According to the invention, there is provided a flight of stairs, which flight comprises a plurality of stairs arranged in a series extending from a lower level to an upper level, the flight of stairs including: shuttering comprising a plurality of pre-formed beams and a plurality of pre- formed panels or blocks supported on the beams; and set cementitious filler material received in the shuttering, the shuttering being incorporated in the flight of stairs by cementitious bonding of the set filler material to the shuttering.

The flight of stairs thus formed is a monolithic structure. By monolithic is mean that the entire flight of stairs is a unitary structure in which the respective components are integrally connected together and fast with one another by cementitious bonding of the set filler material to the respective components from which the shuttering is formed.

Typically, the shuttering includes blocks in the form of hollow pre-cast cementitious blocks supported on the beams. Each hollow block may be trough- shaped, having an open upper side which faces upwardly, set filler material in the interior of eachjbtock forming at least part of each of the stairs, and an upper surface of the set filler material received in each block forming at least part of a tread for each stair.

Each stair may comprise a plurality of two or more of the trough-shaped blocks, the blocks of each stair having open ends and being aligned end-to-end in series, so that the hollow interiors of the blocks of each stair are in communication to form an elongated common cavity in which set filler material is received.

Conveniently, each common cavity formed by the aligned blocks of a said stair is closed pff at each end thereof by a pre-formed end panel forming part of the shuttering.

Typically, each beam is pre-cast from cementitious material. In a preferred embodiment of the invention, the beams include at least two stringer beams extending from the lower level to the upper level, transverse to the lengthwise direction of each stair, each pair of neighbouring stringer beams supporting a plurality of panels or blocks therebetween. The panels or blocks may be stacked in a stack sloping upwardly from a lowermost panel or block to an uppermost panel or block.

Advantageously, each stringer beam may be reinforced by an elongated i reinforcing element embedded in the stringer beam and extending along the length of the stringer beam.

The flight of stairs may include a slab of set cementitious filler material at a lower end of the flight of stairs, the slab forming a foot of the flight of stairs, lower ends of the stringer beams being incorporated in the foot by cementitious bonding of the set filler material of the foot to the lower ends of the stringer beams.

The lower ends of the stringer beams may be supported by a lower landing beam which extends transversely to the stringer beams, the lower landing beam being incorporated in the foot by cementitious bonding of the set filler material of the foot to the lower landing beam. It will be appreciated that it is not essential that the lower landing be incorporated in the foot of the flight of stairs.

In a particular embodiment of the invention, the lower landing beam has an engagement formation which is curved in outline, when the landing beam is viewed in cross-section, the lower end of each stringer beam being provided with a complementarity curved engagement formation in engagement with the engagement formation of the lower landing beam.

The flight of stairs may include a slab of set cementitious filler material at an upper end of the flight of stairs, forming a landing, the upper ends of the stringer beams being incorporated in the landing by cementitious bonding of the set filler material of the landing to the upper ends of the stringer beams.

The upper ends of the stringer beams may be supported by an upper landing beam which extends transversely to the stringer beams, the upper landing beam being incorporated in the landing by cementitious bonding of the set filler material of the landing to the upper landing beam. Again, it should be appreciated that it is not essential that the upper landing beam be incorporated into a slab of cementitious material. The upper landing beam may be omitted altogether, the upper ends of the stringer beams beings supported on a support structure to which the flight of stairs is connected by cementitious bonding of the filler material to the support structure. The same applies in respect of the lower landing beam.

The upper landing beam may have an engagement formation which is curved in outline, when the upper landing beam is viewed in cross-section, the upper end of each stringer beam being provided with a complementarily curved engagement formation in engagement with the engagement formation of the upper landing beam.

Conveniently, each slab of cementitious material may comprise a plurality of hollow pre-formed slab blocks which are connected together to form shuttering for that slab, set cementitious filler material being received in the hollow slab blocks, and forming a cementitious upper surface for the slab, each slab being incorporated into the associatedlslab by cementitious bonding of the set cementitious material to the slab blocks.

The invention extends to a staircase which comprises at least two flights of stairs as described above, the flights of stairs being connected together in series, the upper level of at least one flight being at the same level as the lower level of another flight in the series, and being connected thereto by set cementitious filler material.

Successive flights of stairs may incline upwardly in opposite directions, ! such that the staircase has a zig-zag shape in side elevation.

The invention extends even further to a building which includes a flight of stairs as described above, the flight of stairs being built into the building.

The invention also provides a kit for providing shuttering for a flight of stairs, which kit includes: a plurality of panels or blocks for supporting settable cementitious filler material during setting fihereof to provide stairs; and a plurality of beams for supporting the panels or blocks in an array which provides shuttering which permits the cementitious filler material received in the shuttering to set into a flight of stairs into which the shuttering is incorporated by cementitious bonding of the set filler material to the shuttering.

Typically the blocks are hollow pre-cast cementitious blocks.

Each block may be trough-shaped, having an open side and a locating formation for, in use, locating the block on two or more of the beams such that the open side of the block faces upwardly. In addition, each block may have open ends, i so thatl a plurality of the blocks are supportable in position on the beams with the blocks aligned end-to-end in series with the hollow interiors of the blocks in communication to form an elongated cavity.

The kit may include a plurality of end panels, each end panel being locatable at an end of one of the blocks to close off that end of the block.

Typically, each beam comprises set cementitious material. The kit may includeaat least two stringer beams for extending from a lower level of the flight of stairs to an upper level of the flight of stairs, for supporting, between neighbouring pairs of the stringer beams, a stack of panels or blocks. Each stringer beam may be reinforced by an elongated reinforcing element fast with the stringer beam and extending lengthwise along the stringer beam.

The kit may include a lower landing beam for supporting lower ends of the stringer beams such that the stringer beams extend transversely to the lower landing beam, the lower landing beam having an engagement formation which is curved in outline, when the landing beam is viewed in cross-section, the lower end of each stringer beam being provided with a complementarily curved engagement formation for engagement with the engagement formation of the lower landing beam.

In such a case, the blocks or panels may include a plurality of foot blocks, each foot block having an engagement formation which is complementary in shape to that of the engagement formation of the lower landing beam.

The kit may include an upper landing beam for supporting upper ends of the stringer beams such that the stringer beams extend transversely to the upper I landing beam, the upper landing beam having an engagement formation which is ! curved in outline, when the landing beam is viewed in cross-section, the upper end of each stringer beam being provided with a complementarily curved engagement formation for engagement with the engagement formation of the upper landing beam.

Conveniently, the kit may include a plurality of hollow slab blocks for connection together to form shuttering for supporting a layer of settable cementitious material during setting thereof to provide a slab in which the slab blocks are incorporated by cementitious bonding of set filler material to the slab blocks, a cementitious upper surface of the slab being formed by the upper surface of the set cementitious filler material.

Preferably, the panels or blocks and the beams are shaped and dimensioned to permit assembly thereof into shuttering for a flight of stairs, in which shuttering there is play between the respective panels or blocks and beams, which play permits adjustment of the rake of the shuttering.

The invention further provides a method of constructing a flight of stairs, which method includes the steps of: supporting a plurality of panels or blocks on a plurality of beams to form shuttering; receiving settable cementitious filler material in the shuttering; and allowing the cementitious filler material to set, so that a flight of stairs, incorporating the shuttering, is formed by cementitious bonding of the set cementitious material to the shuttering.

The method may include the step of placing at least two stringer beams side-by ; side and spaced apart in position at a location where the flight of stairs is to be formed, such that the stringer beams extend alongside each other from a lower<BR> <BR> <BR> <BR> ! level of the flight of stairs to an upper level of the flight of stairs.

The method may in such a case include the subsequent step of stacking a plurality of the panels or blocks between the stringer beams, such that the panels or blocks are supported on the stringer beams, each neighbouring pair of stringer beams supporting a stack of the panels or blocks between them, the stack sloping upwardly from a lowermost panel or block to an uppermost panel or block. The rake of the shuttering may then be adjusted, by adjusting the inclination of the stringer beams.

The method may include the step of connecting together a plurality of slab blocks at the lower level of the shuttering, receiving settable cementitious filler material in the slab blocks, and allowing the filler material to set to form a slab at the lower level from the set filler material and from the slab blocks, the slab blocks and lower ends of the stringer beams being incorporated into the slab by cementitious bonding of the filler material respectively to the slab blocks and to the lower ends of the stringer beams.

Instead, or in addition, the method may include the step of connecting together a plurality of slab blocks at the upper level of the shuttering, receiving settable cementitious filler material in the slab blocks, and allowing the filler material to set to form a slab at the upper level from the set filler material and from the slab blocks, the slab blocks and upper ends of the stringer beams being incorporated into the slab by cementitious bonding of the filler material respectively to the slab blocks and to the upper ends of the stringer beams.

The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings, in which: Figure 1 is a partial three-dimensional view of shuttering for a flight of stairs in accordance with the invention; Figure 2 is an exploded side elevation of the shuttering of Figure 1; Figure 3 is an exploded plan view of the shuttering of Figure 1; Figure 4 is an expanded, three-dimensional view, not entirely to scale, of a pre-formed block forming part of a modular kit for the shuttering of Figure 1; Figure 5 is a sectional side view of part of a flight of stairs formed by means of the shuttering of Figure 1 ; Figure 6 is a view corresponding to Figure 1 of a further embodiment of shuttering for a flight of stairs in accordance with the invention; Figure 7 is a view corresponding to Figure 6 of a flight of stairs formed from the shuttering of Figure 7 and from set cementitious filler material received in the shuttering; Figure 8 is an exploded side elevation of the shuttering of Figure 6; Figure 9 is an exploded plan view of the shuttering of Figure 6; Figure 10 is a three-dimensional view, on an enlarged scale, of a pre-formed block forming part of a kit for the shuttering of Figure 6; and Figure 11 is a three-dimensional view of a staircase comprising three of the flights of stairs of Figure 7 In Figure 1 of the drawings, reference numeral 10 generally indicates shuttering for a flight 16 (see Figure 5) of stairs 17 in accordance with the invention.

The shuttering 10 comprises an assembled modular kit for providing such shuttering.

The shuttering 10 includes three stringer beams 14 (two of which are shown in Figure 1) which extend between a lower level 12 and an upper level 13, formed by a lower floor and an upper floor (both not shown) respectively, which are connected by the flight 16 of stairs 17. For the sake of clarity of illustration, the rightmost stringer beam 14 is omitted from Figure 1. The stringer beams 14 are pre-cast concrete units containing steel reinforcing rods (not shown) embedded therein. The stringer beams 14 are positioned such that they are parallel to one another, and are transversely spaced apart by a predetermined spacing, so that pre-formed blocks 18 can be received between neighbouring stringer beams 14. It will be appreciated that the inclination of the stringer beams 14 relative to the horizontal determines the rake of the flight 16 of stairs 17 which is to be formed by means of the sheltering J10.

Each stringer beam 14 is supported at its upper and lower ends by upper and lower landing beams, or cross-beams, 20,22 respectively. The cross-beams 20, 22 are in turn supported by being embedded in the upper and lower floors respectively. Each stringer beam 14 has step-like formations 24 respectively at opposite ends thereof, the step-like formations 24 co-operating with complementary rebates 26 respectively formed in the cross-beams 20,22, to support the stringer beams ; 14 in position.

The pre-formed blocks 18 to be received between the stringer beams 14 form part of the shuttering 10 and are broadly trough-shaped, the blocks 18 having open upper sides 28 (see Figure 4) and open ends 30. Like the stringer beams 14, the blocks 18 are pre-cast concrete elements. A lower surface 32 of each block 18 is provided with locating rebates 34 (Figure 4) at both ends 30 of each block 18, the rebates 34 extending parallel to the stringer beams 14 when the blocks 18 are supported on the beams 14. The locating rebates 34 seat on longitudinally extending flanges of rebates 36 extending along the stringer beams 14. As can best be seen in Figures 2 and 5, the rebates 36 and the rebates 34 are dimensioned such that, when in position, the lower surfaces 32 of the blocks 18 and lower surfaces 38 of the stringer beams 14 together define a flat planar soffit (shown particularly with reference to a further embodiment of the invention in Figure 11) of the shuttering 10 and thus of the eventual flight 16 of stairs 17.

Pairs 40 of the blocks 18 are aligned end-to-end in series so that each pair 40 defines a common cavity (Figure 1) for receiving filler material to form a stair 17. For, ease of illustration, Figure 1 shows five pairs 40 of blocks 18, while only three pairs 40 of blocks 18 are shown in Figures 2,3, and 5. The pairs 40 of blocks 18 are supported on the stringer beams 14 in a stacked arrangement. Each block 18 therefore supports a neighbouring block 18 forming part of an immediately higher pair 40. The blocks 18 of the lowest pair 40 (also designated 42) are shaped so that a front wall 46 (see Figures 2,4, and 5) of each block 18 engages upright surface of the rebate 26 (see Figures 1 to 3) of the lower cross-beam 22. Similarly, each block 18 of the uppermost pair 40 (also designated 44) of blocks 18 has a rear wall 48 which engages the upright surface of the rebate 26 of the upper cross-beam 20 (see Figures 1 to 3).

The front wall 46 of each block 18 (apart from the blocks 18 in the lowest pair 42) has an operatively horizontal lip or step 50 for seating on the upper edge of the rear wall 48 of a corresponding, immediately lower, block 18. An upper portion 52 of the front wall 46 of each block 18 is wider than a lower portion 54 of the front wall 46 of that block 18 (the upper and lower portions 52,54 being separated by the horizontal lip or step 50), so that when the blocks 18 are aligned in series end-to-end, the upper portions 52 of the blocks 18 in a pair 40 together horizontally span the width of the stringer beam 14 located between them, meeting to form a partition between stair cavities defined by neighbouring pairs 40 of blocks 18. This can best be seen in Figure 1 of the drawings. An opening at 55 is defined between the abutting upper portions 54 of each pair 40 of blocks 18 and the upper surface of the stringer beam 14 which supports those blocks 48.

The kit also includes end panels 56 which close off each outermost end 30 of each series of blocks 18. Again, the end panels 56 at the rightmost end of each series 40 are omitted from Figure 1 for the sake of clarity. End panels 56 respectively for closing off the uppermost and lowest series 44,42 of blocks 18 are specially shaped for closing off the specially shaped blocks 18 of those series. As is the case with the other elements of the kit, the end panels 56 are pre-cast concrete elements.

In use and with reference to Figures 1 to 5, a flight 16 of stairs 17 is formed on-site by first locating the upper and lower cross-beams 20,22 in position on their respective floors, at a location where the flight 16 of stairs 17 is to be installed. The stringer beams 14 are then put into position, extending between the cross-beams 20,22 and engaging their rebates 26 as described above. Thereafter, the blocks 18 are placed in position received on the stringer beams 14. The lowest pair 42 of blocks 18 are put into position first, followed by successive pairs 40 of blocks 18, ending with the topmost pair 44. Finally, each pair 40 of blocks 18 is closed off by the end panels 56, thereby completing the shuttering 10.

There is sufficient play between the elements (blocks and beams) of the shuttering 10 so that the rake of the shuttering 10 can be adjusted, within limits, even after the shuttering 10 has been assembled. In this example, the rake can be varied between about 33,5° and about 35°, i. e. by about 4,5%.

Settable cementitious filler material in the form of unset concrete 58 is then poured into the shuttering 10 to form the flight 16 of stairs 17. The lower cross-beam 22 is embedded in a concrete slab (not shown) at the foot of the flight 16 of stairs 17, while the upper cross-beam 20 is similarly embedded in a concrete slab (not shown) forming a landing at the top of the flight 16 of stairs 17. Cementitious bonding takes place between the material of the slabs and the cross- beams 20,22. Steel reinforcing rods (not shown) horizontally spanning the width of the flight 16 of stairs 17 can be located in the interiors of the cavities defined by the troughs of the blocks 18, to reinforce each stair after the filler material 58 sets. Similar steel reinforcing rods (indicated by a chain-dotted line 70 in Figure 5) are positioned to extend at an inclination along the length of the shuttering 10, being vertically spaced above the stringer beams 14 to pass through the openings 55, the inclined reinforcing rods, 70 extending transversely to the horizontal reinforcing rods in the filler material 58 in the stair cavities. The inclined reinforcing rods 70 extending along the length of the shuttering are tied to the horizontal reinforcing rods extending lengthwise in the stair cavities to form a reinforcing lattice or framework (not shown) which is embedded in the set filler material 58, and thus becomes incorporated in the flight of stairs 16 when the filler material 58 sets, by cementitious bonding thereto of the set filler material 58.

The set filler material 58 in the cavity of each block 18 is finally topped off with further wet or unset concrete, so that once the concrete 58 has set, a level upper surface 60 of the set concrete 58 in any pair 40 of blocks 18 forms the tread of a stair 17 formed by that pair of blocks 18. The rises of the stairs are formed by the aligned upper portions 52 of the front walls 46 of the blocks 18 in each pair 40.

As the concrete 58 sets, the shuttering 10 becomes integrally incorporated in the flight of stairs 16, being fast with the filler material 58 of the flight 16 of stairs by cementitious bonding of the cement 58 respectively to the blocks 18, the stringer beams 14, and the end panels 56, to form a more or less unitary or monolithic structure.

When the concrete 58 is poured into the shuttering 10, the wet concrete 58 flows through the openings 55 from the blocks 18 of one stair 17 to the blocks 18 of an immediately lower stair 17, so that the concrete 58 which form the respective stairs 17 are integrally connected to one another by concrete 58 passing through the openings 55. Set concrete 58 in the aligned openings 55 serve to strengthen the flight 16 of stairs 17, effectively forming integrally formed beams extending along the length of the flight 16.

In Figures 6,8 and 10 of the drawings, reference numeral 11 generally indicates shuttering for a flight 62 of stairs 17 (Figure 7) in accordance with the invention. The shuttering 11 is constructed from elements which are largely similar the elements of the shuttering 10 described with reference to Figures 1 to 5, and the method of forming the flight 62 of stairs 17 corresponds largely to the method of forming the flight 16 of stairs 17 of Figures 1 to 5. Unless otherwise indicated, like reference numerals indicate like parts in Figures 1-5 and Figures 6-11. in this embodiment of the invention, inclined reinforcing rods 70 are fast with the stringer beams 14, extending along the length of the stringer beams 14. The reinforcing rod 70 of each stringer beam 14 is parallel to the beam 14, being closely spaced vertically above the beam 14.

As described with reference to Figures 1 to 5, each stringer beam 14 is supported at its upper and lower ends by upper and lower landing beams 20,22 respectively. Each landing beam 20,22 is provided with an engagement formation for engaging the stringer beams 14, the engagement formation in this example being an engagement surface 21 which extends along the length of each landing beam 20, 22, the engagement surface 21 being part-circular in outline, when the landing beam 20,221 is viewed in cross-section, as can be seen in Figure 8. The engagement surfaces 21 of the landing beams 20,22 thus form seats for respectively receiving the upper and the lower ends of the stringer beams 14.

The upper ends of the stringer beams 14 are provided with engagement formations 23 (Figure 8) which are complementary in shape to the engagement surface 21 of the upper landing beam 20, the engagement formation 23 seating on the engagement surface 21 of the upper landing beam 20, when the kit is assembled to form'the shuttering 11 (Figure 6). Each stringer beam 14 is provided with a similar engagement formation 25 at its lower end, this engagement formation 25 being complementary to the engagement surface 21 of the lower landing beam 22, and, in use, seating on the engagement surface 21 of the lower landing beam 22.

Furthermore, the blocks 18 in the lowest pair 42, also referred to as a foot blocks, are each provided with an engagement formation in the form of a recess 43 which extends between the ends 30 of the block 18, the recess 43 being complementary in cross-sectional profile to the engagement surface 21 of the lower landingìbeam 22. Each foot block 18, in use, seats on the lower landing beam 22 in a manner similar to the engagement of the lower ends of the stringer beams 14 with the lower landing beam 22. Similarly, the blocks 18 in the uppermost pair 44 of blocks 18, also referred to as head blocks, each have an engagement formation in the form of a similar recess 45 extending between the ends 30 of that block 44, for engagement with the engagement surface 21 of the upper landing beam 20 in a manner similar to the engagement between the upper ends of the stringer beams 14 with the upper landing beam 20.

The engagement of the curved engagement formations 23,45 of the upper ends of the stringer beams 14 and the head blocks 44 respectively, with the i, curved engagement surface 21 of the upper landing 20, and the similar engagement of the curved engagement formations 25,43 of the lower ends of the stringer beams 14 and the foot blocks 42 respectively, provides articulated connection of the stringer beams 14 and the blocks 18 to the landing beams 20,22. This articulated connection facilitates adjustment of the rake of the shuttering 11, by promoting hinged displaceability of the stringer beams 14 relative to the respective landing beams 20,22.

To promote construction of a reinforcing lattice, each landing beam 20, 22 has a row of loops or eyes 72 (shown only in Figures 8 and 9, for ease of illustration) fast with the associated stringer beam 20,22 and projecting from an upper surface of the stringer beam 20,22, each row of eyes 72 extending along the length of the associated beam 20,22.

As can best be seen in Figure 8, each block 18 is broadly V-shaped in end view, having a front wall 46 and a base wall 47 projecting at an angle from the front wall 46. Each block 18 is shaped such that the rear or tail edge 49 of the base wall 47 is engageable with a front or nose 51 of the base wall 47 of a like block 18, so that, when the blocks 18 are stacked, the nose 51 of each block 18, apart from the foot blocks 18, abuts the tail edge 49 of an immediately lower block 18 in a more or less sealing manner, such that passage of cementitious filler material 58 through the abutting surfaces of the respective blocks 18 is inhibited.

The shuttering 11 includes a plurality of slab blocks 59 (only two of which are shown in Figure 6, for clarity of illustration) which form shuttering for a cementitious slab at the lower level 12 of the flight 62, to form a foot 64 of the flight 62, and a plurality of slab blocks 59 (again, only two of which are shown in Figure 6) which form shuttering for a cementitious slab at the upper level 13 of the flight 62, to form a landing 68 of the flight 62 of stairs 17. Each slab block 59 is shallow trough-shaped, with open ends. The slab blocks 59 are connected together in a grid by means of tongue-and-groove formations on the sides of the blocks 59. In Figure 6 of the drawings, these grids are not shown, but instead only a single series, comprising two blocks 59 aligned end-to-end, is shown for the foot 64 and for the landing 68 respectively. Each block 59 has a tongue 57 projecting from its one side, extending along the length of the block 59, and a complementary longitudinally extending groove 61 on its other side. The respective grids are formed by connecting slab blocks 59 together both end-to-end and side-by-side, the tongue 57 of each block 59, apart from blocks 59 in an outermost series of blocks 59, being matingly received in the groove 61 of a neighbouring block 59, tenon-and-mortise-fashion.

As can best be seen in Figure 8 of the drawings, the lower landing beam 22 has a longitudinally extending rebate 63 in a surface of the landing beam 22 which faces horizontally away from the flight 62, the aligned tongues 57 of the series of slab blocks 59 adjacent the lower landing beam 22 being received matingly in the rebate 63. The lower. landing beam 22 is thus located between the lowest pair 42 of blocks 18 and the slab blocks 59, vertically below an upper surface of the slab blocks 59.

The upper landing beam 20 is located in position in a similar manner, by engagement of a longitudinally extending rebate 65 in the upper landing beam 20 with the aligned tongues 57 of the slab blocks 59 forming the landing 68 at the top of the flight 62 of stairs 17.

The reinforcing lattice or framework is formed by locating steel reinforcing rods (not shown) in the common cavity of each pair 40 of blocks 18, such that the rods horizontally span the width of the flight 62 of stairs 17, being transverse to the lengthwise direction of the stringer beams 14. Further, steel reinforcing rods 74 are threaded through each row of eyes 72 on the respective landing beams 20, 22. The reinforcing rods 70 which are fast with the stringer beams 14 are tied to the horizontal transverse rods extending lengthwise in the stair cavities, to form the reinforcing lattice or framework. A similar reinforcing framework (not shown) is constructed in each of the grids of slab blocks 59.

When the cementitious filler material, in the case wet concrete 58 with a controlled minimum strength of 35Mpa at 28 days, is poured into the shuttering 11 to formi the flight 62 of stairs 17, the lower cross-beam 22 is embedded in a concrete slab forming the foot 64 of the flight 62 of stairs 17. The foot 64 is formed by the concrete 58 and by the slab blocks 59, the slab blocks 59, the lower ends of the stringer beams 14, and the lower landing beam 22 being incorporated into the foot 64 by cementitious bonding of the set concrete 58 to the slab blocks 59, to the lower ends of the stringer beams 14, and to the lower landing beam 22 respectively. The upper surface of the concrete 58 forms a cementitious upper surface 69 (Figure 11) of the foot 64.

Similarly, the upper landing beam 20, the upper ends of the stringer beams ! 14, and the slab blocks 59 at the upper level 13 are incorporated into a concrete slab forming the landing 68 at the top of the flight 62 of stairs 17, by cementitious bonding of the concrete 58 to the landing beam 20, to the upper ends of the stringer beams 14, and to the slab blocks 59 respectively.

After pouring of the wet concrete 58, the concrete 58 is vibrated and towelled to a desired finish, in the usual manner, and a sprayable curing compound is sprayed on to the concrete 58.

In Figure 11 of the drawings, reference numeral 80 generally indicates a staircase which comprises a plurality of the flights 62 of stairs 17 described with reference to Figures 6 to 10. Unless otherwise indicated, like reference numerals indicate like parts in Figures 6-10 and in Figure 11.

The staircase 80 comprises three flights 62 of stairs 17 connected together in series. As can be seen in Figure 11, the upper level 13 of the lowest flight 62 is at the same level as the lower level 12 of the central flight 62, while the upper level 13 of this central flight 62 is at the same level as the lower level 12 of the uppermost flight 62. The successive flights 62 incline upwardly in opposite directions, such that the staircase 80 has a zig-zag shape in side elevation. Of course, in other embodiments of the invention, successive flights 62 can be inclined in the same direction.

Furthermore, the foot 64 of the central flight 62 and the landing 68 of the lowest flight 62 are formed by a single slab 82. Similarly, the foot 64 of the uppermost flight 62 and the landing of the central flight 62 are formed by another unitary slab 84. The entire staircase 80 is thus incorporated into a unitary structure by cementitious bonding of the concrete 58 to the respective components which providelshuttering for the staircase 80.

It is an advantage of the invention as illustrated with reference to the drawings that shuttering for a flight of stairs can efficiently be provided. The modular kit eliminates the need for a separate supporting structure for use as shuttering, while the modular nature of the kit reduces the margin of error in constructing the flight of stairs, facilitating construction to set specifications. It is furthermore possible to construct flights of stairs of varying dimensions by varying the number and/or size and/or slhape of the elements of the kit used in constructing the shuttering. The width of the flight of stairs can for instance be varied by varying the number of stringer beams used, while the rake of the shuttering can be varied, even after assembly of the shuttering.

Reduced construction time due to the simplified construction method also translates into reduced construction costs. All the components of the kit are easily transportable, so that no on-site lifting equipment is necessary for installation.