I am using a 24 " cathedral ceiling support on a flat ceiling as my insulation shield. Can I just  screw through the inside of the box into my joists ?  or would the screws transfer heat into joists? they are #8 1 3/4" bronze ceramic coated decking screws if that makes a difference. pipe is 6"duratech. thanks
	
		
			
		
		
	
				
			 
	 
	 
 
		 
 
		