Quick answer: A baserail is the bottom horizontal rail of a staircase balustrade, fitted between newel posts to support spindles and protect the wall or step edge. UK standard baserails come in 32mm, 41mm, or 55mm profiles for spindle widths from 32mm to 41mm, in lengths of 2.4m, 3.6m, and 4.2m. Available in pine, oak, and other hardwoods.
UK staircase baserails for new builds, renovations, and stair upgrades. Pine, oak, and hardwood profiles cut to standard UK lengths, supplied from our Bridgend yard with delivery across South Wales and beyond.
What is a baserail?
A baserail (also called a stair base rail or balustrade base rail) is the lower rail of a staircase balustrade. It runs horizontally between newel posts and provides:
- A grooved or rebated channel for the spindles to slot into
- Structural support along the bottom of the balustrade
- A finished edge between the staircase and wall or open side
- A matching design feature alongside the handrail above
Baserails are typically paired with a handrail of the same profile and timber species to give a consistent staircase look.
Baserail sizes and profiles
| Spindle width |
Baserail profile |
Standard lengths |
| 32mm spindles |
32mm baserail |
2.4m, 3.6m, 4.2m |
| 41mm spindles |
41mm baserail |
2.4m, 3.6m, 4.2m |
| 55mm spindles |
55mm baserail |
3.6m, 4.2m |
The spindle width must match the baserail's groove width — fitting a 32mm spindle into a 41mm groove leaves a gap. Always measure your existing spindles before ordering replacement baserails.
Baserails for staircases: timber options
Pine baserails — the standard for painted balustrades. Easy to work with, takes paint and primer cleanly, cost-effective for full staircase installs.
Oak baserails — for natural finishes, hardwood staircases, and premium installs. Stronger, denser, takes a stain or wax beautifully. Ideal where the timber will be visible.
Other hardwoods — sapele, ash, and walnut available to match existing joinery. Get in touch with your spec.
How to fit a baserail
- Cut the baserail to length, allowing for the gap between newel posts (subtract 6mm for clearance).
- Mark spindle positions along the groove — typically 100mm spacing centre-to-centre to meet UK Building Regulations Part K (100mm sphere rule).
- Glue and pin spindles into the groove with PVA and 40mm panel pins.
- Fit the assembled baserail+spindle unit between newel posts, screwing through hidden fixings.
- Install the matching handrail above using the same spindle spacing.
FAQ
What's the difference between a baserail and a handrail?
The handrail is the top rail you grip when walking up the stairs. The baserail is the bottom rail — it sits at the level of the stair tread or floor and holds the bottom of the spindles.
Do I need a baserail on a staircase?
Yes — UK Building Regulations Part K require a balustrade with spindles spaced no more than 99mm apart. The baserail is what holds the spindles in position.
What length baserail do I need?
Measure the gap between your newel posts and order the next length up (2.4m, 3.6m, or 4.2m). You'll cut to size on installation.
Can I get oak baserails for stairs?
Yes — we stock oak baserails in 32mm, 41mm, and 55mm profiles for matching oak spindles and newel posts.
For matching newel posts, spindles, and handrails, browse the rest of our staircase parts range. New to staircase work? Read our full UK stair parts guide for sizing, fitting and Building Regulations Part K compliance.
