In areas of high humidity where solid sheathing is required:
- Apply Certi-Last® pressure-impregnated treated shakes or shingles directly to the sheathing.(See Figure 23a)
- Apply vertical strips over the sheathing in alignment with the rafters below, then place horizontal furring strips on top of the vertical boards. (See Figure 23b).
- Apply horizontal furring strips to the deck, spaced at the exposure of the product.
- A continuous ventilation product may be used beneath the Certi-labelTM roofing material (See Figure 23c).
Note: the above figures are depicting a shake application - Do not interlay shingles with felt