Roof Recover and Overlay in Rockford, IL
Recover your commercial roof in Rockford, IL when code and moisture allow, and learn how to test the old roof before you spend a dollar.
Roof Recover and Overlay
Roof Recover and Overlay
Rockford, IL
Putting a new membrane over an old one is the cheapest way to get a fresh roof, and in Rockford it is also one of the easiest ways to bury a problem. The old roof has lived through roughly 134 freezing days a year, a few hundred freeze-thaw swings over its life, and every storm that pushed water under a loose flashing. If that water is still sitting in the insulation, a recover traps it, and the trapped moisture cooks in summer and freezes in winter until the new sheet blisters or the deck underneath gives out. If the insulation is dry, a recover can save you a real amount of money and several weeks of disruption.
Do not agree to an overlay until someone has proven the old roof is dry. That proof is not optional.
Test the roof before you choose the recover
Whether an overlay works comes down to what is under the old membrane. An infrared moisture survey maps warm and cool areas after sunset, and core samples confirm what the scan suggests by showing you wet, crushed or deteriorated insulation in the cut itself. A roof that scans clean and cores dry is a candidate. A roof with scattered wet patches may still be a candidate if those patches are cut out and replaced first. A roof with wet insulation across most of its area is not, and any contractor who says otherwise is selling you the cheaper job.
Walk the roof with whoever writes the proposal. Look at the cores yourself, and ask where the moisture readings came from.
See why Rockford weather punishes an overlay
An overlay adds a second layer to a roof that already has to carry snow. Rockford averages about 36 inches of snowfall a year, and the 1978-79 winter dropped 74.5 inches, so the structure has to handle drifting and ponding on top of the extra dead load. Weight matters, especially on older steel decks and long-span plant roofs. At the other end of the calendar, about 15 days a year top 90 degrees, and a dark sheet sitting on a layer of old membrane and insulation can run hot enough to age quickly. Freeze-thaw does the rest, working at every seam and edge.
Your structural engineer or roofing contractor should confirm the building can carry the added layer before anyone orders material. The Belvidere Assembly Plant opened in 1965, and a building from that era was designed to the snow loads of its day, so a roof that has already had a layer added once may have little reserve left.
Check the code before you sign
The City of Rockford follows the 2021 International Code Council code cycle, including the 2021 International Building Code and Existing Building Code. Those codes limit how many roof coverings a building can hold, and they treat a recover differently from a tear-off on insulation. The statewide energy code that took effect in Illinois on January 1, 2024 follows the 2021 IECC with state amendments, so an overlay may have to bring the roof up to current insulation requirements. A contractor who has not asked how many layers are already on your roof has skipped the first question.
- How many roof layers are in place today?
- Is the existing membrane compatible with the new one, or does it need a separation layer?
- Will the project need a cover board or added insulation to meet code?
- What happens at the edges, curbs and drains?
A recover raises the roof surface by an inch or more, and that changes things you may not think about. Base flashing gets shorter, drain bowls sit lower than the new surface, and parapet coping may need to be reset. Every one of those details is a place where water finds a way in, so insist that the proposal say how each one will be handled and who pays when it takes more work than the bid assumed.
Weigh what the recover really saves you
An overlay skips the tear-off, the disposal and a good share of the labor, so the price is usually lower and the disruption smaller. That is the honest case for it. The honest caution is that a recover seldom lasts as long as a full replacement, because the new layer inherits whatever the old deck and details were already doing. You also close the door on easy inspection of the layers below. Ask for the recover price and the full replacement price on the same page, so you can see what you save today against what you might spend in a few years.
Good candidates for a recover include dry, stable roofs on buildings you plan to keep, and the right TPO or PVC roofing system is often what goes on top. A roof that has already been recovered once is rarely a candidate again. When a recover is the right call, the sheet goes over a properly prepared surface, with a cover board or separation layer where the old membrane requires one, and with fresh flashing at every wall, curb and penetration instead of reused metal that has already seen a decade of freeze-thaw.
Schedule the recover for dry weather
A recover needs a clean, dry surface. That puts the best window in late spring through early fall, when the old roof is not wet from snowmelt and adhesives and welds behave. Cutting open a roof to install fasteners or board in March invites water into a building that has not had a chance to dry. If your roof is already leaking and the schedule cannot wait for warm weather, a commercial roof repair may carry you through the winter, and it is worth pricing against the recover. Have the building looked over by someone who will give you the right answer.
Cargo and logistics owners, from the freight buildings at Chicago Rockford International Airport to the South Rockford logistics corridor about a mile from the airport, often want large roofs finished before peak shipping season. Tell us your calendar and we will plan to it.
For an older roof near the East State Street corridor or the North Main area, verify the number of existing layers, the deck condition and the insulation moisture before considering an overlay. Those checks decide whether the assembly can support another system.
Questions Owners Ask
Can you put a new roof over the old one?
Sometimes. The existing roof has to be dry, sound and within the layer limit the code allows. We test it first. If the insulation is wet, a recover will fail and we will say so.
How do you prove the old roof is dry?
We combine an infrared scan with core cuts. The scan shows where moisture may hide, and the cores confirm it. You get photographs of both so you can see what we saw.
Does a recover void anything?
It can affect a manufacturer warranty if the new system is not installed to the manufacturer's rules over the old one. Ask for the warranty terms in writing before work starts.
Is a recover cheaper than a replacement?
Usually, because there is no tear-off and less disposal. The tradeoff is a shorter expected life in many cases. Ask for both prices side by side.
Can a metal roof go over a flat roof?
In some cases, yes. A retrofit metal system can go over an existing low-slope roof if the structure allows it. Your engineer should confirm the load and framing.
What if the roof has been recovered before?
Most codes limit the number of layers. A building that already has two is usually a tear-off, and we will tell you before you spend money on a test.
