How do I replace rotten wood over steel I beams?

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tinkie

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Apr 23, 2019
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I put this topic originally in the wrong section, sorry to the mods, wasn't sure about a double post.
Hello y'all!
I'm facing a Summer project after a gray water leak into my underbelly went undetected for some time. This 5th wheel is laid out so the interior floor is the roof of bays which run throughout under the living area, then the bay floors are plywood covered below the trailer with insulation and then the membrane.

By the time I got to the leak the damage had been done. I will need to replace several areas along the outside wooden 1x3" framing on each long side, as well as several lengths of 2x2 which run about 12' length of the trailer (iffy/rotten). That framing wood is screwed into from up above through the bay floors. I've seen no bolts into the metal I-beams of the chassis to hold said wood though I know the interior subfloor up front is held with carriage bolts in the crow's nest.

I can unscrew the sides, the wheel well covers and side trim in order to peel back for access to the furthest edge wooden side framing, but what is my best bet to support and lift the bay floor plywood in order to get the new lumber in place?

Was thinking to place staggered jacks down the length of board I want to replace, with thick plywood up top to spread weight load around, then either claw hammer out the most rotten wood, cut, saw, however to get the rest out. Not sure if the screws are under carpet in the bays but I might be able to drill out the worst of the rusted from underneath.

I'm being awfully optimistic with this project.  The least of my worries is replacing pink insulation with a bubble foil type and putting corex up - my worry is how to wrangle this wood framing out and get back up top those steel I-beams. Sistering is an option for wood that's not got dry or wet rot, though all wood including new will be treated with anti-mold and fungals before buttoning up.
Any tips and advice are greatly welcome!
 

jackiemac

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Hi and welcome to the forum. I have moved your other post out of sight.  I'm sure you'll have a few suggestions coming your way soon. Glad to have you join us. Good luck with your project!
 

tinkie

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Apr 23, 2019
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Gary RV_Wizard said:
There is no magic solution - you are going to have to dig around and find those screws or bolts. And hope nothing was built on top of it (the RV is built from the bottom up).

Hehe, yeah magic would be good. There are two bolts on the outermost side framing where I need to pull wood out/replace - one on each side. They are definitely part of the load bearing structure but it is empty bays directly up top that are framed out underneath my living area. The company that built these 5th wheels made mobile homes and park models primarily. Every RV tech who's ever worked on it replacing furnace and water heater has said they've never seen a 5th laid out like this.

After looking closer today, I think I can manage the 2x's fairly easily. Since many screws put in from up top through the bay floors are gonna be rusty, a reciprocating saw and some well-aimed blows should make short work of them. The outer bolts are getting daily coats of WD40 and a bit of elbow grease on a ratchet. Main problem (for me) is getting proper wood ripped into proper sizes, and finding solid chunks of wood to get my bottle jacks up high enough to reach the subfloor of the bays. I'm a 59 yo woman so this isn't exactly my cup of tea. Can't get an RV tech interested in helping me for love or money. Says more about where I live than anything. Finding capable handymen appears to be a losing battle in my experience of 1 1/2 years since purchasing. Have had to do the majority of work myself - at least I know it's done right.
 

tinkie

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jackiemac said:
Hi and welcome to the forum. I have moved your other post out of sight.  I'm sure you'll have a few suggestions coming your way soon. Glad to have you join us. Good luck with your project!
Thank you Jackie! I have a friend living in Scotland. It's a very very lovely place, amazing!
 

Blues Driver

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If you are in doubt about the screws, bolts etc. supplement them with an industrial construction adhesive like Eagle, Pl400 or other commonly used on wood subfloors. It comes in 1 quart containers which require a large caulking gun or you may find it in smaller caulking gun type containers. Make sure the surfaces are clean and dry. This stuff really holds.. 
You might also use self tapping screws into the metal.  Buy good quality blades for the Sawzall or you will be replacing them endlessly.
That's quite a project. Good luck.
 

Camper6

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This kind of thing really stinks.  When water got up in my parents camper, somehow from the underside, they had to take it to a professional that works on camper trailers for a living.  From what I heard about it all the guy basically had to suspend the whole camper frame from a system he had set up and take the rotten floor out slide the new in from the underside.
 

Isaac-1

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Depending on the height and placement you might look at motorcycle jacks, like this one https://smile.amazon.com/gp/product/B01GIPTMLI/  I just bought one in order to drop my Onan generator in order to change out the starter.  Also this sounds like a job for an oscillating saw such as https://www.amazon.com/Rockwell-Oscillating-Multi-Tool-Accessories-Multitool/dp/B07D786PTB/
 

Lou Schneider

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I'll second the suggestion for an oscillating power tool, they do almost as well as a sawzall but give you more control.  I have the Harbor Freight oscillating tool that's about 1/4 of the Rockwell's price and is perfectly fine unless you plan to take apart RVs for a living:

https://www.harborfreight.com/variable-speed-oscillating-multi-tool-63113.html

They also have cutting blades that will let you cut through screws, nails etc. if needed:

https://www.harborfreight.com/search?q=oscillating%20power%20tool%20blades

 

tinkie

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Apr 23, 2019
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Hey All!
Feel kind of bad I didn't reply to all your great suggestions! Just wanted to let you know how it went for anyone needing to do the same kind of work! I hate it when a thread starts with a problem I also have, and then the OP never comes back to say how it went/how they solved it!

So it really wasn't that big of a deal in terms of having to jack things up, which I was worried about. I had ripped and treated my 2X's etc ahead of time, and I honestly only had to jack up about two areas right around the entrance door and on the other side to bang wood in. I was careful to choose which area of rotten wood to start clawing away at, and simply followed more or less the original way the framing had been laid out and did it one section at a time. So if a pretty good length of frame was rotten I made my starting points over the metal cross beams and simply banged in the beginning of a 2X, planing it down if necessary, and kept clawing out the old while knocking in the good with a good bead of PPL up there too (and sometimes actually just knocking out the rotten WITH the new parallel moving right in!). It actually was not that hard and the old rusty screws came out with minimal trouble. I PPL wood glued and screwed all new wood to old wood and the bay subfloor plywood. A few areas I sistered/glued/screwed and also added metal joist hanger type connectors.

The outer side framing was the most difficult due to space issues and I left a few dents on the aluminum but managed to replace the worst rotted out wood.

The very edge of the plywood floor behind the front entrance was truly rotten so I cut out a rectangle back to good wood and then banged in an overlarge replacement over the metal beam on each side, ppl'd it and screwed it in.

Took over two days and honestly the worst part was removing the rotten wood because of the mess it made on my goggles. The rest was old fashioned banging things into place, a few metal screws into the metal framework here and there, replacing the screws holding the aluminum sides in place at the bottom and boom - it was done. My advice to someone would be think out your layout under there, don't try to reinvent the wheel, just take sections one by one if you still have enough good sturdy framing, it's gonna hold up just fine. I had thought it was gonna be a beast getting new wood over those metal beams but it's amazing what a heavy headed anvil type hammer can do with a 2X going into a tight space! But I'll never do it again lol.  ;D

 

Gizmo100

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Thanks for the update......

Sounds like it was lots of fun.

I had a friend that would do autocad drawings for projects that I had going around the house. Every drawing had "HTF-PTN in the corner of the drawing, I asked him one time what that stood for, he replied "Hammer to Fit and Paint to match"
 

IBTripping

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Tinkie, let me add my thanks for updating us. Glad you got repaired. Wish you were my neighbor so I could draw on your expertise in RV repair.
 

emilyresmi

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Why don't you have your wooden beams restored? The easiest way to replace a small rotten section of wood is to use a particular repair kit. If the damage is significant if the wood is varnished or stained and the putty would be difficult to mask, cut out the rotted piece and replace it with a bit of new wood. After removing any rotted areas, allow the wood to dry well before slicing with a new piece of timber or applying putty. Drying may take a week or two if the wood has absorbed a lot of water. I recommend you restore the rotten wood, read miter saw reviews.
 

Rene T

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Why don't you have your wooden beams restored? The easiest way to replace a small rotten section of wood is to use a particular repair kit. If the damage is significant if the wood is varnished or stained and the putty would be difficult to mask, cut out the rotted piece and replace it with a bit of new wood. After removing any rotted areas, allow the wood to dry well before slicing with a new piece of timber or applying putty. Drying may take a week or two if the wood has absorbed a lot of water. I recommend you restore the rotten wood, read miter saw reviews.
This is a two year old post and the last time the OP was here was Dec. of 2019 and he made the repairs.

Oh and for you, welcome to the forum.
 
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