A recover saves money for one reason: the old roof stays in place and nothing gets hauled to a landfill. It costs more than it saves when the old roof is wet. The whole decision turns on moisture and weight, and in Coeur d'Alene, ID both are measured against a city design sheet that lists a 60 psf ground snow load. A second layer adds dead load to a roof that already has to carry that snow.
So we start with a moisture survey, not a quote. If the insulation tests dry and the deck checks out, a recover is a fast, quiet, lower-cost path. If it does not, we say so in the first meeting and price the tear-off instead.
Moisture: The Number That Decides It
Wet insulation does not dry out under a new membrane. It sits there holding water against the deck, and through a Coeur d'Alene winter that water freezes and thaws against the underside of the roof. A recover over a wet field only hides the problem and buries it deeper.
We map the moisture with an infrared and core-cut moisture survey before anything is priced. Cores confirm what the scan suggests. If wet areas are limited, we cut them out and replace the insulation locally, then recover the whole roof. If wet areas are widespread, the recover is off the table, and that conversation is short.
Weight: What a Second Layer Adds
The roof is designed for the snow, and the dead load of the roof assembly counts against that design. Saturated snow runs roughly 20 pounds per cubic foot according to the city's own guidance, so a deep, wet storm on a flat roof is already a heavy event. Adding a cover board and a new membrane over the existing system adds weight on top of it.
Most low-slope roofs handle one added layer without trouble, particularly steel decks on tilt-up buildings. But we do not assume. When the building is older, or a prior owner already put one recover on, we ask for the structural drawings or a quick engineer review. Idaho enforces the 2018 International Building Code statewide, and that code limits how many roof layers can sit on a deck. We check the layer count before we spec a thing.
The Assembly: Cover Board, Membrane, Attachment
A good recover is not a membrane thrown over the old one. We typically add a cover board to protect the new membrane from the old surface, then a new membrane, mechanically attached or adhered depending on the deck. The old membrane becomes a base, and the cover board keeps its blisters, ridges and fastener heads from telegraphing into the new surface.
On a modified bitumen or built-up base, we look at surface granules and any loose gravel. On a single-ply base, we look at shrinkage at the edges and the condition of the old flashings. Flashings almost always get replaced even when the field stays. They are where recovers fail first, so we do not reuse them.
Where It Fits: Buildings That Suit a Recover
A recover suits a building where downtime is expensive and the roof is otherwise sound. Think of a multi-tenant flex building in Riverbend Commerce Park, a tilt-up concrete warehouse where the owner needs the tenants running through the work. Or a light-industrial building in Hayden where a full tear-off would leave a large area open to the weather for days.
It fits poorly where the deck is damaged, where a second recover would exceed the layer limit, or where the existing roof already holds water in several places. Those are tear-off roofs. If your survey lands there, the answer is full commercial roof replacement.
Cost and Timing: What You Actually Save
The saving comes from labor and disposal. There is no tear-off crew, no dumpsters, and far less exposure of the building interior to rain, snowmelt and dust while the work runs. The work often finishes faster, which matters on a roof over operating space. The savings shrink if the roof needs a lot of spot insulation replacement, new drains or edge metal, because those line items cost the same either way.
We price the recover and the tear-off side by side, with the same drainage and edge scope in each, so the difference is the real difference. If the gap is small, the tear-off often wins, because a new assembly resets the clock on the roof's service life and the recover only extends it.
Season: Work Between the Storms
Recover work is lighter than a tear-off, so it can sometimes run later into the shoulder season. With snow that can stay into spring, adhesives and welded seams get a short list of workable days. We watch the forecast and stop when a seam would not cure properly.
Snow gets heavier as you go east. Kellogg, in the Silver Valley, averages 52.4 inches a year, mostly from November through March, and the numbers climb further toward Mullan. A building near Cataldo, on the I-90 route toward the Silver Valley, gets its own snow history checked before any layer goes on, and the layer count goes in the survey first.
Records: What to Keep After the Work
A recover stacks two roofs, and the next owner will want to know exactly what is in the stack. We log the layer count, the cover board type, the attachment pattern and the location of every cut-out for wet insulation. Photographs go with the log. If a leak shows up in five years, that record tells a repair crew where to cut and what they will find, which saves a day of guessing and a pile of cores.
Keep the moisture map too. It is the baseline for later scans, and it ties to a written roof condition report that a lender, insurer or buyer can read without a site visit. On a multi-building owner's portfolio, those baselines make the next capital decision much easier to defend, whether the answer is another recover, a coating, or a tear-off at warehouse roofs that have reached the end of the line.
Commercial Roofing Questions
How many layers can a roof legally carry?
The 2018 International Building Code that Idaho enforces limits the number of roof coverings on a deck, and it restricts recovers over certain materials. We check the layer count and the old system type in the survey, then confirm with the city before pricing.
Will a recover void a manufacturer warranty on the old roof?
If a warranty is still active, a recover can affect it. Read the warranty terms and send us a copy. We will tell you whether the recover is compatible before you sign anything.
What happens to the old flashings?
They are cut out and rebuilt. Recovering over old flashing is the most common cause of a recover leak, so we replace them at walls, curbs and penetrations even when the field is left alone.
Is a recover cheaper over a metal roof or a membrane roof?
The decking and the fasteners drive the price more than the surface does, and most of the cost gap is preparation. A roof coating restoration may be the lowest-cost option on a sound metal roof that is only worn at the surface.
Can we recover a ponding roof?
Not without fixing the ponding. Tapered insulation or added drains go in first, otherwise the new membrane holds the same water. Standing water through a freeze cycle shortens any membrane's life.
How fast can the survey happen?
Usually within days of the site visit. Infrared scans work best on a dry, cooling evening, and cores are cut and patched the same day.