The owners of Chateau Rhianfa want to add a guest wing to the Anglesey mansion.
The Grade II listed house was purchased in March 2011 and converted into a luxury hotel on the shores of the Menai Strait.
It currently has 27 rooms and last year submitted plans to add additional units.
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But the application has been withdrawn for some revisions and an updated plan has now been submitted – complete with CGI images by Gary Johns Architects revealing what the proposal might look like.
The proposed location for the development is the currently disused tennis court located to the south/east of the main property and at a significantly lower elevation.
The new wing would include eight new bedrooms.
A planning statement said: “The construction of this bedroom wing will significantly increase the economic viability of the hotel and in doing so will maintain local employment, increase tourism and preserve the long-term security of the property and its associated historical significance.”
He added: “The proposals have been shown to be of high quality, but with a mass and scale that will be mostly hidden from public view and subordinate to existing structures on the site.
“The program revisions were guided by dialogue with the Conservation Officer and the ACDW to reach a satisfactory conclusion.”
The plans have been submitted to Anglesey Council.
The property dates back to 1849 and was built by Sir John Hay-Williams, Baronet of Bodelwyddan, as a gift for his wife Lady Sarah.
It was influenced by the couple’s travels to the Loire region of France.