Add short lengths of timber behind the inflection and protruding into the gap to seal the air-gap, and to stop the inflection from falling forward.
A screw through this inflection 'tab' will hold the side wall up temporarily while erecting the cabin's sides and back panel.
Table and Lower Shelf:
These dimension assume that both of the shelves fixed to this Table-side panel of the unit and also the vertical fold-out Table/shelf support, will be made from 200x15 dressed pine.
The Table (1.2 x 0.6m) will be made from 9mm or 10mm ply, and it is hinged onto the lower of the two shelves.
The 600mm width allows the table to span across to the bed which will normally be used as the seat. The bed-plank's surface height is 450, and tables need to be higher by 200-250mm than the seat for comfort. This calculation puts the top of the Table, and therefore the lower shelf (and therefore the height position of the shelf hinges) at 700mm above the frame base.
A simple but potentially useful detail, is to attach the table hinges to both the shelf and the table itself with short gutter-bolts rather than screws. This allows the table to be quickly removed in disaster scenarios, and be used as a bunk-bed (see Roof).
The lower shelf is supported at the end next to the door by a batten on the side of the Vertical Shelf Support. In use, it will probably be held firmly in place by a screw into the batten. The Table itself needs to have some direct support via chains to points high on Studs 3 and 4, and angled down to about the mid-point of the Table/Shelf. This point would be about 400mm from the wall so the chain angle will be close to 45 degrees. The chain might be a problem when the unit is folded for transport, however it depends on the chain (or perhaps a stainless steel cable).
Also note that when the shelves and table are folded back against the wall for storage or transport, they will require free height space up of (600+200 = 800mm) before they run close to the space needed by the upper shelf. To allow a little for timber-size variations, we have therefore placed the upper shelf hinges at a height of 1560mm to match the other side's high shelf. This calculation then sets the length of the Vertical fold-out support timber at 1530mm (1560-30mm -- allowing for floor and shelf thickness). The upper shelf will rest on top of this vertical support, while the lower shelf (which supports the table) will need a supporting batten across the timber at a top-height of 700 mm.
The vertical support can only hinge on Stud 2 so the door will swing back against it. However the triangular space behind the door will be very useful for overcoat and long-clothes hanging. You should drill a number of 2mm holes along both the straight and the angle-cut edge . While you are doing this, put a few extra holes along both edges of the High-shelf (say 20mm back from edges and at 200mm spacings) for occupants to add cup-hooks, etc. to hold cables, antenna, clothes hangers, etc.
Strap hinge are used for joinery and construction. The measured sizes are from the "centre of the knuckle (the pivot) to the tip". They range in size from 75mm up to 150mm and in thickness from 1.5mm to 2.5mm. There is nothing in the design that requires the larger sizes, so buy 75mm in bulk.
This longitudinal shelf is a major strengthener of the whole unit, as well as serving as a weight carrier for hanging overcoats, and even supporting one side of a bunk-bed. It needs to be sturdy.
The total shelf length is 3.6m less the thickness of the back panel walls (about 35 to 38mm) and the Door Jamb (which is 70x30, intruding into the space by about 45mm. So cut the timber length to 3515mm.
The shelf then needs the diagonal cut for the front door opening. Mark a diagonal cut line starting from 25mm across at the narrowest on the front-edge and ending 600mm along one side (the point where it will be carried by the fold-out support).
This shelf will likely carry weight because it is the only long-space for coat hanging behind the door. It needs a horizontal glued batten behind the ply, so that support can be provided for attaching hangers. This batten should be wider than normal (say 100mm) and the top should be at 1580 mm from the bottom of the frame.
The narrow 25mm end to the shelf will be supported by just a protruding screw or a short vertical batten behind the front-panel's door-jam.
Some finishing touches: We will need some hangers in the diagonal space under this shelf. Along the diagonal cut line, about 15mm back from the edge, drill a half-dozen 3mm holes about 100mm apart. Screw eyes can be added later, or the holes just left for wire clothes hanger hooks. You may drill a few other holes parallel to the back of the shelf about half-way in which can be used for a hanging rod at a later date.
While you are drilling 3mm holes, perhaps add a couple of holes over the table area and further towards the back, for hanging cables and chargers, etc. say every 20 or 30 cms.
At the back end of this shelf, starting say 20cms in from the end, drill some larger 4mm holes through the full thickness (about 10cm apart - 15mm in from the edges) for hanger hooks. These should run a metre along both back and front edge, and can be used for hanging wire office-paper baskets for small items like socks, etc.
Also along the front edge at this back shelf end, drill and screw in (but leave with a slight projection) three small wood-screws on which to hook the spring-type curtain 'rod'. (say, at distances of 50, 350, and 700mm from the end). A light-weight curtain would not just be for aesthetics, it would help control temperature as well as neatness.
The area behind the opened front door and below the high shelf is useful as clothes hanging space. But this area needs some battens behind the ply to provide support for hanging clothes here.
There are two useful hanging devices:
- you could just add a couple of Screw-Eye bolts under the fold-down shelf (maybe with a length of dowelling between)
- for shirts and light clothing, drill small holes through the ply into battens for screw-eyes, or for S-shaped hooks (Hardware store items).
- You might also consider a length of batten with a line of screw-hooks, etc. which is then glued to the ply.
[Note: Eyebolts and Hook-screws come at different sizes and thicknesses.They are also available either with nuts or with wood-screw threads and in lengths up to about 150mms.]
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
- put a mid-point screw where-ever you can into every stud: (remembering that the centres of the studs (starting from the front) are 600mm apart.)
- Generally overlap successive =sheets to stop wind and weather entering from the front (ie."under-lap" each sheet as you work back),
- put a pop-rivet through every overlapped joint at, say, one-third up from the bottom and one-third down from the top. Because they are demountable, the cladding is more likely than normal to distort and leave gaps.
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.
- Construct the frame to specifications, using screws to hold together the butt joints. (Nails will loosen during transport and with wood shrinkage.)
- Lay the main wall ply piece on the frame and make sure you have 10mm of overlap to fix the liner to the frame (mark with a pencil).
- Tack and glue on the ply liner.
- You will now find it easier to stand the panel against a wall so as to get behind.
- Cut out the holes for the electrical fittings, add them, and do the safety checks. Remember to check that the feed cable is passing through the drill hole in the bottom of Stud 5 and 6.
- Complete the hinged shelf and table fittings and add any supporting battens. Also the hook points for the table chains.
- If you are going to put cross-X straps over the unlined back portion, this is the time to screw them on to the back raised area from the bottom and top of Stud 5 to the bottom and top of Stud 7.
- Now add the insulation into the lined wall cavity.
- Move on to the stage of adding the outside cladding.