What is concealed nailing?
Concealed nailing, also called blind nailing or secret nailing, is fixing tongue-and-groove boards by driving the nail through the tongue instead of through the face. The groove of the next board slides over the tongue and hides the nail. The result is a wall, ceiling or floor with no visible nail heads. In Dutch it is called verdekt nagelen; the related Dutch term ‘verdrinken’ actually refers to punching a nail head below the surface with a nail set.
How it is done
- Place the board with its groove against the previous board and tap it home with a tapping block, never with the hammer straight on the tongue.
- Angle the nail (about 45 degrees) where the tongue meets the board, so it passes at a slant through the board into the batten or joist.
- Drive it almost home and finish with a nail set so the head sits just below the surface of the tongue. A proud head will stop the next board’s groove from closing.
- Repeat at every batten or joist, then slide the next board over.
On the first and last board, concealed nailing usually does not work. Fix those through the face, in a spot that a skirting or trim will cover later.
Application
- Tongue-and-groove cladding boards on walls and ceilings.
- Solid floorboards on joists or battens.
- Panelling where you do not want to fill nail holes.
Tips and points of attention
- Use a thin wire nail or brad with a small head, or a nailer with T-nails or staples. A thick nail will split the tongue.
- Pre-drill in hardwood and close to the end grain: it prevents splitting.
- Keep the hammer off the tongue: a crushed tongue will no longer fit the groove. Let the nail set do the last bit.
- On wide or thick boards, one concealed nail per batten sometimes does not hold well enough. Follow the supplier’s advice; you may need adhesive or a visible screw with a timber plug.
- Alternative: cladding clips that hook into the groove and are screwed or stapled to the batten.
Related terms
- Tongue and groove
- Nail set
- Setting nails
- Wire nail
- Clapboarding
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