Floor in houseboat

[Bdunbar44]

hey guys I’ve got several soft spots in my floor on my houseboat. It’s a 1973 Gibson. I was thinking about putting down advantech 3/4 subfloor or 3/4 marine plywood. I’m thinking just put it over the existing floor. I really don’t know which is best or what is best. I would love to hear any suggestions

 

[Scott Danforth]

the floor is rotten because the underlying structure is rotten. start by removing the old floor, then remove the rotten structure, and keep removing rotten material until you get to good material.

on a 52 year old houseboat with a fiberglass hull and wood stringers and transom, you may have to go all the way to the hull, and replace transom and stringers.

putting a new floor over a rotten floor is neglecting the structure and will lead to your new floor failing in a very short period of time. its called a "deck-over" and is the boating equivalent of a used-car dealer using the sunday paper and 5# of bondo to cover rust holes. may look pretty for a week until you get it home, however will fail in short order.

 

[matt167]

AYO fishing on YouTube actually did a restore on a 70s Steury houseboat which is probably similar to yours. Watch a few from the beginning. I think his is the only houseboat restore I’ve actually seen done, but infinite YouTube money makes it possible

 

[DeepCMark58A]

Properly prepared as Scott stated is removing the rot not covering the rot.

 

[Scott Danforth]

Lets look at it another way. its not really fun to have to fish the refrigerator out of the bilge because the floor structure failed and you now have to pull the whole houseboat out of the water before it sinks because there is a 3" hole in the hull, the bilge pumps are all running max, and you are at least 20 minutes from a ramp.

 

[Bdunbar44]

AYO fishing on YouTube actually did a restore on a 70s Steury houseboat which is probably similar to yours. Watch a few from the beginning. I think his is the only houseboat restore I’ve actually seen done, but infinite YouTube money makes it possible

Yeah I just watched that video. I’m not doing all that. I don’t have the means, money or willpower! Haha

Lets look at it another way. its not really fun to have to fish the refrigerator out of the bilge because the floor structure failed and you now have to pull the whole houseboat out of the water before it sinks because there is a 3" hole in the hull, the bilge pumps are all running max, and you are at least 20 minutes from a ramp.

well if I pull up the old and clean out rot from 1973 then I’m gonna have to pull the boat out anyway. That’s another expense on top of the floor. Like I said it’s spongy in a few spots so hopefully it’s not that bad. The boat is a 73’ model and so am I so I kinda feel like whether it’s “overflooring” or complete renovation it’s gonna outlast me either way! Haha

 

[DeepCMark58A]

Spongy in a few spots is not isolated when it comes to rotted wood. It is way worse under the floor that what you feel on the other side.

 

[Bdunbar44]

Spongy in a few spots is not isolated when it comes to rotted wood. It is way worse under the floor that what you feel on the other side.

Well I’m not much on half assing anything but overflooring it is. It would cost more than the boat is worth to pull it out of the water and gut it. I basically just want to know if advantech or marine plywood is gonna last longer.

 

[airshot]

Do it as cheap as possible because nothing will last more than a few years. Make sure everyone on board wears a life jacket at all times. Remember, if UT were to sunk, you are responsible for the cost of pulling it out of the water. No insurance company will cover a rotten old boat. Just some food for thought.

 

[Bdunbar44]

Well that’s a lot of what if’s…. So whatXXXXX? He might have caught the rabbit?! We can make up scenarios all day. If the boat sunk obviously that would suck so pulling the boat out and completely gutting it or having it pulled up if it sunk i doubt there is gonna be much difference. Lmao Obviously as a boat owner we all have the nightmare of a boat sinking. So I’ll just make a decision on marine plywood or advantech and go with it
MOD EDIT - Rude language is not tolerated.

 

[Scott Danforth]

if a boat sinks, depending on where you are, the EPA fines can be $1800-2500 per day until the boat is recovered.

 

[Bdunbar44]

Well that’s a lot of what if’s…. So whatXXXXX? He might have caught the rabbit?! We can make up scenarios all day. If the boat sunk obviously that would suck so pulling the boat out and completely gutting it or having it pulled up if it sunk i doubt there is gonna be much difference. Lmao Obviously as a boat owner we all have the nightmare of a boat sinking. So I’ll just make a decision on marine plywood or advantech and go with it
MOD EDIT - Rude language is not tolerated.

Thanks for keeping me in check!

 

[briangcc]

Well let's take the structure out of the picture for just one tiny minute. And we'll ignore having to do the work twice as you'll put the new floor down only to have to pull it back out to actually fix the problems below.

Putting a floor over top of an existing floor...adds weight...to something that inherently you want to float. That to me sounds like a very bad plan.

 

[Bdunbar44]

Well let's take the structure out of the picture for just one tiny minute. And we'll ignore having to do the work twice as you'll put the new floor down only to have to pull it back out to actually fix the problems below.

Putting a floor over top of an existing floor...adds weight...to something that inherently you want to float. That to me sounds like a very bad plan.

 

[Bdunbar44]

Well my boat sleeps 8 people I’m 51 and single so I think it can handle the weight of a piece of plywood! Haha

 

[aspeck]

I need to ask, with the over laying of the rotten floor, are you going to shorten the load bearing walls of your houseboat to put good wood under then, or are you just going to but the plywood up to the sides? You better get some solid support for the walls also ...

 

[briangcc]

You seem bound and determined to do it your way. If you're looking for a "go for it", you won't find that here.

The opening note mentions several soft spots...unless they're all grouped in a 4x8 location, we're talking multiple sheets of plywood. There's no free ride, they all weigh something.

Any number of boats that have come before you, ignoring the size, have had much larger issues that a "soft spot" on the floor. All have required major overhaul.

 

[Bdunbar44]

Well there one thing that’s absolute! I’ve had lots of comments on what COULD happen!! I wish I COULD delete this post because I’m gonna put a piece of plywood or advanctech down and call it good. I merely wanted to know which would last longer… whether a month, year or 10 years.

 

[Scott Danforth]

test drill your stringers and transom. use a 5/16" drill, mark off 3/4" length. drill into the encapsulated wood of the stringers and the transom about 4" up from the bottom of the deck. if the wood shavings come out dry, light colored, and smell like fresh sawn wood, then you are good.

however if the shavings come out wet, dark and smelling of rotten mulch, then the structure of your boat is gone.

literally the last thing to rot on a fiberglass boat is the floor.

we are saying this to help you understand exactly how dangerous a boat is with soft spots in the floor, especially a houseboat

at a minimum, read thru link #14 in the hull restoration sticky. https://forums.iboats.com/threads/how-tos-and-other-great-information.283508/

 

[DeepCMark58A]

Post pictures.