As a Harrisburg TPO roofing contractor, we install white thermoplastic membrane on low-slope offices and warehouses, with seams welded and probed at every curb.
Harrisburg TPO roofing fits most low-slope decks, but the roof underneath decides how the job is scoped. These patterns come from the conditions we find most often.
| Roof Condition | Repair | Recover Over Existing | Tear-Off And Replace |
|---|---|---|---|
| Dry insulation and a firm deck under a worn single-ply | Sometimes | Usually Fits | Sometimes |
| Wet insulation found in core samples | Rarely | Rarely | Usually Fits |
| Two existing roof layers already in place | Rarely | Rarely | Usually Fits |
| Open seams near a few rooftop units | Usually Fits | Rarely | Rarely |
| Ponding at drains with a firm deck | Sometimes | Sometimes | Usually Fits |
Most TPO trouble starts at details and traffic, rarely in the open field. These are the conditions we look for first on an existing white roof.
The membrane is one layer. Attachment, insulation, and details decide how the roof performs, so a proposal should spell out each one.
| Assembly Part | Common Choice | When We Change It |
|---|---|---|
| Attachment | Mechanically fastened sheet | Fully adhered when wind exposure, deck type, or noise calls for it |
| Insulation | Polyiso boards in layers | Tapered boards where drains sit high or water ponds |
| Cover board | Gypsum or high-density board | Thicker board over heavy service areas |
| Membrane | Reinforced white TPO sheet | Thicker sheet where traffic and punctures are common |
| Edge and curbs | New edge metal and curb flashing | Raised curbs when insulation thickness grows |
A replacement fixes more than the leak that started the call. These are the practical gains owners see on a properly detailed TPO roof.
Hot-air welding fuses the overlapping sheets into one piece, and every seam can be probed after it cools. That gives the owner a roof whose weakest points were checked before the crew left.
We probe laps around curbs and corners first, because those welds are made in tight spaces where heat and pressure are hardest to control.
Both membranes go on similar decks. White TPO reflects summer sun, while EPDM handles movement at older walls. The inspection points to one.
Walkway pads lead from the hatch to every rooftop unit, so service crews stay off the open field.
Tapered insulation and new drain flashing move water off the roof instead of holding it around the bowl.
We probe the laps, check the curb flashing, and tell you whether a repair holds or the roof is ready for a new TPO assembly.
Get A Free EstimateEach TPO roofing job in Harrisburg follows the same sequence, with sections sized so every day ends with a closed, watertight roof.
We probe existing seams, take core samples for wet insulation, and map curbs, drains, hatches, and the staging area at ground level.
Attachment, insulation thickness, cover board, and sheet thickness are chosen for the deck, the drains, and the traffic each area sees.
Old layers come off only as far as the crew can dry-in that day, and deck damage is repaired before insulation goes down.
Robotic welders run the field seams, hand welders handle curbs and corners, and every lap is probed once it cools.
Edge metal, curb flashing, drains, and walkway pads finish the roof, followed by a final walk with the facility manager.
Some buildings suit a different membrane or a panel roof. These are the other systems we install around Harrisburg.
Rubber membrane suits multi-level roofs with tall brick walls, where its flexibility helps at terminations and the transitions between roof levels.
See EPDM roofing
Plant and distribution roofs are scoped in sections around production lines, refrigeration, and loading docks, whichever membrane they carry.
See industrial roofing
Pitched shop and storage buildings take standing-seam or exposed-fastener panels, with flashing designed at each curb and opening.
See commercial metal roofingTPO is a thermoplastic polyolefin sheet with a reinforcing fabric inside, sold in white for most commercial work. Because it softens with heat, overlapping sheets are welded into one continuous surface. On Harrisburg roofs we install it over insulation and cover board, then flash it up curbs, walls, and edges with the same material.
The specification covers a full assembly. Beyond the white sheet, it should name the insulation type and thickness, the cover board, how the roof is attached to the deck, how seams are welded, and the flashing at every curb and edge. Compare those lines between proposals, because the word TPO alone tells you little about the roof you would get.
Curb welds get extra attention. Corners and tight spaces make heat and pressure harder to hold steady, so we clean the sheet, follow the manufacturer welding procedure, and probe the finished lap along its full length, including the joint where curb flashing meets the field membrane.
Service routes take the wear. Punctures, dragged equipment, and tools set down on the sheet damage TPO near rooftop units, and disturbed seams follow. We map those routes during inspection and add walkway pads and protection, so service work stays on surfaces built for it.
Yes. Each membrane takes its own patch materials and seam method, so we confirm the existing sheet first. Old curb openings are cut back to good membrane and closed, and the new curb location leaves enough working room around it to weld and later service the flashing.
Welding continues in cold weather with adjusted machine settings and test welds at the start of each shift. Adhesives, primers, and sealants carry temperature limits on their product sheets, so fully adhered work and some flashing details are scheduled around those limits during a Harrisburg winter.
Send the building address and what you see on the roof. We will inspect the seams and curbs and price the TPO work in writing.