Basement cold after adding Safe & Sound in ceiling
 

Finishing my basement and added safe and sound insulation between the joists for soundproofing. After a week my basement is freezing which was not like this before. Always heated the upstairs but not downstairs. Why would my basement be so cold all of a sudden.

Sounds like you disconnected your basement from it's radiant, upstairs heat source with the insulation.

...and welcome to House Repair Talk.

how did I disconnect the heat source from upstairs because heat rises. Would the floor being warm upstairs gave any heat value to the basement.

It's true, hot air rises. It also radiates. The flooring acts as a conduit to transfer heat through it, walls, ceilings and floors. When you insulated the basement I assume you insulated the basement ceiling. If so, you slowed the transfer of radiant energy through the structure toward the basement. Warm always travels toward cold.

Do you have any ducts that you can open in the basement? Do you have access to any HVAC trunk lines where you could install a couple?

I guess that makes sense because when I now think about it some guys use radian heat tube in their shop which they place above the floor.