Roofing Repair & Installation Services Indianapolis

Some manufacturers allow 1″ nominal thickness boards, no wider than six 6”. (Commonly referred to as 1×6 boards), these boards are common on older homes. However, these boards always have small gaps between them and were typically green lumber (not kiln dried) and will shrink 5%-10% leaving gaps greater than ¼” and knotholes greater than 1”. Furthermore proper nail placement requires installers to nail shingles only in exact areas, this would often locate nails in gaps instead of into wood holding the nail in place. Moreover, nails close to the edge of these gaps will cause the 1×6 boards to split and will NOT properly anchor the shingles. These aged boards frequently also have knot-holes that have dried out & fell into the attic area of the home or nails accidentally placed in these knot holes will cause the nails to blow through the knot hole resulting in holes that will cause leaks, again leaving a void where a properly placed nail would not be driven into wood.

Older homes also may have 1×8, 1×10, or 1×12 boards that are NOT approved for shingle warranties. Excessive gaps or boards wider than 6″ require a minimum layer of 3/8” plywood or OSB to be installed over the old boards to achieve a solid, smooth, structurally sound deck for the application of felts, metal edgings, and shingles. Final decisions regarding decking costs can typically be made after careful inspection from the underside of the roof structure or when the old shingles are removed and a complete deck inspection can occur.

Sheathing over ship-lap decking, also shows the ridge opened up for ridge venting. Ship-lap, a type of plank decking installed from the 1930s into the 1960s has been known to cause issues with composition shingles due to its irregularities. The ship-lap, or any other “solid” plank type roof decking, were also typically green lumber (not kiln dried) and will shrink 5%-10% leaving gaps greater than ¼” and knotholes greater than 1”. When new it was actually a nice tight roof deck system. Over time the wood dries out, splits and cracks form, knots fall out and the boards warp and pull free from fasteners. It is common to see a bulge in roofs where the end of a plank has sprung from its anchoring and is now curling away from the roof. Because these boards continue to expand and contract with temperature & humidity the problems just keep getting worse as time goes along. Most composition shingle manufactures will not warranty their products when installed over old plank type roof decking.