A roof installation generally moves through six stages: tear-off of old materials, deck inspection and repair, underlayment, flashing work around chimneys and vents, shingle installation with proper ventilation, and a final cleanup with a nail sweep. Knowing these steps helps you spot a rushed job before it becomes a leak.
What Are the Main Steps in a Roof Installation?
Every roof installation follows a similar sequence, whether it's a full tear-off or a reroof over a single layer of shingles:
- Tear-off: old shingles, underlayment, and damaged flashing come off down to the deck.
- Deck inspection: the plywood or OSB sheathing gets checked for soft spots, rot, or delamination.
- Underlayment: a synthetic or felt barrier goes down to protect the deck until shingles are on.
- Flashing: new metal flashing goes in around chimneys, skylights, vent pipes, and roof valleys.
- Shingles and ventilation: shingles are installed in courses, with ridge and soffit ventilation addressed as part of the work, not an afterthought.
- Cleanup: a magnetic sweep for stray nails, tarps removed from landscaping, and debris hauled off.
Skipping steps, especially deck inspection and flashing, is how a new roof ends up leaking within a year or two.
How Is a New Installation Different from a Roof Replacement?
The terms get used interchangeably, but there's a practical difference. A roof replacement usually means tearing off an existing roof that's reached the end of its life and starting over. An installation can also apply to a roof that's being put on for the first time on a section of the house, such as after storm damage removes the covering down to bare decking. The steps above apply either way; what changes is how much of the deck and framing needs attention before the new materials go on.
What Should Happen to the Deck Before New Shingles Go Down?
The deck is the foundation everything else sits on, and it should never go unchecked just because the old shingles came off clean. A crew should walk the full deck, press-test suspect areas, and replace any plywood or OSB that's soft, delaminated, or water-stained rather than covering it up. Sheathing that flexes under a boot is a sign of moisture damage underneath, and shingles nailed over a weak deck won't hold properly in wind. If a section of roof was opened up by storm damage, this is also the point where that damage gets fully assessed, which is part of what our storm damage restoration work covers.
Why Does Flashing and Ventilation Matter as Much as Shingles?
Shingles get most of the attention, but flashing and ventilation are where most roof leaks and premature aging actually start. Flashing directs water away from the places where the roof plane is interrupted: chimneys, vent pipes, sidewalls, and valleys. Ventilation keeps the attic from overheating in summer and from trapping condensation in winter, both of which shorten shingle life and can warp decking over time. A roof that looks good from the street but has reused or poorly sealed flashing, or no real ventilation path, is a roof that will cause problems sooner than it should.
What Should You Expect on Installation Day?
Here's a general sense of what the process looks like from the homeowner's side:
| Stage | What You'll Notice |
|---|---|
| Setup | Tarps over landscaping, a trailer or dumpster placed for debris |
| Tear-off | Noise and some vibration through the house |
| Deck repair | Work may pause briefly if damaged sheathing needs replacing |
| Shingle install | Steady work across the roof planes, usually the bulk of the timeline |
| Cleanup | Magnetic nail sweep of the yard and driveway, debris hauled away |
It's reasonable to ask the crew lead what stage they're at and whether any deck repairs came up along the way.
How Do You Know the Installation Was Done Right?
After the work is done, walk the yard for stray nails, check that gutters and downspouts weren't knocked loose, and ask for documentation on what was replaced versus reused, including flashing and any sections of deck. A straight answer about what was found underneath the old roofing is a good sign the job was done thoroughly rather than just covered over.
We install and replace roofs for homeowners across Stockton and the rest of Southwest Missouri. If you want a closer look at what your own roof would need, reach out to schedule a visit.