Oxford Fabric and PVC Guide for Furniture Covers

Denier is the number buyers quote and the wrong one to focus on

Outdoor cover quotations lead with fabric denier because it is a single impressive number. In practice the coating weight on the reverse of the fabric decides how long the cover keeps water out, and coating weight is rarely quoted unless you ask for it.

Ask for both. A high denier fabric with a thin coating will wet through at the seams in a season; a moderate denier fabric with a proper coating will not.

Seams are where covers fail

Every stitch through a coated fabric is a hole. On a cover that has to keep rain out, seams should be taped or welded rather than simply sewn. This is the single largest cost difference between a value cover and a heavy duty cover, and it is invisible in a listing photograph, which is why cheap covers keep being sold.

Wind lift, not rain, destroys outdoor covers

Most outdoor covers fail because wind gets underneath, balloons the cover and tears it at the hem or an eyelet. Specify the hem: elasticated, drawcord, or straps with buckles. On exposed sites, straps are worth the cost. On a sheltered patio, an elasticated hem is enough.

Clear PVC indoors is a welding question

For indoor chair and sofa covers in clear PVC, seams must be welded. A stitched seam perforates the film and lets liquid straight through, which defeats the product. Ask how the seam is made before you compare prices, because a stitched clear cover will always be cheaper and will always fail.