ENGINEERED BUILDING BLOCK
MODULAR CONSTRUCTION
BACKGROUND
[0001] Modular building construction has attracted much interest over the last decades. The perspective to be able to build your own home out of relatively easy to assemble components is appealing when considering the hourly rates of skilled construction workers.
[0002] Although some former modular building concepts have been satisfactory to a certain degree, there remained room for improvement. SUMMARY
[0003] Some of the main factors which will affect the commercial success of a modular building concept include the level of skill required to complete the assembly, the amount of skilled worker hours required, the manoeuvrability of the components (weight) vs. the amount of components; the durability of the components, the overall appeal of the finished construction, and at least in northern climates, the insulation strategy.
[0004] Increasing the size of the wall components is a way to reduce the amount of components. However increasing the size tends to increase weight, which should be limited to a certain reasonable extent. One aim is to provide walls which are formed of elongated composite logs having at least 8 feet in length, a satisfactory height, a satisfactory structural resistance, and a satisfactory thermal insulation, while being light enough to provide handling by two average persons. It is aimed that the weight of the composite logs be maintained below 80 lbs if possible, for instance.
[0005] In a concept of logs formed of a structural shell with an insulating core, the main structural materials are typically much denser than insulation materials and should thus be used strategically, in an engineered manner, to limit the overall structural component volume vs. the volume of insulation.
[0006] In accordance with another aspect, it was found that using solid foam components in the core as thermal insulation can be beneficial, because although the
structural resistance of solid foam components is typically low when compared to that of engineered structural materials, it remains non-negligible and can contribute to overall structure. It was found that using an adhesive to adhere solid foam components inside the shell to the engineered structural components of the shell allowed to better harness the structural resistance of the solid foam components in the overall structure, and therefore reduce the required amount (weight) of engineered structural materials.
[0007] In accordance with another aspect, it was found that using a separator panel intersecting the cavity can be a strategic way to add structure to significantly improve the structural characteristics with a relatively low cost in weight. The advantages of a separator panel are even further increased when solid thermal insulation components are adhered to it.
[0008] It was also found that using engineered materials such as manufactured wood panels instead of wood in the structural components can reduce weight, because the mechanical resistance of engineered materials are typically better known than that of wood and a lesser excess material safety buffer is required.
[0009] Henceforth, in accordance with another aspect, there is provided a composite log having an elongated structural shell having a first set parallel walls rigidly interconnected with a second set of parallel walls perpendicular to the first set of parallel walls, the interconnected walls enclosing an elongated cavity housing a core having at least one block of rigid plastic foam insulation adhered to inner faces of the walls by an adhesive, and two opposite mating outer surfaces associated with the first set of parallel walls for stacking identical ones of the composite log, and two sides associated with the second set of parallel walls, the walls each having at least one board of manufactured wood. [0010] In accordance with another aspect, there is provided a method of assembling a composite log having a first set of parallel walls having grooves with a second set of parallel walls perpendicular to the first set of parallel walls and interconnected therebetween and engaged into the grooves, and a core having at least one block of rigid plastic foam insulation; the method comprising in sequence : stacking the core onto a first
one of the parallel walls of the first set, with an adhesive applied therebetween; engaging a first end of the parallel walls of the second set into the grooves of the first one of the parallel walls of the first set, with an adhesive between the core and the parallel walls of the second set; folding the parallel walls of the second set onto opposite sides of the core; lowering the second one of the parallel walls of the first set onto the core, thereby engaging the second end of the parallel walls of the second set into the grooves of the second one of the parallel walls of the first set; and applying a predetermined pressure in compression respectively between both sets of parallel walls and allowing the adhesive to set. [0011] In accordance with another aspect, there is provided a composite log having an elongated structural shell having a first set parallel walls rigidly interconnected between a second set of parallel walls, the interconnected walls enclosing an elongated cavity housing a core having thermal insulation material, and two opposite mating outer surfaces associated with one of the first set and second set of parallel walls for stacking identical ones of the composite log, and two sides associated with the other one of the first set and second set of parallel walls, the walls each having a structural engineered material.
[0012] Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure. DESCRIPTION OF THE FIGURES
[0013] In the figures,
[0014] Fig. 1 includes schematic views 1A, 1 B and 1 C showing types of mechanical deformation which a composite log can suffer when subjected to stress;
[0015] Fig. 2 is an oblique view showing an example of a composite log, fragmented; [0016] Fig. 3 is a cross-sectional view of the composite log, shown with additional optional components;
[0017] Fig. 4 includes Figs. 4A to 4C which schematically depicts successive steps of an exemplary method of assembling a composite log.
DETAILED DESCRIPTION
[0018] Fig. 1 shows different types of mechanical stresses to which an elongated composite building module (herein after referred to as a composite log) can be subjected to, and examples of resulting deformation. In Fig. 1A, the composite log 10 is subjected to compression which causes buckling. In Fig. 1 B, the composite log 10 is subjected to compression which causes torsion. In Fig. 1 C, the composite log 10 is subjected to compression which causes bending. The structure in the composite log 10 is engineered to withstand pre-established thresholds of such stresses which can be well above the maximum stresses which can normally be expected.
[0019] Turning now to Fig. 2, an example of a composite log 10 is shown. The composite log 10 can be seen to generally include a structural shell 12 having two pairs, or sets, of opposite walls 14, 16. In this example, the walls in each given pair 14, 16 are parallel to each other and perpendicular to the walls of the other pair 14, 16. Further, each one of the walls of each pair includes an engineered structural material. In this particular example, the engineered structural material is in the form of panel(s) of manufactured wood. Plywood is the preferred type of manufactured wood in this example. In this example, it can be seen that the upper wall 18 and lower wall 20 each include two wide plywood panels 22, 24. Further, plywood boards 26, 27 are adhered to the two plywood panels 22, 24 in a manner to form mating surfaces 28, 30. More particularly, the mating surfaces 28, 30 in this case are of the tongue and groove type, the spacing between the boards 26 of the upper panel 18 being adapted to the width of the boards 27 of the lower panel 20, and vice-versa. Other examples of manufactured wood can be veneer based, particle based, or fiber based, and can include wood-plastic composite or oriented strand board for instance. It will be noted that in this example using structural panels, grooves are defined in the side walls 32, into which the structural panels 22 of the upper and lower walls 18, 20 can be engaged. The presence of this mating engagement can significantly improve structural resistance. The walls can be interconnected in any suitable manner such as by adhesion, fastening, etc. In this example adhesion was preferred. It will be
noted here that other engineered materials than manufactured wood can be used in alternate embodiments, such as fiber cement or instance. Further, alternately to being assembled, the walls of the shell can be integral such as by forming an extruded shell of a plastic material, for instance. [0020] In this example, the side walls 34, 36 each have three parallel and interspaced spacer boards 38 adhered to a full plywood panel 40. The spacer boards 38 form air space channels 42 therebetween. It will be noted here that in alternate embodiments, the air space channels can be oriented vertically rather than horizontally.
[0021] A core 50 is housed inside the structural shell 12. The core 50 includes thermal insulation. In this particular example, the thermal insulation includes solid plastic foam. Outer surfaces of the solid plastic foam thermal insulation the core 50 are fully adhered to the structural panels 16, 14 via an adhesive 52, a feature which can significantly improve the structural resistance of the composite log. In alternate embodiments, adhesion can be provided without an adhesive, such as by using the naturally occurring adhesion characteristics of some sprayed foam insulation (such as sprayed polyurethane) for instance. In this particular example, the solid plastic foam is extruded expanded polystyrene, but it will be understood that any other suitable insulation materials can be used, even loose fill insulation for instance, in some alternate embodiments. Blocks of insulation can be formed of a stack of smaller components if desired. In this specification, the expression thermal insulation refers to materials having a thermal conductivity above 0.35 m2.K/(W.in) or an R-Value above 2, and preferably above 52 m2.K/(W.in) or a R- Value above 3. For instance, low-density extruded expanded polystyrene panels can have an R value between R-3.6 and R-4.7.
[0022] In this example, one separator board 54 is used and interconnects the side walls 16 and the thermal insulation includes two blocks 56, 58 of rigid plastic foam, one on each side of the separator board 54. Each one of the lateral, upper and lower surfaces of the blocks 56, 58 of rigid plastic foam are fully adhered to a corresponding one of the side walls, upper wall 18, separator board 54 and lower wall 20. This configuration can significantly improve the structural resistance of the composite log to deformation such as illustrated in Fig. 1A, for instance. Further, the presence of a separator board 54 which
intersects the cavity, especially when the rigid thermal insulation is adhered to the separator board using an adhesive, can significantly enhance the structural resistance. It will be noted here that in an alternate embodiment, the separator can be oriented obliquely with blocks having a triangular cross-section for instance, and/or there can be more than one separator used.
[0023] Turning now to Fig. 3, further details are shown. In this particular example, the mating engagement between the opposite surfaces 28, 30 is provided with a tongue and groove engagement. More particularly, a double tongue and groove engagement as shown was preferred in this example, with both tongues 60 and both grooves 62 being interspaced from one another. Each one of the grooves 62 can include an adhesive bead (not shown) which is compressed and activated when successive composite logs are stacked against one another. Further, in this particular case, each one of the grooves 62 houses a weather strip 64 to impede air infiltration. In this particular embodiment, given that the bottom wall 20 and upper wall 18 are made of pieces of plywood having the same thickness, the grooves 62 are provided with an elongated recess 66 which houses the weather strip 64 and into which the weather strip 64 can be compressed upon installation.
[0024] Further, in this embodiment, the composite log 10 can optionally include any one of various types of interior finishing panels 70 and/or exterior facing panels 72. When both panels are provided, the wall can automatically have two finished sides once completed, which is very appealing in terms of efficiency of assembly. The panels 70, 72 can enclose the air space channels. In this particular example, the exterior facing panel 72 can be fibro cement, and the interior finishing panel 70 can be wood, for instance. It will be noted that the air space channels 42 can be used to house technical components such as water conduits or electrical wires, for instance. [0025] The composite logs can be stacked into a wall. More particularly, the end of the core 50, upper and lower walls 18, 20 of the composite logs 10 can be placed in abutment against an upstanding pole, and the sidewalls 16 project lengthwisely from the end of the core 50 to overlaps onto a portion of the pole, to which it can be secured. It will be noted that in an alternate embodiment, the composite log can be used in roof structure rather than wall, for instance.
[0026] Turning now to Fig. 4, it will be understood how the example composite log described above and illustrated can be manufactured. First, each one of the four walls can be assembled from corresponding manufactured wood pieces. A first one of the lateral walls 16A is positioned, and the core 50, including foam insulation blocks 56, 58 and separator board 54 is stacked above it. Two perpendicular walls 18, 20 can be engaged in the grooves 32. The two perpendicular walls18, 20 can then be folded onto the core and pressure applied to satisfactorily activate the adhesive between the two perpendicular walls and the core. This step can also align the ends of the two perpendicular walls 18, 20 with grooves 32 in the last panel 16B, which can be lowered into place to form the engagement. Finally, pressure can also be applied in the perpendicular direction to activate the adhesive so that the adhesive is activated in both perpendicular directions. Many alternate manufacturing methods can be used, and the particular manufacturing method can be adapted to the particular configuration of the composite log.
[0027] As can be seen therefore, the examples described above and illustrated are intended to be exemplary only. The scope is indicated by the appended claims.