Welded seams generally perform well in freezing climates when the liner material is designed for cold-weather use and the seams are made with proper equipment and technique. A strong thermal weld essentially fuses the material into a continuous sheet, so the joint is often as sturdy as the liner itself.
In low temperatures, the key factor is whether the liner remains flexible enough to avoid stress points that could strain the seam. Materials like RPE keep their pliability in winter, allowing welded seams to move slightly with the surrounding soil or ice without separating.
