What is a rebate?
A rebate (in American English: rabbet) is a rectangular, stepped recess along the edge of a component, into or against which another part fits. Typical examples are the recess in a window frame where the glass sits, or the edge a door or casement closes against. A rebate gives a fixed seat, improves the seal and prevents a straight-through joint. The Dutch term is sponning.
Types
- Glazing rebate. The rebate in a frame, sash or door into which the glass is set. The glass is held by a glazing bead or sealant. The size of this rebate is the rebate dimension.
- Door or window stop rebate. The rebate in a frame that a door or casement closes against, often fitted with a draught seal.
- Mortar rebate. A shallow rebate on the masonry side of a frame stile that is filled with mortar as the wall is built. This avoids a straight-through gap and keeps the frame from shifting. A related, wider recess is the cloister rebate.
- Rebate in masonry or concrete. A step that something closes against or that leaves room for bricks, such as a stepped foundation edge on which the facing brickwork starts.
- Rebated boards. Insulation boards and planks often have rebated edges so the joints overlap.
Application
- Measure inside the rebate, not the sight size. When ordering new glass, work from the rebate dimension and allow the clearance your glass supplier specifies.
- Keep the rebate clean and dry before glazing. Old sealant and dirt prevent a good seal.
- Prime new timber rebates before glazing, as bare wood absorbs moisture and can rot.
- Check the opening direction. On a new frame, the rebate determines whether a casement opens in or out.
- Use rebated boards for single-layer insulation so no thermal bridge forms at the joints.
Common mistake: ordering a pane to the sight size instead of the rebate size. The glass is then too small and will not sit properly in the rebate.
Related terms
- Glazing rebate
- Mortar rebate
- Cloister rebate
- Rebate dimension
- Glazing bead
- Window frame
- Tongue and groove
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