Roof Batten Spacing Calculator - How Many Battens per Roof

Roof battens and sheathing - what this calculator covers

Six roofing materials, six different spacing rules. Clay tiles need battens every 12.2-13.8 inches, plain tiles every 5.5-6.3 inches, and asphalt shingles skip battens entirely in favor of full OSB sheathing. This calculator handles all six cases: enter your roofing type, slope dimensions and number of roof planes, and it returns the correct batten gauge, total piece count, linear footage and - for shingle roofs - the number of 4x8 ft OSB sheets you need instead.

How to use the calculator - step by step

Choose the roofing material - clay tile, concrete tile, metal tile, plain tile, asphalt shingles or rolled roofing. The calculator applies the correct spacing for each type.
Enter slope length - the distance from ridge to eave measured along the rafter, in centimeters. A typical residential roof slope is 400-800 cm (13-26 ft).
Enter slope width - the width along the eave line. For a 10 m (33 ft) wide house with a gable roof, each slope is about 1000-1200 cm.
Select the number of slopes - gable roof has 2 slopes, hip roof has 4.
Pick batten cross-section - 1x2 in for light roofing, 1.5x2.5 in for standard tile, 2x2.5 in for heavy tile or wide rafter spacing.
Read the results - batten spacing, piece count, total linear footage, and a recommended stock length based on your slope width.

Batten spacing reference by roofing type

Every roofing material has a manufacturer-specified batten gauge. Using the wrong spacing causes tile overlap issues, water penetration or structural failure.

Roofing material	Spacing (cm)	Spacing (inches)	Notes
Clay tile	31-35	12.2-13.8	Varies by tile profile and cover length
Concrete tile	30-34	11.8-13.4	Boral, Eagle profiles specify exact gauge
Metal tile	35	13.8	Matches wave module of panel profile
Plain tile (double lap)	14-16	5.5-6.3	Half the cover length; dense battening
Asphalt shingles	Full sheathing		7/16 in or 1/2 in OSB; no battens
Rolled / built-up	Full sheathing		1 in boards or OSB panels

Practical examples

Example 1: Gable roof with clay tile - slope 650 cm long, 1200 cm wide, 2 slopes, 1.5x2.5 in battens
Result: spacing 33 cm (13 in), 40 battens total, 480 m (1,575 ft) linear

Example 2: Hip roof with concrete tile - slope 500 cm, width 900 cm, 4 slopes, 1.5x2.5 in battens
Result: spacing 32 cm (12.6 in), 64 battens, 576 m (1,890 ft) linear

Example 3: Metal tile roof - slope 450 cm, width 1000 cm, 2 slopes, 1x2 in battens
Result: spacing 35 cm (13.8 in), 28 battens, 280 m (919 ft) linear

Example 4: Plain tile (double lap) - slope 600 cm, width 800 cm, 2 slopes, 1.5x2.5 in battens
Result: spacing 15 cm (5.9 in), 82 battens, 656 m (2,152 ft) linear - plain tile needs dense battening

Example 5: Asphalt shingle roof - slope 500 cm, width 1200 cm, 2 slopes
Result: full sheathing - 120 m² (1,292 sq ft), about 41 sheets of 4x8 ft OSB

Batten sizing guide

Batten size	Best for	When to use
1 x 2 in (25x50 mm)	Metal tile, light roofing	Rafter spacing up to 24 in
1.5 x 2.5 in (40x60 mm)	Clay and concrete tile	Standard for most tile roofs
2 x 2.5 in (50x60 mm)	Heavy tile, slate	Rafter spacing over 32 in or heavy tile
1 x 1.5 in (25x38 mm)	Counter-battens	Ventilation layer under tile battens

FAQ - Frequently asked questions

How do I measure the slope length for this calculator?

Measure along the rafter from the ridge board down to the outer edge of the eave (fascia line). Do not measure the horizontal span - measure the actual diagonal length. On a 6/12 pitch roof with a 15 ft horizontal run, the rafter length is about 16.8 ft (512 cm). If the roof is already framed, measure directly on a rafter.

Can I use battens instead of sheathing for asphalt shingles?

No. Asphalt shingles require a continuous, solid nailing surface - either 7/16 in OSB, 1/2 in plywood, or 1 in tongue-and-groove boards. Battens leave gaps where nails have nothing to grip. Every shingle manufacturer requires full sheathing in their installation instructions, and skipping it voids the warranty.

Why does plain tile (double lap) need so many more battens?

Plain tiles overlap by half their length (double-lap installation). Each tile covers only 5.5-6.3 inches of vertical exposure, compared to 12-14 inches for interlocking tiles. That means roughly twice as many batten rows per slope. A 20 ft slope needs about 40 rows of battens for plain tile vs 20 rows for concrete tile.

How much extra material should I order?

Add 10-15% to the calculated total. Battens need cutting at hips, valleys and gable ends. Damaged or warped pieces get discarded. For complex roof shapes (dormers, valleys), go with 15%. For a simple gable roof, 10% is usually enough.

What is a counter-batten and do I need it?

Counter-battens run vertically along each rafter, under the horizontal tile battens. They create a ventilation gap between the underlayment and the battens, allowing moisture to drain and air to circulate. Required in most building codes when using breathable underlayment with tile roofing. Typical size: 1 x 1.5 in (25x38 mm).

Does roof pitch affect batten spacing?

The pitch does not change the batten gauge itself - that is set by the tile profile. However, steeper roofs have longer slopes for the same horizontal span, so you need more battens overall. A 12/12 pitch doubles the rafter length compared to a flat reference. The calculator accounts for this - just enter the actual rafter length, not the horizontal span.

Related tools

Slab Formwork Calculator

Calculate plywood, lumber and bracing for concrete slab formwork - See calculator

Plumbing Pipe Calculator

Size and count pipes, fittings and hangers for residential plumbing runs - See calculator

Rafter Calculator

Determine rafter size, spacing and lumber quantity for any roof span - See calculator

Roof Pitch Calculator

Convert between degrees, percentage and ratio for any roof slope - See calculator

Roof Calculator

Estimate shingles, metal panels, underlayment and ridge cap for a full roof - See calculator