Setting out a roof for tiling involves precisely positioning the battens to ensure correct tile overlap and weatherproofing, a process critically dependent on accurately determining the tile gauge.
Understanding Roof Gauge for Tiling
Setting out the roof for tiling, often referred to as establishing the gauge, is the foundational step that dictates the correct spacing of battens. The gauge is the exposed length of a tile once it's laid, and its consistency across the roof is vital for both aesthetics and functionality. Precise setting out ensures that tiles lay correctly, providing an effective weatherproof layer and a visually appealing finish.
Key Measurements for Batten Placement
The process begins with securing the first and last battens, which then allow for the calculation of the intermediate batten spacing.
1. Setting the Eaves Batten
The first batten at the eaves (the lowest edge of the roof) is crucial for the correct overhang of the first course of tiles and proper water shedding into the gutter.
- Requirement: The eaves course tiles must overhang the fascia board by 40 to 45mm. This means the batten itself needs to be positioned such that when the tile is laid on it, its tail extends this specified distance.
- Practical Tip: This overhang should ideally position the tile just short of the centre of the gutter, ensuring rainwater flows efficiently without splashing back onto the fascia or running behind the gutter. Measure from the outer edge of the fascia back towards the ridge to determine the exact placement for the batten.
2. Setting the Ridge Batten
The last batten at the ridge (the highest point of the roof) must be positioned to allow sufficient overlap for the ridge tiles.
- Requirement: The ridge tiles need to overlap the top course of main roof tiles by at least 75mm. This overlap is essential for preventing water ingress at the roof's peak.
- Practical Tip: Measure down from the ridge line to mark the position for this batten. The exact position will depend on the type of ridge tile being used and its specific overlap requirements, but the minimum 75mm overlap is a critical guideline.
3. Calculating Intermediate Batten Gauge
Once the eaves and ridge battens are fixed, the distance between them can be accurately measured. This measurement is then divided by the desired number of tile courses to determine the consistent gauge for all intermediate battens.
- Process:
- Measure the clear distance between the top edge of the eaves batten and the underside of the ridge batten (where the top tile would rest).
- Determine the tile's maximum and minimum recommended gauge from the manufacturer's specifications.
- Divide the total measured distance by the target gauge (within the manufacturer's range) to find the approximate number of courses. Adjust the gauge slightly to ensure the measurement divides evenly, creating an identical gauge for all courses.
- Mark out these calculated gauge lines up the roof, typically using a batten gauge tool or a long measuring tape and chalk line.
Table: Key Batten Setting Out Measurements
For clarity, here are the critical measurements to remember when setting out your roof battens:
| Batten Location | Critical Measurement & Purpose |
|---|---|
| Eaves Batten | Set to allow tile tails to overhang fascia by 40-45mm (just short of gutter centre). |
| Ridge Batten | Set so ridge tiles will overlap top course tiles by at least 75mm. |
Practical Tips for Accurate Setting Out
- Use a Batten Gauge Tool: These tools are invaluable for marking consistent gauge lines quickly and accurately. They can be adjusted to the specific tile gauge.
- Snap Chalk Lines: After measuring and marking your gauge, use a chalk line stretched across the roof to snap clear lines for batten placement.
- Check Squareness: Ensure your battens are laid square to the rafters and parallel to each other. Use a large framing square or a 3-4-5 triangle method.
- Account for Tile Type: Different tile types (e.g., plain tiles, interlocking tiles) have different minimum and maximum gauges. Always consult the tile manufacturer's specifications before setting out.
- Dry Laying: For complex areas, consider dry laying a few tiles to confirm the gauge and fit before permanently fixing all battens.
- Start Straight: Any inaccuracy in the first few battens will compound, leading to significant errors higher up the roof. Take your time at the start.
Why Accurate Setting Out Matters
Accurate setting out is paramount for several reasons:
- Weatherproofing: Correct gauge ensures proper overlap between tiles, preventing water ingress and protecting the roof structure.
- Durability: Properly supported tiles are less likely to crack or slip, extending the lifespan of the roof.
- Aesthetics: Consistent gauge creates an even, professional, and visually appealing roof surface.
- Efficiency: A well-set out roof makes the tiling process faster and more straightforward, reducing potential rework.
