What is the tightest curve I can achieve with plasterboard?

The tightest curve is achieved with 6mm flexible plasterboard (e.g. Gyproc Flex or Knauf Flexboard), which bends to a minimum 600mm radius dry. For standard boards: 9.5mm bends to 2500mm radius dry, 12.5mm to 3500mm dry or 2000mm wet, and 15mm to 4500mm dry. Two layers of 6mm flex board give better rigidity while maintaining a tight radius.

What stud spacing do I need for a curved wall?

Studs must be closer together on curved walls than straight walls. For 6mm flex board, studs should be at 150mm maximum centres. For wet-bent 12.5mm board, use 200mm centres. For dry-bent boards, 300mm centres is typical. The tighter the curve, the closer the studs need to be. All studs must be accurately positioned on the curve — use a trammel or template.

How do I wet-bend plasterboard?

Score the face paper at 50-75mm intervals perpendicular to the bend direction. Dampen the scored face with water using a roller or sponge. Leave for approximately 1 hour until the core softens. Then carefully bend the board around the studs and screw in place. Allow to dry fully (12-24 hours) before taping and jointing. Only the face side should be dampened — keep the back dry.

Can I use two layers for a curved wall?

Yes, and it is often recommended. Two layers of 6mm flex board (total 12mm) give better impact resistance and fire rating than a single 12.5mm dry-bent board, while allowing much tighter curves. Stagger the joints between layers by at least 600mm. Fix the first layer with 25mm screws and the second with 38mm screws.

How do I form the top and bottom tracks for a curved wall?

The top and bottom tracks (head and sole plates) are formed by snipping the flanges of standard metal track at 50-75mm intervals and bending to the required curve. Alternatively, use pre-formed curved track or site-bend timber sole plates by kerfing (making saw cuts at close intervals). Fix the track securely to the floor and ceiling before inserting studs.

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Curved Wall Calculator — Board Type, Radius & Stud Spacing

Calculate plasterboard type, stud spacing and quantities for curved walls based on minimum bend radius for each board type.

Curve Radius

Inside radius of the curve

Curve Angle

90° = quarter circle, 180° = half circle

Wall Height

Floor to ceiling

Board TypeChoose based on your curve radius

Board Price (optional)

Per 1200×2400mm sheet

Stud Price (optional)

Per 2.4m timber/metal stud

How We Calculate This

This calculator determines the correct board type, stud spacing and material quantities for a curved plasterboard wall based on the required bend radius.

The formula

Arc length = Radius × Angle (radians)

Wall area = Arc length × Wall height

For a 1500mm radius, 90° curve at 2.4m height: arc = 1.5 × 1.571 = 2.356m. Area = 2.356 × 2.4 = 5.65 m². Studs at 150mm = 16 studs.

Minimum bend radii

6mm Flex Board: 600mm radius (dry)
9.5mm Standard: 2500mm radius (dry)
12.5mm Standard: 3500mm dry, 2000mm wet
15mm Standard: 4500mm radius (dry)

Based on British Gypsum White Book and Knauf technical data sheets.

Frequently Asked Questions

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Last updated: March 2026

All calculations are estimates. Verify with your supplier.