Dado Rail Calculator

The standard dado rail height is 900mm to 1000mm (roughly 3 feet) from the finished floor level — about two-fifths of the way up a standard 2.4m wall. A widely used proportional rule is to divide the wall height by five and double it (2400 ÷ 5 × 2 = 960mm), which gives a classical look. In rooms with higher ceilings you may raise the rail slightly to keep that proportion. The rail historically marked the top of the dado (the lower section of the wall) and protected walls from chair backs.

Internal corners are best cut as a cope joint rather than a mitre, especially on older walls that aren't perfectly square. Cut the first piece square into the corner. On the second piece, cut a 45-degree internal mitre, then use a coping saw to cut along the profile line left by the mitre. This coped joint fits tightly against the profile of the first piece. For a quick job, a 45-degree mitre on both pieces works if the corner is true.

Yes, exactly. Leave the perimeter toggle off and enter the room's overall length and overall width as if it were a full rectangle, or toggle it on and type the measured perimeter in directly. A notch cut from a corner does not change the perimeter, because the two walls of the notch line up with the wall sections they replace, so an L-shaped room needs exactly the same length of dado rail as its bounding rectangle. Set the corner counts to match: a plain L-shaped room has 5 internal corners and 1 external corner (the corner that points into the room) instead of the standard 4 internal. A chimney breast adds rail rather than removing it: add the depth of the breast to your room length measurement (the calculator doubles the length, which covers both return sides), and count 2 extra internal and 2 extra external corners for it. Door openings are deducted by their own field, so do not subtract them yourself.

Use a grab adhesive such as No More Nails, Gripfill or similar PU-based panel adhesive. Apply a zigzag bead along the back of the rail. Pin nails (lost-head or panel pins) hold the rail in place while the adhesive cures. On painted surfaces, lightly sand the wall first for a better bond.

Ogee is a traditional S-curve profile with a concave and convex section — the most popular for period properties. Torus is a simple half-round (semicircle) profile, common in Victorian and Edwardian homes. Pencil round is the simplest, with just a small rounded edge — modern and clean-looking. All three are widely available from Wickes, B&Q and timber merchants in standard 2.4m and 3.0m lengths.

Dado rail is purely decorative in modern homes — it's not a Building Regulations requirement. It adds character and can break up a large wall for two-tone paint schemes or wallpaper above and paint below. It's most commonly fitted in hallways, dining rooms and living rooms. Kitchens and bathrooms rarely have dado rail due to tiling and moisture. For picture rail near the ceiling, use our Picture Rail Calculator.

On dot and dab walls, the plasterboard is bonded to the masonry with dabs of adhesive, leaving a gap behind. Use long screws (90-100mm) that pass through the plasterboard and into the masonry, with wall plugs in the masonry. Alternatively, use grab adhesive combined with spring toggle fixings. Always check for pipes and cables before drilling.