PU Sandwich Panel Retrofit Step‑by‑Step Guide
? Step1 Site survey & assessment: confirm whether to replace with PU sandwich panel Complete site survey first, check aging degree, blister and rust range of existing enclosure panels; verify deformation and load‑bearing capacity of steel structure; clarify renovation goals including energy‑saving, purification upgrade, moisture & corrosion protection. Full replacement of PU sandwich panel is recommended for panels with large‑scale core aging, blistering and delamination; partial replacement works for minor damage. Evaluate salt‑spray and high‑humidity impact for South‑China coastal and plum‑rain sites. SAMZOON offers survey & selection suggestions and free samples for retrofit projects.
⚙️ Step2 Dismantle old panels and pre‑treat steel‑structure base Dismantle aged EPS, rock‑wool or old PU sandwich panel with dust‑proof & safety protection. Remove rust, old sealant and foam debris on steel‑structure surface; apply anti‑rust coating for corroded areas; inspect welds and bolts, repair deformed components; fully ventilate to eliminate residual wall moisture. Never install brand‑new PU sandwich panel on damp base surface, otherwise internal condensation and blistering will occur later.
? Step3 Customized PU sandwich panel selection for retrofit working conditions Determine PU sandwich panel configuration based on survey results. Set insulation thickness according to energy‑saving target and steel‑structure load capacity, do not blindly pursue extra‑thick panels. High‑weather‑resistance color‑coated sheets suit inland ordinary factories; stainless‑steel composite PU sandwich panel is preferred for coastal salt‑spray sites and high‑humidity clean workshops. Adopt factory pre‑cut PU sandwich panel to minimize on‑site cutting. SAMZOON supports fast‑track production for tight retrofit schedules and delivers construction technical guidance.
? Step4 PU sandwich panel installation, focus on joints between old and new structures Fit anti‑corrosion gaskets for all screws of PU sandwich panel. Properly handle overlap gaps between new and old panels and steel‑structure connections. Apply high‑humidity‑resistant sealant with continuous full beads. Minimize on‑site cutting. If cutting PU sandwich panel is unavoidable, seal cut ends immediately. Pay special attention to new‑old joints, screw holes and door‑window openings — high‑leakage & condensation positions during retrofit. Do not apply sealant under heavy fog or rainy weather.
? Step5 Completion inspection & special acceptance for retrofit projects Carry out comprehensive inspection after PU sandwich panel installation. Check surface scratches, full sealing of all cut ends, intact sealing on new‑old overlaps and screw‑point coating. For clean‑room retrofits, re‑check surface flatness and joint treatment against clean‑room acceptance standards. Familiar with acceptance criteria for factories, cold storages and clean‑rooms in South China, SAMZOON provides acceptance reference checklists.
?️ Step6 Post‑retrofit regular inspection to extend service life of PU sandwich panel Build regular inspection schedule after project hand‑over. Inspect surface rust spots and aged cracked sealant of PU sandwich panel before and after every plum‑rain season. Repair damaged coating timely. For cold‑storage projects, watch for condensation along panel joints. Increase inspection frequency for coastal salt‑spray sites to stop minor defects from expanding.
⚠️ Step7 Common pitfalls to avoid for old factory and cold‑storage retrofit
Adopt over‑thick heavy‑weight PU sandwich panel without considering original steel‑structure load capacity;
Install new PU sandwich panel while residual wall moisture is not fully dried;
Simplify sealing treatment for gaps between new and old panels;
Only focus on foam‑core insulation while ignoring face‑sheet anti‑corrosion grade;
Assemble PU sandwich panel directly after on‑site cutting without end‑face sealing.
SAMZOON owns abundant finished retrofit cases for old factories, cold storages and clean workshops across South China. Contact us for technical support for complex working conditions.
