ROOF PANELS
My latest idea is pre-fabricated, arched triangle, roof panels. 12 -18 ft wide--On the ground you build arched triangles in a dish shape. Finish the inside of the dish , flip the dish over, set with a crane and this becomes the ceiling of the dwelling.--No overhead plastering. A row of tiles inside, finishes interior ceiling.
The panels can either be set in a circular pattern to form a "dome" or alternating in a line to roof a rectangular shaped room.
Building triangular dishes-- start with insulation then structural layer and then polish the inside of the dish. THE HARD PART--Turn the dish over and stack it in vertical pile until the crane comes to set 8 dishes. Crane --reality check-- for these dishes on the first floor I'd say 4 hrs at $150/ hr is $600-- or $75 X 8 panels. Set the dishes and stick them together in the valleys-- form work very simple using plaster lath-- mix this pour on site, (pour out of a 5 gal bucket) and vibrate from above.1/2 yd should go a long way
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This is the first roof panel we cast in TX. More or less a sand cast in an old creek bed. This one was quick using
semi-skilled folks . After curing a week this panel was drug out of the form with a backhoe.The owner plans on
reinforcing/fixing the lower mold since we need 5 more roof panels from it and the idea seems to be working.
More coming on flipping and setting the panels. |
The form work was dug out of a sandy creek bottom. We placed FC mix on poly feed sacks which will stick to the panel so sacks can't be wired in place. |
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This photo shows the hardest part --trying to get mud to stick to nearly
vertical surface. Our solution was to go to lunch after the photo and when
we came back it was all easy. |
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Ready for the lath coat-- note, right above the form work rebar notice pieces of paper bag showing near the pointy end of panel (very small in
photo)-- these will reveal rebar (on the upper, exterior surface of roof ) for attaching to lift / flip panel. The interior surface here is polished. |
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Close up of the layers. Our shell was PERFECT--well, structurally anyway Underneath layer (soon to be on top)----- 1 1/2 inches 4,500 psi
around one layer #66 10 10 then a 3/4" sandwich of PVA fibered concrete (both sides) and plaster lath in the middle.
Polish coat goes on after panel comes out of the hole but while upside down.. |
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The basic idea in Texas-- make 6 panels exactly the same and the "cheat" them together with a small section. We still need to figure out exact measurements for the vertical reinforced concrete columns before pouring them. |
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triangular roof panels set in alternating pattern for rectangular room-- side view |
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roof panels used with center post for large domes |
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BO'S COMMENTS
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I used "Smooth Geometry" modeling with Booleans to cut up sections. Then measured and labeled square footage for flipped parts. Maybe other cuts are needed. Cut 219 sf module in half, just a quick look here. Catenary window and door cut outs wold be great too, just add wooden rough openings.
Ya, I bet ferrocement with light-weight aggregate would do it well. Leave reinforcement exposed at seams and at beams, for bonding, etc, etc... Add some wood cross supports, hooks at centroid and as axle holes both sides? Go for it. Actually low 100 sf panels can be handled by a few guys, since the bulk of roofing material goes on last, no? No crane needed, really. Hire the right guys. Alternatively reduce module complications by use of riser-walls which shorten the catenary legs.
Meant to say, these 3D surfaces can be unfolded inside CAD software. Then you will have precise patterns to rely on. The hard part however is deciding on one's preferred, personal design. My sister has been designing her dream house for decades and it keeps evolving. Once we commit to stone, it becomes very hard to change it. (Said from hard experience). see Bo's Page |
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