Roof Decking Guide: What's Under Your Shingles and Why It Matters
Roof decking — also called sheathing — is the structural layer of plywood or OSB boards that sits on top of your rafters and beneath your shingles, underlayment, and flashing. It is the foundation of your entire roofing system. In Pittsburgh, decades of moisture exposure, ice dam cycles, and humidity can compromise decking integrity. Pittsabana's CertainTeed ShingleMaster™ certified crews inspect every square inch of decking during tearoff and replace damaged sections before installing new roofing — a step that some contractors skip to save time and cost.
Types of Roof Decking in Pittsburgh Homes
Pittsburgh homes feature three common decking types depending on age. Homes built before 1960 often have skip sheathing (also called spaced sheathing) — individual boards laid with gaps between them, originally designed for wood shake or slate roofing. Homes from the 1960s–1990s typically have CDX plywood decking (4×8 sheets). Newer construction uses OSB (oriented strand board), which is the industry standard today. Each type has different moisture tolerance and replacement considerations that Pittsabana's experienced crews understand completely.
- Skip Sheathing (pre-1960) — Spaced boards, requires full over-sheeting for modern shingles
- CDX Plywood (1960s–1990s) — Solid sheets, good moisture tolerance
- OSB (modern construction) — Engineered panels, cost-effective, industry standard
How Pittsabana Inspects and Restores Decking
During every roof replacement, Pittsabana's W-2 crews perform a complete deck inspection after tearoff. We walk every section, probing with tools to identify soft spots, water damage, delamination, and rot. Damaged sections are cut out and replaced with matching-thickness OSB or plywood before any new roofing is installed. For homes with skip sheathing, we install full 7/16-inch OSB over-sheathing to create a code-compliant, solid nailing surface. This deck restoration is included in our 6-step process at an honest, pre-quoted price — never as a surprise upcharge after work begins.
What Causes Deck Damage in Pittsburgh
The primary causes of deck damage in Pittsburgh are ice dam-related moisture intrusion (water backing up under shingles and soaking the decking), inadequate attic ventilation (trapping moisture against the underside of the deck), plumbing vent condensation, and long-term shingle failure allowing direct rain penetration. Pittsburgh's 80+ annual freeze-thaw cycles accelerate delamination in both plywood and OSB. Proper ventilation, ice and water shield at eaves, and premium shingles — all standard in Pittsabana installations — prevent future deck damage.
Frequently Asked Questions
What is roof decking made of?
Roof decking is made of plywood (CDX grade), OSB (oriented strand board), or in older Pittsburgh homes, skip sheathing (spaced individual boards). Modern standards call for 7/16-inch OSB or 1/2-inch CDX plywood. Pittsabana inspects all decking during replacement and restores damaged sections to code.
How much does it cost to replace roof decking in Pittsburgh?
Roof decking replacement costs $2–$5 per square foot in Pittsburgh, or roughly $75–$150 per 4×8 sheet installed. Most projects require 5–15 sheets of replacement decking. Pittsabana pre-quotes deck restoration costs based on visible damage indicators — no surprise upcharges after tearoff.
Need Expert Advice for Your Roof?
Pittsabana's CertainTeed-certified team provides free inspections and honest assessments for Pittsburgh-area homeowners.