A metal roof retrofit puts a new roof over an old metal one without tearing it off. The two common ways are a new framing system with new metal panels on top, or flute-fill insulation and a single-ply membrane laid over the old panels. Either way, the building stays in use, the old roof keeps the weather out during the work, and you can add insulation in the process. A retrofit only works if the old panels and the structure under them are sound. We compare it with a new standing seam metal roof so you can see both paths.
The estimate will say which retrofit method we propose, what stays and what gets fixed first.
Metal retrofit work in Downtown Ventura and Ventura Harbor starts with confirming the existing panel profile, how the panels are fastened, how much rust there is and how the roof meets walls, gutters and other roofs. Salt air near the harbor speeds up corrosion on fasteners and panel laps, so we look closely at those. We work out access and work hours with the owner or manager, and we base the plan on what we actually find.
Checking the old metal roof
We start with any drawings you have, then inspect the roof itself. We check the panel type and gauge, the fasteners, the laps and how much rust there is. Panels with holes rusted through, or purlins that have rusted badly, need repair before anything goes on top. If we cannot get to a section, we say so.
If an old coating or patch is on the panels, we note it and check whether it affects the new system.
A commercial roof inspection covers panel condition, laps, ridge caps and trim. Whether the purlins and frame can carry the added weight of a retrofit is a separate question, and an engineer answers it when needed. We do not assume the structure is fine just because the panels look solid from above. We also check the panel laps and ridge for loose or missing fasteners, a common source of leaks on older metal buildings.
Fixing what is under the new roof
Rusted panels, loose fasteners and damaged purlins get repaired before the new roof goes on. For a single-ply retrofit, the flutes in the old panels are filled with insulation and covered with a flat layer of insulation and cover board to give the membrane a smooth, firm base. For a metal-over-metal retrofit, the new framing is attached through the old panels into the structure.
Anything we could not check is noted.
Hidden rust that turns up mid-job is shown to you before we go on. Badly damaged sections may need new panels or structural repair, which we price separately, with an engineer involved where the frame needs strengthening. Fixing those first means the new roof is not sitting on a problem that keeps getting worse underneath.
The new roof and its edges
A single-ply retrofit often uses TPO roofing fastened through the insulation into the old panels or purlins. A metal-over-metal retrofit uses new framing to set the new panels at the right slope. In both cases, the new roof has to drain properly and carry its loads through approved supports. Edges, gutters, ridges and walls all get new flashing and trim.
Every curb and penetration gets a new, properly sealed detail.
The new roof is thicker than the old one, so curbs, vents and rooftop units may sit too low and need to be raised. Gutters and downspouts may need to move outward. We check all of that before choosing the layout, so the new roof does not trap water or block access to equipment. Skylights and roof hatches get the same check, since they often need taller curbs too.
Related Roofing Work
Coordinating with other trades
Retrofits often need help from other trades. Rooftop units may need to be lifted and reset, gutters and downspouts replaced, or skylights and vents extended to clear the new roof. Our roof condition reports lay out which bays are clear for framing and which are waiting.
Because the old roof stays on, the building stays dry even while a bay waits.
Mechanical and electrical work on the roof is handled by those trades, and we schedule around them. If the structure needs added support, the engineer's design is in place before any retrofit materials are ordered. Deliveries of long panels and framing are planned around tenants, parking and traffic. The owner gets one schedule showing every trade in order, and knows ahead of time if any part of the building will be affected by noise or shutdowns.
Closeout and later service
You get pictures of the framing or flute fill, the repairs below and every new edge and curb, plus the panel or membrane specs. We note what stayed and how it was checked.
On older buildings near Downtown Ventura, original trim and gutters that stayed are marked.
Down the road, a commercial roof leak repair tech can see exactly where the new system ends. Other trades' open items and job changes are listed by location. That gives the next crew a clear picture of what is new, what is original and where the old metal is still carrying the new roof.
Before we propose a retrofit, we confirm the panel profile, fasteners, rust and structural condition at several spots across the roof. The retrofit layout has to give the new roof a flat or properly sloped surface, keep water moving and carry loads through approved supports. At edges, curbs and penetrations, we show how the new roof finishes without trapping water or blocking equipment access. If field measurements or hidden conditions do not match the drawings, we fix the layout before anything is fabricated. The closeout keeps the old roof and new work clearly separate, so later maintenance knows which part handles each transition.
Common Questions
How do you know if the old metal roof can take a retrofit?
We inspect the panels, fasteners and rust, and check the purlins and frame. If there is any doubt about the added weight, an engineer reviews it. Rusted-through panels and damaged supports are fixed before the retrofit, and the estimate lists those repairs separately.
How does a retrofit compare with replacing the metal roof?
We price both using the same inspection results. A retrofit usually keeps the building in use, avoids tear-off and adds insulation. A full replacement may make more sense if the old panels or structure are in poor shape. You see both costs side by side.
What changes at curbs and edges when a retrofit is installed?
The new roof is thicker, so curbs, vents and rooftop units may need to be raised, and gutters may move outward. We check those heights first and coordinate with the mechanical trade when equipment has to be reset.
What does the closeout record give future roof crews?
Photos of both layers, the material specs and any items still open. That helps them tell the new roof from the old metal it sits on.
Find out if a retrofit fits your metal roof
Share the address, the building size and any drawings you have. We will inspect the panels and structure and give you an estimate that compares a retrofit with replacement and lists exactly what is included.