Water Resistant v Waterproof?When looking at outdoor furniture or fabrics in particular, we have all come across the terms water resistant and/or water proof. So, what is the difference you might ask? Customers are often confused or misled when it comes to these terms, so let’s try and make them clearer especially with respect to outdoor fabric. First, let’s start with the dictionary definition of each term (Collins English Dictionary):
- Water Resistant: does not allow water to pass through it easily, or is not easily damaged by water.
- Water Proof: does not let water pass through it.
- The fabric
- How it has been made.
Outdoor FabricsThe most common outdoor fabrics are nylon, polyester & cotton, and these fabrics are measured in Denier. Denier is based on a natural standard: a single strand is approximately one Denier. So 400D fabric equals roughly 400 pieces of thread. These fibers are then woven together to create the fabric. That is why when you look closely at a 400D (Standard) fabric the individual lines(fibers) will be smaller than the individual line on a 1680D fabric (Commercial Fabric). Even though these fabrics are woven together very tightly, water is still very small. This means water can get between the fibres where they pass each other. Normally rainfall does not pass through as raindrops don’t weigh much, but if in a heavy down pour water will eventually find a way through. To help these fabrics with their quality of water resistance, some have a protective backing added, using either polyvinyl chloride (PVC), polyurethane (PU) or thermoplastic elastomers (TPE) to help stop water getting through. Many traditional synthetic fabrics will have PVC on the backside of the fabric, to help prevent water from sneaking between the fibres.
Standard (400D – shown in red), and Commercial Fabric (1680D – shown in chocolate)If you are not wanting a backing, there are fabrics that have an added Teflon coating. This is applied to the surface to help water bead up and roll off, as can be seen on our Resortella Fabric. The advantage of this method of water resistance is that the fabric retains its soft feel as it does not have an added layer of PVC/PU. However, the coating can wear off over time, so we recommend applying a “waterproofing” spray occasionally – this can be found in most major hardware stores. If you can afford to spend a little more, there are a couple of fabrics that will stand the test of time. Both Olefin and Acrylic are 100% solution dyed fabrics, which can stand up to the harsh sun for many years to come. (Sunbrella is actually a brand of Acrylic). Like Acrylic, Olefin is quick drying, can with stand the weather, stains and mildew, but is not as water resistant as acrylic. However, it is harder wearing, and cheaper than Acrylic, so it is an excellent choice for outdoor fabric.