Bambi Carpet Removal project 2022

[Aironius]

My 2021 Bambi 19 is well kept and in good shape. That said, Mrs. has requested that I replace the original carpet with something that does not smell like PO's long-dead dog. So I boldly approached the project last Fall. First I removed some carpet inside a storage locker where it didn't show, to see what was underneath. Then I removed all the visible carpet. Next, I began unbolting and removing furniture to get at more of the old carpet. I learned a lot about how AS trailers are built. As shown in the photos, I ended up leaving only the L side cabinets containing the shower, sinks, furnace and water tank (don't need to mess with working plumbing). All the exposed subfloor will be covered with new floor, even under the furniture to maintain the same height as with carpet and pad underneath. And before the new floor goes in, the LH dinette seat will be loosened and raised to slip the new floor under the edge so no molding or trim will be required there.
The subfloor is good, only some minor water stains behind the R wheel from driving in heavy rain. I plan to seal and flash both the inner fenderwells to stop or at least reduce this leak.
After removing the carpet, and also the section of vinyl composite floor in the bath area, I am left needing to build a floor consisting of underlayment plus flooring with a total thickness of about 3/8". At present, I am leaning toward 6mm vinyl stone composite (VSC) for its temperature stability, and a 1/8" underlayment. With a layer of adhesive between the subfloor and the underlayment, I should get about the right total thickness.
Having never done floors before, I am reading everything I can find on this forum and getting some good advice, but most posts are at least a few years old. So I will start this new thread in hope that folks who have done it will chime in with helpful advice or warnings.
In particular, I need advice on what material to use for underlayment (original looked like 1/8" luan panelling), and what adhesive is best. I plan to spread a coat of glue on the subfloor and air staple the underlayment about every 6 or 8 inches, then lay the VSC with a single bead of glue down the center of each plank as the original bathroom floor was done to keep it in place. Probably going to simply screw the furniture down to the floor with no oversize holes, spacers, or whatever. VSC should allow me to ignore thermal expansion.
Here are some photos. The tools are what I used to remove the old glue under the bathroom floor, which turned out to be the hardest part of the demo.

What think you? Where am I screwing up? I have waited all winter for the weather to warm up. Now I am back in the barn to work and finally have photos, so tell me what I need to know..

[Aironius]

The tear-out is pretty much done. I have been looking at details that need to be addressed before I start installing floor. Today I carefully removed the insulation blanket from the RH wheel well to inspect the water leak causing stains on the subfloor. Pictures attached, but the condensed version is:
Installer who cut the hole in the wheel well for the refrigerator compartment drain sealed the floor of the refrig compartment, but left the hole on the wheel well wide open around the drain pipe. 2" hole and 1-1/2" pipe. When towing in the rain, water has been thrown up by the tire and forced onto the top of the wheel well, where it ran down and collected at both front and rear. Every damn time since the trailer was new! It finally rusted through the galvanized steel of the wheel well at floor level and let even more water gush in at the front. Pics show the rust stains on top of the wheel well, the trail where water ran down many times, the light from my drop light shining through the rusted place, and the view of the rust-out from under the fender. So the fix will be two parts. First make a gasket or grommet where the drain passes through the top of the wheel well and seal that up. Second, clean up the rust at front floor level, clear all the debris from the area, and rivet a patch of heavy galvanized steel over a thick layer of urethane gutter sealant. I'm glad I don't have to do anything to the other side. Got a few more mods and fixes in mind before I start the install.

[Aironius]

The floor is done and here are photos. Leaking fenderwell is patched and a few running changes were made to the plans.
After reading and studying, and consulting with a forum member who has used the product, it became clear that the best choice for plank type flooring was Supercore Xtreme for its dimensional stability at a wide range of temperature. In some ways a solid sheet floor might be superior, but I did not strip the whole interior, just removed some of the furniture so a one-piece floor was not feasible. We ordered three boxes of SPC005XG "Arctic Circle". Ended up cutting the last whole board for the last plank needed. I screwed one plank up by cutting it wrong, and there is a whole box of shorts left so three boxes was exactly right. I would have hated to eat another $299 shipping fee for one extra box if I came up short! The bleached gray color will blend with the existing wood and fake wood finishes. After getting some samples I realized that an underlayment was not necessary. Thickness of the Supercore was about the same as the carpet where it was compressed under the furniture, and the subfloor was smooth and sturdy. I filled the holes and gouges from scraping old glue off and sanded the whole floor, even giving a light sanding to the staples and screws that hold the subfloor. Supercore has a layer of cushion material on the bottom that accommodates small irregularities like the large staples holding the edges of the subfloor sheets together. I did end up removing the LH dinette seat and water tank as it was easier than working around it. Tied the electrical wiring and water pipes up out of the way.

Read the Supercore install directions carefully. I did not break any joints but have read many reviews and forum posts about how easy that is to do. The design of the connecting joints requires the flooring to be laid from the rear LH corner working right and backing up for each new row. This meant I had to begin with the three or four most complex shapes and learn everything about how to cut fancy curves and inside corners first thing. I made a test piece from a color sample before I cut a real plank. It turns out the Supercore is easy to work with hand tools and a few power tools. I made all the straight cuts I could on a radial arm saw. Straight lines can also be cut with a utility knife and metal straight edge, like sheet rock. Be careful of the sharp edges and corners, that vinyl cuts like a razor. Round corners and holes were made with a Forstner bit or hole saw and a hand coping saw made the curves. Also used the coping saw to pre-cut the edge joints before breaking a knife cut to keep from damaging the joint. There is a little black plastic insert strip inside the short-end joints which will sometimes fall out when cutting. This is the lock that holds the joint together. When it fell out I made sure to reinsert a piece cut to length from the scraps. I made all the tricky cuts a bit wide and finished them as necessary with a round and a flat file or sanding block. Also made a paper template of the front RH corner of the floor, reference marked to the centerline of the RV, so it can flip over to be any of the 4 corners. This let me measure and lay out the curved ends of those planks and they all fit great. I pre-trimmed the mousefur wall covering to the height of the planks so they could slip under and hide the end. I may be able to avoid using any moldings. Particularly proud of the fit at the entry threshold. Cut that board a tiny bit wide and drove it down with my tapping block so the gap is almost invisible. I am not expecting any problems from expansion or contraction. Since the mfr. shows an expansion gap spec for a 50 x 50 ft room, I divided by the size of my Bambi and figured about 1/16" was adequate. Planning to drill pilot holes for the furniture hold-downs, then move the furniture and oversize the hole through the flooring so the screw doesn't bind or engage the vinyl plank, then reinstall and screw it down tight. Yes, I am basically ignoring the "floating floor" concept. If I am screwing up there will be a post about that some day.
So after pre-cutting and test fitting the first two or three rows of planks, I removed them all, cleaned and prepped the subfloor, and then laid the whole floor. The actual install took one full day and two part days, including making "kick plates" to cover the shower riser and toilet riser which were scuffed up during removal of the old bathroom floor. Next step is to begin reinstalling the furnishings, detailing them as they go in. That is a whole 'nuther deal for another post. Here are some pics.