Fer example here's a fairly complete journey through building a house.

1. Site preparation & groundworks

Site clearance — clearing vegetation, rubble, old structures etc.

Setting out — transferring the architect/engineer's dimensions onto the site so the building is positioned and sized correctly.

Excavation — digging for foundations, drainage, services, etc.

Groundworks — the broad term covering much of the work below and around the building: excavation, foundations, drainage, concrete, hardcore, ground slabs, retaining walls, etc.

Foundations — usually strip foundations, trench-fill, raft or piles depending on the ground and design.

Trench fill — deep foundation trenches largely filled with concrete, reducing the amount of blockwork required below ground.

DPC (damp-proof course) — a horizontal moisture barrier in the wall preventing ground moisture travelling upwards.

Hardcore — compacted crushed material used beneath floors/slabs.

MOT Type 1 — a very common graded crushed aggregate used for hardcore/sub-base.

Blinding — a thin layer of fine material/concrete used to create a relatively smooth, clean surface before the next operation.

Oversite concrete — concrete laid over the prepared ground, traditionally forming the base for the ground floor.

Drainage runs — underground foul and surface-water pipes.

2. Structure starts going up

For a traditional masonry house:

Blockwork — concrete blocks forming the inner leaf, foundations, partitions etc.

Brickwork — external facing brickwork.

Cavity wall — two wall leaves separated by a cavity, normally containing insulation.

Inner leaf / outer leaf — the inner structural wall and external brick/block skin.

Wall ties — metal/plastic ties connecting the two leaves of a cavity wall.

Lintel — structural support over a window or door opening.

DPC — you'll encounter these again at various points, particularly around openings and junctions.

Joists — horizontal structural members supporting floors or ceilings.

Floor deck — boards, often OSB/chipboard, laid over joists to form the floor.

Studwork — timber or metal framing used for internal partition walls.

3. Roof

Roof trusses — prefabricated timber triangular structures supporting the roof.

Rafters — individual sloping structural roof members.

Roof covering — tiles, slate, etc.

Battens — horizontal timber strips fixed to the roof structure to which tiles/slates are attached.

Fascia — board along the lower edge of the roof, normally behind the gutter.

Soffit — underside of the roof overhang.

Bargeboard — board along the sloping edge of a gable.

Roof membrane / felt — waterproof/breathable layer beneath the roof covering.

Once the roof is substantially on and the building is weather-tight, you start moving into a very different phase.

This is where "first fix" comes in

First fix = putting things into the building that need to be installed before the walls, ceilings and floors are finally closed up.

Think behind the finished surfaces.

For example, an electrician doesn't wait until the plasterboard is on to install all the wiring.

They run:

cables

conduit where required

back boxes

routes for lighting

socket wiring

switch wiring

consumer-unit feeds

before the walls are closed.

A plumber similarly installs:

hot and cold water pipework

heating pipework

waste pipes

feeds to radiators

pipework to bathrooms/kitchens

And other trades may install:

ventilation ducting

alarm cables

data/network cables

structural timber required for fittings

concealed steelwork

insulation associated with particular systems

So first fix is basically the hidden infrastructure of the house.

Then comes plasterboard/plastering

Once the first-fix work has been inspected and tested as necessary:

Insulation gets completed.

Plasterboard / drylining goes onto walls and ceilings.

Then:

Plastering / skimming — producing the finished wall/ceiling surface.

You might hear builders say:

"The house is boarded."

or

"We're ready for the plasterers."

At this point, the ugly maze of pipes and cables disappears behind the walls.

Second fix

Second fix = installing the visible/final components after plastering and finishing.

For an electrician, that means things such as:

sockets

switches

light fittings

consumer-unit final connections

accessories

For a plumber/heating engineer:

taps

toilets

basins

radiators

showers

final boiler connections

visible pipework/fittings

For a carpenter:

internal doors

door frames/linings

skirting boards

architraves

stair components

cupboards

fitted joinery

So you could have:

First fix:

cable → inside wall → plasterboard → plaster

Second fix:

socket → connected to that cable

Then you get into 'finishing' trades

A typical house might progress roughly like this:

Groundworks

↓

Foundations

↓

Substructure / slab

↓

Brick/block walls

↓

Floors & upper structure

↓

Roof

↓

Windows & external doors

↓

First fix services

↓

Insulation

↓

Plasterboard / drylining

↓

Plastering

↓

Second fix services

↓

Internal doors & joinery

↓

Kitchen & bathrooms

↓

Tiling

↓

Decoration

↓

Floor finishes

↓

External works / landscaping

↓

Snagging

↓

Completion / handover

A few terms you'll probably hear on site

Shell — the basic building structure, before much of the internal fit-out.

Watertight — roof, windows, doors etc. are installed sufficiently to keep weather out.

Weather-tight — similar idea; the building can now be worked on internally without being exposed to the elements.

First fix complete — hidden services are substantially installed.

Second fix complete — visible/final fittings are substantially installed.

Fit-out — installing the internal components that turn the shell into a usable building.

Making good — repairing/finishing surfaces after another trade has disturbed them.

Snagging — identifying defects, unfinished items or things that need correcting before handover.

Setting out — establishing exact positions and dimensions.

Datum — a reference level from which heights are measured.

FFL (Finished Floor Level) — the level of the finished floor.

Formation level — the prepared level at which construction/excavation is taking place.

As-built — drawings/information showing what was actually constructed, rather than what was originally designed.

PC Sum (Provisional Cost/Sum) — an allowance in a contract for something whose exact cost/specification isn't yet known.

Variation — a change to the agreed work.

Practical completion — broadly, the point where the building is sufficiently complete to be handed over/occupied, although there may still be minor defects.

And one terminology trap worth knowing

“First fix” doesn't necessarily mean one single moment in the build.

People will say things like:

"The electrician's first fix is done."

or

"We're first-fix plumbing."

It refers to the stage of that particular trade's work, rather than the entire building suddenly becoming “first fix complete.”

So you can have a house where the electrical first fix is finished, while the plumber is still doing first fix and the carpenter is doing structural work.

And second fix can overlap between trades too - clear as mud?