Tear-Off vs. Overlay
When you replace a roof, there are two basic approaches. An overlay (or "layover") installs new shingles directly on top of the existing layer, while a tear-off strips everything off first and starts from a clean deck. Overlays are cheaper up front, but they trap the problems of the old roof underneath and add significant weight.
A tear-off costs more in labor and disposal, but it is the only method that lets the crew see and address what is actually happening on your roof deck. Most manufacturer warranties, including GAF's strongest coverage, are written around a proper tear-off installation.
What Actually Gets Removed
A thorough tear-off removes far more than the visible shingles. The crew strips off:
- All layers of old shingles and any cap or ridge pieces
- The underlayment (felt or synthetic) beneath the shingles
- Old flashing around chimneys, valleys, and sidewalls
- Damaged or rotted sections of decking once they are exposed
- Pipe boots, vents, and other penetrations that need replacing
Once the deck is bare, it can be inspected, dried, and re-sheathed where needed before new ice-and-water shield, underlayment, and shingles go down.
Why Tear-Off Matters in the Spokane / Inland NW Climate
Our region is hard on roofs. Heavy snow loads, repeated freeze-thaw cycles, ice dams along the eaves, wind, and summer hail all work moisture into hidden places. An overlay simply buries that hidden damage, while a tear-off exposes it.
This matters for two specific reasons here:
- Hidden deck rot and mold. Ice dams and freeze-thaw force meltwater under shingles, soaking the decking. A tear-off reveals soft, delaminated, or rotted plywood that an overlay would seal in and let spread.
- Snow load and weight. A second layer of shingles adds dead weight to a structure that already has to carry deep winter snow. Removing the old layer keeps the total load lower and the deck sound.
It also allows proper installation of self-adhered ice-and-water membrane at the eaves and valleys, the most important defense against ice dams in our climate. That protection is only effective when applied to a clean deck during a full roof replacement.
What a Tear-Off Day Looks Like
On most homes a tear-off and re-roof happens in a tight sequence: the crew protects landscaping and siding, strips the roof down to the deck (often in a single morning), inspects and repairs the sheathing, then dries-in and re-roofs the same section before weather can reach the exposed wood. Debris is collected in a dumpster or trailer and the yard is magnet-swept for nails afterward.
Because the deck is briefly exposed, timing and weather awareness matter, which is one reason it pays to work with an experienced local crew. If you are weighing a tear-off versus an overlay, you can request a free estimate and have the roof inspected first.