Building elements: structure, envelope and services

Loads travel from roof to floors to walls or columns to foundations to the ground. Common systems:

• Load-bearing walls (masonry, timber or steel framing) — typical for houses.

• Frames (concrete, steel, timber columns and beams) — open, flexible floors.

• Slabs (concrete) or framed floors (joists).

• Foundations: strip or pad footings, slabs on ground, piles where soil is weak.

Grids in your plans usually come from the structure; spans drive depths of beams and floors.

The envelope separates inside from outside. It must keep out water (with flashings, membranes and drainage paths), control air leakage, control heat (insulation), manage vapour and condensation, resist fire where required, and look right. Most building defects happen where envelope elements meet — around windows, roof edges and wall junctions.

Mechanical (heating, cooling, ventilation), electrical (power, lighting, data), hydraulic (water, drainage, gas), fire (detection, sprinklers, hydrants) and vertical transport (lifts). Services need space: ceiling voids, risers, plant rooms and roof areas. Allow for them early — they are a common cause of height and coordination problems.

A beam deep enough for its span leaves less room for ducts; a big window needs a lintel; a plant room needs structure for heavy equipment and a route to get it in. Good architects plan these interactions early with the consultants.