«The Cob Builders Handbook You Can Hand-Sculpt Your Own Home Table Of Contents: Acknowledgements and Warning INTRODUCTION What is cob? Why build ...»
Any wooden shelves, shelf supports, counter tops, or wood to support cupboards or lofts can be embedded into the cob as you build. It's much easier to sculpt cob around wood than to cut the wood later to the organic shape of the dry cob. Everything that you build in as you go will save you a lot of fussy wood cuts later. You may want to keep the wood clean by covering it with cloth or plastic while you build. The counter, loft, and sturdy shelves can serve as scaffolding. Make sure the cob has hardened enough to support the protruding wood with your weight on it before you stand on it.
If you choose to put your counter or loft in later, you can leave a little cob shelf (2 or 3 inches) to set it on.
To support something small like a counter or shelf, compensate by making the walls a little thicker below the ledge. For a loft, you might want to make the whole wall a little thicker from the foundation up. You can cut the counter (or floorboards) to fit and set it on the ledge. Fill any gaps between the counter and the wall with cob or plaster.
Counters may need extra 'legs' to support their outside edge. These can be made out of wood or you can build cob pillars. These can also support shelves under the counter.
If you want to attach cupboard doors, bury in a piece of wood to attach the hinges to.
Remember to add something to help key the wood to the cob.
Making niches or cubbies in the walls Niches are recessed spaces built into walls to create an altar, bookcase or a place for candles. These are fun to sculpt in as you build. If you finish a wall and then wish you had built a niche, you can carve one out later. This is much easier to do if the cob is still wet.
If you bury colored bottles though the back wall of the candle or light fixture niches, you'll see the colored light shining through the walls when you're outdoors.
The tops of the niches can be treated like any other opening. They will need a lintel or an arch. If you make niches less than a foot wide, you can forget about the lintel or arch rule and let your imagination go.
SCAFFOLDS You'll need something to stand on as your walls grow to keep your upper body weight over the wall. Standing on straw bales or on planks that are resting on straw bales works well for the lower part of the wall. Only stack the bales two high; three is too precarious. The straw bales against the walls will slow down the drying so you may want to move them once in awhile to give each part of the wall a chance to dry out.
It's OK to stand on the partially dried window sills, cantilevers, and built-in furniture.
Use your judgment. You can straddle the wall, sitting on it like a horse.
As your walls get higher, pieces of wood can be buried through the walls to support the scaffolding planks, both inside and out. Put the supports into the walls at least a foot from an opening.
89 90 Four or five feet off the ground is a good place for the first scaffolding supports.
Depending on how tall your walls are and how agile you are, you may want to put more supports every two or three feet. Be safe, rest strong planks on the buried wooden supports and attach them well. Add some additional sticks to help hold up the outsides of the scaffolding supports. (See illustration.) You can use a ladder or straw bale steps to get up onto your scaffolding. The cob can be piled into dishpans or tubs and set up onto the scaffold, then lifted up onto the top of the wall.
When you're finished cobbing, the supports can be left in the walls to permanently carry the weight of shelving or cabinets. In many countries, the scaffolding sticks are left in the walls as decorative ladders and to stand on during replastering later.
If you want to remove them, they can be sawed off and plastered over or they can be knocked out of the walls with a sledge hammer, and you can fill the hole with cob before you plaster.
On the sunny, glass-intensive wall, it's likely that you won't have enough cob between the windows to hold embedded scaffold supports. A simple scaffold can be set up using two stepladders with the scaffolding planks running between the ladders, and resting on the ladder rungs (not on the top of the ladders!) Make sure the ladders are well-balanced where they stand.
If you haven't put the access pipes for the electric wire and plumbing through the foundation, make sure you set them on top of the foundation and cob them in place. If you haven't decided exactly where the access pipes should go, just put in extra ones and fill the ones you don't need later with cob. (See more about this in the chapter on foundations, page 43.) Because cob is completely fire proof, electric wires can be buried right into the cob walls or put in conduit pipes and buried in as you build. Bury them at least an inch deep in the wall to avoid chopping into the wires later when you do the final shaping of the walls. Mark where the wires are buried in the cob so you can find them in the future.
To hold the electric receptacle boxes in the cob, get a piece of wood a little bigger than the box, and nail or screw it to the back of the box. Cob it in where you want it.
If you'd rather deal with finishing the electricity later, leave a hole and, when you get to it, embed the box into the hole with cob.
Another approach to installing the electric wires is to carve a groove out of the cob where you want the wires to be, either when it's wet or dry. Lay the wiring in the grooves after you've finished the walls and just fill the groove with cob or plaster afterwards.
I know very little about termites, but would like to pass on an idea I heard in Australia. The concern was that the termites might bore up through the cob and get at the wood in the frames and the roof. One suggestion was to place termite mesh through the wall with tin strips welded or soldered to the sides, protruding out of the wall about 3/4 of an inch both inside and out.
Termite mesh is a heavy duty mesh available where termites are a problem. It has holes too small for the termites to get through but will allow the walls to breathe. The solid strip of tin makes it easy for the home-owner to see whether the termites have built their own little cob tunnel over the tin. The tunnels can simply be knocked down to discourage the termites from getting up the wall. Any other ideas?
In Australia, I talked with an old friend who lived in a mud brick (adobe) home that she had built herself and had been living in for 12 years. She said she had a problem with silverfish (little destructive moths) breeding in the walls and eating holes in her books and clothes. She hadn't found a nontoxic solution. If any of you have some tips you would like to share about this, please let us know so we can include them in another edition of this book. Thanks!
Planning for future additions
Planning things in advance always saves work, so think ahead. If you know you'll be adding on later, build the beginning of the foundation for the future addition where it attaches to the original foundation. This way the foundations will be tied together well. Put in the door frame that will access the new room. You can either hang the door or temporarily board up and insulate the opening.
92 As you cob the surface where the addition will one day be added, partially bury sticks and leave them sticking out into the future wall's location.
You can also leave keying holes in that part of the wall. Where walls are protected from the rain, you can leave a stair/step with sticks and holes.
Interior walls Interior walls take up precious inside space. You may want to make them as thin as possible, unless they are load bearing and/ or sound barriers.
All the interior partition walls can be partially supported by the main cob walls at the places where they meet. Elsewhere, they can be supported with posts or milled lumber running from the ceiling to the floor. These posts can be buried into the floor or set on top of something to keep them off the ground. The wooden uprights can be used to help support the roof and/or a loft.
Wattle and daub is a name for a type of construction used in many countries for centuries. Walls are made of woven sticks to form a net or mesh, then covered on both sides with a thin layer of cob. This is a way to make thinner interior walls. Thinner walls inside are an advantage because you don't use as much precious space.
The woven sticks can be beautiful room dividers just by themselves.
Interior walls can be made using woven sticks, metal mesh or fencing covered with layers of newspaper or magazine pages dipped in clay slip. (See page 147 for more details.) 2x4 frame walls can be used for interior walls. Because these are so straight and flat, it takes a little imagination to get them to look right with the organic shapes of the cob. Plywood and sheet-rock will take an earthen plaster or thick earthen paint to help them match the cob walls.
Thin cob walls will block the noise pretty well, giving you more privacy between rooms. If the interior walls are not responsible for holding up the roof beams, they can be made as thin as 5 inches at the top with a 1 inch in 3 foot taper. Make some test walls and see how thin you can get away with.
If the interior walls are helping to hold up the roof or the loft, make them thick enough at the place where the roof beams will rest to support them.
Very thin walls can be made out of peg board. The board can be bent to make lovely flowing walls. The plaster squishes through the holes to attach itself to the peg board.
Cobbing is most fun when done with others! Having regular weekend cob houseraising, potluck parties is a great way to get to know your neighbors, and a fun way to play with your friends and get your house built.
It is important for your health to drink plenty of water while you're cobbing.
Because it doesn't seem like hard work, it's easy to get dehydrated. Encourage cobbers to drink by having inviting drinking water easily accessible on the site. Remind each other to drink.
Do like the English do and have morning and afternoon tea on the site. A little rest and a snack help keep cobbers keen.
Take time to be artistic. This is a wonderful opportunity for you to use all your amazing imagination and creativity. You can bury magic things in the walls. Make up rituals. Allow sacredness and beauty in your life.
Cob walls preserve things that are buried in them very well. It's fun to bury a time capsule, a bottle full of things that are likely to last a few centuries (coins, computer disks, ceramic, plastic). This will tell a story about our time in history. An archaeologist hundreds of years from now will have some clues about you, the mysterious modern/ ancient builder.
Singing, drumming, and cobbing go together perfectly. Work goes faster and tiredness disappears! People can reach states of total ecstasy combining these three things. Remember to enjoy yourself and your cobbing friends!
It's fun to have a special photo album / journal of the building process. This can be combined with a guest book, or have a separate book for co-creators and visitors to sign and make comments in.
If you want to cob when it's too cold for your fingers, wear those cloth gloves whose fingers have been dipped in green rubbery stuff. You can wear thinsulite liners under
The cob builders checklist On the following page is the check list. Read over it to get ideas. This is to help you remember what to add to the walls as you build. I recommend that you enlarge, photocopy and laminate the checklist. Hang it up at the building site so it's easy for you to check it often as your home grows.
COB BUILDERS CHECKLISTSELECT SITE develop access design house gather materials and tools get water to site set up temporary shelter for while you build plan drainage and floor levels create drainage do septic make cob tests FOUNDATION dig for foundation to solid ground, below frost level?remember foundation for buttresses and fireplace (optional) plan for foundation insulation (optional) lay pipes for water and electric wires and for fire vent (slanting to outside of house & overhanging wall) build door threshold set up, square, plumb, and brace door frame put keying system on outside of door frame build foundation and door threshold
WALLS FIRST TWO FEETput pipes in for water and electric wires if you haven't already put them in foundation 95 set up electric start cobbing build in stove and/or fireplace as you go and bury woodstove pipe in wall (optional) start cantilevering for benches (top of seat height usually 14" from floor) put in low vent to admit air on cool side of house build in branches for future additions if you're having wooden upright supports for floor-to-ceiling shelving, put them up and brace incorporate wood into walls for (optional) lower cupboard shelving lower ladder rungs bench support poles (inside & out) opening for firewood box install electric outlets (optional) angle backs of benches so they're comfy roughly level floor(s) as you gather cob mix material establish wall taper angle as you build build window seats
WALLS TWO TO FOUR FEET
key in window sills and windows on sun-facing wall bury shelf supports or create cantilevered cob shelves sculpt in niches leave ledges to support counter-tops or bury counters into walls; if necessary, add posts for counter supports put in openable windows (keyed to cob) bury scaffolding supports 3-1/2 to 4 feet up walls (inside and out) and brace them keep incorporating branches for future additions continue wall taper
WALLS FOUR FEET AND UPput in lintels or arches over windows sculpt art into walls or fatten wall for future carving art (optional)
ROOF bury rafters and keys for rafters put up roof beams and rafters attach keys put up ceiling or leave a place in cob to slide ceiling sheathing onto insert screened tubes in cob between rafters to ventilate insulation space insulate roof well install roofing hang gutters (this is very important!) put in stove pipe, chimney, flashing, skylights