The correct flooring fixing is chosen from the job backwards. First identify what is being fixed, what it is being fixed into and the flooring manufacturer's approved method. Then match the fastener's type, profile, gauge and length to a compatible machine. Two fixings that look similar may not be interchangeable.
Check the complete floor before fixing
Locate joists and check for electrical cables, water, gas and heating pipes before drilling, screwing, nailing or stapling. WWFS recommends experienced professional installation. Always follow the current instructions for the flooring, subfloor system, fastener and machine, as these take priority over this general guide.
Quick fixing selector
Start with the part of the build-up you are actually fixing. A finished wood floor, structural floorboard, plywood overlay and scotia trim all need different fasteners.
Finished tongue-and-groove flooring
Where the exact floor permits mechanical installation, assess a secret screw such as Tongue-Tite or the specified 16-gauge T or L flooring cleat. Do not assume every thickness or joint can be secret-fixed.
Structural boards or panels to joists
Floor-Tite anti-creep screws are designed for secure, removable face-fixing into timber joists. They are different from small-headed secret-fixing screws.
Plywood or hardboard overlay
Use the fixing schedule required by the complete preparation system. Depending on that system this may be screws, 4000 or 606 divergent staples, or SFN19 ring-shank coil nails. Some smoothing-compound systems specifically require screw-fixed plywood.
Scotia, mouldings and light trim
Use suitable 18-gauge brads with a compatible finish nailer where the trim material and background permit. Brads are discreet trim fixings, not structural floor or joist fixings.
| Job | Fixing family to assess | Do not miss |
|---|---|---|
| Secret-fix an approved interior T&G floor | Standard Tongue-Tite or the floor's specified 16G cleat | Floor approval, base, angle, edge distance and penetration |
| Secret-fix approved T&G timber where moisture or corrosion resistance matters | Tongue-Tite Plus stainless steel | Exposure class, timber approval and pilot-hole advice for hard timber |
| Fix suitable floorboards or structural panels to known joists | Floor-Tite | Joist position, hidden services and correct length |
| Secret nail an approved thicker finished floor | Specified T-headed cleat, L-profile nail or T-profile nail | Exact profile, 16G machine, length and floor instructions |
| Mechanically fix sheet overlay to timber | Specified screws, ring-shank coil nails or divergent staples | Overlay thickness, centres, edge spacing, joint support and the next product in the system |
| Fix scotia or a light moulding | 18G brad | Fix to the wall or skirting where appropriate, not through a floating floor |
What does gauge mean?
Gauge describes the nominal thickness or fastener family, not its length. As a general guide, a higher gauge number means a slimmer fastener, so an 18-gauge brad is finer than a 16-gauge flooring cleat. However, gauge is not a universal millimetre conversion. The shape may be round, rectangular, L-headed, T-headed or stapled, and manufacturers design machines around a complete fastener system.
Read the full description, not just “16G” or “18G”
Gauge tells you the thickness family. Length tells you how long the fastener is. Profile or series tells you its shape and system. A 16G T cleat and 16G L cleat are not automatically interchangeable, and a 606 staple does not fit a 4000-series stapler.
| WWFS fastener family | Stocked sizes | Machine or system | Typical purpose |
|---|---|---|---|
| 16G T or L flooring nails and cleats | 38mm, 45mm or 50mm, depending on profile | The exact compatible angled flooring nailer for that T or L profile | Secret-nailing finished wood flooring only where the flooring manufacturer approves it |
| 18G finish brads | 15mm, 19mm and 25mm stocked | Maestri ME30, ME606 or MC606, subject to the machine's stated range | Scotia, mouldings and light finishing work, not structural floor fixing |
| 4000-series divergent staples | 16mm and 20mm | Maestri ME4000 or MC4000 | Suitable flooring-preparation sheets and similar approved applications |
| 606-series divergent staples | 18mm and 22mm | Maestri ME606, MC606 or Pneumatic 606 | Suitable plywood, hardboard, gripper and preparation work |
| 2.0mm ring-shank sheet-collated coil nails | 19mm, 22mm, 25mm and 28mm | Spotnails SFN19 coil nailer | Approved plywood, hardboard or sheet overlay to timber |
Machine ranges can be broader than the particular fasteners stocked by WWFS. Always match the code, profile, collation, crown and stated length range shown on the tool and fastener packaging.
Which flooring screw should I use?
Standard Tongue-Tite: discreet interior T&G fixing
Standard Tongue-Tite 3.5 x 45mm screws are hardened-steel TX10 screws intended for discreet fixing through the tongue of suitable engineered, hardwood, softwood or fibreboard flooring. The manufacturer shows the screw driven through the tongue at approximately 30 to 45 degrees. Its small head sits into the tongue so the next board can close over it.
- Use only where the flooring instructions permit mechanical secret fixing.
- Drive to the specified angle and depth without splitting or weakening the tongue.
- Fix into a suitable timber base, not into an unsupported sheet edge.
- The screw can be removed more readily than a cleat if a board must be lifted.
- This standard zinc/yellow version is primarily an interior fixing. It is not the corrosion-resistant choice for exposed or damp-risk work.
Tongue-Tite Plus: stainless steel for corrosion resistance
Tongue-Tite Plus is manufactured from 305 stainless steel. WWFS stocks 3.5 x 32mm, 45mm and 49mm versions. The stainless construction makes it the better option where damp, condensation or exterior exposure means corrosion resistance is important, provided the timber and complete construction approve this method.
| Feature | Standard Tongue-Tite | Tongue-Tite Plus |
|---|---|---|
| Material | Hardened steel with yellow finish | 305 stainless steel |
| WWFS-stocked sizes | 3.5 x 45mm | 3.5 x 32mm, 45mm and 49mm |
| Drive | TX10 | TX10 |
| Best suited to | Approved dry interior T&G flooring | Approved flooring or T&G timber where corrosion resistance is required, including suitable exterior applications |
| Main benefit | Discreet, controlled and removable interior secret fixing | Greater resistance to corrosion from moisture and exposure |
| Important note | Do not use as an exterior stainless fixing | Stainless does not mean universally stronger; pilot drilling may be advisable in dense hardwood to reduce resistance and protect the screw |
Floor-Tite: structural boards and panels to joists
Floor-Tite Tri-Lock PZ2 screws are face-fixing screws for securing suitable timber, fibre or structural flooring boards to timber joists. Their anti-creep thread and double-countersunk head help clamp the board and reduce movement while leaving a removable fixing.
- 4.2 x 45mm: the manufacturer identifies this as the usual size for 18mm boards.
- 4.2 x 55mm: the manufacturer identifies this as the usual size for 22mm boards.
- Those are selection guides, not permission to ignore services, the board manufacturer's schedule or the required penetration.
- Do not confuse Floor-Tite's visible face-fixing role with Tongue-Tite's small-headed secret-fixing role.
For inspection, strengthening, plywood overlays and detailed fixing patterns, use the suspended timber subfloor preparation guide.
Secret nails and cleats for finished flooring
Secret nailing uses an angled flooring nailer to drive a cleat through the tongue of an approved board into a suitable timber subfloor. The next row conceals the fixing. It is fast and leaves the face mostly clear, but the flooring thickness, construction, tongue position, board width, cleat profile and base must all suit the system.
Do not mechanically fix a floor just because it has a tongue
Many manufacturers permit secret fixing for suitable 18mm to 20mm structural tongue-and-groove products, but this is not a blanket rule. Do not treat a 15mm board as suitable unless its own instructions clearly approve the method. Parquet, herringbone, chevron and design panels are normally fully bonded rather than secret-nailed.
T-headed and L-headed profiles
WWFS stocks several 16-gauge finished-floor fixing profiles. Select the one specified by the nailer and floor, not the one that looks closest.
| Profile | WWFS product | Stocked length | Compatibility check |
|---|---|---|---|
| Porta-Nails T-headed cleat | 16G T-headed Porta-Nails cleats | 38mm and 50mm | Use only with the specified Porta-Nails-compatible system |
| Spotnails L profile | 38mm L nails or 45mm L nails | 38mm and 45mm | Requires a machine designed for this exact L profile and 16G body |
| Spotnails T profile | 38mm T nails or 45mm T nails | 38mm and 45mm | Requires a machine designed for this exact T profile and 16G body |
How is cleat length chosen?
Length is based on the board thickness, fixing angle and the required penetration into a suitable timber base. It must provide reliable hold without creating an avoidable risk to hidden services. Longer is not automatically better. Follow the floor and machine instructions, and test the machine pressure or driving force on an offcut so the cleat finishes correctly without crushing or splitting the tongue.
The first and last rows may not leave enough room for the angled nailer. The flooring instructions may therefore require approved face-fixing, another permitted fixing method, or a carefully planned adhesive detail. Never improvise a mixed method merely to pull boards over an uneven subfloor; prepare and level the base correctly first.
Plywood, hardboard and sheet-overlay fixings
Overlay fixings secure a preparation layer to timber. They are not automatically suitable for the finished floor above it. The correct choice depends on the overlay material and thickness, joist or board construction, supported joints, fixing centres, edge distances and every primer, smoothing compound, adhesive or floor that follows.
SFN19 ring-shank coil-nail system
The Spotnails SFN19 pneumatic coil nailer works with WWFS 2.0mm ring-shank, sheet-collated coil nails in 19mm, 22mm, 25mm and 28mm lengths. It is intended for rapid fixing of suitable plywood, hardboard and sheet overlays to timber subfloors. The ring shank improves resistance to withdrawal compared with a smooth nail.
This is an overlay tool, not a secret-nailing machine for the tongue of a finished wood floor. A pneumatic set-up also needs a suitable compressor, hose and couplings. WWFS offers the SFN19 and SFC240 kit, the separate SFC240 low-noise compressor and a 10m hose and coupling set.
Divergent staples for preparation work
Divergent-point staple legs spread as they enter the timber, helping the staple resist withdrawal. They still have to match the exact machine and be approved for the overlay system.
4000 series
4000-series 16mm or 20mm staples fit the ME4000 electric stapler and MC4000 cordless stapler. They do not interchange with 606-series staples.
606 series
606-series 18mm or 22mm staples fit the ME606 electric, MC606 cordless and Pneumatic 606 tools.
The next layer may change the fixing requirement
A staple or ring-shank nail may be permitted for some general overlay work, but not for every proprietary system. For example, F. Ball's timber preparation guidance requires plywood used beneath STOPGAP 700 to be securely screw-fixed rather than nailed or stapled. Check the current data sheet for every product in the build-up before choosing the fastener.
Machine and fastener matcher
| Machine | Correct WWFS consumable | Main job | Power or extra equipment |
|---|---|---|---|
| Maestri ME4000 | 4000 series, 16mm or 20mm | Approved flooring-preparation sheets | Electric |
| Maestri MC4000 | 4000 series, 16mm or 20mm | Approved flooring-preparation sheets | 20V cordless kit |
| Maestri ME606 | 606 staples, 18mm or 22mm; compatible 18G brads | Approved overlay, gripper and light finish work | Electric |
| Maestri MC606 | 606 staples, 18mm or 22mm; stocked 18G brads in 15mm, 19mm or 25mm | Approved overlay, gripper and light finish work | 20V cordless kit |
| Spotnails Pneumatic 606 | 606 staples, 18mm or 22mm | Approved plywood, hardboard and gripper | Suitable compressor, hose and couplings |
| Maestri ME30 | Compatible 18G brads; WWFS stocks 15mm, 19mm and 25mm | Scotia, moulding and panel finishing | Electric |
| Spotnails SFN19 | 2.0mm sheet-collated ring-shank coil nails, 19mm to 28mm stocked | Approved plywood, hardboard and sheet overlays | Suitable compressor, hose and couplings |
| Angled finished-floor nailer | The exact approved 16G T or L flooring cleat and length | Secret-fixing approved finished flooring | Check model-specific power, nose, magazine and profile |
Repairs, squeaks and trim fixings
Loose or squeaking floorboards
Movement has to be diagnosed before it is hidden. Where a suitable traditional floorboard crosses a known sound joist and hidden services have been located, a Floor-Tite screw can provide a controlled, removable face fixing. Sink the head appropriately, then fill the recess only after movement has been stopped. Filler is cosmetic; it cannot secure a loose board.
Use the full guide to repairing loose and squeaking floorboards before drilling. If the issue is a weak joist, unsupported end, damaged panel, rubbing service or poor subfloor, extra screws alone are not the complete repair.
Scotia and trims
18G brads provide a small, discreet fixing for suitable scotia and mouldings when driven with an approved ME30, ME606 or MC606 machine. Keep floating flooring free to move: scotia is normally fixed to the skirting or wall, not pinned through the floor. Thresholds, nosings and movement profiles have their own fixing requirements; see the threshold, trim and nosing guide.
Common fixing mistakes
Choosing by appearance
A fastener that looks similar can have the wrong gauge, crown, head, collation or driver profile. Match its exact code to the machine.
Confusing gauge with length
“16 gauge” does not tell you whether a 38mm, 45mm or 50mm cleat is needed. Gauge and length answer different questions.
Swapping T and L cleats
Both may be 16G, but their heads, magazines and drivers can differ. Use only the profile named by the nailer manufacturer.
Using brads structurally
An 18G finish brad is intended for light finishing work. It is not a substitute for a structural floorboard screw or flooring cleat.
Fixing an unsuitable 15mm floor
Do not assume a thinner engineered board can be secret-nailed or screwed. Use only a method approved for the exact product.
Ignoring the next product
The smoothing compound, adhesive or flooring system above an overlay may demand screw fixing even where staples or nails are common elsewhere.
Using fixings to flatten the floor
Do not add glue and fixings simply to force boards over an uneven subfloor. Repair, stabilise and level the base correctly.
Missing hidden services
Never assume a joist line is safe. Scan, inspect and confirm cable and pipe routes before choosing the fixing position or length.
Fixing FAQs
Is 18 gauge stronger than 16 gauge?
No. Gauge numbers run in the opposite direction for these fastener families: 18G is normally slimmer than 16G. Holding performance also depends on profile, length, material, angle, background and application, so gauge alone does not determine strength.
Will any 16-gauge flooring nail fit my nailer?
No. A 16G T cleat, L cleat and proprietary T-headed system can require different magazines, noses and drivers. Check the exact tool model and approved consumable code.
Should I choose Tongue-Tite Plus for every indoor floor?
Not automatically. Plus is valuable where stainless-steel corrosion resistance is needed. Standard Tongue-Tite is the normal dry-interior option where approved. Choose for the environment and specification rather than treating stainless as a universal strength upgrade.
Can I secret-fix 15mm engineered flooring?
Only if the exact flooring manufacturer expressly permits it and provides the fixing specification. Do not use a generic thickness rule. Many mechanically fixed systems are intended for thicker structural tongue-and-groove boards.
Can I use the SFN19 to secret-nail finished wood flooring?
No. The SFN19 and its sheet-collated ring-shank coil nails are for suitable sheet overlays such as plywood and hardboard. Finished-floor secret nailing requires the floor's approved angled nailer and cleat system.
Can I staple plywood before applying smoothing compound?
Only when the complete smoothing system permits it. Some systems require plywood to be securely screw-fixed. Read the current primer and smoothing-compound data sheets before fixing the sheet.
Can a longer fixing stop a squeak?
Not safely by guesswork. First identify the cause and locate the joist and services. The fixing must provide suitable penetration without creating a hidden-services risk. Unsupported joints, damaged joists or rubbing services need the actual defect repaired.
Related WWFS guides
- Which wood-floor installation method should I use?
- How to prepare suspended timber subfloors
- How to prepare a subfloor for engineered wood flooring
- How to repair loose and squeaking wooden floorboards
- Which wood-flooring adhesive should I choose?
- How to test moisture and choose a DPM or primer
- Underfloor heating and engineered wood flooring
Still unsure which fixing fits your machine?
Send WWFS the flooring name, thickness and joint, the subfloor construction, the exact machine model and a photo or code from the existing fastener box. That information is far more useful than gauge alone.