Cant Rails

What Are Cant Rails?

Cant rails are rectangular timber fence rails characterised by a distinctive angled or sloped top edge. This 'canted' profile is specifically designed to encourage rainwater to run off away from the fence structure and the vertical boards fixed to it, helping to prolong the life of the timber. Unlike the triangular profile of arris rails, cant rails offer a flat face for fixing.

How They Work 

• Provide Horizontal Support: They act as strong horizontal beams running between fence posts (like timber or concrete posts). This creates the essential framework for a fence section or 'bay'.   
• Act as a Fixing Point: Vertical fence boards, most commonly feather edge boards used in closeboard fencing, are nailed or screwed directly onto the flat face of the cant rails.
• Aid Water Runoff: Cant rails have a distinctive sloped top edge. This design feature helps rainwater to run off easily, preventing water from sitting on top of the rail and reducing the risk of rot affecting the rail itself or the top edges of the boards fixed below it.   
• Contribute to Strength & Stability: By connecting the posts horizontally and providing a solid backing for the vertical boards, cant rails add significant strength and rigidity to the overall fence structure, helping it withstand wind and general wear.

Installation Guidance

Cant rails are typically installed horizontally, fixed securely to the face of fence posts using appropriate exterior-grade galvanised screws or nails.

• Number of Rails: For fences up to around 1.2m high, two rails are usually sufficient. For fences 1.5m - 1.8m or taller, three rails (top, middle, bottom) are recommended for adequate support.
• Positioning: Ensure rails are parallel and evenly spaced. The bottom rail should sit just above the gravel board.
• Cut Ends: Remember to treat any cut ends of the timber with a suitable end-grain preservative to maintain the integrity of the pressure treatment.

Understanding 'Unseasoned' Timber Cant Rails

You will notice our timber cant rails are described as 'unseasoned'. This is a standard term in the UK timber industry and simply means the wood has not been artificially dried (for example, in a kiln) down to a low moisture content after being felled and sawn. It retains a higher level of its natural moisture when supplied.   

Supplying external landscaping and fencing timbers like cant rails in an unseasoned state is common practice. Here’s what it means for you:

• Natural Drying: Once installed in your fence line, the unseasoned timber will naturally dry out and acclimatise to the ambient moisture levels over time.
• Potential Movement: As the timber dries, some natural movement, such as slight shrinkage across the width and thickness, or the appearance of minor surface 'checks' (small cracks), can occur. This is a normal characteristic of unseasoned wood as it settles and is generally expected in robust external components like fence rails.
• Suitability for Purpose: For sturdy applications like fencing rails, this natural drying process and potential minor movement do not typically compromise the structural integrity or suitability of the timber.
• Treatment is Key: Importantly, our cant rails are pressure treated. This treatment provides the essential long-term protection against rot, fungal decay, and insect attack, and works effectively regardless of whether the timber was seasoned or unseasoned beforehand.   

In essence, while unseasoned cant rails will dry naturally once installed, their pressure treatment ensures they are durable and fit for purpose in constructing long-lasting fences. This differs from 'seasoned' or 'kiln-dried' timber which is pre-dried for applications requiring greater initial dimensional stability, like internal joinery.

Choosing Your Treatment Colour: Brown vs Green Cant Rails

Our unseasoned sawn timber cant rails are available in two popular pressure-treated colour finishes. While both offer the same essential protection, the initial appearance differs, allowing you to select the best fit for your project's aesthetics:

• Green Treated: This finish results from the standard copper-based preservatives used in the UC3 pressure treatment process (e.g., Tanalith E Green). When new, the timber will have a distinct pale green or yellowish-green tint. Exposed to UV light and weather over time, this colour will gradually fade, usually settling into a natural silvery-grey or light honey-brown appearance.
• Brown Treated: For this option, a brown dye is added during the pressure treatment (e.g., Tanalone or Tanalith E Brown). This gives the timber a darker, richer brown colour from the outset, often preferred for a more traditional look or to blend immediately with natural surroundings or existing brown timber structures. This brown colour will also weather over time, generally fading to lighter brown or greyish-brown tones depending on exposure.

Key Consideration:

It's important to note that the colour, whether Green or Brown, is primarily for initial aesthetic preference. Both treatments provide the same level of long-lasting UC3 preservative protection against rot, fungal decay, and insect attack. The underlying durability and performance of the cant rail remain consistent regardless of the colour choice.