Both sentences are a little odd, but they are not actually ungrammatical. They can, however, have different meanings.
First of all, I'll assume that a lounge at first means a lounge at the room's entrance.
(1) The room was such so that there was a lounge at first.
🠆 The room was designed as it was in order to put a lounge at its entrance.
In other words, the room was created as it was because a lounge was desired at its entrance. A lounge being at its entrance was a key factor in its design. Other designs, that wouldn't have put a lounge at its entrance, might have been rejected.
(2) The room was such that there was a lounge at first.
🠆 The layout of the room happened to result in a lounge being at its entrance.
In other words, the room was created in such a way that a lounge happened to be at its entrance. Whether or not a lounge being there was originally intended is unknown.
So, the use of was such so that here can imply intent, while just was such that simply states a fact.