I contacted Bailey about this very issue 4 years ago when I purchased a new caravan. Their reply was that over many years of production they had never had any issue with rot in the exposed edges of holes such as these so there was no need to apply anything. They also stated the floor wasn't painted with any waterproofing material, just a single coat of emulsion type paint as the circulation of air underneath ensured any moisture dried out. . They advised against any form of paint as there was then a risk of any water becoming trapped between it and the ply.Surely the edges can get contaminated with water spray from the tyres causing damp issues there?
Installation time, and the cost, for something deemed not essential.What’s wrong with a simple semi sealed “inspection plate”?
I read on another forum some years back wrt a similar discussion. There were lots of suggestions on what could be done, or should not be done to seal the edges. There were views that paralleled what Bailey told you, that sealing could create a problem that doesn’t exist.I contacted Bailey about this very issue 4 years ago when I purchased a new caravan. Their reply was that over many years of production they had never had any issue with rot in the exposed edges of holes such as these so there was no need to apply anything. They also stated the floor wasn't painted with any waterproofing material, just a single coat of emulsion type paint as the circulation of air underneath ensured any moisture dried out. . They advised against any form of paint as there was then a risk of any water becoming trapped between it and the ply.
I have never heard of anyone having an issue with the exposed edges of these holes, or damp issues away from the edges, so it appears Bailey know what they are talking about.