Roll Goods Acceptance After Improper Site Storage
A contractor’s crew is scheduled to install 48 rolls of SBS-modified bitumen cap sheet on a 22,000 ft² roof. The pallets were delivered 10 days earlier and left uncovered at grade because the hoist was down. Daytime temperatures reached 96°F; nights dropped to 50°F. Two pallets sat directly on the ground, and several wrappers are torn. Most rolls were stored on end rather than upright. The crew foreman reports that some rolls are flattened and “blocked,” with granules loose in the wrapper, and one roll has a 3 ft transverse crack starting at the core. The manufacturer’s label states: store upright, dry, out of direct sunlight. The general contractor wants the roof dried in tomorrow and asks whether the material can be installed as-is, with damaged rolls used at the perimeter. The membrane is 4 mm SBS with a polyester mat and a factory-applied granule surface; matching replacement rolls are 5 days out.
1. How should the consultant classify and disposition the 48 rolls? Identify which conditions are rejectable and what field checks are appropriate before accepting or rejecting material.
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Disposition: do not accept the lot as-is; evaluate roll by roll and segregate suspect rolls. The storage conditions violate the label and are sufficient to make the lot suspect, but the physical condition of each roll controls.
Rejectable conditions:
- Transverse crack at the core: the polyester mat is discontinuous. The sheet cannot develop reliable lap strength or weathering continuity, and the crack will propagate during unrolling.
- Blocked or flattened rolls: heat and stacking have caused asphalt flow and roll-to-roll adhesion. The sheet will not unroll flat; forcing it creates wrinkles, thin spots, and poor laps.
- Excessive loose granules: surface loss reduces UV resistance and often signals asphalt bleed or heat damage.
- Rolls stored on end with distortion: end storage can flatten the roll and deform the selvage, making consistent side laps difficult.
Acceptance checks: A roll may be considered only if it unrolls freely by hand, has full width and intact selvage, shows no cracks, pinholes, or blocking, and has well-adhered granules. Torn wrappers alone are not automatic rejection if the roll is dry and otherwise sound. Confirm lot and product with the manufacturer. Do not use damaged rolls at the perimeter-perimeter areas are high-wind and high-water zones, not a repository for defective material.
2. The contractor proposes using the cracked and blocked rolls as a base ply beneath the new cap sheet. Evaluate that proposal.
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Reject the proposal. A base ply is not sacrificial. It must transfer wind uplift, provide a continuous substrate, and resist water intrusion if the cap sheet is damaged. A cracked roll creates a deliberate discontinuity in the membrane assembly. A blocked roll cannot be laid flat; it will bridge, wrinkle, and create voids that can telegraph through the cap sheet and trap moisture. Using defective material in the base ply simply hides the defect until a later inspection or leak investigation. The correct approach is to reject the damaged rolls, obtain replacement material, and document the schedule impact. If the manufacturer authorizes salvage of a specific roll, any defect should be cut out and the remaining sound material used only in a permitted location-not as a concealed base ply without written approval.
3. What documentation and communication steps should accompany the rejection?
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Prepare a nonconformance report that records delivery date, storage location, weather exposure, wrapper condition, roll orientation, roll tags/lot numbers, and photographs of each defective condition. Mark and segregate rejected rolls so they cannot be installed. Notify the general contractor and manufacturer representative in writing, state the basis for rejection (label storage requirements and observed defects), and request replacement material. Preserve labels and samples. Record the dry-in delay and any temporary protection measures. Do not allow the crew to “work around” the issue by installing suspect rolls in less visible areas. The goal is a traceable disposition, not an informal field compromise.