Johns Manville Roofing in Brockton, MA
Owners look at the membrane. The leak lives in the insulation. A Johns Manville roof in Brockton, MA can look fine from above while the board under it holds water. The ceiling stain comes later and in the wrong place. We cut a core and read the layers before anyone picks a fix.
Johns Manville makes commercial roofing products across several lines: single-ply membranes, insulation boards, and the fasteners and accessories that go with them. Insulation is the part owners cannot see. It is also the part that decides when a roof is repair work and when it is replacement work.
Find the wet insulation first
Wet insulation stops insulating. It adds weight and holds water against the deck. In winter it freezes and cracks. In summer it feeds blisters and softens adhesives.
We find it with an infrared moisture survey and confirm it with a core. The survey maps the wet boundary. The core shows what the board is and how wet it has become. Rigid board that is only damp at the top may dry. Board soaked through has to come out.
The wet boundary sets the repair boundary. We cut out the wet board, replace it with new board of the same thickness, and rebuild the sheet over it. A patch on the surface above wet board hides the problem for one season. Water with nowhere to go stays in the layer and spreads.
Compressed board is a second finding. Foot traffic and equipment loads crush insulation at curbs and along service paths, and crushed board leaves a dip that holds water. We press along those paths and mark any board that gives underfoot. A soft spot that tests dry still goes on the plan, since a dip today is a pond after the next thaw.
Add a cover board where traffic and hail hit
A cover board is a thin, hard layer between the insulation and the sheet. It protects the board from foot traffic, dropped tools, and impact, and it gives the sheet a firmer base. A roof with rooftop units, where technicians walk daily, wears faster without one.
We price a cover board as an option in every replacement scope. It adds cost at the start and saves it later. A crushed board under a sheet leaves a soft spot, and soft spots pond. On a recover the board helps too, because a new sheet over an old roof needs a stable base that spreads load and bridges small gaps. It does not cure wet insulation underneath, which has to be cut out first.
Respect what freezing does to a damp roof
In an average year Brockton gets about 34 inches of snow, most of it in February at nearly 13 inches, plus roughly 50 inches of precipitation in all. The record low reached minus 19 degrees. Water inside a roof layer freezes and expands, and it pries the layers apart. A small leak in autumn becomes delaminated board by spring.
That is why we ask for the roof before the cold, not after. A pre-winter visit looks at drains, seams, and flashings and flags any area where the board may be wet. Those spots get repaired or marked for the next dry window. Snow load is a separate concern. A roof holding wet board carries extra weight under snow, so we note any sagging deck and pass it to the owner in the report.
Check seams and flashing, then trust the board
Water reaches the insulation from above. It comes through a seam, a flashing, a drain, or a puncture, and finding the entry matters more than finding the stain. We walk the roof, probe the seams, press the flashings, and photograph every opening.
A seam failure repair on a single-ply sheet is cleaned, welded or bonded, and probed. A flashing repair gets a mechanical termination, since sealant alone is a temporary hold. Wind loads the edges too. Brockton's 14.3 mph average makes loose metal worth fixing before the field, so we secure the edge metal first.
Check how the board is held down
Insulation board is held down by mechanical fasteners, by adhesive, or by ballast. Each fails in its own way. Fasteners back out and leave the board loose. Adhesive loses its bond when moisture gets under the board. Ballast shifts and leaves bare spots.
Wind tests every one. A 1938 hurricane clocked a 186 mph gust at Blue Hill Observatory, and nor'easters still bring hurricane-force winds today. A board that is not secure at the roof edge is the first thing wind lifts, and the sheet follows.
We check the fastener pattern near corners and edges, where uplift runs highest. We press the sheet to feel loose board and look for ridges where board edges telegraph through. Loose board gets re-fastened or replaced. A board that was never secured will not hold the second time either.
Size new insulation to the code and the building
A replacement is a chance to fix the insulation, not just the sheet. Insulation depth is set by the code now in force: the 10th edition state code built on the 2021 International Building Code, with the 2021 energy code supplying R-values. We price the required layer and show what extra thickness would cost.
Tapered board is the second option. Cut in wedges, it gives a flat roof a fall toward the drains. It costs more than flat board, but a roof that sheds water avoids the ponds behind most repeat leaks.
The same insulation questions come up on a large roof such as the 109,000-square-foot distribution building on Parker Drive in the Avon Industrial Park beside Route 24, and on a mid-century hospital campus such as the Brockton VA, which has more than 20 buildings. The method is the same: core, test, match, repair. It carries into Avon and Brockton, and the same board questions apply to a Holcim Elevate or GAF roof.
Write down what the core found
A core is only useful if it is recorded. We log each one with a photo, the layer thickness, the board type if known, and the moisture reading, tied to a spot on the roof plan. Next year's visit starts from that record.
Owners get a one-page summary: what is wet, what is dry, what to repair now, and what to watch. The core locations stay on the roof plan with dates, so a second visit does not cut where the first one already looked. If the board is dry and the sheet is sound, the report says so and prices maintenance. If the board is wet, the report shows the extent and the cost to cut it out. The warranty file keeps the dates and terms beside the core log, since a manufacturer warranty may require notice of a leak and approved repair methods.
Commercial Roofing Questions
How can I tell whether the insulation is wet?
An infrared survey maps likely wet areas, and a core confirms them. Surface stains alone are not reliable.
Does wet insulation always mean replacement?
No. If the wet area is local, we cut it out and rebuild that section. Wet board across many sections points to full replacement.
Will a cover board stop leaks?
It does not stop leaks. It protects the board from traffic and impact and gives the sheet a firmer base.
Can I recover over wet insulation?
No. The new sheet traps the water. Cut out the wet board first, or choose replacement.
What does tapered insulation add?
Slope. It sends water to the drains and cuts down ponding. It costs more than flat board and often pays back in fewer repairs.