I have been working on removing a section of flooring just inside the door that had significant rot in it. Along that doorway wall the rot went fully along the edge of the 4' wide area against the entry wall and also extended further up the sides. Then there was a large area right as you walk in the aisle that extended in about 15".
If the rot had just been a small area I would have cleaned it out and filled it with thickened epoxy. However this being an area that will have a lot of stress on it from the in and out traffic and also while standing there to prepare meals I decided that structurally I really needed to replace a wider panel that ran all the way from side to side so that the point load of a human body would be spread out over a wide area for stability and longevity of use over the years.
The plywood floor in my Campster
was installed with thickened epoxy onto the fiberglass under shell. I do appreciate that it was done that way even while I am doing the fairly miserable task of prying up that old plywood. At least that is what I keep telling myself as I am working.
The first task was to decide on how large a section of flooring needed to be removed. I settled on 17" as being the minimum and of course it had to be at least 4 foot wide as was the original flooring. My piece is a little longer as they had also added some addition plywood sections at each side of that 4' width. The original floor is 3/8" thick, my plywood piece is metric so it is very slightly thinner which is nice as that leaves room for adhesive under it to level it up to the rest of the floor.
I did some testing to see what would be the easiest way for me to remove the old flooring given the tools I had and also my hand strength and comfort. I do have some wear and tear arthritis in my hands so I do want to take it easy on them to avoid getting into too much inflammation. Slow and steady is the speed I drive
My test quickly sorted out that if I scored the plywood into approximately 3/4" inch squares I could quickly pop out the chunks using an old garage sale purchase chisel. This is not a task for your good chisels.
First I used my replacement piece of plywood to mark my line onto the old floor for the area I was going to remove. Then guiding along that line with a straight edge I cut that line down into the original plywood floor using my small Porter Cable circular saw that was set to just shy of 3/8" in depth. That nice straight line will give me a good fit between the original floor and the replacement piece.
To create the hash grid of small squares I used a carbide coated, grinding type of blade in a Dremel Saw Max. That carbide grit coated blade is forgiving of not being guided with a straight edge or run in a perfectly straight line since it is a grinder rather than a regular saw blade. So that made cutting the small squares go very quickly as I did not have to stay as focused on not binding up the saw blade while making cuts. My back is not as limber as it used to be so being able to be a little sloppy in cutting the hash grids was of real benefit as far as personal comfort went. I can work very precisely but don't always need to
. The grinding blade also gives me a wider space for getting a chisel into the kerf. This saw depth was set just shy of 3/8" to avoid any possibility of cutting into the shell.
I did need to be sure to avoid cutting into the bolts in this area that tied the fiberglass shell down to the trailer frame. I could not get them out because they were epoxied in place with wet epoxy engaging into the threads when the original floor was set in place. You can see in the photo below where I stopped that lowest line on the left where I stopped the cut line just short of one of the bolts. Oh well, no big deal, I just cut around them and leave them in place. They are not hurting anything being there. I will make clearance holes for them in the new floor panel and add in two new hold down bolts through the new floor section. Someday a new frame underneath but not this year.
Hooray, only 15 more inches of old plywood to remove then some cleanup work with a different style of carbide grit grinding tool to get rid of the last of the old wood fibers. Tomorrow I can mix up thickened epoxy and install the replacement plywood piece. Of all the remodeling work that needed to be done this is actually the most yucky of the jobs with all that sawdust it generated. (Yes of course I take safety precautions and I use respiratory protection!)