A dado rail is the horizontal moulding that caps the top edge of a wainscot. It is also called a chair rail, after its original purpose of protecting the wall from chair backs. In Dutch it is the lambriseringslijst, in German the Stuhlleiste.
Function
The rail does three things at once:
- Covers. It hides the joint between the top of the wainscot and the plaster above it, along with the dimensional discrepancies that are always present there.
- Protects. The projecting nose takes the knock from chairs and furniture.
- Terminates. Without a rail a wainscot ends raw; the rail turns it into a deliberate horizontal division.
Profiles and materials
Common profiles are the cove, the quadrant, the ogee and the bead. Materials: solid timber (pine, spruce, oak), MDF with paint carrier foil, or a plaster profile run in situ.
The size follows the wainscot: a low wainscot at 85 cm suits a rail of roughly 40 to 60 mm in height; a substantial framed wainscot at 120 cm can carry something heavier.
Points to watch
- Set the height in context. 85 to 110 cm is usual. Line the top of the rail through with window sills or a door transom so the line carries around the room.
- Scribe internal corners. A 45° mitre almost always fails in an old room, because corners are rarely exactly square. Cut the first length square into the corner and scribe (cope) the second to the profile; that joint stays closed as the timber shrinks.
- Mitre external corners. Measure the actual angle and halve it.
- Glue as well as pin. Construction adhesive on the back, finishing nails through it, holes filled. Pinning alone gives you loose sections after one heating season.
- Caulk along the top. A thin bead of paintable acrylic makes the junction with the plaster crisp and absorbs movement. Do not use silicone — paint will not take on it.
- Seal the end grain. With MDF rails too: seal the cut ends first, or they will drink the lacquer.
Related terms
- Wainscoting
- Cove moulding
- Ogee
- Mouldings
- Skirting
- Transom
Want to know more about building terms? Take a look at our knowledge base on fredsdiyplans.com.