Roof Decking & Plywood Replacement in Wasaga Beach & Simcoe County
705 Roofing provides professional roof decking and plywood replacement services for damaged, weakened, or rotting roof structures. A strong roof deck is critical for the performance, lifespan, and safety of your entire roofing system.
If your roof has soft spots, leaks, sagging areas, or water damage, damaged plywood may need to be replaced before a new roofing system is installed.
Roof decking is the wood surface installed over the roof framing that supports the roofing system.
Most residential roofs use:
Roof decking can become damaged due to:
Damaged decking should be replaced before installing new shingles or metal roofing.
You may have damaged plywood or roof decking if you notice:
In many cases, decking damage is hidden beneath old shingles and only becomes visible during roof replacement.
1. Roof Inspection & Tear-Off
We remove the existing roofing materials and inspect the roof deck thoroughly for damaged or weakened areas.
2. Damaged Wood Removal
Rotten, soft, or deteriorated plywood and decking materials are removed safely.
3. New Decking Installation
New plywood or roof decking is installed securely to create a solid foundation for the roofing system.
4. Roof System Installation
Once the decking is repaired, we install:
Underlayment
Roofing materials
A weak roof deck can lead to:
Proper decking replacement helps ensure a longer-lasting and safer roofing system.
During roof replacement projects, it’s common to discover hidden decking damage after shingles are removed.
We believe in fixing the roof properly, not covering damaged wood with new shingles.
Two kinds of panel are used for roof decking on houses today:
Both meet the building code when they are the right thickness for the spacing of the rafters or trusses. Replacement panels are matched to the thickness of the sheets around them, so the new section sits flush and the shingles lie flat across it. Where the code calls for it for that panel thickness and framing spacing, metal clips (H-clips) or wood blocking support the panel edges between the rafters or trusses.
Many older homes and cottages around Georgian Bay have no plywood at all. Their roof deck is boards, often 1×6 planks, nailed across the rafters, sometimes with gaps between them. Shingle makers require a solid deck. Some accept a board deck within limits on board width and on the gaps between boards, and some advise against board decks. A tight deck of sound boards can stay only where the shingle maker’s instructions allow it, with any rotten boards cut out and replaced.
When the boards or the gaps are outside the maker’s limits, or the deck has many loose or split boards, or a surface too uneven for new shingles, the usual fix is to cover the whole board deck with new plywood or OSB sheets during the roof replacement. That gives the new roof a flat, solid surface with no gaps for the nails to miss.
Only over wood that is sound. New sheets laid over a solid board deck, as above, are normal practice. New sheets laid over rotten plywood are not: the nails do not hold in soft wood, the rot can keep spreading wherever the wood stays damp, and the problem is hidden until it shows as a leak or a sag. Rotten decking is cut out and replaced, not covered.
If a rafter or truss under the deck is also rotten, cracked or sagging, that is a structural problem. It must be assessed before the deck goes back on.
Roof decking that stays dry can last for the life of the house. Decking does not wear out from age the way shingles do. It fails from water: a long, slow leak, years of frost in a badly ventilated attic, or ice dams that push water under the shingles at the eaves. A deck that is replaced once, with the cause fixed, should not need replacing again with the next roof.
Nobody can see the whole deck until the old roof comes off, so the amount of plywood a roof needs is often unknown when the quote is written. Ask how the quote handles it: a set number of sheets included, a price for each extra sheet, or both. A quote that never mentions the deck leaves the most important question open.
If the roof is being replaced anyway, the deck is checked as part of the roof replacement. If only one area is soft, for example around a leaking vent, the bad wood can often be replaced as part of a roof repair.
Over a sound board deck, yes: that is a normal way to give a new roof a flat surface. Over rotten plywood, no. The rotten wood must be cut out and replaced: nails do not hold in it, and the rot can keep spreading wherever it stays damp.
Roof sheathing is exterior-grade plywood or OSB, at the thickness the building code sets for the spacing of the rafters or trusses. A replacement panel is matched to the thickness of the deck around it so the roof stays flat, as long as that deck meets the code.
Have the rotten section cut out back to sound wood and replaced with a new panel nailed to the framing, then fix the cause of the water. Do not walk on a roof deck you think is soft, and do not cover rot with new shingles or a new layer of plywood.
Kept dry, roof plywood can last as long as the house, through more than one set of shingles. It fails early when water reaches it, from leaks, ice dams or attic moisture.
Often, yes. On a bright day, look at the underside of the roof deck from the attic hatch with a good light. Dark stains, water trails, frost or mould, and wood that looks swollen or flaking all point to moisture. Do not step onto the drywall or the insulation. If you cannot see well from the hatch, leave the attic to a roofer. Some damage only shows from the top, once the shingles are off.
Excess moisture trapped inside the attic can lead to:
We inspect ventilation systems during roofing projects to help prevent future moisture problems.
We focus on long-term roofing solutions built to last.
705 Roofing provides roof decking and plywood replacement services in:
If you suspect roof decking damage or are planning a roof replacement, contact 705 Roofing for a professional roof inspection and decking assessment.
Visit us at: https://705roofing.ca/
Your trusted roofing experts for Wasaga Beach and the surrounding Georgian Bay area.
