1.

METHOD OF SECURING A CEILING THIS INVENTION relates to a method of securing a ceiling, to a ceiling kit, to a securing kit for securing and tightening ceiling material in roll form, and to a building structure having a ceiling. In accordance with a first aspect of this invention, there is provided a method of securing a ceiling between opposing walls including loosely spanning a length of flexible ceiling material via opposite ends thereof between opposing walls; mounting at least a first retaining member at a predetermined position proximate a respective first end of the ceiling material on a respective first one of the walls; urging a first tightening member into a tightening position against the ceiling material to tighten the ceiling material; locating the first tightening member in the tightening position to the first retaining member. Advantageously, the flexible ceiling material may be supplie in bulk in roll form, the method including handling the flexible ceiling material in roll form in the course of loosely spanning it between the opposing walls. Preferably, tightening of the ceiling material may be also at the second of the respective ends of the ceiling material at the second of the opposing walls by means of a second retaining member and a second tightening member. That would double the tightening effect and would allow the ceiling material to be spanned even more loosely initially. The method may include tightening the ceiling material along an elongate edge thereof against a side wall extending between the opposed walls by means of a retaining member mounted on the side wall and a complemental tightening member. In addition to enhanced tightening, that would also promote a peripherally uniform appearance to a room being provided with a ceiling. More specifically, each of the respective ends or a side of the ceiling material may be secured to the respective wall by sandwiching the respective end portion or an edge portion of the ceiling material between the wall and a cleat, the cleat being tightly secured along the respective wall, e. g. by means of mechanical fasteners such as nails, staples, or the like, especially nails, staples or the like applied by means of detonation driven tools. In accordance with a second aspect of this invention, there is provided a ceiling kit for spanning a ceiling between opposing walls, the ceiling kit including flexible ceiling material in roll form; cleating for loosely securing opposing ends of a length of ceiling material to the respective walls; at least one length of an elongate retaining member which includes an elongate retaining formation and which is mountable along correspondingly at least one of the walls; at least one length of an elongate tightening member complemental to the retaining member for interposing between the retaining member and the ceiling material for spacing the ceiling material from the retaining member to tighten the ceiling material, the tightening member being locatable in the retaining member. Preferably, the ceiling kit may include second lengths of respectively the retaining member and the tightening member to tighten the ceiling material also along the second of the opposing walls. The or each retaining member may include a concave retaining formation. The retaining formation may conveniently be integral with or may be formed in the cleating. The retaining formation may be concave part round cylindrical. Then, the tightening member may be in the form of an elongate cylindrical extrusion, which may conveniently be round tubular. Thus, advantageously, the elongate cylindrical extrusion may be in the form synthetic polymeric tubing. In accordance with a third aspect of this invention, there is provided a securing kit for securing and tightening flexible ceiling material provided in roll form between opposing walls, the securing assembly including cleating securable to the walls to secure opposite ends of a length of the ceiling material to the opposing walls; a length of elongate retaining member which includes an elongate retaining formation and which is mountable along at least one of the walls; a length of elongate tightening member complemental to, to be retainable by, the retaining formation, the tightening member having a transverse dimension to be interposed between the tightening formation and the ceiling material to space the ceiling material from the retaining formation to tighten the ceiling material. The elongate retaining member may be integral with the cleating. Instead, it may be separate and apart from the cleating. In accordance with a fourth aspect of this invention, there is provided a building structure including opposed walls and a ceiling of a ceiling material provided in roll form installed in accordance with the method of this invention.

2.	The invention is now described by way of examples with reference to the accompanying diagrammatic drawings. In the drawings Figure.

3.	shows, fragmentarily, securing and tightening of one end portion of a length or band of flexible ceiling material to a building wall; Figure 2 shows the arrangement of Figure.

4.

in sectional side view; and Figures 3 and 4 show other embodiments in views corresponding to that of Figure 2. With reference to Figures 1 and 2 of the drawings, a ceiling is to be spanned of flexible and spannable ceiling material provided in roll form between opposing walls of a building structure. The building structure is indicated fragmentarily by reference numeral 10. One of the opposed walls is indicated by reference numeral 12, the other opposing wall not being shown, and reference numeral 14 indicates a side wall extending between the opposing walls. A length or band of ceiling material 16 is loosely spanned between the opposing walls. Only the portion at the wall 12 is shown, the portion at the opposing wall, which is not shown, being similar or identical. The end portion of the ceiling material 16 is firmly secured to the wall 12 by means of cleating 18 sandwiching the end portion of the ceiling material against the inner surface of the wall 12. The cleating 18 is secured over the end portion of the ceiling material 16 to the wall 12 by means of mechanical fasteners such as nails, indicated by reference numeral 20 in Figure 2. It is to be appreciated that the length of ceiling material 16 is spanned loosely to a predetermined extent. As can best be seen in Figure 2, an upper edge of the cleating 18 is rendered into a concave, part round cylindrical retaining formation 22 leaving a remaining edge 24 along the length of the cleating 18, remote from the wall 12. A plurality of lengths or bands of ceiling material extend alongside one another to cover the area to be covered by the ceiling. A length of tightening member 26 in the form of a round cylindrical tube 26, and which is complemental to the retaining formation 22, is interposed between the retaining formation 22 and the ceiling material 16 such that the ceiling material 16 is spaced from the retaining formation 22 and is thus tightened. This can best be perceived from Figure 2. It is to be appreciated that the ceiling material 16 is advantageously slightly resilient to allow slight stretching thereof and thus to relax the tolerance to which it is to be loosely spanned prior to tightening. It is further to be appreciated that, when the tightening tube 26 is seated in the retaining formation 22, it is held in position by pressure exerted by the ceiling material 16 thereon. More specifically, a resultant force vector to which the tightening tube 26 is subjected acts along a line extending through the retaining formation, i. e. below the edge 24, thus preventing the tightening tube 26 from being forced over the edge 24. As can be seen in Figure 1, also an elongate edge of the length or band of ceiling material 16 can be secured to and tightened against the side wall 24 in similar manner. This has the added advantage that the appearance of the interface between the ceiling material and the respective walls around the circumference of the room is uniform. When tightening has been completed, the excess ceiling material is trimmed underneath the cleating 18. With reference to Figure 3, another embodiment of a retaining member is shown. Instead of having the retaining member integral with the cleating as in Figure 2, a separate extruded length 121 providing an angled seat 122 is secured together with the cleating 118 to the wall 12. In other respects the mechanism of tightening and of retaining the tightening tube 26 is the same. With reference to Figure 4, yet a further embodiment of a retaining member 221, also in the form of an elongate extruded member having a seat 222, is shown. The Applicant regards it as a first advantage that ceiling material in roll form can be used to form a ceiling. This has a number of important advantages, for example low cost of the material itself; and ease and low cost of storing the material, transporting the material to site and handling the material on site. The use of ceiling material in roll form, with the advantages mentioned above, is made possible by providing a spanning and tightening method and arrangement in accordance with the invention. Securing of the ceiling material is easily done, because the ceiling material is initially spanned loosely. Then tightening of the ceiling material takes place effectively in user friendly manner, by inexpensive means and which can easily be done by unskilled labour. The Applicant regards it as a major advantage that the invention allows a ceiling to be installed easily and at low cost. This is extremely important as it allows ceilings to be installed where, previously, ceilings would not have been a possibility, notably in low cost dwellings. The mere fact that a ceiling is provided has a large beneficial effect on heat insulation of the dwelling, firstly because of its retarding effect on heat transmission and even more so because of the stratification effect within the dwelling. It further reduces the effect of radiation from roof surfaces. The heat insulating effect is advantageous in keeping the dwelling cool during periods of uncomfortably high ambient temperature, and keeping the dwelling warm during periods of uncomfortably low ambient temperature. Furthermore, the presence of a ceiling has the ancillary advantage of reducing infiltration of air to and from the dwelling which has the further advantage of reducing ingress of undesirable material such as grit, sand, and the like. Initial calculations indicate that a very high amount of heating energy can be saved by means of a ceiling in a house. This, firstly, has the advantage of saving on the electricity used and it has the additional, and very large, advantage of saving on the requirement of installed peak capacity electricity generation. This invention greatly promotes and facilitates the provision of ceilings in low cost housing and thus makes the above savings and advantages possible. CLAIMS 1. A method of securing a ceiling between opposing walls including loosely spanning a length of flexible ceiling material via opposite ends thereof between opposing walls; mounting at least a first retaining member at a predetermined position proximate a respective first end of the ceiling material on a respective first one of the walls; urging a first tightening member into a tightening position against the ceiling material to tighten the ceiling material; locating the first tightening member in the tightening position to the first retaining member.

5.	2 A method as claimed in Claim 1 which includes providing the flexible ceiling material in bulk in roll form and handling the flexible ceiling material in roll form in the course of loosely spanning it between the opposing walls.

6.	A method as claimed in Claim 1 or Claim 2 which includes tightening the ceiling material also at the second of the respective ends of the ceiling material at the second of the opposing walls by means of a second retaining member and a second tightening member.

7.	A method as Claimed in Claim 1 or Claim 2 or Claim 3 which includes similarly tightening the ceiling material along an elongate edge thereof against a side wall extending between the opposing walls by means of a retaining member mounted on the side wall and a complemental tightening member.

8.

A method as claimed in any one of Claim 1 to Claim 4 inclusive in which each of the respective ends or a side of the ceiling material is secured to the respective wall by sandwiching the respective end portion or an edge portion of the ceiling material between the wall and a cleat and tightly securing the cleat along the respective wall.

9.	A method as claimed in any one of Claim 1 to Claim 5 inclusive in which locating the respective tightening member to the respective retaining member is by seating the tightening member in a complemental seat provided for that purpose in the retaining member.

10.

A ceiling kit for spanning a ceiling between opposing walls, the ceiling kit including flexible ceiling material in roll form; cleating for loosely securing opposite ends of a length of ceiling material to the respective walls; at least one length of an elongate retaining member which includes an elongate retaining formation and which is mountable along correspondingly at least one of the walls; at least one length of an elongate tightening member complemental to the retaining member for interposing between the retaining member and the ceiling material for spacing the ceiling material from the retaining member to tighten the ceiling material, the tightening member being locatable to the retaining member.

11.	A ceiling kit as claimed in Claim 7 which includes second lengths of respectively the retaining member and the tightening member to tighten the ceiling material also along the second of the opposing walls.

12.	A ceiling kit as claimed in Claim 7 or Claim 8 in which the or each retaining member includes a concave retaining formation.

13.	A ceiling kit as claimed in Claim 9 in which the retaining formation is integral with or is formed in the cleating.

14.	A ceiling kit as claimed in any one of Claim 7 to Claim 10 inclusive, in which the or each retaining formation is concave part round cylindrical, and in which the or each tightening member is in the form of an elongate cylindrical extrusion.

15.	A ceiling kit as claimed in Claim 11 in which the or each tightening member is round tubular.

16.

A securing kit for securing and tightening flexible ceiling material provided in roll form between opposing walls, the securing assembly including cleating securable to the walls to secure opposite ends of a length of the ceiling material to the opposing walls; a length of elongate retaining member which includes an elongate retaining formation and which is mountable along at least one of the walls; a length of elongate tightening member complemental to, to be retainable by, the retaining formation, the tightening member having a transverse dimension to be interposed between the tightening formation and the ceiling material to space the ceiling material from the retaining formation to tighten the ceiling material.

17.	A securing kit as claimed in Claim 13 in which the elongate retaining member is integral with the cleating.

18.	A securing kit as claimed in Claim 13 in which the elongate retaining member is separate and apart from the cleating.

19.	A building structure including opposing walls and a ceiling of a flexible and spannable ceiling material installed in accordance with the method of Claim 1.