Flooring over deck with Hardi-Backer/Durock

OK, so here's the situation. The boat I have (1988 18' Fish/Ski) sat out in the elements, summer and winter for 3 years before I got it. There are quite a few soft spots in the plywood, but now, the passenger pedestal chair has ripped its bolts through and fallen off.

I have read what needs to be done in regards to removing the floor, redoing the stringers, replacing the floor, etc. Sadly, there is no way I have the money to do that, but I would like to continue to use the boat for the next couple years until I can afford to do that, so here is my interim solution, and I would like your opinions on whether you thing it will be a suitable bridge to get me through the next couple years.

Home Depot sells .42 Hardi-backer board, similar to Durock, but smooth. It is typically used as the backer for walls around bathtubs, because of its resistance to water, and under tile floors as well. So I'm thinking, get enough to lay it out over the existing deck area, screw it down tight with the proper screws, seal the joints, and paint over it with a waterproof paint. Then glue down some new carpet over it and reinstall the pedestal chairs and ski locker door.

This boat is garage kept, and we're almost never out in the rain for any extended period of time if ever...

I figure it can't possibly be any worse than my current situation, and I don't see how it would worsen the situation for the repair in a few years. In the mean time I will have a solid floor, and can continue to enjoy my boat.... Thoughts?

Re: Flooring over deck with Hardi-Backer/Durock

If you can't afford to fix your boat the right way, you really can't afford to own the boat you have. I suggest you sell the boat and buy another one in better shape or put the money in a savings account and saveup to buy another. You'll be saving money by not having to buy fuel, pay insurance, or maintain your boat.

Your boat has a bad case of cancer and your decking is most probably only part of the problem, the longer you leave your boat "as is" the more the cancer will spread.

Your foam is probably waterlogged and your stringers are probably rotten too... and things aren't pointing in a good direction for your transom either.

The cement backer board will add a lot more weight to your boat, and that's the last thing your boat needs right now.

Sorry if this sounds harsh, but it's my realistic view of your situation.

Re: Flooring over deck with Hardi-Backer/Durock

Ok, I can't say I didn't expect that response.

So if I translate that I read, "You can do that and use it the next two years, or you can do nothing for the next two years and the problem will be the same, but either way it needs to be addressed properly sooner rather than later."

The weight added will be equivalent to that of a child, so I can deal with that.

So that being said, I could also just get some 5/8 treated plywood, coat it with some Thompson's waterseal and do the same thing as long as I keep it out of the rain and keep it garaged.

Re: Flooring over deck with Hardi-Backer/Durock

Do not use that stuff. It is too stiff and is made for a stationary mounting (bathroom application). A boat flexes and that stuff does not. It will just crack and break. After all, it is concrete.

Re: Flooring over deck with Hardi-Backer/Durock

Makes sense... Plywood it is...

Re: Flooring over deck with Hardi-Backer/Durock

DK in Chicago said:

Ok, I can't say I didn't expect that response.

So if I translate that I read, "You can do that and use it the next two years, or you can do nothing for the next two years and the problem will be the same, but either way it needs to be addressed properly sooner rather than later."

The weight added will be equivalent to that of a child, so I can deal with that.

So that being said, I could also just get some 5/8 treated plywood, coat it with some Thompson's waterseal and do the same thing as long as I keep it out of the rain and keep it garaged.

Click to expand...

Your translation was a little off.

The boat will not be the same in 2 year, it'll be worse, and things will continue to break and go wrong with increasing frequency in the next 2 years.

How do you plan to fasten dura board or plywood to an already rotten deck? Do you actually think you'll be able to get any fasteners to hold the patch?

You can do anything you want to your boat, I just thought you were asking how to do it the right way.

... but since you aren't listening, I won't tell you about the high moisture content in PT plywood and the problems it causes.

Re: Flooring over deck with Hardi-Backer/Durock

Ok, fair enough...

I want to, and my intention is to, do it correctly. The problem I'm facing is reality, the reality that that will not happen until the 2013 season.

Here is the lowdown: This boat is used in the Chicago area, so we have about 4 months realistically to recreational boat. On average the past 2 years we got out about 7-10 times per year. Never in the rain. The boat is trailered into and out of a garage everytime we go out. All that being said, we would be planning to use it about 14 more times before it is fixed. All would be while it's not raining, and it will be stored indoors. So, given the fact that whatever decking I put down (Please insert best suggestion given the circumstances here), will be seeing minimal moisture during that time if any. I think that it is reasonable considering the option of simply letting it sit as is in the mean time....

DK

Re: Flooring over deck with Hardi-Backer/Durock

You asked for thoughts , here is mine, If your stringers are rotted you have a safety issue, and I sincerely hope you dont go on to Lake Mi. with not knowing their condition, at this point rain is of little concern. I would check them with help of the experts here. It sounds like you love being out on the water and boats but do not let that cloud your safety judgement please. I liked the one suggestion sell it as is for a winter project dig hard and get yourself at least a safer craft.Dave

Re: Flooring over deck with Hardi-Backer/Durock

Daveydoodle is correct, and not only your stringers may be rotting but also your transom.

Even storing your boat in the garage won't put the decaying into remission, it will slow it down if your garage is climate controlled... but the garage will be damp in the winter and spring if it is not. Just taking your boat out into the humid air on the lake will contribute to more decay, and if you swim, tube or, ski it'll be even worse with wet people climbing into your boat.

If you use your boat that infrequently, why not just start the project now? Go ahead and tear everything out and then put it back a little at a time as you get the money. Then you'll have a nicely restored boat for the 2013 season.

You're going to get tired of things going wrong and stuff breaking sooner or later, I just hope no one gets hurt in the process.

Lastly, if you insist on patching the floor use the 5/8" CDX sheathing. It's not very expensive and you're just going to have to tear it out anyway.

Re: Flooring over deck with Hardi-Backer/Durock

Ok, thank you for the honest feedback.

The last thing I ever want to do is compromise anyone's safety, so Lake Michigan is definitely out until it's properly fixed.

Help me out here if you can, thinking back about it I never did get a quote just for this issue.

What am I looking at ballpark for:
A. Just deck removal and replacement. (If I'm lucky and that's all it is)
B. Deck removal, replacement and stringer repairs.
C. Attempting it myself with the guidance of the great threads from this forum

To get through the end of this season, maybe 3 more short outings on the river, not tubing, I will just leave it as is and not remount the passenger seat. Then depending on the figures, see what I can do this winter.....

Re: Flooring over deck with Hardi-Backer/Durock

I guess the forum members told you.

Wonder if they realize what you're talking about? Durock is not near as heavy or as rough as Wonderboard. It's easier to deal with, but not nearly as waterproof. (I continue to use Wonderboard when around tubs and when fabricating shower walls.) The only way to get Durock completely stable is to put it down with thinset mortar and put ceramic tile over it with thinset. You don't want something on a boat installed that way, and don't need to to be so concrete like.

I think you're being told that it would be much better to fix the boat now, before it deteriorates to where it cannot be repaired. I cannot argue with that, since your boat has great lines. You might want to start by taking the boat to a fiberglass boat repair for an estimate--picking their brains for what needs to be done. The repairs can be easy, or they may be hard to complete. Much of fiberglass repair is not that difficult--more stinky and sticky than actually hard. Now, if it came to pulling the engine for transom repairs, it's a different matter.

Good luck!

Re: Flooring over deck with Hardi-Backer/Durock

judging by the pics the floor doesnt look all that bad. i would think the vinyl would look alot worst if it was that weathered. maybe the seat wasnt bolted down proper, or the PO had a XXL fishin buddy. if the hull is soild and the transom is in good shape you may have hope. I would go with 3/4 exterior ply, 1/2 is gonna warp if it gets wet(even painted). That being said i still think it should be fixed right. If you dont have the time/money to fix you should sell it. Its not gonna be worth anymore money in the future. Then save up and buy something in the winter months that is more manageble.
I have a small boat but couldnt afford a bigger one if it was free, the maintenance is what kills you. Even on brand new boats.

Re: Flooring over deck with Hardi-Backer/Durock

Well I wend over to the boat and got some of the carpet up, and managed to takes some pics under the floor by sticking the camera under in in the engine compartment, and I think I may be in luck.... Let me know either way....

First hing I liked to see is that the floor was glassed. Secondly I found out that most of the spot where it is soft is where the 2 pieces of plywood met in the middle of the floor, and there is no support under where they meet! Whomever put the floor in, put the seam right sown the middle of the boat, found this out when I reached under there in the back, and felt the seam, but there was literally just air under it....

So if I am deducing what I see correctly under the floor, that looks like my stringer in the background, and it looks glassed and in decent shape? We'll see eventually, but I have to say I was expecting worse...
From what I can tell it is only having issues where it has been breached, but not sealed, like where the bolts for the seat were, and where the ski locker is... ???

Re: Flooring over deck with Hardi-Backer/Durock

Things look good under there.. And the hole under the chair shows that the ply looks dry, and the foam too. If you dig into it, is it dry? If so then either patch the seam with a piece of 1/2" ply from below. If you can't get under the floor, then cut the floor back even with the stringers, attach a strip of plywood to the side of the stringer, and cut a new piece of floor to drop in and rest on the ply that was attached to the side of the stringer. Then glass over the new center section overlapping to the old.

Screw and glue all the new ply pieces in place. Seal anywhere a screw passes through anything. Use stainless deck screws if possible. PL1 is a good adhesive to use, or attach all the ply together with thickened epoxy resin.

BTW, it is common for pedestal chairs to break free of the floor, especially when installed with wood screws. That floor looks solid, and I would reinstall the chair base by through bolting it using nuts and bolts, or blind toggle bolts. That is the preferred method, and holds up to the lateral stresses that pedestal chairs get.

Re: Flooring over deck with Hardi-Backer/Durock

DK, maybe you could just cut and lay a piece or two of ext ply over the area,( one on top of the other maybe 1 1/2 in thick) glass it in and tabb it in to the deck and then you would have a nice solid piece of wood to bolt or screw your seats into.
I think you said you are going with carpet so you could just carpet over it.

Re: Flooring over deck with Hardi-Backer/Durock

You really should take core samples of the stringers that you can reach and the transom. Maybe you could get really lucky and just replace the deck. Is that foam soaked where the hole is? Drill some 1/4 holes, check the shavings, refill with 3M 5200. Don't drill too deep on the transom. You don't want to go through.

Re: Flooring over deck with Hardi-Backer/Durock

What am I looking at ballpark to have someone remove and replace the deck for me?
I don't mind tackling most things, but I know what I'm comfortable with and what I'm not, and removing the deck myself is not one of them.

When the passenger chair first fell off at the end of last season, the foam was wet if I dug down into it. Now it's dry as far as I can poke. During the winter I pulled the Captains chair off, and there was some water there, haven't done that recently, but may to see where it is now...

I'm comfortable now taking it out a couple more times on the river this year, and am resigning myself to seeing what I have to deal with during the off season, and going from there...

Re: Flooring over deck with Hardi-Backer/Durock

DK in Chicago said:

What am I looking at ballpark to have someone remove and replace the deck for me?
I don't mind tackling most things, but I know what I'm comfortable with and what I'm not, and removing the deck myself is not one of them.

When the passenger chair first fell off at the end of last season, the foam was wet if I dug down into it. Now it's dry as far as I can poke. During the winter I pulled the Captains chair off, and there was some water there, haven't done that recently, but may to see where it is now...

I'm comfortable now taking it out a couple more times on the river this year, and am resigning myself to seeing what I have to deal with during the off season, and going from there...

Click to expand...

If your foam was wet, it still is wet. It will not dry out.
That means you def have problems under your deck and to have someone just replace your deck is going to be a waste of your money. Your going to need to cut the deck out and dig out all the foam and double check stringers and transom. Sorry about the news.
Boat mecanics charge around 90$ an hour.

Re: Flooring over deck with Hardi-Backer/Durock

That's fine, better safe than sorry... Looks like it's almost time to cross the fingers and move forward. We'll see how it goes.

Re: Flooring over deck with Hardi-Backer/Durock

DK, It's really not that hard to do and as you know everyone would help you with every step. It is time consumeing trying to juggle a project,work and home life but if you stay at it you could have it done in no time.
My thoughts are if you pay someone to just do your deck it will cost just as much as if you redid the stringers,transom, foam and deck yourself.