A design for small, low-cost demountable homes with full facilities (cooking, washing, shower and toilet).
© Plateau Group
This H4H design is available to any volunteer groups for non-commercial use, but please make a formal request.
Small homes for the homeless
H4H Basics & layout
These are the full design and production specifications for small demountable homes for the homeless and other disadvantaged groups. The aim is to mass-produce very cheap, small homes of this kind which can be stored until needed without having capital tied up -- and which can be fabricated in any covered space by unskilled people with an absolute minimum of tools.
Main Structure: The units are designed to be demountable, which effectively means that they are flat-packs consisting of six panels (floor, roof, two sides, front and back) with all internal fittings hinged to the walls for a variety of reasons. Essential fittings consist of:
The H4H water is supplied by a standard garden hose linked from a drip-feed garden divider to a controlling tap on the water-tank. Two embedded lights and a couple of power-points are built-in to the side walls. And we would use a double electric hot-plate for cooking, water-heating and room-warmth in winter.
The easy-to-clean-and-unclog tip-toilet has its disposal output through a standard U-bend and plastic pipe network to the conventional sewerage system's entry points ... or to a septic tank or pump-out bladder. This approach easy to link, and it is very flexible.
The shower tray has an independent disposal output through a flexible hose system for garden-watering in dry regions. Guttering can be added to the back of the roof (the gal iron overhangs 15mm) and so rain can be harvested. Solar panels can also be carried on the roof.
The ceiling and the main room walls are universally 2.1 m high (standard ply size -- no roof slope). They are lined for a distance of only 2.4 m in the main area, while the last two studs serve as locking points for the Water Closet and water tank. The ceiling liner of the roof panel will require both a 2.4 x 1.8 m length of normal 3mm ply, and an extra 1.2 x 1.8 m part-sheet of the more expensive water-proof ply. The rest of this sheet will be used for the back of the Divider Cupboard since it is adjacent to the shower.
The timber frame structure depends on pre-cut lengths of rough-cut pine (70x30mm in 2.1 m lengths for studs, and also some from 30x30mm) The butt joints are all double-screwed rather than nailed (for strength during transport), and the rooms are lined with uncut standard sizes of 3mm cheap plywood which is glued to the frames to provide flexible but strong diagonal strength to all panels. The floors (Main and Raised) use 8mm or 10mm formwork ply (water tolerant), and the shelving would generally be 200x15mm dressed pine in various lengths which is also used to make the Water Closet.
Inside fittings all hinge onto wall-studs which add longitudinal strength to the walls (among other advantages). Hinged fittings are often also supported by wall battens which can be glued and screwed to the panel liner ply. The main shelving on both of the side panels is an important component of structural strength; when it is folded up for transport it also protects the lining ply and electrical-fittings from damage.
The roofing material is probably standard CustomOrb galvanised corrugated iron in 3.9 m lengths (to allow a 30 cm front overhang), and the outside wall coverings would be fairly standard iron or aluminium cladding screwed to the top and bottom plates, and perhaps pop-rivetted half-way along the overlap. We have not used noggins since the height of the wall probably doesn't justify the cost, weight and sawing accuracy problems.
Floors: The Main Room is 1.8 m wide and the open-space length is 2.7 m. The room ends with a 200mm wide Divider Cupboard and Step-Box which divide it from the 0.7 m wide Raised Floor area with shower and toilet. The Divider Cupboard has shelving for kitchenware and food-stuffs and it sits on the lower floor with a 100mm air-gap between its top and the ceiling. The cupboard is stabilised by two fold-out curtain rods which span from the top of the unit to the back wall, and one of these can be used as a hanger/drier over the shower-tray and the other for a conventional shower curtain.
Note that the Main Room floor panel (1.8 x 3.0) is shorter by 0.6m than the H4H on the whole. Utility access and the sewerage system occupy the last 0.6- 0.7 m of overall unit space. The floor frames are made from the standard 70x30 sawn pine (with white-ant protective spray beneath), and all walking surface are water resistant thick plywood (8-10mm) with some special water-proof treatment where required.
The shower-tray floor is raise 0.3 m above the main floor area to create an under-space for the utilities and sewerage pipes. The tray itself would be just well-lacquered ply with a raised surround and a strengthening ridge across under the curtain end. This 0.3 m of under-floor space provides enough flow-height to handle about six units in a row. And since the Shower-tray and Dry Floor area are separate ply pieces, all utility runs and sewerage fittings can be connected from the inside during erection and floors added last. This is also true of the roof lock-downs and back-wall assembly ... everything can be done from the inside (necessary to fit into some tight locations).
Utilities: The intention was definitely to avoid the use of gas-bottle cookers. So a double-plate hot-plate would be supplied to also heat water in the tank for a hot shower and occasionally for winter warmth. A standard builder's extension cable and safety-switch terminates the incoming electrical feed in the Box-Step. This safety-switch unit allows a 3-pin plug and cable link to each side-wall. These cables carry current to a double-power point and embedded light socket high in the walls (protected during transport by the hinged shelving). The Step-Box is actually a hinged, lidded box, 15 mm high, which also stores spare light bulbs, electrical multiple sockets, feed cables, a first-aid kit, plate, knife, fork and spoon, and miscellaneous hardware and useful op-shop items.
Insulation: The Table- and Bed-side cavity-walls are 70mm thick and lined for 2.4 m of their length. They will use glass-wool insulation, as will the ceiling panel. The unlined, uninsulated back portion of the side walls provides fixing space for the Water Closet and hot-water tank on the bed side, and relies of clothes storage and curtains on the table side. Front and back cavity walls are only 30-35mm thick, and since these are potentially wet areas (shower and rain) they are insulated with reclaimed Coolite foam from fruit boxes.
Front door: The front door would need to be strong, and possibly the only component which is purchased ready-made (although if possible it could be made better and cheaper, using a router and/or bench saw). The door would have two vertical frosted-perspex window-lites (the only windows in the unit). Note that adding a full-window to the front panel would compromise the diagonal strength of the unit, and larger sheets of perspex or glass would probably break in transit. The door would also require a conventional Yale-key lock and possibly also a sliding bolt; security is important to women residents and others who are fearful when forced by circumstances into house-groups of this kind.
Bed: The bed is a cut 2.0 x 0.9 piece of heavy ply which is hinged to the side wall as well as resting on battens attached to the front and side walls. The bed is also used as a seat, and it rests on a 0.5 m high, L-shaped (hinged ply) supporting 'plinth' under the other two sides; this also forms two sides of the under-bed bulk storage space.
The shelf above the bed (not shown in Layout diagram) could also support a small child's bunk bed or baby's cradle. It would need a substantial screw-eye and chain fitting to also hang it from the ceiling.
Table: The ply table (1.4 x 0.6 m) is set at a height of 0.7 m, and is hinged to a longitudinal lower shelf -- which is itself hinged to the wall studs. During erection, this lower shelf will be locked firmly down, while the table is suspended by chains extending back to wall studs. To create space, anything on the table can be pushed back onto the shelf behind, and the table raised to rest back against the wall.
Water Closet: This is a seperate component which requires a modicum of carpentry or joinery expertise and the use of saws. It should be made by the local Men's Shed or by the more experienced supervisors. It is probably best mass-produced off-site.
If demountable housing of this kind is to be stacked, stored and transported by being thrown onto the back of a truck it can't afford to use porcelain toilet fittings. This timber-only fold-out design (with a disposable plastic liner) is a good substitute. It can be easily cleaned, unclogged, connected to a sewerage system, and maintained by replacing the liner when the home has new residents.
In use, the toilet tray is tipped vertically, and then flushed by water from a plastic tip-up wash-basin positioned directly above. Conventional U-bends and other sewerage pipe fittings are used throughout.
Hot water tank: A hot water shower is probably not essential, but it certainly is desirable in cold weather. We have experimented with different ways of heating water without buying expensive ready-made units, but we are not convinced we have a solution. Some commercial units also draw excessive electric current, and this could potentially be a problem with six home units running from a single source.
The best appears to be to use the hot-plate under a metal tank, but the tank needs to hold about 40-50 litres (which weighs 40 to 50 kilograms). A comfortable warm shower consumes a litre every 7-8 seconds. [See the discussion section on the water system.]
See the different explanations for each panel and component.