If you are having an extension or renovation, you will hear the words first fix and second fix a lot. Electricians use them, plumbers use them, and joiners use them. They are shorthand for two different stages of the job, and understanding them helps you know what is happening, when, and why the plasterer cannot start until the joiner has finished.
The basic idea
- First fix is everything that happens before the walls and ceilings are plastered or boarded. It is the structure and the hidden work.
- Second fix is everything that happens after plastering. It is the finished, visible work.
Between the two sits the plasterer.
First fix joinery
On a typical extension, first fix joinery can include:
Structural timber
- Floor joists, if the extension has a suspended timber floor
- Roof structure: joists for a flat roof, or rafters and trusses for a pitched roof
- Wall plates and lintels where timber is used
- Timber frame walls, if the extension is timber framed
Studwork
- Internal partition walls in timber studs
- Framing for boxing in pipes or steels
- Noggins (short pieces of timber between studs or joists) to give fixing points for things like radiators, wall cabinets, TV brackets and handrails
Openings
- Door linings set in place, plumb and square
- Window boards' supports and fixing details
- Rooflight kerbs or trimming in a roof
Floors
- Floor decking: chipboard, plywood or timber boards laid onto joists
Stairs
- In larger projects, the stair carcass may be fitted at first fix, with protection
Coordination
The first fix joiner works closely with the electrician and plumber, who are running their cables and pipes through the same walls and floors. Notching and drilling joists has rules, and the joiner and engineer care about where holes go.
Why noggins matter
This is one small detail homeowners should know about. Before the walls are boarded, think about anything heavy that will hang on them: kitchen wall units, a TV, shelves, a radiator, a basin, grab rails. A noggin in the right place means a solid fixing later. Without it, you are hunting for studs or using cavity fixings into plasterboard.
Tell your joiner what is going where before the boards go on.
Between fixes: the plasterer
Once first fix is complete across all trades (joinery, electrics, plumbing), and any building standards inspections required at this stage are done, the walls and ceilings are boarded and plastered. The plaster needs time to dry before second fix and decoration.
Second fix joinery
Second fix is what you see when you walk into the finished room:
- Internal doors hung in their linings, with handles, latches and hinges
- Architraves around doors and windows
- Skirting boards
- Window boards (internal sills)
- Stair balustrades and handrails
- Built-in cupboards, wardrobes and shelving
- Kitchen fitting, in some projects
- Loft hatches, access panels, boxing finishes
- Ironmongery: handles, locks, hooks, coat rails
Second fix is precision work. Gaps, uneven mitres or a door that sticks are visible every day. It is the stage that makes the room feel finished.
Matching the existing house
In Edinburgh, a lot of extensions are added to older houses with their own character, including in Morningside. Second fix is where the extension can be tied into the existing house:
- Matching skirting and architrave profiles
- Doors in a style that suits the rest of the house
- Consistent finishes across old and new
Bespoke profiles can be made where standard mouldings do not match.
The order of trades
A simplified sequence for an extension interior:
- Structure complete and watertight
- First fix joinery, electrics and plumbing
- Insulation and any required inspections
- Boarding and plastering
- Drying out
- Second fix joinery, electrics and plumbing
- Kitchen and flooring (order varies)
- Decoration
- Snagging
Getting this order right, and making sure each trade finishes their stage before the next starts, keeps the job moving. A missed cable or a forgotten noggin found after plastering costs time and money.
How you can help
- Decide early on door styles, skirting profiles and built-in storage
- Mark up where heavy items will be fixed
- Make decisions on ironmongery before second fix
- Allow drying time after plastering; rushing second fix onto wet plaster causes problems later
FAQ
What is the difference between first fix and second fix?
First fix is the hidden work before plastering. Second fix is the finished, visible work afterwards.
Is first fix just for joiners?
No. Electricians and plumbers also have first and second fix stages, and they need to be coordinated.
How long between first and second fix?
It depends on plastering and drying time, and on the size of the job. Plaster needs to dry adequately before second fix.
What is a noggin?
A short piece of timber fixed between studs or joists to provide a solid fixing point or stiffening.
Can second fix match my existing period joinery?
Yes. Matching profiles can often be sourced or made to tie new and old together.
Ready to talk through an extension, conversion or fitted joinery job?
Book a site visit.
