Instantantiate relative to parents position

Hi all,

Newbie here. I have a Room Object with my Room_Generation C# Script attached. When the Game started it randomly generates the room size and fills it with 4x4 tiles.

Problem being that it instantiates the tiles at Global 0,0,0 rather than the Room object 0,0,0. I can only manage to make the Tiles a parent of the Room Object after the instaniate. Any Ideas?

 using UnityEngine;
 using System.Collections;
 
 public class Room_Generation : MonoBehaviour {
 
     public GameObject Floor;
 
     void Start () {
         float fSpacing = 4.0f;
         int iRoomWidth = Random.Range(0,4);
         int iRoomLength = Random.Range(0,4);
         for(int z = 0; z <= iRoomWidth; z++){
             for(int x = 0; x <= iRoomLength; x++){
                 GameObject gFloor = Instantiate(Floor,new Vector3(x,0,z) * fSpacing,Quaternion.Euler(-90,0,0)) as GameObject;
                 gFloor.transform.parent = transform;
                 gFloor.name = "Floor_" + z + x ;
             }
         }
     }
 }

Thanks, got this fixed.

 using UnityEngine;
 using System.Collections;
 
 public class Room_Generation : MonoBehaviour {
 
     public GameObject Floor;
 
     // Use this for initialization
     void Start () {
         float fSpacing = 4.0f;
         int iRoomWidth = Random.Range(0,4);
         int iRoomLength = Random.Range(0,4);
         for(int z = 0; z <= iRoomWidth; z++){
             for(int x = 0; x <= iRoomLength; x++){
                 GameObject gFloor = Instantiate(Floor) as GameObject;
                 gFloor.transform.parent = transform;
                 gFloor.transform.localPosition = new Vector3(x,0,z) * fSpacing;
                 gFloor.transform.rotation = Quaternion.Euler(-90,0,0);
                 gFloor.name = "Floor_" + z + x ;
             }
         }
     }
 }