PLYWOOD CUT PATTENS
Reminders for the supervisors on the day
TOOLS AND SPARES
Volunteers will turn up with electric drills + chuck keys + multiple power points and extension cables that they will want to take home. You need some way of labelling these at time of arrival, or for certain they will be left behind and give you more problems than they are worth. Have some masking tape and a permanent marker and insist that all cables, tools etc. have some identifier.
Chuck keys are a special problem because they often break out of their holders. Best is to have a length of coat-hanger wire, cutters and large pliers. Wrap the wire a couple of times around the shaft of the chuck-key (leaving it loose), then cut the wire 70mm up. This can now wrap tightly around the cable about 50 cm down and so always remain attached.
Don't be afraid to ask someone to go to the shops, or to turn up with biscuits or a cake. These are volunteers and they like to be useful, so recognise this.
Do you know where the nearest toilets are?
Do you know where the nearest doctor is?
Need a large wheelie rubbish bin, because of offcuts etc.
There will undoubtedly be some jobs that do call on higher levels of skill or strength, so we will also need the supervisor to have access to such items as:
- Tin cutters
- Possibly a small vice.
You do need to have a reasonable First Aid kit.
Fill some old milk bottles with fresh water. Maybe even some cordial. and have some paper cups.
Coffee and electric kettle
Supervisors Check List
Create a record number
This should be written with a permanent Pentel on some normally-concealed area of each panel or frame so that problems can be traced back, and components of each unit remain together. Especially in the early stages we can't guarantee that all standards will be exactly the same.
You need a booklet with this record number prominently on the cover.
It should be a three Alpha code (choose something appropriate for the group) + a three Digit code beginning with 001. [ie JTK003]
Keep a record yourself.
Record participation in each workshop
Have a booklet on hand to do this: it will stay with the cabin when it is complete as a record of involvement, changes, applications, etc.
You should record the name, contact details and address of anyone who helped build each cabin. Start with your own Supervisors details.
Record any accidents.
Record any notable measurement or calculation discrepancies
General supervisor advice
Presumably you will
• Construct the floor panel first
• Use this as a bench-top surface to construct the two side frames.
• These should be taken to the point of having lining panels for each Side Frame.
• The two side panels need to then be checked against each other, and also checked for squareness.
• Next work on the back wall.
• Now make the roof (this requires the use of an electric circular saw)
• Now take on the most difficult of the panels, the Front.
When this is done have a trial assembly. Everything else can be carried in through the front door.
- A First Aid Kit (+ Glad wrap)
- Masking tape to identify tools
- PR items
- Stick-on clothing tags for first-names.
- Wash basin, soap and paper towel roll.
- Tea/Coffee sugar and sweeteners.
- A couple of cups, glasses, knives, spoons.
- Working conditions.
- At least four trestles or milk-crates to raise the floor-plank to bench working height. (Ideally, with a couple of heavy sleepers across the crates)
- Heavy woodwork marking pencil or Pentel Permanent Marker (older people have trouble seeing pencil marks)
- Either have a large builder's square or use a large off-cut of plywood -- but clearly mark which is the original 90 degree corner.
- Set Square
- Your own electric drill and a full set of drills. Buy a couple of extra 3mm drills; they will get broken)
- A counter-sinking bit (few people have these, but, if not, use a large bit)
- Cruciform/Philips and standard Slot-drive screw-driver bits for a few electric drills.
- Panel saw
- Handheld circular saw (only the supervisor to use)
- Good 3m+ tape measure.
- 20mm wide sharp chisel.
- Rasp, hand-plane, heavy sandpaper or sanding blocks (to take off sharp edges)
- Screwdrivers, hammers, etc.
- G-clamps or spring-clamps
On the day
- Print outs of the material at this site which is relevant to the day.
- Check that you have the Booklet/Diary to record names addresses phone numbers of those involved.
- Also check you have a mall booklet to go with the cabin which records: CodeNumber to be written on each panel and component; Date of construction; Who funded materials; Who was involved.
- Long electric extension lead and the unit's Builder's reel with safety switch.
- Multiple power point and spare short leads.
- (possible) clamp-on work lamp
- Boxes of hinges - both small 75mm strap hinge and butterfly.
- Screws for the above that will drive in, but not through 15mm shelving.
- Boxes of large countersunk wood screws
- A few Jolts of various lengths
- Some 20mm panel nails
- Woodworking Glue
- Metal working tools
- metal file
- Tool-sharpening stone
- Extendible magnet pick-up tool (older people can't bend down to pick up screws dropped).
- Broom, brush and pan.
- You will need some sort of large rubbish bin.
Wash basin, soap and paper towels.
Do you know where the toilets are?
In Revision 3 we abandoned the more elaborate idea of cutting and bending corner angle-iron in favour of a simple system which only uses moderately light 20x20 galvanised iron angle-iron for the corners and some flat 20mm hold-down straps when and where needed. The previous approach was complicated through trying to do too many things.
When the panels are being erected on-site there must be a very simple and quick way of locking them together at right-angles without needing more than two men. The joints need to be both strong and air-tight and held together by just a few screws.
We now use as corner-joiners, 2.1m and 1.8m lengths of moderately thick (1.2mm), 20x20mm galvanised angle-iron which are pre-drilled and attached to the sides of both the front and the back panel.
There is no angle attached to either of the side panels, until the erection stage.
This gal iron angle is strong yet it gives the joints a small amount of flexibility, and it also allows the addition of short tie-down metal straps for the roof and floor panels when the units are erected outdoors. To handle severe weather conditions, the angles can also be linked to ground stakes (short star pickets driven into the ground) and so we can get a continuous metal-to-metal link from the roof to the ground
Angle corner locks:
Notes for Supervisors
We suggest the use of medium weight 20x20 angle galvanise iron for locking together the front and back panel corners with their side-frames. This material is generally available in long lengths in most good hardware stores.
Front Corners: The angle would be cut to 2140mm lengths for both front-panel junctions. However the angle's value as a vertical tie-down, would be extended later by adding flat iron straps which can lock to the floor panel below (sharing the same screw fixing points), and then to ground stakes if the cabin was being erected outdoors.
Back Corners: For fixing the back panel to the side panels, the two angle-irons lengths would need to be shorter at 1780mm (1800-20mm for ply-overlap) so that the angles will fit between the top and bottom plate of the raised section. The roof tie-downs for the back-corners are on the inside, and the back Stub legs can be handled any way you choose: wire loops are probably quite acceptable.
[See the discussion on tie-down techniques in the Roof section]
Standard Drilling: We suggest making the angles to a fairly rigid standard by drilling them in an identical way. Wall panels can then be interchangeable, and no one is concerned about mixing up different angle irons during the fabrication process.
- Drill top and bottom holes through all corner angles, in the centre of both tongues, These should be 15mm from both the top and bottom of the angle, and you should use a drill a little larger than necessary.
- Then drill the angles at their centre point (both tongues).
- Now halve the gaps between centre and top, and add holes here. (we don't actually need these on both tongues, but it will overcome the problem of angles being fitted to the wrong sides.)
- You should countersink these holes so that the screws seat down fairly well and are close to flush with the surface.
Fixing the angle in place
Use five 25mm countersunk wood screws on each angle. This side of the angle attachment is now a permanent fixing.
For the Front panel, the angle's free tongue must be on the outside (cladding) of the frame. A possible problem can be caused by the Stud A Door Jamb being 70x30 timber while Stud D is 30x30. Obviously the angle needs to be attached 20mm back to align with the major wall frame.
The back panel can now be attached to the side-frames with only three screws in each corner (one top and bottom, one at the mid-point), but the angle here is attached from the inside back during the erection phase, so the free tongue must align with the plywood surface of the back panel. This angle fixing needs also to take into account that the top is limited by the side-wall's top plate (down 30mm from the top of the back wall panel).
You will need to tie the roof panel to the walls; then the walls to the floor panel; and the floor panel must be tied to ground pegs. However this creates a full-distance, lightening proof, metal strength link if the angle is extended through the metal straps making contact through the top and the bottom screws of the angle's fixing points.
The back corner angles need to be fitted from inside the unit so they are a bit more complicated. The strap tie-downs of the roof panel are already built in, but a metal-to-metal link between the floor panel and the ground can be made by wire. The tie-down of the whole back in the cavity space of the unit (with its stub legs), would be made to star pickets driven into the ground. It is probably best to use solid fencing wire to the lowest of the corner fixing screws, but coat hangers appear to be equally as strong.
The fifth angle - under the front panel
Obviously these angles should be made in mirror-pairs and packaged together. At the same time, there is need for a fifth length of 1800mm angle which reinforces and air-seals the bottom of the front panel. It also crosses the door opening, and is set back from the outside cladding line by 10mms (the front wall overhangs the floor frame by this amount). This length of angle holds the door frames together during transport and strengthens the whole front panel.
Hold-down straps which are short pre-drilled lengths of flat gal iron (20mm to 30mm) are best made in bulk, because, while only a few are used during the panel-fabrication process, a few will be needed during the erection, and a few spares should be included in the Step-Box for later-date erections. Some will be lost or misused, and they are often needed.
Where hold-down straps may come in useful unexpectedly is as "O-loops" screwed onto the sides of the floor panel, through which a star-picket can be driven on an angle
These straps would be very simple sections of flat 20mm gal iron cut to lengths of 70+30 = 100mm. They would all be drilled with 5mm holes in the straps centres at distances of 15mm from each end and at the 50mm mid-point from both ends. With these dimensions the screw could now be in the center of a 30mm timber face and allow a choice of two screws holes in any wider 70mm wood face.
See also the note about adding descending straps along the back Roof Panels frame at the time the ceiling interior lining is being installed. They need a minor cut-back of the edge of the ceiling lining, and extend downwards for wall attachment during erection.
General Fabrication Details
Some General Explanatory Material
Booklet Names of funders
Name and contacts of group
Allocate each cabin built a code number
Ask for junk
Ask people to turn up with jars of old nails and screws they no longer need
Ask people to turn up with lengths of 10-15mm timber that can be cut down to make battens (Make them 30mm wide) You need a lot of scrap timber in the 10mm to 40m sizes as battens behind the ply, so length is not important.
Plateau Group Convenor: Stewart Fist
Click here to email