counter batten
vertical wood strips installed on sloped roofs over which horizontal battens are secured. The primary roof covering is attached or secured to these horizontal battens.
counter batten: vertical strips that make sloped roofs level for tiles
A counter batten is a vertical wooden strip, typically 25 to 50 mm wide and 40 to 75 mm deep, fixed perpendicular to the slope of a pitched roof. It serves to level out and support the horizontal battens that carry roof tiles or slates. On a sloped surface, horizontal battens would sit unevenly; counter battens create a plumb vertical reference, allowing horizontal battens to run true and parallel across the roof face.
Counter battens work in tandem with the roof rafter timbers and the horizontal battens above them. The counter batten is nailed or screwed directly to the rafters, running up the slope. Horizontal battens are then fixed across these counter battens at regular spacing, usually 300 to 600 mm apart depending on the tile or slate size and roof pitch. This creates a consistent support structure onto which roof tiles are hung or nailed.
Materials and Installation Variables
Counter battens are usually softwood, commonly sawn timber or preservative-treated wood to resist moisture and rot. On steep pitches, thicker and more robust counter battens may be required. The spacing and sizing of counter battens must account for the roof pitch, wind exposure, tile weight, and local building codes. Undersized counter battens or poor spacing can lead to sagging horizontal battens, tile slip, and water ingress.
The term "counter" refers to the opposing direction: these battens run against (counter to) the slope itself, whereas the horizontal battens run across it. Poor workmanship with counter battens, such as uneven fastening, warped timber, or inadequate nailing, creates waviness in the horizontal batten plane, leading to cracked tiles, movement, and premature weathering. In older or poorly maintained roofs, rot in counter battens can compromise the entire tile support system.
Counter battens are standard in pitched roof construction across Europe and are particularly important in high-exposure locations where wind uplift and thermal movement place stress on the tile fixing system. They are sometimes omitted on low pitches or in dry climates, but building standards in most regions now mandate them for durability and performance, especially on slopes steeper than 35 degrees.