Quick answer: PSE stands for Planed Square Edge. It's timber that has been machined on all four faces from rough-sawn stock to a smooth, square-edged finish. PSE and PAR (Planed All Round) describe the same product — both terms are used interchangeably across the UK timber trade. PSE timber is the standard for interior joinery, shelving, trim and finishing work where a clean, ready-to-use section is needed.
We stock PSE timber in redwood, whitewood, pine and American white oak across a full range of UK standard sizes. All sections planed to smooth, square faces — no further preparation needed before finishing or installation.
What does PSE mean in timber?
PSE = Planed Square Edge. The timber is taken from a rough-sawn section and run through a four-sided moulder (or planer) to produce a finished piece with:
- Two flat, parallel faces
- Two flat, parallel edges
- Square 90° corners between faces and edges
- A smooth surface ready for paint, stain, or natural finish
This is the timber you'd use for skirting, architrave, shelving, furniture, joinery details — anything that's going to be visible or finished, where rough-sawn stock would need extra preparation.
PSE vs PAR timber: is there a difference?
In practice, no — they're the same product. PSE (Planed Square Edge) is more common in England. PAR (Planed All Round) is more common in Scotland. Both refer to timber planed on all four faces with square edges.
Some older trade definitions used PSE to mean "planed faces with sawn edges" and PAR to mean "all four sides planed", but modern UK suppliers (including us) use both terms for the same fully-planed product. Always check the finished dimensions on the product listing if you need to be sure.
Nominal vs finished sizes
PSE timber is sold by nominal size (the rough-sawn dimension before planing), but the actual finished size is smaller because material is removed during the planing process. Typical reduction:
-
25mm nominal → finishes around 20–22mm
-
50mm nominal → finishes around 44–47mm
-
75mm nominal → finishes around 69–72mm
Each product page lists the exact finished dimensions. Always order to finished size when matching to existing trim or drawings.
PSE timber species and applications
| Species |
Typical sizes |
Best for |
| Redwood |
25mm, 50mm, 75mm thick × 50–225mm wide |
General joinery, painted finishes, skirting, shelving |
| Whitewood |
32mm thick × up to 275mm wide |
Boards, deep shelving, painted joinery |
| Pine |
6×44mm up to 34×44mm |
Beading, stops, decorative trim |
| American white oak |
25mm thick × various widths |
Hardwood joinery, furniture, premium trim |
PSE vs C24 structural timber
PSE timber is for finishing and joinery. It's not graded for structural load — use C24 graded timber for joists, rafters, studs, and anything load-bearing. PSE is what you use after the structural work is done, for the visible elements of the build.
If you need structural sections, browse our C24 timber range. Read our C24 vs C16 guide for the strength figures.
Buying PSE timber from Nottage
All PSE stock kiln-dried for stability and supplied in standard UK joinery sizes. Trade pricing on bulk orders, fast delivery across South Wales and beyond, collection from our Bridgend yard.
For matching skirting and architrave profiles, see our skirting and architrave collection. For larger structural sections, browse the construction timber range.
