Recently the Lilly Library has been awarded a $10.9 million grant and part of these funds, given by the Lilly Endowment, will go towards renovating the library. The Library has created a special web page that will provide news and updates on the renovation.
This will have an affect on researchers going to look at the Sylvia Plath collection. And, because they do actually hold more stuff than Plath materials, it will also affect those collections, too.
Chances are if you have plans to visit the library this spring and summer you will be fine and not experience and delays or disruptions. But visitors later in the year and toward the end will definitely want to double-check their plans and thus plan accordingly.
Smith College is also in the midst of a several-year renovation project affecting their Sylvia Plath papers, too. (I presume they have non-Plath holdings, too, but let's be honest, they hardly matter.) Normally housed in the Neilson Library, their special collections are temporarily in the Young Library. Writing this now I realized that I have not been to Smith College since January 2017, before the Neilson closed, and now that I have moved away, I may never go back. Weird.
All links accessed 11 April 2019.