Slipform stonemasonry is a method for making a

reinforced concrete Reinforced concrete, also called ferroconcrete or ferro-concrete, is a composite material in which concrete's relatively low tensile strength and ductility are compensated for by the inclusion of reinforcement having higher tensile strength or ...

wall with stone facing in which stones and mortar are built up in courses within reusable slipforms. It is a cross between traditional mortared stone wall and a veneered stone wall. Short forms, up to 60 cm high, are placed on both sides of the wall to serve as a guide for the stone work. The stones are placed inside the forms with the good faces against the form work.

Concrete Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...

is poured in behind the rocks.

Rebar Rebar (short for reinforcement bar or reinforcing bar), known when massed as reinforcing steel or steel reinforcement, is a tension device added to concrete to form ''reinforced concrete'' and reinforced masonry structures to strengthen and aid ...

is added for strength, to make a wall that is approximately half reinforced concrete and half

stonework Stonemasonry or stonecraft is the creation of buildings, structures, and sculpture using rock (geology), stone as the primary material. Stonemasonry is the craft of shaping and arranging stones, often together with Mortar (masonry), mortar ...

. The wall can be faced with stone on one side or both sides. After the concrete sets enough to hold the wall together, the forms are "slipped" up to pour the next level. With slipforms it is easy for a novice to build free-standing stone walls.

History

Slipform stonemasonry was developed by New York architect Ernest Flagg in 1920. Flagg built a vertical framework as tall as the wall, then inserted 2x6 or 2x8 planks as forms to guide the stonework. When the masonry work reached the top of a plank, Flagg inserted another one, adding more planks until he reached the top of the wall. Helen and Scott Nearing modified the technique in Vermont in the 1930s, using slipforms that were slipped up the wall.Elpel, Thomas J. Living Homes: Stone Masonry, Log, and Strawbale Construction. HOPS Press, 2010, p. 85.

Gallery

File:Oiled slipforms.jpg, Slipforms oiled to prevent concrete from sticking to the wood. File:Placing Stones in Formwork.jpg, Placing stones inside the forms. File:Window Frame in Stonework.jpg, Window frames are placed in the forms. File:Forms are leap-frogged up the wall.jpg, Slipforms are leap-frogged up the wall. File:Finished Slipform Stone House.jpg, A finished slipform stone house.

Notes

The diagram of the slipform wall section is completely misleading without showing the 2nd form.

External links

Slipform Stone Masonry
{{Stonemasonry Stonemasonry Construction Types of wall