What is skeleton frame construction?
Skeleton frame construction is a building method in which a frame of columns and beams carries the loads from floors and roof down to the foundations, while the external and internal walls are non-load-bearing. It contrasts with load-bearing masonry or wall construction, where the walls themselves support the floors. Because the loads are concentrated in the frame, it allows long spans, open and adaptable floor plans and lightweight or fully glazed facades. The frame itself is often simply called the structural frame.
Frame types and examples
- Reinforced concrete frame: columns, beams and slabs, cast in situ or precast, often with hollow-core floor slabs. Common for offices, schools, car parks and residential towers.
- Steel frame: rolled sections such as universal beams and columns, fabricated off site and bolted together on site. Standard for warehouses, industrial sheds and high-rise buildings; the early Chicago skyscrapers made the steel skeleton famous.
- Timber frame: from historic oak post-and-beam barns to modern glulam column-and-beam structures.
A frame alone is not stable against wind. Stability comes from a stiff core (stair or lift shaft), shear walls, cross-bracing or rigid moment connections between columns and beams. Le Corbusier captured the idea in his Dom-ino diagram: slabs on columns, walls free to be placed anywhere.
Application
- Before altering, find out what is structural. Non-load-bearing partitions can usually be removed, but bracing and shear walls cannot. Get the structural drawings or ask a structural engineer.
- Detail the facade separately. Cladding or a curtain wall is hung off the frame and must accommodate its movement without cracking.
- Provide fire protection. Steel loses strength quickly in a fire and is usually boarded or coated with intumescent paint.
- Avoid cold bridges. Insulate carefully where slab edges and columns meet the external envelope.
- Common mistake: drilling or cutting openings in columns or beams without engineering approval.
Related terms
- Structural frame
- Concrete frame
- Double skeleton structure
- Column
- Beam
- Curtain wall
- Timber frame construction
Want to know more about building terms? Visit our knowledge base at fredsdiyplans.com.