31 January 2026 by Banana Passion
Fibreglass blankets (like welding or fire blankets) are engineered for heat and flame protection, not for keeping liquid off your bed or sofa.
The glass fibres themselves do not absorb water, so these blankets are naturally water‑resistant and can shrug off splashes or light spray.
However, they are not designed as a sealed barrier, so water can seep through gaps in the weave or around stitching if the fabric is soaked or under pressure.
In industrial settings, manufacturers describe fibreglass welding blankets as “water‑resistant, but not waterproof”, meaning occasional contact with water is fine, but they are not meant to act as a leak‑proof membrane.
They can also become heavy, uncomfortable and potentially degraded if left saturated, which is very different from a washable TPU‑based waterproof blanket built for everyday spills and body fluids.
Polyester fibre is hydrophobic, so it repels water better than cotton or rayon and dries quickly, which is why it’s popular in outdoor gear and furniture.
On its own, though, plain 100% polyester fabric is classed as water‑resistant: tightly woven fibres slow down water penetration, but they won’t stop a spill or heavy rain forever.
To make polyester truly waterproof, manufacturers usually add one or both of these:
Without this extra layer, a “100% polyester blanket” will eventually let liquid soak through under body weight or standing puddles, especially with oils, sweat or thicker fluids. We at Banana Passion have biodegradable 0.02 Thermoplastic Polyurethane (TPU) used for our blankets.
For bedding and intimacy blankets, you want the fabric (often polyester or a polyester blend) to feel soft, while a dedicated waterproof membrane inside the blanket does the actual blocking.
Marketing claims like “polyester is waterproof” can be misleading; the real questions to ask are whether the blanket has a bonded waterproof layer, how the seams are finished, and whether it is tested as fully waterproof rather than just water‑resistant.
So while fibreglass and plain 100% polyester can handle a bit of moisture, they’re not designed to give you that soft, truly leak‑proof protection you want on your bed or sofa.
Banana Passion waterproof blankets use plush, cosy fabrics wrapped around a dedicated TPU waterproof layer, so you get the comfort of a regular throw with the confidence of real spill and splash protection for your most intimate moments.
