“What fabric do you use?”
That’s a question that we hear a lot, but the answer isn’t always the same. There are a few different options that we like to use. But it really comes down to how you answer this question: “What do I want my cover to do?”
We’re going to mostly talk about houseboat choices, whether you’ve got a Big top or a Party top. We favor several options but the decision is based on what most appeals to you.
Are you looking to stay cool in the shade? How about safe from the rain? Do you remove the top during the offseason? How about a White top? We’ve been working in Lake Powell over the past seven seasons. All of these things get talked about while we’re down there. Let’s dive in.
By a long shot, Sunbrella is the most commonly used fabric for houseboat Big tops. The main reason is that the colorfast has proved to stay the same over a long stretch of time – in some cases up to 10 years. That’s a great run for a boat that’s out in the sun all the time. Sunbrella brings with it one of the longest manufacturer warranties and an extensive color palette. It’s also a woven product, so it’s much more forgiving during installation. If you take your old cover to a shop and ask them to copy it, this is a real bonus.
Sunbrella’s main downside? It’s only water repellant, it’s not waterproof. If it’s not retreated with 303 Fabric Guard each year, it’s likely to leak. And we’re talking a lot, not a little. It’s also not very dimensionally stable. That can cause it to stretch out or shrink up. While the color does last quite a long time, bear in mind that the dark colors last much longer than the lighter ones.
This is the newest material that we’ve been using recently and here’s why. Stam 6002 is a weldable product, which means that we’re able to bond two pieces together to make one solid membrane. Why do that? Because now it’s waterproof; provided new sewing is done. The PVDF coating helps to keep the product clean. That means you can choose a white fabric with no fear that it’ll soon turn red from the Lake Powell sand.
The main downside is that it’s 18.5 oz/yard which, depending on installation, can make it very difficult to remove and store during the winter. It also won’t be very forgiving if you want to take an old cover out to be copied. If Velcro flaps are used, sewing them in place will cause small holes from the needle, so it will leak a bit. It also costs twice as much as Sunbrella usually does.
Glen Raven sends a regular Sunbrella to Haartz, where they apply a PVC coating to one side. This is an excellent choice if you’re looking for all the qualities found in a Sunbrella, but you want it waterproof and not just water resistant.
This product has been known to shrink after a while, so be careful when removing it for long periods of time. It can be tricky to get back on. We’ve also noticed that the Sunbrella itself will sometimes outlast the PVC coating on the underside. Stability-wise, it will have similar qualities as a coated product. This makes it a bad choice if you want to have a local shop try to replicate an old top.
At Sewlong, we do not offer Hardtop conversions, but we have picked up some amount of knowledge over the years. We are not, by any means, the be-all and the end-all information source, but we do know a thing or two and we’re happy to share what we know if you’re considering this option.
Through most of our research, the product being used was extended PVC. There are two types of extended PVC: KomaTex and KomaCel. Make sure to ask which one is being used on your top. KomaCel is the one that your installer should be using. That’s because KomaTex does not survive sun or rain. KomaCel does not absorb water, so it keeps the top safe from rot and water degradation.
As for UV strength, you can expect three to four years in direct sunlight before degradation begins. To extend its life, there’s an additional UV clear coat that can also be added. If you’re going this route, we’d recommend getting a cover slip or some type of covered storage so you’re not having to replace the whole thing every few years. KomaCel is about 40% more expensive than KomaTex. Most likely, that’s the reason why KomaTex is being used. We think it’s worth spending the extra money if you want to keep your hardtop looking the way it’s supposed to look.