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Reference library

Building Components

Reference entries for the discrete elements a building is assembled from — named by where they sit and what they do, rather than by what they are bought as. Each explains what the element is, what it depends on, the material families it is commonly formed from, the systems it belongs to, and the junctions where it meets other elements.

107 components across 12 categories, connected to 38 junction concepts and 21 building contexts.

How this library differs from the other two

Materials are what you procure — a substance or a product format that can be specified and delivered. Plasterboard, structural softwood and facing brick are materials, and each has an entry in the Materials Library.

Components are what you position — an element identified by where it sits in an assembly and what job it does there. A wall stud, an outer leaf and a rafter are positions, and the same position can be realised in several different materials. That is what these pages describe.

Systems are what components add up to — a coordinated assembly whose parts interact, explained in the Building Systems Encyclopedia.

Where an element already has a Materials Library entry — a lintel, a wall tie, a roof truss, a damp-proof course — this library does not repeat it. It links to it instead.

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Structure & Ground

Elements that carry load or prepare the ground to receive it — from the surface a foundation bears on to the members that span between supports.

13 entriesSubstructure & Ground →The prepared surfaces, layers and buried members between undisturbed ground and the first structure above it.24 entriesFrame Members →The columns, beams, joists, rafters, plates and bracing that make up a load-carrying frame, identified by the position each occupies.

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Envelope Elements

Elements of the outer shell: the leaves that form a wall, the carcass and edges of a roof, the framing around openings, the supports behind a facade, the layers that control heat and water, and the pieces that terminate them.

8 entriesWall Leaves & Backing →The distinct vertical layers that make up a wall — outer and inner leaves, the cavity between them, and the backing that supports what is fixed to the face.7 entriesRoof Carcass & Edges →The battens, boards and edge elements that finish a roof structure and prepare it to receive a covering.9 entriesOpenings & Frames →The frames, heads, jambs, sills, thresholds and closers that form and finish an opening through a wall.8 entriesFacade Support →The brackets, rails, subframes and framing members that hold a facade off a backing structure, and the panels they carry.6 entriesLayers & Barriers →Continuous positioned layers within a build-up — insulation, separation, protection, drainage and root barriers — named by the job they do rather than the product used.6 entriesTerminations →The elements where a plane stops, turns up, sheds water or is deliberately interrupted — parapets, upstands, flashings, drips, weeps and movement joints.

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Interior Elements

Elements within the occupied volume: the layers built up on a structural floor, and the framing and voids above a ceiling.

6 entriesFloor Build-Up →The deck, toppings, floating layers, isolation strips and voids that sit between a floor structure and its finish.5 entriesCeilings & Voids →The joists, hangers, independent frames, voids and access provisions that form the plane above a room and the space behind it.

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Water & External Elements

Elements outside the enclosure: the build-up beneath paving and decks, and the elements that collect, carry and discharge water.

6 entriesPaving & Decks →The laying course, wearing course, edge restraint, deck framing and guarding posts that make up trafficked surfaces outside the building.9 entriesDrainage Elements →The gutters, outlets, downpipes, channels, chambers and traps that collect water, carry it and let it be inspected.

Junctions

Interfaces between components

Junction concepts where the condition between two elements governs how the construction behaves. These are a data layer rather than a set of pages: each surfaces on the pages of the components it connects, because a junction concept without those two elements around it would be a page with nothing substantive to say. They name what a junction has to do and the subjects it raises — they are never details, arrangements or approved ways of building.

Envelope junctions
  • Cavity Barrier Across a Cavity
  • Facade Bracket Through Insulation
  • Outer Leaf to Inner Leaf Restraint
  • Sheathing to Frame
  • Slab Edge to External Wall
  • Wall Head to Roof Insulation Continuity
Finish transitions
  • Movement Joint Through a Surface
  • Reveal to Frame
Floor & wall junctions
  • Floating Layer to Perimeter
  • Partition Head to Ceiling Void
  • Sleeper Wall to Subfloor Ventilation
  • Topping to Structural Deck
Moisture-control junctions
  • Cavity Tray to Weep Discharge
  • Membrane to Roof Outlet
  • Protection Over Waterproofing
  • Upstand to Flashing Termination
  • Wall Base Damp-Proofing Junction
  • Wet Area Floor to Wall Tanking
Opening interfaces
  • Cavity Closer to Frame
  • Frame to Opening Head
  • Frame to Jamb
  • Sill to Frame
  • Threshold to External Ground
Roof junctions
  • Counter-Batten to Tile Batten
  • Eaves to Gutter Discharge
  • Jack Rafter to Hip
  • Jack Rafter to Valley
  • Parapet Base to Roof Upstand
  • Rafter to Ridge
  • Tilting Fillet at Upstand Base
  • Verge Covering Termination
Structural connections
  • Beam End to Column
  • Column Base to Foundation
  • Ground Beam Bearing on a Cap
  • Joist End to Masonry Bearing
  • Purlin to Strut Support
  • Rafter Foot to Wall Plate
  • Trimmer to Trimming Joist

Contexts

Where components are applied

Functional building contexts — where in a building, and for what purpose. Also a data layer: an application groups components and systems rather than adding knowledge of its own, and a page per context would restate what those entries already say. A component listed against a context is commonly encountered there; that is an association, never a recommendation.

Envelope
  • Building Envelope — External Wall, Facade, Flat Roof, Opening, Pitched Roof
External works
  • External Works — Boundary Structure, Deck & Terrace, Hardstanding, Site Drainage
Interior
  • Building Interior — Ceiling, Internal Partition, Separating Construction, Wet Area
Structure
  • Superstructure — Intermediate Floor
Substructure
  • Substructure — Basement, Ground Floor