"Homes-for-the-Homeless ‐ built by the homeless"
A design for small, low-cost demountable homes with full facilities (cooking, washing, shower and toilet).


•   Original Concept
•   Basic Layout
•   Prelim. + Planning

Main Panels
•   Floor Panel
•   Side frames
•   Bed-side fit-out
•   Table-side fit-out
•   Roof details
•   Front Panel
    • L Bed-support
•   Back Panel

•   Water Closet/toilet
•   Divider Cupboard
•   Hot-Water tank
•   Electrical/safety

•   Erection sequence

•   Major variations
•   Materials



© Plateau Group


This H4H design is available to any volunteer groups for non-commercial use, but please make a formal request.

H4H Fabrication Details

[Lowest Skill Level]

  Note: The dimensions detailed given below are down to the millimetre, but the required accuracy is only within 3-4mms.
  However, have the timber cut as accurately as possible.We have calculated on the basis of sawn timber which is 70x30mm, but 70x35mm makes no difference

Floor Panel


  1. The floor panel uses 30x70 frame timbers on edge. The panel consists of a flat floor area of roughly 3.0 x 1.8 metres, with a hinged inflection panel of 1.8 x 290mm at the back end. This inflection becomes the support for the raised floor, and also provides part of the room end.

  2. The main floor length is 3 metres which is shorter than the overall unit by about 600mm. This leaves bare earth behind the inflection panel. Two raised floor panels (with shower-tray) sit above this so this utility cavity can accommodate the toilet-sewerage and shower-disposal pipe system. This two-level design creates a space of 370mm (300mm + floor panel thickness) in height and 600mm in front-back width, which is sufficient to run a chain of sewerage pipes with enough drop-angle to handle the flow of, say, six or more H4H cabins side-by-side.

  3. All frames are butt-joined with two 60mm countersunk screws in each. We use screws at all frame junctions so that they can be tightened if the timber shrinks. Demountable panels get flexed during transport, and the ply may loosen off unless also glued.

    • Note that the two end timbers are wider by 50mm on each side than the main longitudinal timber frame. This leaves an extra 50mm of support both sides, at the front and back, which provide stability to the box unit added above (consisting of the side, front and back panels).
    • We have added a couple of offcuts of the heavy frame timber to the floor frame sides at about the mid-point along the length. This is a way of providing extra stability to the side frames. This not critical by any means.
    • Use heavy duty 12mm structural or form-work ply -- or the cheapest you can find in the 12-15mm range that is tolerant of occasions water spills.

Ply sizes aren't always available, and costs vary extraordinarily. Generally these days, any real plywood (as distinct from core-board, etc.) is relatively water tolerant, and therefore usable in every part of the house other than the Water Closet and Divider Cupboard backing where we strongly recommend the use of the more expensive Marine Ply. The main component of ply costs, therefore is the quality of the surface finish, and in this application this is a secondary consideration.

The standards for ply quality include the selection of resins used to glue the veneers together. The Marine Ply comes from America so it is in an Imperial (rather than Metric) standard, usually of 2440x1220) The veneer surface quality has a two-alpha designation. AA is premium quality: BC has one surface (B) with good continuity and the other (C) not so good; CDis often called "Structural" because while the ply is just as strong, neither surface is without blemishes. (The minor gaps in the veneer will be filled and sanded, but acceptable if you paint over them.

On the Internet you will find a totally confusing range of plywood sizes advertised. This is because the importers are anxious to bring in cheap ply by the container load from anywhere in the world, but this doesn't mean that the sizes you choose will necessarily be available when you go to buy.

Our experience is that the only size consistently available is the 1200x2400 standard for lining and structural ply and 2440x1220 for Marine Ply.

Ply thicknesses and the number of veneer layers are also highly variable. 3mm "three-ply" is OK for the ceilings, but 4mm would be better for wall linings. The 15mm five ply is strong and rigid enough for floors, beds and tables.

  • Ply cutting plans: The material cutting plans included here are all based on the 1200x2400 and 1220x2440 (Marine) standards, and there is very little wastage. You may find larger sheets. These cutting plans do leave some gaps in the floor (mainly under the bed). So once you have the main Floor Frame assembled, turn it over and glue battens on the underside of the joints to stop air-gaps and unwanted animal intrusions.

  • Ply over-lap: The dimensions allow 10mm of over-reach (front and both sides) ... by which we mean there is at least 10mm of contact between the front and side frame timbers and the plywood floor sheet. The front positioning of the floor ply is important (leaving 20mm of frame uncovered), but the back doesn't matter much. This 10mm of overlap allows glue-nailing the ply edges, and still leaves 20mm of the timber-width to carry the vertical frames. This is basically to save timber costs, while also sealing the edges of the home from air-gaps as much as possible.

  • The construction of the floor panel is the only component where we recommend using nails. These would be "jolts" of about 50 or 60mm in length. You can glue the contact areas along these edges, then drill (2mm) holes in at an angle and drive the jolts towards the centre of the side timbers. Jolt heads should be driven below the surface, but don't crush or crack the ply edge. [We recommend drilling for novice builders. But the nail-guns in the hands of someone with experience, are probably OK.]
  • We suggest that treated pine is used structurally and that the floor-panel should be painted underneath with some white-ant protection solution if it is to be used outdoors.

Inflection Panel

This is a fold-up panel (1800x285) of 15mm ply which is hinged just forward of the back edge of the floor. When erected it sits on the floor-panel, not on the frame.

This carries the weight of the Shower-tray and Raised Dry Area floor. These raise floor panels are the last to be added during the erection, and both have ribs added to their underside which fit both sides of the Inflection and lock it in place.

The inflection panel also has two side 'tabs' which lock behind the vertical 'Inflection Attachment' timbers in what is otherwise the Utilities underfloor cavity.

Frame Dimensions:

As with all of the main frames, the dimensions have been carefully chosen to make maximum use of standard timber sizes. The ply is significantly expensive, so we have aimed for a design which utilises the full uncut sheets of ply whenever possible. Offcuts of the framing timber can generally be used for battens, and offcuts of the ply are also useful.

  • Length:The outside length of the floor frame is 3060mm [Sum of 3.0 m (timber lengths) + 60mm (two timber widths of 30mm)]
  • Width: The end cross timbers of the frame are 1940mm in length [Sum of ply width of 1.8m (less two x 10mm of overhang) + 60mm (for side timber widths) + 50mm (for projections each side).
    [CHECK THAT THE PLY OVERHANGS EACH SIDE BY 10mm for glue-nailing]
  • Both of these outside longitudinal timbers should be inset by 50mm, to create a main frame width of 1840. The other two longitudinal frame timbers are spaced between, roughly on 603mm centres.
  • The ply will now over-reach the frame timbers 10mm on both sides and the front so it can be glued and nailed in place.
  • It may be wise to add some off-cuts half-way along the outsides of floor frame to provide extended supports.

Frame Widths:

  • Between longitudinals = 1780mm
  • Outside 1820mm (giving plywood edge support of 10mm each side).
  • Front and Back Cross timbers extend a further 50mm on each side.
  • Front of frame to ply edge 20mm.
    [Note: When assembled, both the Side Wall panel and the Front Wall panel sit on the floor's frame, not on the floor ply.]

    Floor Ply Dimensions:

      Ideally, the 15mm plywood floor (3.0x1.8) would be cut from a formwork ply sheet of 1.8 x 3.3 m. It would then have been cut to create the main floor length of 3015mm with a cut-off inflection of 285mm.

      Ply of these dimensions is not easily found in Australia so we propose making the floor up from three sections cut from two 1200x2400 ply sheets, with the inflection cut from another panel.

      The ply gauge used for the floor could be the lighter 12mm thickness, but we tend to think it will feel flexible and therefore insecure.

      The inflection will be hinged upwards at a point close to 3000mm along the floor length. This is a ply-thickness distance from the end of the main floor ply.

      → The back of the erect inflection should be at the 3m point (not absolutely critical)
      → It should be 600mm from the back of the whole unit.
      → It should align with both side-wall Inflection Attachments. (The short timbers intruding into the under-floor cavity.)

    • The inflections supports the raised floor, so any weight must be carried onto the floor ply itself, not onto the frame. If air entry is a problem here, you may need to add a batten behind the inflection [See note later].
        The inflections should be able to hinge forwards, but not back past the vertical. In use it is stopped from moving forwards by tab-battens added behind the inflection (which also closes the side air-gap). These come up against the Side-wall Inflection Attachments (perhaps screwed to them). There are also ribs attached under the raised flooring, both in front and behind the inflection.
    • The inflection height above the frame is now 285mm + 15mm ply thickness = 300. This height is needed to align with the other raised floor supports.
    • The Stub Legs which carry the Bottom Bearer of the Back Wall panel will now align with the top of the inflection.

    CHECK - The distance of the raised inflection from the end of the whole unit is about 600mm, while the raised floor is 700mm wide. This means that the raised floor will have an 100mm overhand forward of the inflection support. This is deliberate.


    1. Construct the frame as illustrated using the 30x70 timbers on the vertical. All joints are simple butt joints, joined together by two countersunk 60mm screws at each junction. We do not glue butt joints between framing timbers.
    2. Glue and nail the main floor ply to the frame, using the 10mm over-reach on front and both sides. (The back can be flexible.)
    3. Hinge the inflection panel as far back as possible (while still on the floor surface), ensuring that it can only fold forward. Use four small double-sided gate hinges. Using short (20mm) gutter bolts to attach the hinges to the inflection panel is better, but screws should be OK..
    4. Glue-nail a couple of 70x30mm offcuts to the sides of the floor frame for increased stability and to add further support for the Side Wall panels.

    Finishing off:

    Inflection air gap The inflection will introduce air-gaps above and below the 285 height, and since these are at foot level, these may be an annoyance in cold climates. The bottom gap should be easily fixed by adding a batten to the end of the frame directly behind the hinged inflection. The top gap is not likely to produce an air-gap problem if the two raised-floor sections (the shower-tray and the dry-area floor) are given ribs (for both strength and position stability) on either side of the inflection.

    Electrical feed notch:We need to bring the electrical feed into the unit in some safe way, and the way the electrical system is handled will be of key importance in gaining any local council approvals of these cabins. The main incoming electrical feed is via a standard off-the-shelf builder's extension cable with an earth-leak safety protection switch. The incoming cable goes initially to the Step-box box which becomes the distribution point.

    Therefore cut a small (but deep notch = 8mm wide x 20mm deep) into the top of the inflection at the mid-point, so that the incoming cable enters the unit at a point which is high off the ground, directly under the raised floor, and behind the Divider Cupboard (rather than the Step-box itself).

    We have positioned this cut behind the Divider Cupboard not behind the Step-box because a cable entering directly behind the step point it is likely to be easily kicked or displaced. The depth of the cut is to allow for the supporting/positioning battens on the underside of the shower-tray and dry floor area.

    Also, we suggest that you:
      • drill a small hole through the inflection directly under the cable-entry notch, and thread through a piece of quality string and tie it firmly into the notch.
      • The dangling ends of this string are now available to tie down the incoming electrical cable during the erection phase.

    This seemingly trivial detail is important: We are concerned that the cable could be accidentally jammed between the inflection and the raised floor/shower-tray timbers. The erectors won't necessarily think to protect the cable if the string tie-down isn't already in place and ready to be used. This is the way accidents happen.

    Erection on site:

    The floor is obviously the first panel to be set in place at the site, and it establishes the potential amount of roof rain flow-off when setting up outdoors. Since there is no inherent slope in the roof itself, you need to get this angle right, especially where torrential rain can be expected. Don't bother with spirit levels: the best judgement of the slope angle will be a flat (baking?) tray of about 30 cms with a cup-full of water, or a length of transparent PVC tubing with both ends blocked. This will show you clearly how well your choice of slope will perform.

    If you are erecting the home outdoors, you should drive steel star-pickets deeply into the ground at all four corners, and perhaps also across the back and sides between the corners, before you add the other panels. Lock the floor down with wire (and later with some flat metal straps. Later after the side panels have been assembled you should also lock down their back corners near the Stub Legs. Fencing wire is a good material for tie-down.

    Materials needed:

    • Sheet of thick ply (possibly formwork) water-tolerant - 3.6 x 1.8 m (8-10mm thick)
    • 4 lengths 70x30 at 3 metres
    • 2 lengths of 1.94 m (from 2.1)
    • 1 length of 75x15 cross inflection timber 1.9m
    • 4 small gate hinges