Sources suggest that in Chapter 5, you can learn that the style of the house is "period" (the house probably resembled a large manor home such as one might find in England) and it was built by a brewer.
In the last six or so pages of the chapter, when Jay is showing Daisy through his house, you will learn that there are gardens around the house and marble steps leading up to the main entrance. Inside the house, it is told that the interior design varies somewhat from room to room with "Marie Antoinette music rooms and Restoration salons".
There is a large library and upstairs the bedrooms are decorated in period styles. Gatsby's suite of rooms includes a bedroom, a bath, and an "Adam study". Gatsby's bedroom, though simple in decor, has two large cabinets that he opens, then he pulls his shirts from them.
The Great Gatsby is a story told by Nick Carraway, who was once Gatsby's neighbor, and he tells the story sometime after 1922, when the incidents that fill the book take place. Check out this book summary shared by Cliffsnotes.com.