I own a 1973 Ericson
37 and have just completed replacing the deck. On that size boat it is a monster job to tackle by yourself and (I assume) very expensive (probably more than the cost of the boat) to have done at a yard. The boat was constructed with a balsa core
deck and there were several design flaws that allowed water
to penetrate. Once it does, the area turns to black pudding and provides no support for the laminate. I had to replace around 90% of the deck as well as the cockpit
and several bulkheads. This issue is not limited to my boat as in 1987 the owner of a sistership advised me that he had had to replace the entire deck. I can't say anything about Ericson 27 - my boat was built as a race
boat in its day and the Ericson 27, as a production boat may have had thicker laminates to protect the core
. However, that I suspect it may not be uncommon for boats of any manufacture of that vintage. If you Pull a fitting in the area or us a moisture meter you can probably tell. A surveyor with a good ear can probably tell a lot just by tapping with a hammer. Good luck.