AU7618998A - Improved method of building construction - Google Patents

Description

i

V.

j P/00/011 Regulation 3.2

AUSTRALIA

Patents Act 1990

ORIGINAL

COMPLETE SPECIFICATION STANDARD PATENT Invention Title: "IMPROVED METHOD OF BUILDING CONSTRUCTION" The following statement is a full description of this invention, including the best method of performing it known to us: 2 THIS INVENTION relates to a method of building construction.

The invention also relates to buildings and building panels constructed by the method.

The term "buildings" shall include houses, apartments and other domestic dwellings; commercial, civic and agricultural buildings abattoirs and pig-sties) and the like; fencing; and other I building constructions.

Brick veneer houses typically have a wind load rating 10 capacity of 3.5-3.8 kilopascals per square metre; while category 1 houses typically have a wind load rating of 3.7 kilopascals per square metre. (Category 1 houses commonly are erected from 200mm blocks reinforced by steel and concrete.) Wind loadings of 4 kilopascals per metre squared and 1 5 above are rated as cyclones and it will be readily apparent that conventional houses are liable to damage under cyclonic conditions. It is particularly so when the roof structure is not securely anchored through the walls to a floor structure as the loss of the roof almost inevitably leads to complete destruction of the building.

7 Apart from conventional on-site construction methods for steel and timber framed brick veneer structures as well as solid masonry block or day brick walled structures, it is known to utilise prefabricated panels.

e 1 Prefabricated panels may be of load bearing and non !oad; bearing configuration and may be constructed at a remote location and transported to the site for erection or they may be fabricated on-site.

Examples of on-site fabricated panels.include cast concrete "tilt-up" panels.

Prefabricated panels intended for load bearing applications typically include reinforcing members such as steel mesh and/or steel S' reinforcing rods. Such load bearing panels usually include brackets or flanges for upright edge to edge connection and may also include brackets or other fastening members for attachment to slab floors and rocf truss members.

While generally effective for their respective intended purposes such pre-fabricated panel building systems are usually applicable only to a specific type of building construction rather than to a wide range of applications ranging from domestic dwellings, low rise residential structure, commercial buildings, fences, retaining walls and the like.

j .It is an object of the present invention to provide a method of building construction which is flexible in application and 20 which offers a durable and cost effective structure.

It is a further object of the present invention that the structure walls have wind load ratings which meet or exceed a wide range of wind loading factors.

_I It is another object of the present invention to provide a method of building construction where the walls can be tied to the footings or floor structures to improve the integrity of the building.

It is a further preferred object of the present invention to provide a novel method of in-situ wall construction.

Other preferred objects of the present invention will become apparent from the following description.

In one aspect, the present invention resides in a methodof building construction including the steps of: erecting on a base an upright support frame for a wall structure, said upright support frame including spaced upright joist members; supporting sheet-like formwork on an inner or outer surface of the frame; applying to an inner face of the sheet-like formwork a flowable curable cementitious material to occupy an interior portion of said support frame; and screeding or surface finishing an exposed surface of said cementitious material to form a wall surface.

Suitably the cementitious material comprises a sprayable concrete composition.

If required the sprayable concrete composition includes reinforcing fibres.

If required the support frame may include upper and/or lower transverse frame members.

The support frame may include transverse intermediate frame members.

Suitably the support frame includes aperture frames to define door and/or window apertures.

Preferably, the support frame includes reinforcing members selected from steel rods or mesh or combinations thereof.

The support frame may include upright steel reinforcing members: between adjacent joist members.

Suitably the support frame includes transverse steel reinforcing members extending between adjacent joist members.

If required at least portion of an upper end of some or all of said upright steel reinforcing members protrudes through respective apertures in said upper frame members.

Preferably some or all of said transverse steel reinforcing members extend through aligned apertures in adjacent joist members.

If required said joist members may include enlarged apertures adapted to permit engagement of cementitious material located on opposite sides of said joist members.

The support frame may include lower transverse frame members having apertures therein to receive starter bars extending from said base.

6 Preferably the cementitious material is applied between alternately spaced pairs of joists and after surface finishing is allowed to at least partially cure before application to alternately spaced walls regions therebetween.

Alternatively the cementitious material may be applied to adjacent wall regions between respective joists before surface finishing.

S, f required, the sheet-like formwork may be removed from I the support frame after the cemnentitious material has at least partially o10 cured.

Preferably, the sheet-like forrmwork is retained on the support frame to form an inner or outer surface of a wall structure.

The sheet-like formwork preferably comprises fibre cement sheet.

The sheet like formwork may-comprise gypsum board as an inntr wall surface.

Suitably the wall .structure includes decorative and/or protective surface finishes on the inner and outer wall surfaces.

Preferably the wall structure includes a water stop means at the junction between the lower portion of the wall and a base surface.

The water stop means may comprise a water reactive, material adapted to expand when exposed to water to seal the junction between the wall structure and the base surface.

Suitably the water stop means is locate by locating means adjacent the base of the support frame.

In an alternative construction, the '.upright members comprise hollow steel box members supported on or in the base..

Suitably, one or more starter bars extend from the base into the hollow interiOr of said hollow steel box members.

Preferably, said hollow steel box members include a tie bar encapsulated in a column of cementitious grout.

0 The upper ends of each tie bar may be adapted for securing to a roof structure.

If required, the roof structure may comprise trusses.

extending between transversely spaced upright members.

The support frame may include service conduits.

Preferably, services, eg., electricity and plumbing, are placed in the frame before the concrete is sprayed.

Removable blockouts may be provided within the frame, eg., where doors and/or windows are to be provided within the wall.

SThe reinforcing steel and/or the lower portion of the support frame mayextend into the base to tie the wall to the base.

S.:To improve the fire rating of the wall, condensed silica fume concrete may be used instead of conventioral concrete.

In a: second aspect, the invention resides in a method of conrstruction for a building panel including 4 ~at-taching sheet-like formwor farrnwork: k applying to the inner surface buil sreding cosrcinnorpsurfaeinwis thce method ofll thand~ad eo se emodmetsallwin th e eos cb views Th ofho wall constructed~ cc oac 2 IG a r secto the r wulal cntutonicroatn al the mehodso th first an seimilar vi e To qobl hetvni t the steps of: k to one side of a frame as of the formwork a flowabie ig the exposed cementitous nposition to cure.

ni of the building panel may s of the first aspect of the sent invention resides in a or wall panels constructed by :tse fully understood, preferred d -with reference to the e -internial elevation and plan with the method; rough a typical single storey .,ere -the walt has a wi.ndowi FIG 5 is a cross-section through a typical 2-storey wall; and FIG 6 is a cross-sectional view of a typical footing detail.

FIG 7 shows one form of joint between a wall structure according to the invention and a cast in situ floor slab.

FIG 8 shows a wall construction associated with a multifloor construction or a high wall construction.

FIG 9 shows an enlarged end view of a lower region of the wall shown in FIG 8.

10 Referring to FIGS 1 and 2, the wall 10 has a frame (shown in dashed lines in FIG 1) where the studs 11, noggins 12 and head rail 13 are constructed from top-hat section cold roll-formed IS. steel.

Depending on the intended wind load rating of the wall Y10, Y12 to Y20 reinforcing rods 14 extend through the frame from the footings 15 to be anchored or tied to the roof structure 16 (see FIG 3).

Fibrous cement (FC) sheeting 17 is fixed to the interior of the frame and styrene blocks (not shown) are placed in the locations of any window 18 or doorways (not shown).

Services, eg., plumbing and wiring are located in the frame and then concrete 19 is sprayed into the cavity defined by the frame and the FC sheeting 17.

i The concrete may contain condensed silica fume to increase the final fire rating and water proofing of the wall.

\When the concrete has at least partially set, the external face may be screeded and the concrete may then be allowed to set before the external face is rendered, painted or an external sheet is applied thereto to complete the external finish of the wall.

The styrene blocks may be removed to enable a window frame 18a see FIG 3) to be fitted to the wall and the subsequent window fittings and hardware could be located in the wall.

o It will be readily apparent to the skilled addressee that the FC sheeting 17 may be provided on the external face of the frames to Sform the external finish to the wall 10, the internal face of the wall being screeded and then finished as desired. Although the wall may .be only 80 to 100mm thick, it may have a wind load rating of kilopascals per square metre plus. The ultimate wind load rating will be dependent on factors such as the thickness of the wall, the thickness and number of reinforcing bars used, thickness and number of studs or noggins used and the strength of the concrete.

However, it also will be readily apparent to the skilled addressee that the resultant wall construction is particularly suitable for use in areas subject to cyclonic conditions.

In the embodiments shown in FIG 5, the floor slab 20 for the second storey is tied into the frame structure to ensure integrity between the walls and the floor.

Referring to FIG 6, studs 11 and reinforcing rod 14 extend down into the footing 15 and the reinforcing rods 14 may be tied to the reinforcing steel or mesh 22 in the footings 15 to increase the anchorage of the wall to the footings 15 and/or floor slab 23.

The FC sheeting 17 extends, eg., 150mm below ground level and an internal sheeting finish 17a may extend just below the internal floor level if the wall is constructed before the floor slab is poured.

10 In this embodiment, it will be noted that the FC sheeting 17 provides the external finish to the wall whereas in the embodiments in FIGS 3 and 4, the FC sheeting was provided as the internal finish to the building wall While it is preferable that the frame and reinforcing be 5 anchored in the footings 15 and/or floor slab 23, it is permissible to use the method to form building panels where the bottom rail of the panel, and the !ower end of the reinforcing rods 14, are fixed to a floor structure, eg., of the type having bearers and joists supported on piers or stumps.

For more robust structures such as factories, sheds and the like, the wall frames are constructed from fabricated steel box uprights or open c section members having, say, a 3mm wall thickness and measuring 300mm x 400mm in cross sectional t -i 12 dimensions.

The box or c sections are placed in an upright position on hardened footing or otherwise with a lower portion of the box or c I sections cast into the footings. One or more starter bars extend up 5 from the footing to the hollow interior of the box or c sections.

Reinforcing bars are positioned vertically within each box or c section and the interior is filled with cementitious material to leave a portion of the reinforcing bar extending above the top of the upright filled column. Prefabricated roof trusses are then secured to the top of the spaced columns via the tie bar to form a totally integrated portal frame Mke structure.

~.;:Channel-like purlins are affixedto the columns to support formwork and the sprayed in-situ walls are completed as described previously herein.

While it is preferable that the sheeting provides both a formwork for the concrete and either the internal or external finish to the wall, the sheeting may only be used as a temporary formwork so j that the cast and screeded surfaces may then be finished as desired.

The screeding -of the wall may be carried out by the method and apparatus disclosed in AU-A45524/96 which has been assigned to the present applicants.

FIG 7 shows a joint between a wall structure according to the invention and a cast in situ upper floor slab.

-n 13 An outer wall structure 30 is constructed as previously described with portion of the upright reinforcing rods 31 extending above the top plate of the wall frame.

By means of props and formwork an upper floor structure 32 can be formed by conventional methods with an upper portion of wall structure and the upper portion of the reinforcing rods embedded in the floor structure 32 to form a tied integral structure, the bent over portion 31a of reinforcing rods 31 being secured to reinforcing (not shown) located with the floor structure.

FIG 8 shows a particularly preferred configuration of wall structure according to the present invention.

E ~The wal! frame 40 comprises an upper plate 41 extending between end studs 42 having their respective lower ends resting on a base surface 43.

Intermediate studs 44 extend from the top plate 41 to a transverse locating member 45 spaced from the base surface 43, locating member 45 being adapted to locate a strip of waterstop material (not shown).

The frame members 41, 42, 44 are suitably roll formed c section steel channel of the type employed as wall studs in steel framed houses or commercial partition walls.

Extending from base 43, which may be reinforced concrete footings or a cast floor slab, are reinforcing rods 46 which ~E~P"0~9L9~1~ 14 extend upwardly between each of the end and intermediate studs 42, 44 and protrude via apertures in top plate 41.

As shown in phantom, an upper floor slab 47 may then be cast on the top of plate 41 in the manner generally described with reference to FIG 7 except that some or all of the free ends 46a of reinforcing rods 46 extend above the floor slab 47 in the plane of the wail structure therebeneath.

A similar wall frame can then be located on the floor slab 47, over the protruding ends 46a of the reinforcing rods and further reinforcing rods can then be placed in the wall cavities with upper free ends thereof protruding through the top plate and the lower ends thereof secured to the free ends extending through the floor slab 47.

In this manner muiti-storey buildings such as residential apartments or the like can be simply and inexpensively constructed.

15 Alternatively a similar technique may be employed to construct commercial buildings having walls to say 5-6 metres tall or even taller.

In this alternative method, a perimeter wall is first constructed on footings, a slab floor or similar base using an initial frame height of say 2.5-3 metres tall as illustrated in FIG 8.

Instead of casting a floor slab onto that frame as illustrated, scaffolding may then be erected around the upper region of the completed wall and then further frame members 40 can then be ~iBP ~l~ip~ qCro~a~as~p~

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locate over the lower wall with the upper ends 46a of the reinforcing rods 46 extending into the wall frame cavity.

After securing additional reinforcing rods to the ends 46a of the lower rods within the upper wall frame cavity, sheet-like S formwork is then secured to one side of the upper frame and the upper wall section is then completed by spraying a cementitious composition into the wall cavity and subsequently surface finishing the exposed concrete wall surface.

The resultant wall construction provides a greater structural integrity than a "tilt up" wall construction of similar dimensions in that the reinforcing bars extending through the wall are I: tied directly to the base structure rather than relying upon bolted brackets or the like.

FIG 9 shows an enlarged end view of the lower part of is. frame structure Studs 42 and 44 are provided with aligned spaced apertures 48 to locate transverse reinforcing rods if required within the ,I wall cavity bounded on one side by sheet-like formwork 49.

Locating member 45 comprises an angle section strip of metal beneath which is located a strip of waterstop material 51 such as UNISEAL (Trade Mark). A notch 50 is cut out of end studs 42 to permit the waterstop material 51 to extend,'-between the junction of the finished wall and the base surface 43 to form a continuous ~C~B~wlLV4l~g~as~ I? 1 16 perimetral barrier against ingress of water.

The lower ends 44a (shown in phantom) of studs 44 are S: located on or adjacent the outwardly extending web of support member The waterstop material 51 is employed at the junction between a wall and the base surface 43 and also at the junction with any upper slab floors such as slab 47 shown in FIG 8.

When exposed to water seeping between the junctions S.the UNISEAL waterstop expands to form a permanent water barrier.

:method of wall construction described above will be equally applicable i: to rapid and inexpensive construction of fences and other barrier like structures.

Typically in the construction of perimeter fences for domestic dwellings, reinforced concrete footings are prepared with starter bars extending therefrom at desired intervals.

After erection of the wall frame structure from say 50 mm roll formed steel wall stud channels, additional vertical and horizontal reinforcing bars are located within the wall cavity.

Permanent or temporary sheet like formwork can then be attached to a selected side of the frame structure with self tapping screws or the like.

For permanent formwork 4 mm fibre cement sheeting is I -i 17 preferred but for removable formwork any durable sheet like material such as fibre cement sheeting, plywood, steel or plastics sheet may be employed.

The permanent formwork may have a textured or decorative outer finish or the removable formwork may be adapted to impart a textured finish to the outer wall surface which is exposed Swhen the formwork is removed.

After erection of the formwork, each alternate cavity between adjacent pairs of wall studs is sprayed with concrete and o10 then screeded or finished to form an inner wall surface.

vi Thereafter, the alternate unfilled cavities are sprayed with concrete and screeded or otherwise surface finished to form an integral fence structure which can then be painted or treated with decorative finishes.

15 Although not wishing to be bound by any particular theory, it is considered that the preferred method of filling and finishing alternate wall panels and subsequently filling and finishing the remaining alternate cavities gives rise to substantially less shrink cracking in the structure with improved overall structural integrity.

Flexible polymeric based cementitious finishes such as "ROCKCOAT" (Trade Mark) or the like provide an effective means of providing a smooth or textured continuous finish to both inner and outer wall surfaces. Such finishes also fill screw hole cavities and

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sso~ar I joints between adjacent sheets of fibre cement formwork.

IPre-fabricated door and window frames can be secured within the wall frame structure before sheeting with formwork to locate the door and window frames integrally in the final structure.

Alternatively apertures for doors and windows can be formed with removable formwork to allow subsequent installation of door and window frames.

Various changes and modifications may be made to the embodiments described without departing from the present invention.

-10 However, it will be readily apparent to the skilled addressee that the method disclosed results in building walls orbuilding panels which have a high wind load rating and potential fire load rating and which can be finished with a number of alternative aesthetically attractive finishes so that the method can be used from relatively low-cost buildings, eg., public housing and .commercial buildings up to very expensive houses and departments. sis C~s~e~Llr

Claims (29)

1. A method of building construction including the steps of: erecting on a base an upright support frame for a wall structure, said upright support frame including spaced upright joist S members; supporting sheet-like formwork on an inner or outer surface of the frame; applying to an inner face of the sheet-like formwork a flowable curable cementitious material to occupy an interior portion of 10 said support frame; and screeding or surface finishing an exposed surface of said cementitious material to form a wall surface. S2. A method as claimed in claim 1 wherein the cementitious material comprises a sprayable concrete composition. 1 5 3. A method as claimed in claim 2 wherein the sprayable concrete composition includes reinforcing fibres.

4. A method as claimed in any one of claims 1-3 wherein the support frame includes upper and/or lower transverse frame members.

5. A method as claimed in claim 4 wherein the support frame includes transverse intermediate frame members.

6. A method as claimed in any preceding claim wherein the support frame includes aperture frames to define door and/or window I apertures.

7. A method as claimed in any preceding claim wherein the support frame includes reinforcing members selected from steel rods or mesh or combinations thereof.

8. A method as claimed in any preceding claim wherein the support frame includes upright steel reinforcing members between adjacent joist members. S9. A method as claimed in any preceding claim wherein the :i support frame includes transverse steel reinforcing members extending 1. 10 between adjacent joist members. A method as claimed in claim 8 or claim 9 wherein at least portion of an upper end of some or all of saidgupright steel reinforcing members protrudes through respective apertures in said upper frame members.

11. A method as claimed in claim 9 or claim 10 wherein some I or all of said transverse steel reinforcing members extend through ~4 aligned apertures in adjacent joist members.

12. A method as claimed in any preceding claim wherein said joist members include enlarged apertures adapted to permit engagement of cementitious material located on opposite sides of said joist members.

13. A method as claimed in any preceding claim wherein the support frame includes lower transverse frame members having .r jr- ru~ r- a l 21 apertures therein to receive starter bars extending from said base.

14. A method as claimed in any preceding claim wherein the cementitious material is applied between alternately spaced pairs of joists and, after surface finishing, is allowed to at least partially cure before application to alternately spaced walls regions therebetween. A method as claimed in any one of claims 1-13 wherein the cementitious material may be applied to adjacent wall regions between respective joists before surface finishing.

16. A method as claimed in any preceding ciaim wherein the 10o sheet-like formwork is removed from the support frame after the cementitious material has at least partially cured.

17. A method as claimed:in any one of claim 1-15 wherein the sheet-like formwork is retained on the support frame to form an inner or outer surface of a wall structure. 15 18. A method as claimed in any preceding claim wherein the sheet-like formwork comprises fibre cement sheet.

19. A method as claimed in any one of claims 1-17 wherein the sheet like formwork comprises gypsum board as an inner wall surface for said building construction. 'o 20. A method as claimed in any preceding claim wherein the wall structure includes decorative and/or protective surface finishes or inner and/or outer wall surfaces.

21. A method as claimed in any preceding claim wherein the ~UII1BI~ i' 22 wall structure includes a water stop means located: at the junction between the lower portion of the wall and a base surface.

22. A method as ciaimed in claim 21 wherein the water stop means includes a water reactive material adapted to expand when exposed to water to seat the junction between the wall structure and the base surface.

23. A method as claimed in claim 21 or claim 22 wherein the water stop means is located by locating means adjacent the base of the support frame.

24. A method as claimed in any preceding claim wherein the upright joist members comprise hollow steel box members supported on or in the base. A method as claimed in claim 24 wherein one or more starter bars extend from the base into the hollow interior of said hollow steel box members.

26. A method as claimed in claim 24 or claim 25 wherein said hollow steel box members include a tie bar encapsulated in a column of cementitious grout.

27. A method as claimed in claim 26 wherein the upper ends of each tie bar are adapted for securing to a roof structure.

28. A method as claimed in claim 27 wherein the roof structure may comprise trusses extending between transversely spaced upright members.

29. A method as claimed. in any preceding claim w.,crein the support frame includes service conduits. A method as claimed in any preceding claim wherein utility conduits are located in the framre before the concrete is sprayed.

31. A method as claimed in any preceding claim wherein removable blockouts are provided within the frame to define apertures therein. S32. A method as claimed in any one of claims 8-31 wherein Sthe reinforcing steel and/or the lower portion of the support frame 10 extends into the base to tie the wall to the base.

33. A method as claimed in any preceding claim wherein said cementitious material includes condensed silica fume concrete.

34. A method for the construction of building panels for a wall structure including the steps of: 15 attaching sheet-like formwork to one side of a building frame; I applying an inner surfac:of the formwork a flowable curable cementitous composition; screeding or surface finishing the exposed cementitous face of the wall; and allowing the cementitious composition to cure. A method as claimed in claim 34 wherein said building_ frame is supported in an upright position. i-9 24

36. A method as claimed in claim 34 wherein said building frame is supported in a generally horizontal position.

37. A method as claimed in any one of claims 34-36 further including the features of any one of claims 2-20.

38. A building whenever constructed in accordance with the method of any one of claims 1-33.

39. A building panel whenever constructed in accordance with the method of any one of claims 34-37. A method of building construction substantially as i10 hereinbefore described with reference to the accompanying drawings.

41. A building wall substantially as hereinbefore described with reference to the accompanying drawings. DATED this Sixteenth day of July 1998. TRISTANAGH PTY LTD I By its Patent Attorney FISHER ADAMS KELLY