Plasterboard screws: bugle head, thread types, lengths, and install

TL;DR

Fine thread for steel stud, coarse thread for timber: mixing them up is the single most common plasterboard fastening mistake on Australian sites. For 13mm wall board to timber, use 32mm coarse thread; for steel stud, use 25mm to 32mm fine thread needle point. Spacing per AS/NZS 2589:2017 is 300mm on walls, 230mm in the ceiling field, 150mm at ceiling board ends. Drive heads just below the paper face without breaking through, a dimple not a puncture.

What it is

A plasterboard screw is a bugle-head, phosphate- or zinc-finished fastener sized to fix gypsum sheet to timber or light gauge steel (LGS) framing without tearing the face paper. In Australian residential construction the dominant form is a 6g or 7g screw in 25mm to 50mm lengths, driven with a collated auto-feed gun or a dedicated drywall screwdriver.

Also known as: drywall screw, gyprock screw (informal).

Category: Fixings and fasteners.

Properties

Property	Fine thread	Coarse thread
Thread pitch	Tight pitch, close spirals	Wider pitch, deeper engagement
Substrate	Light gauge steel stud up to ~1.2mm BMT	Timber framing (pine, LVL, hardwood noggings)
Point type	Needle point or drill point	Needle point (Type 17 also available)
Head	Bugle (concave taper, auto-countersinks)	Bugle (same profile)
Drive	PH2 Phillips	PH2 Phillips
Finish	Zinc yellow or black phosphate	Zinc yellow or black phosphate

Fine thread screws drive into steel stud cleanly because the tight thread engages the metal sheet and pulls the board tight. A coarse thread in steel stud strips out. Conversely, a fine thread in soft pine sits in shallower thread engagement and backs out under frame movement (verified 2026-05-10, Siniat Australia, All you wanted to know about plasterboard fixing referencing AS 2589 fastener guidance).

Common lengths and applications

Length	Common use	Board thickness
25mm	Steel stud, single 10mm or 13mm board	10mm ceilings (steel frame), 13mm walls (steel frame)
30mm	Timber, 10mm ceiling board minimum	10mm ceilings to timber (verified: 30mm is the AS 2589 minimum, not 25mm)
32mm	Timber, 13mm wall board (standard)	13mm walls to timber framing
41mm	Timber, double-layer or 13mm + 16mm laminate	Double plasterboard systems
50mm	Timber, thick board or laminating layer	25mm shaftliner or double-board systems

Collated 6g screws in 25mm, 32mm, and 41mm are the standard trade sizes stocked by Macsim, Buildex, and Allfasteners in Australia (verified 2026-05-10, Macsim plasterboard screws; Allfasteners 6G collated fine thread; PMC Store coarse thread).

The 30mm minimum for 10mm ceiling board to timber frames was first codified in AS 2589 (2007 revision) and carried through to AS/NZS 2589:2017. Using 25mm in this location is a common and persistent site error (verified 2026-05-10, Siniat Australia, All you wanted to know about plasterboard fixing).

Grades and variants

Type	Description	Where used
Loose (bulk)	Individual screws, bucket or box	Screwgun or manual driver; older install practice
Collated (strip)	Strips of 50 on plastic carrier	Auto-feed gun; standard for new residential
Zinc yellow finish	Standard coating, Class 1 AS 3566	Internal dry walls and ceilings
Black phosphate	Same Class 1; older trade preference	Internal only; phosphate is corrosion-susceptible externally
Laminating screw	Fine thread, longer (50mm+), sometimes pan or bugle head	Fixing one plasterboard layer to another in multi-layer fire or acoustic systems

Class 1 (AS 3566.2-2002) is adequate for internal dry plasterboard fixing. Do not use standard plasterboard screws in external or wet area applications (verified 2026-05-10, AS 3566.2-2002 corrosion class guidance, Standards Australia).

Where to use

Fixing 10mm plasterboard ceilings to timber or steel framing
Fixing 13mm plasterboard walls to timber or steel stud
Fixing 16mm or thicker fire-rated board to timber or steel in tested fire systems
Fixing the inner layer in a double-board acoustic or fire system (laminating screws)
Attaching plasterboard to batten or furring channel in ceiling systems

Where NOT to use

Externally or in wet areas. Standard plasterboard screws are Class 1 (minimal corrosion protection). Use the substrate-appropriate screw per the wet area system spec.
In masonry or concrete. Use a purpose-designed masonry anchor. A plasterboard screw has no grip in concrete.
As a structural fastener. Plasterboard is a lining, not a structural element. Do not use plasterboard screws to join framing members.
Mixed substrate in a fire-rated system without checking the system spec. Some fire wall tested systems specify fine thread regardless of stud material, or specific screw brands. Follow the tested system documentation.

Fixing and installation

Depth-of-set rule

Drive the screw head just below the board surface, creating a slight dimple in the paper. The rule: paper dimpled, not pierced.

Too shallow: head sits proud of the board face. Compound cannot skim flush. Hard spot visible after painting.
Correct: shallow dimple, paper intact. Compound fills cleanly, invisible after setting.
Too deep: head breaks through the face paper. The gypsum core crumbles around the shank. No holding power. Drive a new screw 50mm away.

On a collated auto-feed gun, the depth-stop nosepiece and clutch control this automatically. Set depth on a scrap piece before starting (verified 2026-05-10, Siniat Australia).

Screw spacing per AS/NZS 2589:2017

Location	Spacing
Walls, field (centre of sheet)	300mm max centres
Walls, sheet ends at external angles	200mm max centres
Ceilings, field of board	230mm max centres
Ceilings, board ends	150mm max centres

Source: AS/NZS 2589:2017, Gypsum linings, Application and finishing (verified 2026-05-10 via Siniat Plasterboard Installation Guide referencing AS/NZS 2589:2017, adxdepot.com.au).

Fire-rated and acoustic tested systems specify their own screw spacing. The tested system document governs; the AS/NZS 2589 general spacing is a fallback for standard residential linings only.

When using a screw-and-adhesive hybrid method, keep screws at least 200mm from adhesive daubs to avoid concentrating stress (verified 2026-05-10, Siniat Australia).

Auto-feed (collated) gun

A collated auto-feed gun feeds strips of 50 screws from a magazine, drives each screw to the preset depth, and advances to the next. Standard on Australian residential plasterboard sites.

Key settings:

Depth adjustment: Twist the nosepiece to set the dimple depth. Check on a scrap piece of the same board before driving into the job.
Clutch: Disengages drive as soon as the screw seats to avoid over-driving. Do not defeat the clutch.
Screw length compatibility: Most auto-feed guns accept 25mm to 55mm collated screws (check manufacturer compatibility). Makita DFR450, DeWalt DCF620, Milwaukee M18 FSG, and Senco DS series are common in Australian residential (verified 2026-05-10, Allfasteners 6G collated fine thread drywall screws).

Manual screwguns (dedicated drywall driver with adjustable clutch) are used for small quantities, repairs, or in confined areas where the auto-feed magazine does not fit.

Tolerances and acceptance

Workmanship

Numerical screw pull-through, dimple depth, and fastener spacing deviation tolerances are drawn from the HIA Guide to Materials and Workmanship. Exact values pending HIA member access. [HIA-152]

Visual acceptance at PCI

Item	Acceptable	Not acceptable
Screw head depth	Paper dimpled, intact	Head proud, or paper torn and core visible
Screw spacing	At or within AS/NZS 2589 limits	Screws missing, spacing obviously exceeded
Screw pattern	Consistent rows	Random placing, clustering
Rust staining	None within DLP	Any rust bleed from screw head
Backing-out	None	Any screw backing proud post-install

Checking screw depth is visual at install time, not at PCI. By PCI the screws are set and painted. Issues show as hard spots or dimples in the finished surface under raking light.

Working with other trades

Framing carpenter (chippy): Frame at the right centres before lining. Plasterboard screws have no fixing if the frame is bowed, off-centre, or at wrong spacing. Screw pops are often a frame problem, not a screw problem.
Plasterer: Fixes the board, sets the screws to depth, and is responsible for correct spacing. Screw spacing disputes at PCI are documented in AS/NZS 2589:2017.
Painter: Primes screw dimples after first set coat. A head that is over-driven and patched will show through paint under raking light. Correct depth at install, not at paint.

Health and safety

Silicosis dust: Drilling or cutting plasterboard generates gypsum and, in some thicker products, other fine mineral dusts. P2 mask minimum. On-tool vacuum extraction preferred for bulk drilling.
Eye and hand protection: Collated screw guns eject plastic strip carrier fragments at speed. Safety glasses and gloves standard.
Service locator: Before driving screws through board into framing, confirm no live services are in the stud bay. Screws into live cabling or copper pipework cause immediate safety incidents.

See silicosis for the regulatory dust exposure standard.

Suppliers

Buildex (ITW) (buildex.com.au): broad plasterboard screw range, fine and coarse thread, collated and loose.
Macsim (macsim.com.au): collated drywall screw range, standard in Australian plasterers’ supply chains.
Senco (senco.com.au): collated screw and auto-feed gun systems, DuraSpin compatible.
Allfasteners (allfasteners.com.au): fine and coarse thread, loose and collated, multiple lengths.

[Supplier slot. ACCC disclosure required for any commercial relationship.]

What can go wrong

Wrong thread for substrate: Coarse in steel stud strips out immediately. Fine in timber backs out over time as the frame dries and moves.
Screw popping: Screw head works back proud of the board face after install. Causes: under-length screw, green or wet framing that moves as it dries, over-driven screw (no initial holding power), or insufficient screw count. Common callback on new residential.
Paper tear (over-driving): Head breaks through the face paper. No fix: drive a new screw 50mm away and fill the failed hole with compound.
Under-driving: Head sits proud. Hard spot under compound. Visible under raking light after paint.
Spacing too wide: Board flexes between fixings, especially on ceilings. Joint cracking and delamination follow. Re-fix with correct spacing.
Screws too close to board edge: Edge crumbles, pulling screws. Minimum 10mm from any cut or recessed edge (manufacturer guidance).
Wrong length for substrate: Too short means inadequate penetration into the frame. Too long on thin steel stud means the point protrudes through the far face of the stud, creating snag points behind the board.

References

AS/NZS 2589:2017, Gypsum linings, Application and finishing (Standards Australia) (verified 2026-05-10 via Siniat Plasterboard Installation Guide)
AS 3566.2-2002, Self-drilling screws for the building and construction industries, Part 2: Corrosion resistance requirements (Standards Australia) (verified 2026-05-10)
Siniat Australia, All you wanted to know about plasterboard fixing (siniat.com.au) (verified 2026-05-10)
Macsim plasterboard screws product range (macsim.com.au) (verified 2026-05-10)
Buildex plasterboard screw range (buildex.com.au) (verified 2026-05-10)
Allfasteners, 6G collated fine thread drywall screws (allfasteners.com.au) (verified 2026-05-10)