A baserail runs horizontally along the bottom of a decking balustrade, holding the spindles in place at their lower end. It sits on or just above the deck surface and works in tandem with the handrail above to form a complete balustrade system. Without it, spindles have nothing secure to locate into, which compromises both the appearance and stability of the finished structure.
Baserails for Decking Spindles and Balustrades
The baserail sits at the bottom of a decking balustrade system, anchoring the decking spindles in position and giving the whole structure its rigidity. Without it, spindles shift, the balustrade loses stability, and the finished result looks unfinished. MacBlair stocks baserails in treated softwood, machined to accept spindles snugly so there's no movement once installed.
Most baserails in the range are reversible, meaning the same profile doubles as a decking handrail at the top of the balustrade. This keeps the overall look consistent and cuts down on the number of separate components to buy. Typical dimensions run to 38x88mm or similar, with lengths of 2.4m being the most common, though other lengths are available depending on the project. The groove cut into the rail holds spindles firmly without needing additional fixings at every point.
Pressure treatment is standard across the range. It protects against rot, fungal decay, and moisture ingress, which matters in the Northern Irish climate where outdoor timber takes a battering year-round. Once fitted, apply a decking stain or preservative coat to extend service life and maintain appearance. Balustrades on raised decks over 600mm should comply with Building Regulations Part K, which specifies minimum balustrade heights and loading requirements.
To complete a balustrade system, pair baserails with the full range of components available at MacBlair:
- Decking posts to carry the load at each end and corner
- Decking spindles to infill between the rails
- Handrails to cap the balustrade at the top
- Timber decking boards for the deck surface itself
Basrail FAQ's
Yes. Most decking baserails are reversible in profile, meaning the same piece of timber can be flipped and used as the top handrail as well. This is sometimes called a universal or dual-use rail. Using the same profile for both positions gives the balustrade a consistent, symmetrical look. If you plan to do this, buy double the quantity you would need for baserails alone.
The most common baserail size in the UK is 32x78mm, available in 2.4m lengths. Some suppliers also offer profiles around 33x78mm or 45x70mm. The right choice depends on the spindle size you're using, as the groove in the rail needs to match the spindle width for a secure fit. Check the spindle dimensions first and then match the baserail accordingly. If in doubt, buy from the same range to avoid compatibility issues.
For outdoor use, yes. Untreated timber left exposed to rain and moisture will begin to decay relatively quickly, particularly in a wet climate. Pressure-treated baserails have preservative forced deep into the wood fibres, giving far better protection than a surface coat alone. After installation, applying a decking stain or wood preservative adds an extra layer of defence and helps the timber maintain its colour and condition over time.
It depends on the system. Some composite balustrade kits include their own integrated channel or base channel that replaces a traditional timber baserail. However, if you are mixing timber and composite components, or using a system that doesn't include a base channel, then a timber baserail is still needed to anchor the spindles. Always check the installation instructions for the specific spindle system you are using before ordering.