Floor Boards - Kingston Trailer

You need to remove and inspect the wall and floor juncture as it shows water damage.
Kingston trailers were known to be a top of the line trailer made but still had issue of seepage near the windows and puddling on the floor under them...that is what I see on those boards.
You have rot at the rear where door or rolled down rear tarp flap did not seal out the blown in debris I bet sat and created again rot and a look to not ignore but replace.

The trailer is 10+ years old and by staining seen on the floor mats not swept out as carefully as it should of been done every time.
Replacing a floor is a lot of work but....to me, peace of mind is so worth knowing any rot is gone, any structural issues the support braces underneath may have is addressed cause when you remove the floor you now see all naked and exposed.
To me, knowing my horses stand on a solid floor well supported is worth the time and expense ...and honestly, your trailer shows signs a new floor is warranted. Maybe not every board, but enough seen to make me want to know safety has been addressed.

I'm originally from the North-East and that is where Kingston trailers were king of the road and commonly seen...that also means caustic road salts used many months of the year on the undercarriage that create damages to underpinnings hidden by things like floorboards....
Yea, time to pull the floor for a much needed look-see check and restore if needed or just a new floor installed so you know all is good for that safe trip on your journey.
🐴.... jmo...

charrorider said:

Is it customary for a seller to allow a prospective buyer to carry such an extensive check?

Click to expand...

If you buy it you can do whatever you want....

If you are looking to purchase, a competent trailer mechanic would have that trailer off the ground and sliding underneath it searching for such issues...a thorough evaluation done.
Buyer Beware truly applies here...
If I can raise concern from pictures that would have me looking closer in certain areas...imagine what should be being done in person and where a screwdriver, a ice pick and some tapping gently with a hammer in various places would and should be uncovering or not.

See, I find it interesting that it "appears" a paint line of black paint is on the edge of the boards...now why would that be showing??? Was the floor installed and then factory painted or something else having cosmetic work done to ....
There is also a potential staining of repeated soak and dry on some of those boards...again, you bet I would be looking very closely and critically to the frame and supports that would be holding my horses safe during travel.
🐴....