Can I use the board and battens as my outside wall form?
My avid straw-bale construction enthusiasm is definitely being replaced with straw clay slip as I look into it more. Framing for it seems like cake, and the process of making slip (mud water), mixing it with straw, and packing it into a form seems to good to be true.
Can anyone add insight into this situation. I have a structure that I am planning on having board and batten on the exterior and I want to do the falls with straw clay slip. Can I use the board and battens as my outside wall form?
In straw-bale I think it would be recommended to coat the exterior of the bales with a base coat of mud or something to prevent fire, rodents and insects before applying an exterior like wood, so i was just wondering if the straw clay slip is similar in that regard.
..Clay straw slip takes longer to dry than any other method and with battens it will take a bit longer still. Personally I would use forms, fill with the slip, remove the forms and allow to dry before coming back to finish the walls on either side...
No, slip straw is not the same build as straw bale or solid cob for that matter. Each has it's own best methods and particulars, however all should be finished on both sides for best results. Usually with a natural breathable lime plaster. Even adobe brick, long ago, was finished with lime plaster or lime wash to help prevent erosion or compromise of the walls.
Remember: you do not need permanent external support (battens) for any of the natural building method(s) walls, nor for lime plasters as they will stick to rough straw, cob, slip well enough.
The real question is why would you go through all the work of light straw clay with risk of problems and poor insulation value?
My shop-and ideal construction method- is ext B&B with dense pack cellulose for a mold and bug free super insulated wall, at low cost. With white oak B&B, sawn locally, you have a wall that will last many decades, likely a century, with no maintenance if done right.
I don't have a month to plaster more less three and if in a humid or rain climate longer to put windows and doors in. I also recommend checking code it's not just fire or combustion alot of jurisdictions have smoke requirements, if not following code the Fire Marshal will want to see data.
Too much for me I think of better less costly ways to build. Not at the top of my list. I can get all this with interior clay plaster and mineral wool core in a 8" wall in my climate. To each their own...
I question taking an expansive clay if I remember right some of which can expand up to 40% its volume and trapping it between rigid cladding permanently too. He discussed plasters and stucco that have the same or close expansion/contraction ratios. In my mind, there should be expansion gaps or a chamber, and/or ventilation gaps both on the interior and exterior. 12-14 inch depending on climate and r-value one needs to understand. Perhaps double studded walls or at least some nailers for cabinets, molding, pictures, etc....
I found those temp rises interesting to from microbes metabolizing. Also, how the clay protected not only the straw but wood window and door framing.
PS: I think I am backing out of MGO until the industry stabilizes, rethinking my walls now, unless our friend Ron proves me wrong with the samples coming....But yes properly manufactured MMM would be fast and effective and not so dependent on drying or weather. I'm thinking wood siding, mineral wool, plaster or wood interiors if budgets allows.
...We don't have a structural engineer on staff. Our buildings are designed and overseen by a Ladakhi mechanical engineer who has designed and executed and lived in many earthen buildings and also did a masters at CRATerre in France; and an architect who has mostly been building and teaching earth building....Out There all the time, inventing and trying new things..
...RCC concrete tie beam around the top of the wall...
Terry Ruth wrote:Philip. am I missing something why not use the board and batten exterior as forms?
Terry Ruth wrote:I'd leave some ventilation gaps to ground and out the soffit_ridge vents behind the boards and battens so drying can occur in that direction if need be but, now form work has to be pulled...have large overhangs so water cannot get into the wall, slopes at least 30% grade. If it is super humid there and no wind I'd rethink that one. Understand how the coating's on fasteners are going to react with the mixes.
Jay C. White Cloud wrote:Remember you can replace the straw with hemp hurd, sawdust, wood chip, ground or layered old felt carpet padding and even ground new paper (aka cellulose insulation) in various density configurations and forms. This entire "light cobb" system is very ancient in orgin and flexibility of design...
Jay C. White Cloud wrote:Absolutely you can!! I still would recommend a "rainscreen" system to mount your b&b to, but this type of finish is more that plausible. I would need to know more specifics to give and detail advice or make further recommendations...