How To Repair a Leaking Boat/Houseboat

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If you own a houseboat for any length of time then you will probably run into some leaks at some point in the future. Leaks are relatively common occurrences especially as the boat ages. Some different places that may leak on a houseboat are: 

  • Roof
  • Windows 
  • Deck
  • Hull

Anytime you run into a leak it is important to know what you should do to fix it. 

How do you repair a leaking houseboat? Depending on where the boat is leaking will depend on how you should fix it. If the roof or windows on your boat are leaking then you should be able to fix it with some caulk or other sealant. If your hull is leaking you will need to dry dock the boat to make repairs. 

Anytime that your boat has a leak it can be stressful as you don’t know what is causing the leak so you don’t know how to fix it. In this article I will give you some helpful tips to help you determine what is causing the leak so you can find it and fix it easier. 

1. Locating the Leak

One of the biggest issues when you discover that there is a leak on your boat is determining where the leak is at. Having a leak is not only stressful, but they can also cause other unrelated damages to the boat and the gear that you have on board because of water damage. 

Most often than not, it is quite difficult to figure out where these leaks come from just by looking at the boat. The best way to be able to identify where the leak is coming from is to do a water/air test. This can be done by using a hose or even an air compressor and shooting water or air on different portions of the boat while you have someone else at the wet spot.

This can be annoying and time consuming but as long as the leak isn’t in the hull time isn’t a huge issue. Keep squirting the water or compressed air until the person on the other side feels the air or water. Then you will know that is the leaking spot. 

Another way to be able to identify where in the boat leaks are present is to look out for different areas that have stains. Leaks can happen because over time the constant presence of water can tarnish the paint or stain of the boat. If there is a spot that is showing signs of water damage that is the perfect place to start the water/air test or to use the next step on.

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The last method of locating the leak is the nuclear option. This is what many people do when they have a leak from their tub surround, on their windows, or even sometimes their roof. You will want to go through and reseal every single possible spot where water could possibly come in. 

This is the most time consuming option but it is the one that works the best. Growing up, the church I was attending had issues with water leaking from the roof during heavy rainstorms. The problem was that it was only certain rainstorms and they couldn’t replicate the leak with a hose or pressure washer. The last hope was to replace the entire roof. 

Before doing that someone in the church recommend that they try more black jack. Of course it had been done many times at many spots and it never fixed the problem but this person said they would try their hand at it. They went and bought a five gallon bucket of black jack and filled the entire valley that was leaking with the black jack! It was truly the nuclear option as it covered multiple hundred square feet of the roof! But it worked! 

The leak was gone and the roof lasted until a hail storm came through and pounded holes in all of the shingles. The nuclear option might sometimes be more expensive or more time consuming than pinpointing the exact leak but it is sure to work if you caulk everything. 

2. Material to repair the leak

There are several materials needed to be able to properly fix the leak that you are experiencing. The type of materials or sealant needed will depend on where the leak is located. Some possible materials you might need are:

  • Black jack
  • Caulk
  • Adhesive sealant
  • Epoxy

Make sure that all the materials that you use are waterproof and mold and mildew resistant or proof. For most leaks a waterproof caulk will be enough to fix the leaks. Make sure to get caulk and caulking gun to do the job properly. There are some caulks that come in squeeze bottles but those are hard on your hands and you can never seem to get all of the caulk out. 

 After applying the right amount of caulk, the next step is to use a gloved finger to spread it across the entire area of the leak and make sure that it is covered properly. This will not only make the caulk look nicer but it will also make sure it gets into the smaller cracks that might not be on the exact spot when you placed the caulk. 

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If it is a crack in the deck boards or even in the wall of the cabin it is a good idea to seal both sides of the crack if at all possible. In some cases you can’t access the other side but if possible be sure and do it. It’s also important to make sure that the fix is spread out enough so that it adheres to the material on both sides of the leak. 

If you were to take a ball of caulk and push it into a hole it wouldn’t fix anything. You have to make sure that you use enough caulk or sealant to cover the entire hole or crack as well as all sides of where it is leaking. 

Aside from knowing the basic procedures needed to fix these damages on the boat, it is also a necessary step to be able to choose the correct sealant. Depending on where the leak is and what materials are nearby will determine what you need to use to seal the leak. Black jack should be used on the roof of the houseboat while waterproof and mold/mildew resistant caulk should be fine for most other leaks. 

After choosing the correct type of sealant, it is also important to use just the right amount of sealant for the patch that needs done. You should  use a liberal amount of sealant over the spot that is leaking- whether these are holes or cracks. In addition to making sure that the entire perimeter is covered, it is also necessary to check that the sealant is thick enough to counter any more leaks.

In most cases it is better to have a little extra caulk or sealant than to not have enough and have the spot continue to leak.  If the leak is multiple cracks in the same area it is a good idea to use something to push the caulk or sealant down into those cracks. That can be done by individually sealing each crack or by putting tons of caulk down and squishing it all together using clamps or other fasteners. 

3. Stop Leaks from Happening

Leaks are not something that anyone wants to experience so preventing leaks on your houseboat should be at the top of every houseboat owner’s mind. How could you prevent most leaks in the first place? Preventative maintenance! 

Take the time to peel off caulking that is pulling loose and replace it. Scrape and repaint or reseal any wood that is showing some age. Keep tar on the roof fresh enough so it doesn’t crack and start leaking. 

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These and many other preventative measures will keep your boat from experiences as many leaks and keep your boat dry inside! 

4. The Hull

A leak in the hull of your boat is the elephant in the room that I have been avoiding this entire article. The reason is that I would NEVER recommend that anyone fixes their own hull when it is leaking. Most people spend 50-100k on their houseboat and you want to DIY a leak in the hull that if not repaired properly can cause your entire boat to sink to the bottom of the lake or river? 

If your hull is leaking get your boat to shore and get a professional to come out and repair it properly. Don’t hire some handyman off of Craigslist to try and save a few bucks either! Go to a local marina, tell them your hull is leaking and see who they recommend.

 Houseboats sinking are rare but it does happen and your boat is far more likely to sink if you try and fix a hole in your hull when you don’t know what you are doing. Watching a youtube video or reading some articles on the internet doesn’t make you an expert! Spend the money, hire a professional and get the leak fixed right!


Many people might worry that figuring out how to repair a leaking houseboat will require a certain level of expertise in the subject matter, but the truth is that it just isn’t that difficult. There are  a lot of resources available online to be able to help in clarifying details that might be confusing for a newer boat owner or someone who doesn’t have much experience doing handyman type things. 

When it comes to fixing leaks most of the time it just involves finding the right sealant and smearing it all over the place. Finding the leak is the hardest part of any fix but you can get around that by using the nuclear option and sealing every possible spot that might be leaking on your boat! Regular routine maintenance is the best way to prevent leaks in the first place so if you do that right you shouldn’t have to deal with many leaks at all. 

As Always

Happy Boating

Matthew Robbs

I love the outdoors and especially spending time with my family. Whether on a boat or at the beach, my happy place is near the water.

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