Building components · Roof Carcass & Edges
Counter-Batten
Explains the counter-batten as the element that creates a path, which is a different purpose from carrying anything.
Educational reference entry. What this element has to do, and whether any particular arrangement of it is adequate, depends on the whole assembly, the loading, the exposure, local requirements, the manufacturer's instructions and qualified professional design.
Overview
What a counter-batten is
A counter-batten runs up the slope, fixed over the rafters or over a boarded deck, and the tile battens are then fixed across it. The effect is to lift the tile battens clear of the underlay.
That lift creates a continuous space above the underlay running down the slope. Water that gets past the covering can drain freely, and in ventilated arrangements air can move up the space rather than being interrupted by every batten.
Boundaries
How it differs from nearby elements
The distinctions that keep this entry from being a restatement of its neighbours.
- It is not a tile batten. Tile battens run across the slope and carry the covering; counter-battens run up it and carry the tile battens.
- It is not a rafter, despite running in the same direction. It carries only the battens and creates a space; it spans nothing.
- It is not insulation or a membrane. It creates the void those layers depend on rather than being one of them.
Terminology
Common names and aliases
These names describe the same element. The library keeps one entry per component so that a trade term or a regional name never becomes a second, thinner page.
- counter battens
- vertical battens
- drainage battens
Dependencies
What it depends on
What has to be right elsewhere for this element to do its job.
- The underlay beneath it, since the space it creates is above that layer and only useful if the underlay is shedding water.
- Being continuous up the slope, so the path it creates is not interrupted.
- Provision at eaves and ridge for the path to be open at both ends where ventilation depends on it.
- Fixings that pass through it into the structure without compromising the layers beneath.
Considerations
Topics that genuinely apply here
Subjects worth discussing about this element. These are discussion topics, never measured values, ratings or performance claims.
The space a counter-batten creates is what lets water reaching the underlay run away rather than sit against the battens.
Where a roof depends on a ventilated space above the insulation, counter-battens are commonly what keeps that space open and continuous.
Adding counter-battens raises the roof plane, which affects verge, eaves and abutment arrangements and has to be planned rather than discovered.
Materials
Commonly formed from
Material families this element is commonly realised in. This states common practice only — it is not a statement that any of these materials suits this component in a particular building, which depends on the whole assembly and on qualified review.
Assemblies
Building systems this element is met in
The role this component fills inside each assembly. A role describes what the element does there — it is not a statement that this component suits that system in any particular building.
Junctions
Interfaces this element takes part in
Junctions where the condition between this element and another governs how the construction behaves. These name the junction and the subjects it raises; they are not details, arrangements or approved ways of building.
Counter-Batten to Tile Batten
Where battens cross above the underlay, creating or blocking the path water uses to leave the roof.
Raises: Moisture · Drainage · Buildability · Weathering
Where it is met
Application contexts
Building contexts where this element is commonly encountered. Association is not recommendation: appearing here does not mean the component suits every instance of that context, or any particular one.
- Pitched Roof
Related elements
Neighbouring components
Typed relationships to other elements. There is deliberately no generic “related” category: an edge that cannot be classified does not exist.
Clarifications
Commonly misunderstood
- That counter-battens are an optional extra. Where the roof build-up depends on drainage or ventilation above the underlay, they are what provides it.
- That they can be added without consequence. They change the roof's thickness at every edge.
Conversations
Questions for qualified professionals
Questions worth asking someone with the project in front of them. This page cannot answer them.
- Does this roof build-up depend on a drained or ventilated space above the underlay?
- Is the path continuous from eaves to ridge, and open at both ends?
- How does the additional thickness affect eaves, verge and abutment arrangements?
- How do fixings pass through without compromising the layers below?
Go deeper
Related Build Design Hub guides
Planning guidance behind the decisions this element involves.
Preparation
Related planning checklists
Owner-side preparation before the conversation where this element comes up.
What this entry does not do
- No size, spacing, ventilation provision or fixing is stated here.
- Whether a roof requires a drained or ventilated space above the underlay follows from the build-up design.
Roof Carcass & Edges
The battens, boards and edge elements that finish a roof structure and prepare it to receive a covering.
Browse all roof carcass & edges entries →