Subfloor damage

[ck21084]

Ok so this is my 4th post and I have bad news. Upon removing the check valve and water regulator so that i could clean out a dirt wasp that decided to make a home in the water inlet. I was cleaning the carpet in that area and noticed a soft spot in the floor. I was thinking of cutting out this area as well as a few extra feet to allow for proper support.

What are you thoughts and recomendations on plywood to use.

I also thought about reinforcing the seems with 1/4" plate alum.

[SpaceEgg]

Hi. I just completed a similar task on my brand-new second-hand '59 Trade Wind.

I had plywood rot in a few places, and here's what I learned.

-marine grade plywood is what you want to use, just measure the depth and buy from a home supply store ("marine grade" is defined by the glue used to seal the sheets of plywood together and also the degree that they fill any knots in the wood. "Marine grade" is also known as something else too, just ask at the lumber store.). I was lucky and there were scrap pieces of the plywood I needed at the back of the store, and I made out like a bandit. $2.01 for an 8'x4'x5/8" (or 3/4" can't remember exactly) at Home Depot, so it's possible not to spend a lot to do this job right.

-the subfloor that you have a hole in is bolted (or riveted) to the aluminum shell, so find these "studs" when you are deciding where/how to cut your replacement piece. The subfloor is bolted with very large pieces to the metal chassis, you can find them if you look for them at the seams of the plywood, and this indicates where the metal skeleton is underneath you.

-depending on how much traffic the area receives, you'll need to think about anchor points. I laid my pieces over two rungs of the chassis where possible, and then used small "mending plates" purchased from hardware store to attach new plywood to existing plywood subfloor. Works like a charm.

-you only need to remove enough existing plywood subfloor to either (a) get to good wood again, or (b) find another rung to brace your plywood on (see skeleton comment). you may need to notch the portion of your new plywood piece that will fit under the skin if you need to avoid the "studs" connecting the skin to the frame - I couldn't figure out an easy way to reattach them to these studs (and therefore the aluminum shell).

-set a circular saw to 3/4" inch depth and you are safe to cut any floor you need. A jigsaw helps near the interior wall, but be VERY careful because the belly pan slopes up at these places and you can punch right through it with a jigsaw. I found that if I go close enough to the wall with a good cut from the circular saw that I could just pry the rest of the wood off.

-Bonus points: The problem with the mending plates is that they are ~1/8" tall, and so higher than the existing subfloor. Now that I am going to relay the floor, I have a dilemma. What I just thought of is using a dremmel to notch the new and existing floors so that I can set the mending plate in the floor nice and flush.

I can send you photos later if you are interested. Good luck!

(btw, I think your idea of the aluminum braces underneath is a good one, but for me, it wasn't necessary - low traffic areas)

p.s. you may want to consider investigating where the leak is coming from before you fix the floor!

[ck21084]

space egg,

Thanks for the quick reply.

I just finished cutting out the bad wood. This is in a low traffic area so i am not worried about flexing I just want the repair to be as solid as new.

Around the edges I removed the leftover plywood with a 3/8" chisel to cut the rest. i am really trying to figure out the cause of the wood rotting as well as the superficial rust on the frame supports.

I think instead of 1/4" plate Al i will use the support to "scab" plywood or use 1/8" Al and use fastners simular to the original used.

[68 TWind]

Find the leak, before you put your new wood in. Job #1 is stopping water, then fix the mess.

[VIKING]

Originally Posted by ck21084

Upon removing the check valve and water regulator... in the water inlet.
I also thought about reinforcing the seems with 1/4" plate alum.

I think I found the source of the leak. Water inlets are notorious leakers. Check both the hose attachments(inlet and tank) and check the sealant around the cover on the outside of the shell.
Aluminum makes a strong doubler but it's a bear to run a woodscrew into. I would use scraps of the flooring plywood, about 6" wide, glued to the underside of the floor, and screwed into from the top. Then the patch can be laid in and glued and screwed into the doublers, also from the top.
Not all floors are 3/4". Mine was 5/8". If you set the saw 1/16" too deep you will cut right through the crossmembers and have to go get a welder. If you do try this, set the saw 1/16" too shallow.
If you cut the floor back to a frame member you can seam the flooring on top of the frame, and secure it to the frame with floor repair screws from Vintage trailer supply.

Best of luck

Rich the Viking

[VIKING]

Welcome to the forum!

Originally Posted by SpaceEgg

-Bonus points: The problem with the mending plates is that they are ~1/8" tall, and so higher than the existing subfloor. Now that I am going to relay the floor, I have a dilemma. What I just thought of is using a dremmel to notch the new and existing floors so that I can set the mending plate in the floor nice and flush.

setting the mending plates flush will solve the bump in the floor issue, but it will weaken the joints you are trying to hold together a lot. If it's not too late, I would suggest pulling up the patch and using plywood doublers, glued and screwed to the flooring and to the patch. It will be stronger by far.

You have done a lot for a 4 poster! keep it up!

Rich the Viking

[centennialman]

Viking....what is a plywood doubler?

Thanks!

[Wabbiteer]

"Plywood doubler": add-on backer panel under free floating seams, usually around six inches total width to make a 3-inch ledge under each sheet.

Realistically, even glued and screwed, it is not truly load bearing being weaker than an unbroken plywood span but it does keep floating edges completely aligned.

[internat6]

I am new to forum but have owned a 1972 Argosy since 1990. We have used it twice.
I now have removed about 12 ft of floor in front part of trailer . Plan on doing the other half later in the year. Looks like it is a pain to put in hole sheets .My plan is to put in more stingers (2x4) in and segment the plywood then glue and screw. Any help would
be great. Had to repair latch system for steps to.

Thanks BOB

[ck21084]

I forgot to follow up on this thread.

The project was completed on saturday(5-1-10). I used 3/4" plywood as a filler piece. as for the support i used the 1/8" Al plate (my friend owns an Al shop in tampa) to secure this to the original plywood i took the plate and used C clamp vise grips and held it in place while i used Phillips brand wood to metal screws.(just like the original execpt they self tap.) once this was attached I put the new plywood in. It had a very tight fit, so tight that i had to use a 16lbs hammer to put it in. After this was secured i put gorilla glue on the seam and let it dry over night. The next day I sealed the joint further by applying a 2" bead of silicon and smeared it with a putty knife.

Problem solved..

Thank you to all that responded for sharing you knowledge.