installation of modular units is started from the lowest floor, i.e. the modular
unit of the lowest floor is lowered first in its place on the base floor 16. The base
floor has a cavity 17 (Figure 1a) in the lowering point of the modular unit, the outer
dimensions of which cavity are the same as the dimensions of the openings in the intermediate
floors 12. The depth of the cavity is dimensioned so that the upper surface of the
floor slab and the upper surface of the base floor 16 of the modular unit placed in
the cavity set substantially on the same level. The modular unit of the lowest floor
is attached to the base floor by grouting.
[0025] Next, the modular unit 50 of the second lowest floor is lowered in its place. The
modular unit is lowered down in the manner described above by a crane 100 through
the openings in the roof covering 18, roof 14 and the intermediate floors 12. The
modular unit is attached from the edges of the floor slab to the edges of the opening
30 of the intermediate floor 12 by appropriate fixing elements so that the dead weight
and person loads are transferred through the fixing elements to the edges of the opening
of the intermediate floor. The fixing elements can be for example steel fixing plates
generally used in concrete elements, which fixing plates are cast with the rod-like
attachment parts so as to fix to the edges of the opening 30 of the intermediate floor
and to the edges of the floor slab of the modular unit. Steel fixing plates can be
attached to each other by welding with the aid of a connector. The gap between the
floor slab of the modular unit and the edges of the opening of the intermediate floor
is filled with grouting.
[0026] Modular units are installed in a respective manner to all floors and all apartments
of a floor of the block of flats. After the modular units of the uppermost floor have
been lowered and fixed in their places, the openings 30a in the roof 14 and roof covering
18 are covered (Figure 1d). After the covering of the openings the roof is entirely
thermally insulated and the roof covering is waterproof.
[0027] Figure 2 shows by way of an example a cross-sectional view of a modular unit 50 in
a building constructed with the method. The modular unit is a closed "room-like" space,
which has a floor slab 52, walls 54 and a ceiling 56. One wall has an opening door
58 for getting in to the modular unit. The walls 54 of the modular unit are in their
structure normal walls having skeleton construction and being coated with lining plates
on both sides. The ceiling has horizontal supporting beams, on the under surface of
which there is an interior lining plate. The floor slab of the modular unit is dimensioned
so that it bears the loads coming from its dead weight as well as the service loads
when supported from its edges. The floor slab is manufactured from reinforced concrete.
The floor slab is attached from its edges to the edges of the opening 30 of the intermediate
floor 12 so that the upper surface of the floor slab and the upper surface of the
intermediate floor are substantially set to the same level. For fixing the modular
unit, there are steel fixing plates 60 on the edge surfaces of the floor slab and
on the edge surface of the opening 30, which fixing plates are cast by rod-like attachment
parts so as to fix to the edges of the opening of the intermediate floor and to the
edges of the floor slab. The steel fixing plates are welded together with the aid
of connectors 68. The gap between the floor slab of the modular unit and the edges
of the opening of the intermediate floor is filled with grouting 62.
[0028] Inside the modular unit, there are fixed equipment and/or furniture for use in the
bathroom (furniture and equipment are not shown in the Figure). At least a WC seat,
hand basin with accessories, shower wall or curtain, shower faucet, bathroom cabinet,
lamp, heat distribution system, floor drain and washing machine connections belong
typically to the equipment of a bathroom modular unit. The modular unit has in one
corner a vertical channel 66, a so-called duct, defined by the walls, the first end
of which channel opens through the opening in the floor slab 52 under the floor slab
and the second end opens through the opening in the ceiling 56 over the ceiling. The
channel is designed for placing the pipes and wires of the heating, plumbing, ventilation
and electrical installation systems of the block of flats. Such pipes and wires to
be placed in the channel are among others drain pipes, air pipes, pipes for cold and
warm service water, pipes for the water circulating heating system, pipes for sprinkler
system and electric cables. The channel can have all above-mentioned pipes and wires
ready-fitted, wherein the pipes and wires of the superimposed modular units are connected
to each other when installing the modular units. The floor height of a block of flats
is according to the building regulations at least 3 meters, wherein the clearance
between the upper intermediate floor and the lower intermediate floor of the story
is about 2700 mm, The modular unit is dimensioned so that the distance between the
upper surface of the floor slab and the upper surface of the ceiling is about 2400
mm, i.e. clearly smaller than 2700 mm. Between the two superimposed modular units
installed in their places, i.e. between the upper surface of the ceiling of the lower
modular unit and the lower surface of the floor slab of the upper modular unit remains
thus an assembly space 64, in which pipes and wires passing in the channels 66 of
the modular units can be connected.
[0029] Some advantageous embodiments of the method and building according to the invention
have been described above. The invention is not limited to the solutions described
above, but the inventive idea can be applied in different ways within the scope of
the claims.
1. A method for constructing a building, which building has at least two floors (26),
in which method a frame (10) of the building is erected, which frame comprises at
least one intermediate floor (12) and load-bearing structural parts, such as load-bearing
walls (20) and/or pillars (22), supporting the intermediate floors, an opening (30)
is formed in at least one intermediate floor (12) in connection with the construction
of the intermediate floor and a modular unit (50) is lowered to at least one floor
(26) under the intermediate floor through said opening, characterized in that a roof covering (18) is built substantially ready to the building before lowering
the modular units (50) to the floors (26), an opening (30a) is formed to the roof
covering (18), which opening is in alignment with the openings (30) of the intermediate
floor (12), and the modular units (50) are lowered to the floors through the opening
(30a) of the roof covering (18).
2. The method according to claim 1, characterized In that a frame (10), which has several intermediate floors (12), is erected and at least
one opening (30) is formed to substantially each intermediate floor (12) of the frame
(12) in connection with the construction of the intermediate floors so that the openings
(30) are in alignment with the same vertical line and at least one modular unit (50)
is lowered to substantially each floor (26) through the openings (30).
3. The method according to claim 1 or 2, characterized in that outer walls (24) and a roof (14) are constructed to the building, to which outer
walls and roof a thermal insulation is installed before lowering the modular units
(50) to the floors (26).
4. The method according to any of the claims 1-3, characterized in that at least a part of the outer walls (24) of the building is built substantially ready
before lowering the modular units (50) to the floors (26).
5. The method according to any of the claims 1-4, characterized in that the modular units (50) have a floor slab (52) and the modular units are supported
from the floor slab to the edges of the opening (30) of the intermediate floor (12)
in a manner so as to bear the vertical loads.
6. The method according to any of the claims 1-5, characterized in that with the method, a modular unit (50) is lowered to the floor (26), which modular
unit comprises a floor slab (52), a ceiling (56) and walls (54), which walls (54)
have a first surface and a second surface, the first surfaces of which walls define
a bathroom, which bathroom has fixed equipment and/or furniture for use in the bathroom.
7. The method according to claim 6, characterized in that with the method, a modular unit (50) is lowered to the floor (26), in which modular
unit a part of said floor slab (52) extends along the length of at least one wall
(54) outside the area defined by the second surfaces of said walls and said part of
the floor slab (52) and/or the second surface of at least one wall have second fixed
equipment and/or furniture for use in the second room space.
8. A building comprising at least two floors (26), a frame (10), which comprises at least
one intermediate floor (12) and load-bearing structural elements, such as load-bearing
walls (20) and/or pillars (22), supporting the intermediate floors, and at least one
modular unit (50) in the floor (26) under at least one intermediate floor (12), which
modular unit (50) has been lowered to the floor (26) through the opening (30) formed
to the intermediate floor (12) in connection with the construction of the intermediate
floor, characterized in that the building has a roof covering (18), which is built substantially ready before
lowering the modular units (50) to the floors (26), and an opening (30a) is formed
to the roof covering (18) in alignment with the openings (30) of the intermediate
floor (12) and the modular units (50) have been lowered to the floors through the
opening (30a) of the roof covering (18).
9. The building according to claim 8, characterized in that the building has outer walls (24) and a roof (14), to which outer walls and roof
a thermal insulation has been installed before lowering the modular units (50) to
the floors (26).
10. The building according to claim 8 or 9, characterized in that the modular units (50) have a floor slab (52) and the modular units are supported
from the floor slab to the edges of the opening (30) of the intermediate floor (12)
in a manner so as to bear the vertical loads.