I have never seen a search warrant that limits a search to a single room or area within a house. Evidence could be hidden anywhere inside a house/garage. I think it would be impossible for LE to know in advance where to look.
JMO
The Supreme Court said in Groh v. Ramirez, 124 S. Ct. 1284 (2004) that a search warrant must describe with reasonable certainty the place to be searched and the items to be seized. If it does not, the warrant is unconstitutional.
Our 4th Amendment give us a right to be secure in our persons and property and free from unreasonable searches and siezures. LE must follow the requirements/procedures laid out by the S. Ct. or risk losing any evidence they might be able to gather.
That said, it is true that the warrant does not have to say "search of the brown couch in the living room" but it does have to state that LE would like to search the interior of the house and all the rooms therein and the front and backyards. The key is "reasonable certainty." LE can make general statements like "based on the information we have, we believe this happened and we want to search the interior of the house to see if we can find this item or other items connected to this item/event, which we believe is still in the house" or something like that.
HTH,
Salem