Abstract:
A stay in place concrete formwork wall element comprises a major surface defining a portion of a face of the concrete wall, said surface having a plurality of uniformly sized and spaced apertures substantially throughout the surface allows concrete to seep partially through the apertures thereby providing an irregular trowelable surface facilitating the application of stucco or other wall coverings.

Description:
FIELD OF THE INVENTION  
         [0001]    This invention relates to formwork for pouring concrete structures. In particular, this invention relates to such formwork which is designed to stay in place after the concrete has set.  
         BACKGROUND OF THE INVENTION  
         [0002]    It is known to provide PVC formwork for forming concrete walls that stays in place after the concrete has set to thereby form sheathing for the resulting concrete wall. However, by its natures PVC does not provide a very good surface for the application of paint or stucco. Typically in order to be able to apply stucco to such PVC sheathing, it is necessary to first apply a base coat having some adhesive properties, applying a mesh to the material and subsequently applying the stucco.  
           [0003]    It is an object of this invention to provide stay in place formwork which nonetheless provide a surface suitable for the application of stucco.  
           [0004]    It is a further object of this invention to provide stay in place formwork adapted to optionally provide an external layer of concrete overlaying the formwork.  
           [0005]    These and other objects of the invention will be better appreciated by reference to the following disclosure.  
         SUMMARY OF THE INVENTION  
         [0006]    The invention comprises stay in place formwork wall elements which are provided with a plurality of small holes to enable the concrete poured into the formwork to seep through the holes and to thereby provide a thin layer or beads of concrete on the side of the formwork forming a face of a wall.  
           [0007]    Preferably, the holes are approximately one-eighth inch in diameter and are spaced about one sixteenth of an inch from adjacent holes.  
           [0008]    Other aspects of the invention will be appreciated by reference to the detailed description of the preferred embodiment and to the claims. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    The preferred embodiment of the invention will be appreciated by reference to the following description and to the drawings thereof in which:  
         [0010]    [0010]FIG. 1 is a cross-sectional view of stay in place formwork according to the prior art;  
         [0011]    [0011]FIG. 2 is a front view of a formwork element according to the invention;  
         [0012]    [0012]FIG. 3 is a cross-sectional view of a formwork element according to the invention;  
         [0013]    [0013]FIG. 4 is a cross-sectional view of a portion of a formwork assembly according to the invention wherein concrete has been poured into the formwork and has seeped through the holes in the element; and  
         [0014]    [0014]FIG. 5 is a side elevation of a wall element according to the invention showing beads of concrete having seeped through the apertures.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0015]    Referring to FIG. 1, one embodiment of PVC stay in place formwork according to the prior art includes wall elements  10  and connecting members  12 . Each of the wall elements  10  defines part of the stay in place sheathing for each of two faces or sides  14 ,  16  of the resulting concrete wall. The connecting members  12  act to maintain facing wall elements  10  in spaced relationship. Adjacent wall elements  10  are interconnected, for example by means of engaging means  11  on the connecting members  12 .  
         [0016]    The wall elements  10  illustrated in the prior art formwork of FIG. 1 include a flat portion  13  extending between engaging means  11 , the falt portion  13  defining a flat face for the resulting formwork (which also defines a face of the concrete wall). Other designs of wall elements include non-flat surfaces such as concave or corrugated surfaces. The present invention may be applied equally to such elements, and indeed to any formwork element having a surface that contributes to defining a face of the resulting wall.  
         [0017]    [0017]FIG. 2 illustrates a plurality of apertures or holes  18  provided in the surface of a wall element  20  in accordance with the invention. The apertures are uniformly sized and spaced, the dimensions being between one thirty-second and one quarter of an inch in diameter and being spaced from one another between one thirty-second and three sixteenths of an inch. The preferred diameter of each aperture is approximately one eight of an inch and the preferred spacing is approximately one sixteenth of an inch.  
         [0018]    The apertures  18  are provided substantially throughout the surface. FIG. 2 illustrates interruptions  21 ,  23  in the uniform spacing of the apertures due to the presence of structures  25  (shown in FIG. 3). Nonetheless, it will be appreciated that the apertures are still provided substantially throughout the major surface of the element that contributes to defining a face of the wall.  
         [0019]    The apertures are illustrated as being round, but they may in fact be of arbitrary shapes provided there is substantially uniform spacing between the apertures to allow uniform flow of concrete through the apertures.  
         [0020]    In an assembly using the wall elements of the invention, a plurality of apertured wall elements would be provided in interconnected relationship so as to define a face of the overall formwork wall, which of course also defines a face of the concrete wall. Similar apertured wall elements may be used on the opposite face of the formwork wall depending on the desire to achieve the objects of the invention for that face.  
         [0021]    When concrete is poured into the formwork, the apertures allow a small portion of the concrete to seep through the apertures and to form either a thin layer of concrete overlaying the wall element or a plurality of beads of concrete.  
         [0022]    [0022]FIG. 4 illustrates a portion of such an assembly wherein one face  32  of the wall is formed using apertured wall elements  28  according to the invention while the opposing face  34  of the wall is formed using unapertured wall elements  26  according to the prior art. The overall formwork also includes prior art connecting members  22  and  24 . It will be appreciated that the formwork segment illustrated in FIG. 4 is repeated with interconnected segments to form an overall wall of formwork. In FIG. 4, concrete  27  has been poured into the formwork. The concrete seeps through the holes  18  to form heads  30  of concrete that protrude slightly to the outside surface of the wall element  28 .  
         [0023]    In the case where the concrete seeps through the apertures to a sufficient extent to form a substantially uniform layer of concrete covering the face of the formwork, it may be desirable to trowel the layer of concrete to produce a more irregular surface for the application of stucco, paint or other covering. In cases where the seepage of the concrete through the apertures causes a plurality of beads of concrete, the resulting surface may already be sufficiently irregular for the application of stucco or other covering.  
         [0024]    It will be appreciated that the invention provides a simple and effective solution to the problem of providing stucco, paint or other coverings over stay in place formwork.  
         [0025]    It will also be appreciated by those skilled in the art that although the preferred embodiment of the invention has been described in some detail, variations and modifications thereto may be practised without departing from the scope and principles of the invention.