US3745730A

US3745730A - Prefabricated modular housing

Info

Publication number: US3745730A
Application number: US00875152A
Authority: US
Inventors: R Layne
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-11-10
Filing date: 1969-11-10
Publication date: 1973-07-17
Anticipated expiration: 1990-07-17

Abstract

This invention relates to improvements in prefabricated modular housing. These improvements comprise the combination of extruded aluminum beams, rafters and joists; plastic wall studs; wall sections having a styrene or butadiene foam in intermediate sections, plastic or butadiene thin solid sheets for interior and exterior wall surfaces, flexible plastic wiring comprising copper laminated on plastic inserted between the interior wall surface plastic and the foam; aluminum sandwich structural load carrying members on the perimeter of the wall sections; fluid conduits running in interior apertures of the wall studs; and the combination of these features being fabricated into modular units where each unit consists of several rooms of the resultant structure.

Description

United States Patent 1191 Layne 1 July 17, 1973 PREFABRICATED MODULAR HOUSING [76] Inventor: gqhgrt W. Lang, 25106 8 Mile Primary Examz ner-Henry C. Sutherland Road, Southfield, Mich. 48075 Attorney-Dav"! [22] Filed: Nov. 10, 1969 [21] Appl. No.: 875,152 [57] ABSTRACT [52] US. Cl 52/236, 52/173, 52/588 This invention relates to improvements in prefabri- [51] Int. Cl E04b I/343, E04b 1/38, E04b 1/62 cated modular housing. These improvements comprise [58] Field of Search 52/588, -79, 289, the combination of extruded aluminum beams, rafters 52/236, 173 and joists; plastic wall studs; wall sections having a styrene or butadiene foam in intermediate sections, plastic [56] References Cited or butadiene thin solid sheets for interior and exterior UNITED STATES PATENTS wall surfaces, flexible plastic wiring comprising copper 2,694,475 11 1954 Crafton 52/588 x laminated Plastic inserted between the interior 2,710,584 6/1955 Ross 52089 X surface plastic and the foam; aluminum sandwich struc- 2,717,s01 9/1955 Neil 52/289 x mm! load Carrying members on the Perileter of the 2,825,036 2/1958 Sorensen 339 17 R a sections; fl conduits running in interior p 2,828,842 4/1958 Plumley et al..... 52/79 X tures of the wall studs; and the combination of these 6 ,13 1 /1960 Marsi 52/583 features being fabricated into modular units where 3,237,368 11/1966 Becker- 52/220 each unit consists of several rooms of the resultant 3,301,147 1/1967 Clayton et al. 52/588 X Structure 3,422,582 H1369 Van Der Lely 52/79 FOREIGN PATENTS OR APPLICATIONS Sweden 52/79 7 Claims, 9 Drawing Figures PAIENTED JUL 1 7 I973 NVENTOR ATTORNEY PATENTEU JUL 1 7 I873 SNEET20F3 INVENTOR ROBERT W. LAYNE av 9 I q jfle ATTORNEY PATENFEU L 1 975 SHEET 3 0F 3 IUIIHHII v INVENTOR BY ROBERT. w. LAYNE ATTORNEY PREFABRICATED MODULAR HOUSING This application relates generally to improvements in prefabricated construction of housing units. More particularly, this invention relates to prefabricated modular units of housing construction where each modular unit comprises several rooms manufactured and assembled at a factory rather than at the site of the resultant building.

In the past several years, there has been considerable interest and effort exerted in the prefabricated housing industry. These interests and efforts have been encouraged by discouraging elements in the traditional way of fabricating a building on the site of its ultimate location. These discouraging elements comprise lengthy delays in erection of a building caused by inclement weather, fluctuating financial demands, fluctuating labor supply, lack of coordination of sub-contracting efforts, labor strikes, and other factors. These discouraging developments also include higher cost of construction attributable to accelerating mortgage rates and accelerating interest rates on the financing of construction, increased wage demands by labor, high costs of traditional building materials, large costs of materials due to the need for a large weight of material for each building because of the need for structural load carrying capabilities required to carry heavy materials traditionally used, and expenses in transportation of building materials from the supplier to the site of construction aggravated by the heavy weight of such materials.

The prefabricated housing industry has sought to overcome many of these handicaps by increasing the proportion of effort required in manufacturing and assembly at a factory under controlled conditions rather than at a site of construction under uncontrolled conditions. These efforts in the past include the building of walls in large sections rather than by structural components; use of light weight materials on some portions of the housing; reliance upon indistrially organized labor for more effective bargaining for wage rates rather than reliance upon balkanization of labor organization along craft lines; and elimination of extended financial support for a prolonged construction period by speeding up production at a factory and more rapid construction at the site in order to obtain earlier occupancy of the resultant building.

The present invention adds several improvements to these past efforts by the prefabricated housing industry. A number of these improvements lie in specific structural elements that are either novel per se or novel in combination in a modular housing structure.

Accordingly, it is an object of this invention to provide a prefabricated modular housing unit comprising several rooms that is built at the factory and that is light weight in construction throughout and capable of rapid erection at the site of occupancy.

It is another object of this invention to provide a light weight modular prefabricated housing unit with walls fabricated in large sections that are light weight and capable of carrying portions of the structural load on the unit in vertical and non-vertical directions.

It is another object of this invention to provide a prefabricated modular housing unit comprising at least several rooms in each unit with prefabricated wall sections where each wall section has dimensions corresponding in magnitude to the side of one room and each wall section has electrical conduits built within it comprising thin flexible plastic cable having even thinner copper laminations deposited thereon for conduction.

It is still another object of this invention to provide a light weight prefabricated modular housing unit wherein each unit comprises at least several rooms and where the walls are made ofa combination of plastic or butadiene materials capable of carrying a portion of the structural load on said unit and plastic wall studs are utilized to carry a portion of the vertical loads on said housing unit. 1

It is still another object of this invention to provide a light weight prefabricated modular housing unit where each unit comprises at least several rooms, wall sections are made of light weight plastic materials, and the beams, rafters and joists consist of uniform extruded aluminum ribs and corrugated shapes having corresponding male and female connections for carrying a substantial portion of the structural load on said housing unit.

It is still another object of this invention to provide a light weight prefabricated modular housing unit where each unit comprises at least several rooms that consist entirely of light weight elements such as aluminum, butadiene and/or plastic elements that can be shipped by truck from the factory to the site of occupancy.

It is a further object of this invention to provide a light weight prefabricated modular housing unit wherein each unit comprises at least several rooms wherein one unit can be stacked upon another at the site of occupancy.

It is a further object of this invention to provide a light weight prefabricated housing unit wherein each unit comprises at least several rooms together with precast concrete slabs forming the walls of a basement or foundation wherein the only fabrication necessary at the site of occupancy is the pouring and curing of concrete footings for the slabs and the connection of components that are subsequently stacked thereon.

It is a still further object of this invention to provide a light weight prefabricated modular housing unit where each unit comprises at least several rooms and wherein a building structure comprising several of these units placed either side by side or on top of one another and which can be erected within a few days after the footings for the foundations have been poured and cured.

It is another object of this invention to provide a modular housing unit that is light weight, inexpensive to build, inexpensive to maintain, that has interchangable walls and structural elements, that can be shipped inexpensively and rapidly, that can be erected inexpensively and rapidly, and that is uncomplicated in design and manufacture.

These and other objects are achieved by the fabrication of a modular housing unit comprising at least several rooms at a factory. Such a housing unit has walls that have a length and height corresponding to the size of at least one room. The walls comprise an inner core of a bubble-like structure resulting after initial liquid application of a plastic or butadiene foam. The inner and outer surfaces of the wall structure are formed from plastic or butadiene sheets applied to the core to form a sandwich-like construction. Electrical conduits are provided through the wall by means of flexible plastic sheets having copper laminations deposited thereon and placed between the plastic sheet wall surfaces and the bubble-like core. Honey comb aluminum having apertures that extend parallel to the wall surface sheet plastic and sandwiched between butadiene or plastic sheets extending perpendicular thereto are fixed on the perimeter of each wall section. Hollow plastic or butadiene wall studs are provided at the corners and door and window apertures of the wall sections. Extruded aluminum ribs provide structural support for a floor of a housing unit. Extruded aluminum corrugation having inter-locking male and female portions are provided for floor panels and supports therefor. In addition to the modular housing units immediately described above, pre-cast concrete slabs are provided for the basement or foundation upon which the modular units rest. Plumbing fixtures and other fluid conduits such as ducts for heating and air conditioning are provided in apertures of the plastic wall studs at the factory. After a hole is dug at the site of occupancy, and concrete footings are poured and cured, the concrete wall slabs for the foundation are trucked to the site of occupancy and erected on the concrete footings. The modular units are also trucked to the site of occupancy and either placed side by side or stacked, and are then connected in forming a finished building.

Other objects of this invention will appear in the following description and appended claims, referring to the accompanying drawing forming a part of this specification.

ON THE DRAWINGS FIG. 1 is a three dimensional projection showing portions of the preferred embodiment of this invention;

FIG. 2 is partial cross sectional view taken along the section lines 2-2 of FIG. 1;

FIG. 3 is partial transverse sectional view taken along the section lines 3-3 of FIG. 2;

FIG. 4 is a cross sectional view showing the intersection between two wall portions of the apparatus shown in FIG. 1;

FIG. 5 is partial cross sectional view showing the intersection of an exterior wall portion with an interior wall portion of the apparatus shown in FIG. 1;

FIG. 6 is a partial cross sectional view showning the connection of a wall portion with a floor portion of the apparatus shown in FIG. 1;

FIG. 7 is a partial cross sectional view of the apparatus shown in FIG. I detailing in part a view of the connection with one modular unit on topof another and one modular unit with a concrete slab;

FIG. 8 is a partial transverse sectional view of the apparatus shown in FIG. 7 detailing the aluminum sandwich construction ofa ceiling and bottom and top portion of a wall of the preferred embodiment of this invention;

FIG. 9 is a cross sectional view of an interior wall along the section lines 9-9 of FIG. 7 detailing in part the provision of the preferred embodiment of electrical conduits in an interior wall.

Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details in construction and arrangement in parts illustrated in the accompanying drawings since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology and terminology employed herein are for the purpose of description and not of limitation.

AS SHOWN ON THE DRAWINGS The preferred embodiment of a modular housing unit 10 is shown in part in FIG. 1. A second modular unit 12, identical to the first mentioned modular unit 10, is also shown in part. The second modular unit 12, is shown placed on top of the first modular unit 10. These modular units can be stacked on top of one another as shown in FIG. 1, or they can be placed side by side, or can be both stacked and put side by side to form the resultant desired structure. The lowest modular unit 10 is placed upon a concrete portion 14. This concrete portion can be either cast on the site or preferably, comprise pre-cast slabs that are placed upon a footing or a foundation poured on site. The details of the connection between modular units stacked upon one another and between a modular unit and the concrete portion 14 will further described hereinafter.

In FIG. 3, an array of the preferred embodiment of panels 16 is shown in cross section. In FIG. 2, one of these panels 16 is shown in transverse section.

A single one of these panels 16, panel 18 will now be described. Panel 18, like all the other panels 16, is preferably an aluminum extrusion. It has a top flooring plate 20 that extends across the width, preferably 4 feet, of the extrusion. It has a valley, rib or full foot portion 22 located midway of its width, and half foot portions 24 and 26 respectively at its respective male and female sides. The aluminum panel 18 has a lower plate portion 28 extending across its width. Intermediate support shim portions 30 connect the lower and upper plates. These shim portions extend at spaced uniform intervals between the full and half foot portions.

The intermediate full foot portion 22 comprises opposing sloping

sides

32 and 34 respectively on the respective sides of the full foot portion 22. These

sloping side portions

32 and 34 extend at a slight acute angle from the normal to a bottom foot portion 36. An intermediate web portion 38 extends vertically from the foot 36 to the plate portions 20 and 28, and is midway between the

sloping side portions

32 and 34. The distance between the lower plate portion 28 and the foot portion 36 is several times greater than the distance between the upper plate 20 and the lower plate 28.

The female half foot portions 26 comprises a sloping side 40 similar to sloping side 32 of the intermediate foot portion 22. The sloping side portion 40 extends between the bottom or lower plate portion 28 of the rafter to a foot portion 42 at the bottom of half foot portion 26. Foot portion 42 is similar to foot portion 36 of the full foot section 22. An intermediate vertically extending web portion 44 is provided between the sloping portion 40 and a lip portion 46 extending from the foot portion 42. Intermediate web portion 44 is similar to intermediate web portion 38 ofthe full foot section 22.

Extending immediately above the intermediate web portion 44 is web extension portion 48. Web extension portion 48 extends from the lower plate 28 to a point slightly below the bottom surface of upper plate 20. A curved lip portion 50 extends from the upper portion of extension 48 back down to the bottom plate 28.

One of the shim portions 30, namely shim portion 52 extends from the bottom plate 28 to the upper plate 20. It is also horizontally displaced from the upper portion of the sloping portion 40. This displacement is horizontally closer to portion 44 of the female half foot section 26 and further away from the portion 38 of the full foot intermediate section 22. A curved lip portion 54 extends from the upper plate to the lower plate 28 adjaeent the shim portion 52. This relationship between the lip portion 54 and the shim portion 52 is similar to the relationship between the lip portion 50 and the extension 48, except that the lip portion 54 extends all the way to the top surface of the top plate 20.

The male half foot protion 24 comprises a sloping wall section 56 that extends from a foot portion 58 to the lower plate 28. Sloping wall portion 56 is similar to sloping wall portion 34 of the intermediate full foot section 22, except that it extends only to a level corresponding with the top surface of foot section 36 of intermediate full foot section 22. A normal vertically extending wall portion 60 is provided in male half foot section 24 that extends from the foot portion 58 to the top plate 20. A lip portion 62 is provided on the end of top plate 20 that extends horizontally beyond the vertical wall 60 to engage a female half foot section of an adjacent panel 64. Panel 64 is identical to panel 18 in that it is one of the array of panels 16.

From the foregoing description of the preferred embodiment of an extruded aluminum panel 18, it can be appreciated that each of the panels 18 fit snuggly to an adjacent panel of one of the array of panels 16 in a male-female relationship that provides a snug fit. The effect is of one panel nesting its male portion into an adjacent female portion of an adjacent panel. This nesting provides a convenient and inexpensive means of firmly attaching one panel to an adjacent panel. Also the use of aluminum extrusions in uniform dies reduces the cost of construction and eliminates complications in assembly.

Another nesting feature is used in firmly placing the panels in an aluminum joist which in turn rests on either a concrete slab or a lower adjacent modular unit. This last mentioned nesting feature, to be described further hereinafter, together with the above described nesting feature provides a means of efficiently achieving assembly dimensions and maintaining appropriately flush surfaces such as floors in an uncostly, controlled, and pricise manner.

The immediately afore-mentioned aluminum joists are shown in cross section in FIG. 2 and in transverse section in FIG. 3. These joists comprise a top section 68 uniformily spaced across the length of the joist to receive the ends of the arrays of panels 16. Vertically extending wall portions 70 inter-connect each of the top sections 68. Horizontally extending top portion 72 extends between the top portions 68 and support the ends of the lower plates 28 of the array of panels 16. Vertically extending abutting portions 74 contact the ends of the intermediate plate portions 20 and 28 of the panels and limit the horizontal displacement thereof to provide exact dimensional control of the placing of the panels with respect to the joist.

A second top portion 76, located above the top portion 72 of a joist 66 is provided. The distance between the top portions 76 and 72 is equivalent to the distance between the top surface of top plate 20 and the bottom surface of bottom plate 28 of each of the array of panels 16. Thus, the top surface of top portion 76 is preferably flush with the top surface to top plate 20 of the panels. The joists are provided with a second vertically extending portion 78 that extends beyond the end of the panels and comes into contact with a wall portion 88. The top of portion 78 is flush with the top of top portion 76. The bottom of portion 78 extends below the bottom of the cup portions 68. The joists 66 can be used to rest the panel 16 on concrete slabs 82 forming apart of the basement or foundation structure of the resultant building. These joists 66 can also be used to rest the panel assembly on the top of a wall section 84 of an adjacent lower modular unit.

Wall members 86 are shown three dimensionally in FIG. 1; cross sectionally in FIGS. 2, 6, 7, and 9; and transverse sectionally in FIGS. 4 and 5. The intermediate portion 88 of each of the wall sections 86 is preferably a solid structure with bubbles in it. The preferred material is either a styrene that has been solidified after initial application in a liquid state into the interior area of the wall, or the bubble-like interior portions of a butadiene material such as acrylonitrile butadiene styrene. The exterior walls 90 and interior walls 92 of the sandwich construction of the walls comprise sheets of smooth plastic or butadiene material. The preferred material for these sheets is smooth unbubbled acrylonitrile butadiene styrene.

In the preferred embodiment of this invention, a strengthened structure is provided around the perimeter of the walls. The preferred embodiment of this strengthened structure is honey-combed aluminum 94, the apertures running parallel to the vertical displacement of the wall, and the top and bottom of the honeycomb 94 faced with portions 96 and 98 of plastic or preferably ABS material similar to the exterior interior surfaces of the walls. Alternatively, the honey-comb can be embedded in liquid styrene which subsequently hardens so that large no air spaces are provided in the apertures of the aluminum honey-comb. Metals other than aluminum can be used for the honey-comb structure, such as steel, however aluminum is preferred because of its light weight consonant with the light weight material used throughout the preferred embodiment of this invention. By providing the strengthened perimeter around the walls, structural loads can be taken in a vertical direction by the wall, thus reducing the need for structrual load carrying capabilities in the wall studs.

At the foot of the walls, a long aluminum member having a cross section of a cup-like appearance 188 shown in FIG. 6 is provided to secure the bottom of the wall to the rafters or joist.

In the preferred embodiment of invention, wall studs are necessary only at the connection of wall sections and easements for doors and windows. FIG. 4 illustrates a cross section of a pair of adjacent wall studs interconnecting two wall sections. Each of the wall studs 102 has a square or rectangular cross section that is hollow in its interior. The material of the wall studs is preferably plastic or ABS or ABX or other acrylonitriale butadiene styrene smooth material. A flanged clip 104 is provided for the connection of the two wall studs through apertures provided in the wall studs. FIG. 4 illustrates the inter-connection of two wall sections at the corner of the exterior of the housing module. FIG. 5 illustrates a similar interconnection between an interior wall 186 and exterior wall 188.

FIG. 9 illustrates a cross sectional view of an interior wall that discloses the feature of a relatively flat piece of flexible plastic 118 to which copper laminations are applied. This provides a resultant very thin structure that can be placed behind an interior wall surface 112 of a wall structure 86. Thus an easy flexible and inexpensive means is provided for wiring the house. In the preferred embodiment of this invention, a ceiling structure is supported beneath the rafters by the walls. This ceiling structure 112 is shown in cross section in FIG. 7. It comprises a sandwich construction of metal, preferably aluminum honey-comb. Plastic sheets can be placed on the top and bottom surfaces of the structure 1 12 to provide smooth and non-biting engagement with supporting wall structures 114. A transverse sectional view of the honey-comb is shown in FIG. 8 at numeral 116.

In the preferred embodiment of this invention, the doors are made of a sandwich comprising a honeycomb structure in the core, such as that shown in numeral 116 in FIG. 8 or, alternatively, of an inner core of hardened initially liquid applied styrene foam or ABS foam. The interior and exterior surfaces of the door are preferably provided by plastic or butadiene sheets similar to such interior and exterior surfaces provided in the wall structure.

In the preferred embodiment of this invention, electrical outlets are provided on the interior wall surfaces of the wall portions proximate the flexible wire portions 110. Plumbing and ducts for air conditioning and heating can be provided in the interior 118 of the wall studs 102. Alternatively ducts can be placed between the ribs of the rafters.

From the foregoing description of the components of the preferred embodiment of the modular housing units, it can be appreciated that a new and useful apparatus and method for construction has been provided. Whole rooms or combinations of rooms can be manufactured at the factory. The resultant unit is light weight in construction and does not require elaborate and heavy structural support. The modular unit can be constructed in units of several rooms or even several apartments at one time. The units can be trucked to the site of construction. After an initial foundation is poured and cured, and pre-cast, preferably prestressed, concrete slabs are attached thereto, the modular units can be placed thereon simply by stacking one unit on top of another. All critical dimensions have already been provided for and means for controlling relationship of one unit to another if provided by the novel means of connection of one modular unit to another. The wiring, as indicated above, as well as heating, air conditioning, and plumbing ducts and tubes can be installed in the factory. The connections between walls and outlets for the above mentioned fluid ducts and tubes can be provided at the factory. The only connections electrically and fluid that have to be made at the site of construction is that between whole modular units. The walls of the modular units are able to take a substantial portion of the structural load supplied thereto and are capable of sustaining loads in vertical or non-vertical direction or a combination of both.

While most of the features of the present invention have been explicitly stated in this specification, a number are apparent or implicit in the description of the invention in the drawings and do not require further comment.

I claim:

1. In a prefabricated modular housing construction,

extruded aluminum panels including rafters in a uniformly spaced-apart parallel array and the flooring of said construction;

a first pair of joists engaging concrete structural members at the upper surfaces of said concrete structural members;

said first pair of joists supporting on the upper surfaces thereof a first array of panels;

non-metallic plastic studs having a relatively thin shell and a relatively large interior aperture extending vertically and fixed to the flooring of said construction and carrying a portion of the vertical load on said modular housing construction; a

each of said panels having hills and valleys and a male interlocking portion on one end thereof and a female interlocking portion at the other end thereof, each panels engaging in a male-female relationship a next adjacent panels;

a first plurality of wall members resting on said panels, each of said wall members having a height corresponding to the height of one story of said modular construction and having a width of the same order of magnitude as the width of a room in said modular construction, and having a thickness of an order of magnitude corresponding to 5 inches;

each of said wall members having interior and exterior skins of plastic material chosen from one of the following groups consisting of: acrylonitrile butadiene styrene and any other acrylonitrile butadiene substance, and having an interior core formed of a styrene foam;

a second pair of joists resting on upper horizontal surfaces of said wall members;

a second array of extruded aluminum panels resting on the upper surface of said second pair of joists;

each wall member having a honeycombed metal strengthening member on the horizontal edges thereof with the direction of the apertures of the honeycomb extending vertically.

each of said wall members bearing a substantial portion of the vertical structural load imposed by portions of the modular housing construction above said wall members;

whereby the entire modular housing construction can be made in units of one floor comprising several apartments and transported by truck to the site of the resultant building.

2. The article of claim 1 wherein said wall studs are placed at the ends of said wall sections and at the portions of wall sections immediately adjacent doors and windows; and said wall studs are limited to carrying a small proportion of the vertical structural load of the module. cm 3. The article of claim 1 and a sheet of copper laminated flexible plastic for conducting and forming terminals for electrical connections interposed between said core and said interior plastic skin of said wall sections.

4. The article of claim 1 and plumbing conduits inserted in the hollow interior apertures of said wall studs.

5. The article of claim 1 and ducts for heating inserted in the interior hollow apertures of said wall studs.

6. The article of claim 1 and air conditioning ducts inserted in the interior of said hollow apertures of said wall studs.

7. The article of claim 1 and a clip attached to said wall studs wherein said clip is yieldably urged into contact with said wall studs.

Claims

1. In a prefabricated modular housing construction, extruded aluminum panels including rafters in a uniformly spaced-apart parallel array and the flooring of said construction; a first pair of joists engaging concrete structural members at the upper surfaces of said concrete structural members; said first pair of joists supporting on the upper surfaces thereof a first array of panels; non-metallic plastic studs having a relatively thin shell and a relatively large interior aperture extending vertically and fixed to the flooring of said construction and carrying a portion of the vertical load on said modular housing construction; each of said panels having hills and valleys and a male interlocking portion on one end thereof and a female interlocking portion at the other end thereof, each panels engaging in a male-female relationship a next adjacent panels; a first plurality of wall members resting on said panels, each of said wall members having a height corresponding to the height of one story of said modular construction and having a width of the same order of magnitude as the width of a room in said modular construction, and having a thickness of an order of magnitude corresponding to 5 inches; each of said wall members having interior and exterior skins of plastic material chosen from one of the following groups consisting of: acrylonitrile butadiene styrene and any other acrylonitrile butadiene substance, and having an interior core formed of a styrene foam; a second pair of joists resting on upper horizontal surfaces of said wall members; a second array of extruded aluminum panels resting on the upper surface of said second pair of joists; each wall member having a honeycombed metal strengthening member on the horizontal edges thereof with the direction of the apertures of the honeycomb extending vertically. each of said wall members bearing a substantial portion of the vertical structural load imposed by portions of the modular housing construction above said wall members; whereby the entire modular housing construction can be made in units of one floor comprising several apartments and transported by truck to the site of the resultant building.