Installation Details
The line items that separate a 30-year roof from a 12-year roof are mostly invisible after installation — flashings, ventilation, ice barriers. These guides cover the install-day details Trill won’t cut corners on.
Attic Ventilation Sizing
How to calculate the intake and exhaust your attic needs to avoid premature shingle failure.
Roof Flashing Explained
Where flashing matters most and how Trill installs it on every penetration.
Tear-Off vs Overlay
Why Trill almost never recommends overlaying — and the two cases where it’s defensible.
Ridge Vent vs Box Vent
Continuous ridge ventilation versus traditional box vents on Illinois roofs.
Madison County Roofing Permits
Permits, inspections, and HOA paperwork Trill handles before tear-off day.
Cold-Weather Roofing in Illinois
What’s safe to install below 40°F and what we postpone until spring.
Gutter & Roof Integration
How drip edge, fascia, and gutters tie into a watertight system.
Skylight Installation & Replacement
Replacing skylights during a re-roof saves cost and prevents the most common leak source we see.
TPO & EPDM Commercial Roofing
Single-ply membrane options for flat and low-slope commercial buildings.
Installation Details That Affect Long-Term Roof Performance
A roofing system is more than the visible shingle or membrane. Decking, underlayment, ice and water protection, starter material, flashing, fasteners, ventilation, ridge details, drainage, and penetrations all work together. Weakness in one detail can allow water or heat problems even when the main roof covering looks intact.
The guides in this section explain common installation terms and the purpose of key components. Use them to understand an estimate, prepare questions for a roofer, and recognize why two proposals with the same surface material may describe different scopes of work.
Details should be selected for the roof design, manufacturer requirements, local conditions, and the property’s ventilation and drainage needs. Trill Roofing reviews those conditions during inspection and explains the installation approach before work begins.
Installation Details: common questions
Is Trill Roofing licensed and insured in Illinois?
Yes. Trill Roofing holds Illinois roofing contractor license #104.020330 through IDFPR and carries general liability and workers compensation insurance.
- An IDFPR license number you can verify online before work starts
- A current general liability insurance certificate
- Workers compensation coverage for the crew on the roof
- A written, itemized estimate rather than a verbal number
Does Trill Roofing offer free roof inspections?
Yes. Roof inspections are free and produce a written report with photos and a prioritized repair list. A standard inspection documents:
- Shingle condition, including granule loss, curling, and missing shingles
- Flashing at chimneys, sidewalls, valleys, and pipe boots
- Attic ventilation balance between intake and exhaust
- Gutters and downspouts, including separation from the fascia
What areas does Trill Roofing serve?
Trill Roofing works out of 2705 St Ambrose Dr in Godfrey, IL and serves Madison County and the Riverbend with no trip surcharge inside the primary service area:
- Godfrey, Alton, Bethalto, and Brighton
- Edwardsville, Glen Carbon, Maryville, and Troy
- Wood River, East Alton, Roxana, and Hartford
- Jerseyville, Grafton, Elsah, and Cottage Hills
- Collinsville, Granite City, Hamel, Marine, and Worden
How much does a roof replacement cost in Madison County, IL?
A roof replacement in Madison County, IL costs $4.50 to $7.50 per square foot installed for architectural asphalt shingles. Every estimate is written and itemized before work begins.
What roof installation details actually affect how long a roof lasts?
The roof installation details that decide how long an Illinois roof lasts are the ones hidden under the shingles:
- Tear-off to the deck rather than an overlay, so decking can be inspected
- Ice and water shield in valleys, at eaves, and around penetrations
- Synthetic underlayment across the full deck
- Step, valley, chimney, pipe, and drip edge flashing done as separate details
- Balanced attic ventilation between intake at the soffit and exhaust at the ridge
Ready for a real estimate?
Trill Roofing offers free, no-pressure roof inspections across the Riverbend.