Installation

Replacing a Roof With Two Layers of Shingles: The Tear-Off

By Littleton Roof Repair · October 17, 2026 · 8 min read

Replacing a roof with two layers of shingles starts with knowing you have them. Look at the edge of your roof from a ladder. If you can see two thicknesses of shingle stacked on the drip edge, the last roofer laid a second layer of shingles directly over the old one. It was common on 1970s and 80s houses in Southpark, Ridgewood, Woodlawn and Columbine, usually to save $1,000–$2,000 on tear-off and dump fees, and it usually happened during a hail claim when the crew was in a hurry. The next roof is going to be a full tear-off, and here's what that involves.

What the rules say

The model residential code (IRC R908) allows a maximum of two layers of asphalt shingles, and it prohibits laying new shingles over an existing roof that is water-soaked, deteriorated, or over wood shake or any other material. Littleton and the surrounding counties have adopted recent editions of that code. In practice:

• One existing layer, sound: the code technically allows a second layer. Most reputable local contractors won't do it, for the reasons below, and some manufacturers limit the shingle warranty on a roof-over, so check the warranty terms.
• Two existing layers: full tear-off. The code caps asphalt shingles at two layers, so a third won't pass the mid-roof inspection; confirm with your building department.
• Shingles over shake: tear everything off, including the skip sheathing situation underneath. See below.

Ask your roofer to name the jurisdiction on the permit and to confirm the tear-off in writing. A "roof-over" quote on a two-layer roof is a quote for a roof that won't pass inspection.

Why a double layer roof is a bad idea here

Even with one layer, a roof-over is a bad roof in this climate:

• It hides the deck. Nobody has seen the OSB under a 1990s roof since it went on. Hail-fractured or water-softened decking stays hidden and keeps softening.
• It doesn't lie flat. The new shingle sits on the bumps of the old one. The seal strips don't bond fully, and the downslope winds off the hogback find every unsealed tab.
• It runs hot. Two layers of black asphalt on a south slope at 5,400 feet hold heat, and the top layer ages faster.
• It adds weight. A layer of architectural shingles is about 300 pounds per square. On a 26-square roof that's nearly two tons sitting on trusses that were sized for one roof, plus a foot of March snow.
• It skips the membrane. You can't put ice-and-water membrane under a roof-over. The old felt is what's under there, and it's why so many roofed-over houses have ice dam stains.

What replacing a roof with two layers involves

Day one, morning. Tarps over the landscaping, plywood over the AC unit, a dump trailer in the driveway. The crew strips both layers to the deck with tear-off shovels and forks, from the ridge down. Two layers on a 26-square roof is about 11,000 pounds of old shingle, nails and felt — two trailer loads at the transfer station, charged by weight.

Deck inspection. This is the moment the roof's history comes out. The crew should walk every sheet. On a roofed-over house, expect some of: soft OSB around old boots and at the eaves, delaminated sheets on the south slope, hail fractures from a storm nobody repaired, and nails from three roofs. Replacement is $90–$150 per sheet; a good quote carries an allowance, and the contractor should photograph every sheet that gets swapped. Our post on roof decking replacement has the details.

Dry-in. Ice-and-water membrane at the eaves and valleys, synthetic underlayment over the rest, new drip edge. By the end of day one the deck is covered even if the shingles wait for day two.

Day two. Starter, shingles with six nails each, new flashing and boots, ridge vent, ridge cap. Magnet sweep for nails — a two-layer tear-off leaves a lot of them.

Roof tear-off cost with two layers

A single-layer tear-off is built into the normal per-square price. A second layer adds $1,000–$2,500 to a typical Littleton replacement in labor and dump fees, so a 26-square two-story that would be $16,000 with one layer is $17,000–$18,500 with two. Decking replacement is on top, and a roofed-over house tends to need more of it.

Full ranges on the cost page.

The shake-under-shingle case

Some Ken Caryl and Columbine Valley homes had shingles laid directly over cedar shake in the 1990s, which the code doesn't allow, and it is still up there. Shake sits on 1x skip sheathing with gaps between the boards, not solid decking. When it all comes off, the skip sheathing has to be overlaid with OSB or plywood before a new roof can go on: $1,500–$4,000 on a typical roof. Cheap quotes on these houses leave it out and discover it on day one.

Insurance and layers

If a hail claim is paying for the replacement, the adjuster's scope should include the second-layer tear-off as a line item — it's part of replacing the roof. If it's missing, that's a supplement, not a fight. The hail damage page explains the sequence.

Comparing tear-off estimates side by side

When two layers of shingles are coming off, quotes can differ by thousands for reasons that have nothing to do with the shingle brand. Lay the written estimates next to each other and check each of these:

1. Layer count stated. The quote should say "remove two layers to the deck," not just "tear-off."
2. Disposal included. Twice the weight means twice the dump fees. Find out if haul-away is in the price or billed later by the load.
3. Decking priced per sheet. A number per sheet and an estimated count, with photos promised for every sheet replaced.
4. Skip sheathing addressed. On any house that once had shake, the overlay should be a line item or a clearly stated allowance.
5. Membrane and drip edge listed. These are the parts a roof-over never had, and the cheapest bid is the one most likely to skip them.
6. Permit named. Who pulls it, and which jurisdiction issues it.

If one estimate is far below the others and is vague on items 1 through 4, the gap usually reappears on the final invoice.

Mistakes homeowners make with a layered roof

• Patching it for years. Repairs on a two-layer roof rarely hold, because the new shingle can't seal flat against the bumpy surface below.
• Accepting a third layer. It saves money once and fails the inspection or the next buyer's inspection.
• Skipping the attic look. Stains and soft spots seen from inside before the job tell you roughly how much decking to budget.
• Forgetting the weight. Two tons of old roof and a wet spring snow load is a reason not to delay the tear-off once it's planned.

Common questions

Can a roofer add a second layer instead of tearing off?

On a single sound layer the code may technically allow it, but most careful contractors decline on Front Range houses because the deck stays hidden, the new shingles don't seal well and no membrane can go under them. On two layers it isn't an option.

How do I know if my roof has two layers?

Look at the drip edge from a ladder for two stacked shingle edges, or look at a pipe boot. On a roofed-over house the boot flange is often sandwiched between layers and visibly thick. If you can't tell, ask for an inspection; layer count is one of the first things an inspector checks.

Does tearing off two layers cost more?

Yes. On a typical Littleton replacement the second layer adds about $1,000–$2,500 in labor and dump fees, because there's twice the weight to strip and haul. If a hail claim is paying, the second-layer tear-off should be its own line on the adjuster's scope.

Is rotten decking more likely under two layers?

Often, yes. Nobody has seen the deck since the first roof went on, and the old felt under a roof-over can't stop the ice-dam water that membrane would. Budget for more sheets than a single-layer roof, and if the roof is leaking now, read repair versus replacement first — repairs on layered roofs are the ones that don't hold.