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.
H4H Fabrication Details
Bed-side shelving and fit-out
[Low Skill Level]
AssumptionsThe main frame has been constructed and you have added (and glued) a batten behind Stud 1 to increase its width for good ply attachment. Also just to help as a guide, drive a short protruding nail into the front-end of the bottom plate, exactly 10mm back. This aligns with the gal angle which is used full-width under the Front Panel, and ensures that side and front panels overhang by the required 10mm distance.
A screw through this inflection 'tab' will hold the side wall up temporarily while erecting the cabin's sides and back panel.
The junction of the Bed-side panel and the Front panel has a problem because the bed needs fairly strong supports against the wall, and also because of the lack of substantial attachment area for the ply liner in this corner. A length of scrap batten timber be nailed and glued to the inside of Stud 1 before the ply liner is added to provide extra attachment points, especially for the bed support batten.
The bed plank (2000 x 900mm) sits on these wall battens, and also on an L-shaped double-fold vertical support which completes the under-bed storage box. The wall support battens (25x15) are at 465mm (450+15mm floor thickness), and the L-shaped double-fold ply box walls are 450mm since they sit on the floor. This bed-plank surface hinges the thickness of the bed-plank above this onto Studs 1 to 5.
This is higher than normal for a bed, but ideal when used as a seat with a cushion/mattress. Getting this height right is important. The L-shaped double-fold supports carry the front weight of people sitting on the bed and, and are hinged to vertical battens on both front and side wall. These components are strengtheners when extended, and also protective elements when the disassembled panels are bing carried.
The bed supports and hinging battens are visible, so it is recommended that they be, say, 40 x 15mm dressed timber. You will need two horizontal battens which are best extended across the distance to the door-frame on the front panel (each 1 metre), and a longitudinal batten under the 2 metre length of the bed. While you are cutting these timbers, make two short wall-hinging battens (remember the 10mm of floor, and the width of the longitudinal battens). The thickness of these is important, because they need to allow the supports to fold back against the wall (which already has a batten).
The L-shaped Bed Support is made from 8-9mm ply with some vertical strengtheners/attachments The important dimension is that the two L-panels stand 450mm above the floor surface (so allow for the floor thickness). See separate details of the L-shaped supports in the Miscellaneous section.
The shorter (450x800/850 mm) of the two is hinged onto the Bed-side Wall panel ... but not directly. It should hinge onto a batten added to Stud 4, so that the batten raises the hinges away from the interior liner ply, and allow the support to fold flat against the wall for transport (directly under the hinged bed). It doesn't reach out the full distance (the bed is 900mm wide), but provides support where it is needed most.
The longer support panel (450 x 1800mm) is double-hinged. It is hinged first to a vertical batten attached to the front wall. This may appear to be unnecessarily complicated, but it provides protection and rigidity to the front wall with its door-way and door fittings during transport. [Note: This fixing point on the front wall should only be put in place after all other dimensions are fixed.]
Both the Bed itself, and the support system we recommended in Version 2 were originally very cumbersome during transit and they added little to the structural strength of the unit. The approach taken here is much stronger, and it can use cheaper materials.
During transport, both L-shaped panels locked down with a couple of long screws against their respective walls until the unit is re-erected. The bed tray itself is screwed back against the wall to protect the ply liner. See the details of the L-shaped double-fold component in Miscellaneous/L-shaped Support.
This can be 860mm in length (limited by the need to fold-up on the wall alongside the bed), and its ideal width is 300mm. It's main hinges will be on Studs 5 and 6 (but another hinge could be attached to the bed end, using toggle bolts into the ply liner). The unlined gap between Studs 5 and 6 is primarily to provide for a water-tank and its carrying frame. The gap between Studs 5 and 6 of about 400mm below the kitchen bench has the only noggin in the design, which provides attachment for the ply-liner piece under the bench (helps with strength, mainly)
This bench extends from the hinges on the wall, to the side of the Water Closet (supported on a batten), and then rests on a batten added to the Divider Cupboard. It provides a good way of locking together these units with just a single screw into each batten.
The other important additional component which the side-panel supports when erected is the Water Closet. It is a complete unit in itself, and it sits on the Raised Floor-support plate at the back (with no flooring beneath it). The absence of a floor allows for the U-bend, and easy additions of sewerage pipes angled in every direction. During erection it will be held in place by two pairs of screws, stop and bottom, into Studs 6 and 7 from within the WC unit itself.
The WC unit should be exactly 700mm in width and we allow another 5-8mm or so between Studs 6 and 7 for the angle-iron joiner. You should check that Stud 6 has been positioned to allow this 705mm to 708mm gap. At this stage it is easy to adjust its position.
The Bed-side frame carries only one long 200mm-wide hinged shelf.
The Upper Shelf: While this is just a normal shelf made from 200x15 dressed pine. It could be at any height above the bed but we suggest the hinged top-height should be at 1525mm from the frame base simply to match the Table-side panel and it should be hinged to every stud because it provides wall stiffness as well as carrying weight. A secondary use for this shelf is as support for a cradle, or possibly even a small child's bunk bed, with a couple of light chains hanging from the rafters.
For this reason the upper-shelf needs a supporting batten across the front panel, and this would be about 1 metre long between the corner and the door-frame. It would match the one supporting the bed.
We also suggest drilling a couple of holes along the front of this shelving above the bed [See Note on Bunk-Bed below] for no apparent immediate use. However these could prove useful later for hooks, hinges, and other fixings which are added to secure an above-bed bunk/cradle for children.
These cabins are probably too small for children, except for disasters and other emergency use. However we suggest that simple provision should be made for the possibilities of babies in cradles and possibly one or two young children needing small bunk beds ... mainly because it is relatively easy to adapt the table as a bunk-bed, to be hung either over the main bed, or above the back Dry Raised Floor area. To provide for these events we only need to drill a few extra holes in the shelving, walls and ceiling.
In normal use, the table's strap hinges are best locked to its ply and the lower shelf by short gutter-bolts rather than wood screws.
After you have finished and check-assembled the cabin, you should temporarily remove the table and its hinges, and use it create the appropriate drill holes for the hinges in the high shelving above the bed and in the Dry raised floor area.
The bed can be used in these locations either sitting on the shelves (where it will be only 600mm wide) or hinged to the shelves (where it will be 800mm wide). It gives enough bed space with these dimensions for two small children.
The high-shelving was set at a height of 1550 in order to give the necessary clearance below the ceilings to all the hinged 'bunk' to fold up out of the way during the day.
You should also drill holes into the rafters (and the battens) for chain-suspension hooks at distances away from the side walls at, say, the 500mm and 700mm so the chain angles back towards the wall. You should also drill a couple of holes in the walls on either side to allow some sort of safety net to surround the bunk and its chains.
Check on main dimensions
The electrics are entirely in both side walls, with nothing in the roof frame. Both electrical wall systems are the same, the only difference being the lengths of the feed cables which run back (just in front of the floor-inflection) to the Step-Box which contains the safety drop-out switch and builder's cable reel.
Plastic soup-bowls are an ideal reflector for embedding in the wall. Add a batten-holder light-socket and you've got a first-class light fitting. Drill the cable hole into the side of the bowl (not the back) so there are no cables up against the outside wall cladding, and fix the batten-holder to the bowl with a couple of self-tapper screws
We embed a single light fitting into each side wall just below the high shelf at Stud 5. It will be controlled by a seperate switch, which can be either a normal embedded wall switch, of better, by a double-power point with the extra light-switch included. These three-switch, two socket, components are now readily available for little extra cost.
The soup bowl will need to fit neatly into the ply, at nearly full-depth (however it is protected during transport by the thickness of the fold-down shelving). Put the bowl face down on a piece of cardboard and mark around, then cut the shape out inside your line. This can be transferred to the wall ply, just overlapping onto Stud 5 enough to make you sculpt out a bit of the stud to handle the curved shape. On the opposite side you only have ply, but you can glue on a short batten to provide a grip point for the fitting.
The power-point should be fitted into the wall liner directly below and alongside Stud 5 so one screw in the face-plate has a good purchase on the Stud itself. Ideally, this plug should be at least 150mm above any bench-top (some power chargers need this space). As with the soup-bowl, the other side of the power-point will need a short batten glued to the back of the ply.
Use the flexible type of three-wire cable (rather than the electrician's normal stiff in-wall cable) to connect everything, and simply cut out the green earth wire when you don't need it (to the light fitting). From the power point, the cable will drop down and pass through drill holes made in the centres of Studs 5 and 6, where it can emerge through the small add-on ply panel here. The original intention was to make this a small screw-on door to store the cable during transport but this is probably over-kill of a minor problem.
From the bed-side wall, the cable will run across the inflection, behind the Divider Cupboard and into the Step-Box and terminate in a normal 3-pin plug. Don't be tempted to use a cheap piggy-back plug here; you want a solidly-made, well-insulated plug which can grip the individual wires at the point of contact.
Always make the earth (green) connection first. In a standard 3-pin socket this is always the vertical one. A batten holder light-fitting doesn't need an earth, but they often supply with one just to provide an extra tether for the cable. If it doesn't have an earth point then just cut the green wire cleanly to keep it away from the other two.
The three wires in a cable and fitting are the Black "neutral" and the Red "active" ... but don't be fooled by these names!. The black wires in your walls can also be carrying 240 volts when used as a "switch wire".
You will probably notice that the earth contact point in a plug is larger and the hole deeper in the fitting than the others; and this is for a good reason. It is the most important of the three to be maintained if the cable gets partly damaged or ripped out for some reason.
Look at the depth of the hole into which you will insert the copper; then bare the wire by removing the insulation for DOUBLE this length. You do this by just 'nicking' the plastic sheathing with a sharp knife, then just physically moving and stretching the insulation until it breaks by itself. This way you don't get left with stray strands of half-cut copper.
You should now twist the copper strands to tighten them, the double-back the copper by folding it in half; this doubled the thickness and doubles the electrical contact between cable and plug. When you screw the copper into the fitting (do this 'firm', but not so tight you cut into the strands) this larger bundle of metal-to-metal contact also hold the wires tightly. Don't be tempted to leave the end of the insulation in the screw-down; it just creates a greater likelihood that the contact will weaken over time.
Treat the red and black wires the same way, and connect them to the two angled-prongs/sockets. In some plugs you need to wrap the copper around a screw and just tighten the screw down on the copper wire. Make sure you cut off any loose ends of copper.
Always test electric connections. You can buy a range of cheap to very expensive testing devices, most of which are unnecessary. There is a very cheap and small earth-leak indicator that tells you whether a wire is active or not, and allows you to test that switches are working, and that they are attached to the right wires.
The exterior height of these panels is 2140mm and they sit over the top of the floor panel frame which has a height of 70mm. The cladding needs to start at the top of the top plate and hang down with a projection of, say, 10mm over the bottom. That makes the cladding lengths 2150mm - and these can usually be ordered precut. Anything longer and it will get too easily bent during transport.
Lay the frame on the flat, and start at the front and work backwards laying the sheets out with minimum overlap to see what excess or short-fall you may have in coverage length. In most cases, if you have a short-fall, you can either used a half-sheet, or a length of roof flashing to make up the distance. Most iron cladding is relatively easy to cut lengthwise using a special disk on an electric handsaw.
It will depend on the profile of the cladding you have chosen (use the lightest weight for greatest coverage you can get). With a tin-snip, most men will have no problem cutting sections out for the raised floor, but it is best to leave as much as possible and let the assemblers cut out anything necessary for the sewerage pipes.
Use short (25mm) flat-head galvanised screws to attach cladding to the frame top and bottom. Start at the front (with the possibility of having enough to bend around and cover the corner. Work from the top, and backwards.
Since we don't have any central noggins to hold the sheets together around the mid-point, you should
It is difficult to advise the treatment of the cladding over the raised floor area at the back of the unit, but the rule of keeping it "as long as you can ... for as long as you can" is a good guide. Obviously the sewerage pipe fitting will need to enter and exit in the last half-metre of the raised area, so there's little point in covering this.