What is a corner brace?
A corner brace is a diagonal member — a batten, plank or metal bracket — fixed across a corner joint to prevent the frame from racking. For example, where a stud meets a rail, the corner brace forms a triangle that keeps the connection rigid and square.
How does a corner brace work?
A right-angled connection (e.g. a stud and a rail) is vulnerable to lateral forces. Without bracing, the frame can distort into a parallelogram. The corner brace creates a triangle with the two connected members — and a triangle cannot deform. This is the same principle as diagonal bracing in large structures.
Application
Corner braces are used in:
- Timber frame construction — in the corners of wall and floor frames
- Window and door frames — to keep the frame square during installation
- Fences and gates — diagonal braces in gate frames and fence panels
- Scaffolding — diagonal members serving the same stiffening function
- Roof structures — where purlins rest on posts
Materials and fixing
Corner braces are typically made from:
- Timber — a batten or board, cut at an angle and screwed or nailed in place
- Steel — angle plates or flat bars for heavier constructions
- Plywood — triangular gusset plates screwed across the corner
For DIY projects, a corner brace is often cut from the same timber dimensions as the studs and rails, placed at a 45-degree angle.
Related terms
- Timber frame construction
- Diagonal bracing
- Post
- Rafter
- Structural frame
Learn more about building terms in our knowledge base at fredsdiyplans.com.