Big Sandy, Tennessee – This article is for the boat owner who has a boat or two with headliners as well as for the tradesmen tackling the replacing of headliners. We met the most wonderful couple with the most adorable boat traveling the Great Loop. They reported to us that tradesman after tradesman would be willing to install electronics or do this or that repair on the boat but none would touch the headliner.

Why is that? Probably because they tried it once and it sagged and vowed to never do it again. Actually with some prep work and patience it can be done without such anguish. They asked if I’d do it and in a heartbeat said, “Yes, no problem!” Their reaction was amazement – someone agreed so readily. Hence, I did their headliner. I recall years ago, a custom yacht in south Florida was being retrofitted with a headliner.

The boat was large and the headliner was 20 feet across and 35 feet or more long. Of course it is hot in south Florida; the custom yacht jobs are the plum jobs and pay well. One Friday night a crew of guys flipped on the AC and started working on the reinstallation of the new headliner and long into the wee hours of the morning they finally finished. Exhausted but filled with pride they were done and locked up the cabin and headed for home.

The next morning the crew boss got an urgent call and the crew had to scramble back to the yacht post haste. The headliner was sagging to all depths throughout the entire cabin. It looked like stalactites growing overhead. Actually this happens too often and does not need to. It also introduces a whole new set of dilemmas, not the least of which is the tradesman’s reputation plus who shoulders the cost of a new headliner if it can not be re-stretched and saved.

Who pays the crew again? And what happens if the boat owner was due to leave and this delays the departure. What about those costs? It is actually a nightmare and does not need to be. A sagging headliner is completely avoidable with some practical know-how. For step-bystep practical solutions, keep reading. First, some boats don’t have headliners. It depends on the design.

Our boats never had headliners, we had planked, double planked and sealed decking which on the underside was our cabin ceiling and consequently we never had the headliner problems that many boat owners have. Many fiberglass boats use vinyl headliners to make a neat, clean looking ceiling overhead. This covers up the raw surface of the cabin and top.

It also provides a one or two inch space for wires to run without being seen so that it is visually pleasant. The headliner is usually made of vinyl and stapled to wooden framework which covers the fastening and backing plates for deck hardware. Everything is okay until moisture leaks in and starts to slowly (or quickly) wreak havoc. Often the water damage has been going on for years before it is noticed.

All the while there is mold growing that you are breathing in while in the cabin. Water can come in from any and every mounting screw hole in the cabin roof, such as those of the hand rails or the running lights, radar mast, dingy davits, etc. Any and every hole is a potential leak. The source of the leak may be ten feet away from where the water shows through the headliner.

Water runs along wires, the wood framework, or even running inside the core of a laminated deck. A big source of leaks is at the point where radar wires go through the cabin roof. The wires can move around and twist which breaks the seal. The initial installation mechanic may have inadvertently twisted a wire so minutely that on a quick glance it is not noticeable. But over time with the boat inevitably flexing, the wire bends a little more and the seal is broken.

Water must be given its due, because if there is a hole or crack water will find it and travel into it. Add to this scenario the gel coat deteriorating over time from age, sun and other factors. Water seeping through may not show up for a few years but just dampen the wooden framework enough to cause rot. Once the headliner starts to sag and loosen at the seams it’s time for a new headliner.

Another reason to start examining the headliner is because it is time to upgrade the electronics and the boat owner wants the wires run and hidden in the headliner. Here are the basics for head liner installation: Click here for a printable, condensed cheat sheet. No step outlined below is too minor to ignore or your results will be disappointing.

As you prepare the cabin for taking down the headliner, moving breakables out of harm’s way, take note of the cabin ceiling substructure. Note how the original vinyl is tacked under the wood battens and is pulled to the next batten. Try not to destroy or distort the original headliner. If the original vinyl is not too brittle or dirty you might be able to reuse it. If it’s not useable, use it as a pattern at least for length.

Most boat headliners are 36” wide. They are typically different than a headliner for automobiles. Upon taking the headliner down examine the wooden frame. If it is decayed it will have to be replaced. Battens are best made from sugar pine, white pine, fir or any other straight grain wood with no knots. If the battens show no evidence of deterioration due to water, double check their edges.

The batten edges should be sharp and straight, resulting in crisp edges when the vinyl is pulled 90 degrees to the next batten for tacking and so on until the job is complete. If the edges are worn replace them with new straight edged battons. Battens are 1⁄4” x 3⁄4”; it should not be a big deal to cut new ones for installation. If there is wood rot you must find the source of water entry before the wood is replaced.

Every screw penetrating the cabin top is a potential leak. Radar masts that are thru-bolted to the cabin roof are a big culprit. The mast carries the weight of the radar antenna and other antennas plus the weight of the mast itself. Installation of electronics thru-bolted to the ceiling are often installed using only bolts with washers. Washers are a small bearing surface. Under the cabin roof, backing plates should be used because they have a large bearing surface.

Backing plates cover larger areas, distributing the weight more evenly overall throughout the ceiling. Small bearing surfaces cause a big strain on the cabin roof and can cause the caulking to let go or even crack the fiberglass which allows water through. Backing plates should always be used. If you are re-doing your headliner area insist on backing plates instead of simply screws with washers.

If you are unable to watch or view this process tell your mechanic you want photos of the backing plates installed in the ceiling before the new headliner is installed. Do not accept less. Sometimes a starboard side running light may leak and the water shows up on the port side. A strong wind might list the boat to port causing water to fl ow to port.

Finding a leak can be very frustrating. I would recommend removing all possible sources of leaks on the cabin roof and rebedding them while the headliner is down. Have someone spray water from a hose onto the top of the roof; vary the intensity and water angles to locate where the water comes in. Go below to watch the water leak. Keep a watchful eye and trace back to the source hole.

This may take time–even waiting for the water to work its way through its trail. If this doesn’t lead you to a source leak, have someone spray the water from the other side of the boat, varying direction and fl ow intensity while you watch below. Since you have the headliner down, remove each piece of roof hardware and rebed everything with 3M 5200 or equivalent sealant.

Be sure to clean every surface well, scraping all old caulking off. Use plenty of 5200 so it squeezes out everywhere under pressure. If there is a spot you don’t see any sealant squeezed out that may indicate a void inside and the result will be another leak. This is not good, especially after the new headliner is installed! Redo that fitting now. Seal up every seam even ones that look like they can’t leak because soon after this exercise they will probably let go.

You may wonder how you’ll ever get the piece of deck hardware off after all that 5200 is cured. I always use a heat gun or propane torch to heat the metal part until it lets go. Be careful not to ruin the paint, gel coat or to melt wires. Point the heat away from everything you do not want to heat up. I warmed the metal piece to just slightly too hot to handle and this usually is adequate.

Plan ahead for a hot pad where you will place the hot barrel of the gun when done. If you have a cored cabin roof, measure the old screws and use new stainless steel screws of the same length so they do not puncture the outer skin of the roof. When putting up new wood frame work to staple and attach the headliner material, use 5200 and the correct length screws.

The wood strips must be exterior plywood or solid wood, must be smooth and in a fair plane so that no bumps or joints show when the vinyl is stretched tight over them. Even a splinter on one corner can cause an ugly dimple or tear. I prefer Monel stapes over steel They’re often harder to locate than steel but they do not rust. Don’t let anyone tell you that they cannot be found–keep looking. Many marine suppliers sell them.

You will be pleased with the results in the long run. Request the aid of a helper, you might find it helpful having someone hold up the vinyl as you staple it in. Before beginning the headliner installation, wash your hands! Everything shows up; every particle of dirt and smug of dust will be visible in various lighting. Take a break every so often to wash and dry your hands with clean towels.

Generally headliner work is done in the summer and wouldn’t we all agree it is so much more comfortable to work in A/C! I caution you not to turn on the air conditioning during this project. In fact you should warm up the cabin like I do, turn on the heat or if the boat does not have heat close the doors and windows and use a heat gun to gently warm the air.

Think this through – it is hot – you’ll be hot – you’ll be wiping your brow use toweling not your hand. Place toweling nearby and handy. Be careful where you point the gun nozzle – you don’t want to melt anything or damage any knickknacks, start a fire or stain anything. If you are unfamiliar with working with a heat gun – set up a practice bench outside somewhere safe far from anything you can damage.

Place several nuts with bolts screwed into a board and fastened down with 5200; practice aiming the heat gun at only one screw at a time and see how much heat it generates. While you are at the test bench, heat up and pry loose a few of the other bolts you set up with 5200 for practice removal before tackling the cabin roof. The headliner material stretches when warm and shrinks when it is cold.

I start the installation by turning on the heat and close the doors and windows – even in the summer – and install the headliner when the temperature is warmer than usual in the cabin. In some troublesome spots sometimes I use a heat gun to warm the ambient air but not aiming the heat at the actual vinyl. Warm up the air to relax the vinyl for stretching so you can smooth it all over. Viola’! No wrinkles.

When the cabin returns to regular temperature the vinyl will stay tight without wrinkles. Ahhh, nice job! Most importantly know your skill level. Maybe this time you should be the assistant or distant observer. Watch and learn from the experts then tackle it. If this task is beyond your skill level, pull up with several pizzas, feed the guys first, have them wash their hands and watch the magic begin.