Roof battens are strips of wood or plastic that form the base to which you connect roof tiles. Because the battens raise the tiles up by a small amount, they provide some ventilation. Battens also may help with drainage when water leaks under the roof if they are not made of a material that will absorb water. The total length of battens you need for a roof depends on the number of rows of tiles.
Things You'll Need
Long, sturdy measuring tape
Measure the length of the eave, or the bottom edge that hangs out over the home, for each section of the roof. Do not add these up; keep the numbers separate.
Multiply the number of rows on each section by the length of the eave of that section. This gives you the total length of battens needed for each section. For example, if you are adding battens to two sides of a roof, each with an eave length of 20 feet, and you will have 15 rows of tiles, multiply 15 by 20 to get 300 feet.
Add together the length of the battens needed in each section to get the total length of batten material needed for the whole roof. Using the example from Step 2, add 300 and 300 to get 600 feet total.
Convert the measurement to meters, if it is currently in feet, by multiplying the number you got in Step 3 by 0.3048. A total of 600 feet of batten material would equal 182.88 meters of batten material.
Add extra lengths of batten material so you have more on hand if you make a mistake or damage part of the batten.
If you are measuring eaves on a tall roof or upper story, estimate by measuring at a lower height or along the ground. Alternatively, have several assistants help you measure the eaves by steadying ladders and holding up the other end of the measuring tape up at the eave.