On Fri, 02 Feb 2007 14:39:49 -0500, Goedjn wrote:

On Fri, 02 Feb 2007 19:23:20 GMT, Mike E. Fullerton
wrote:

On Fri, 02 Feb 2007 12:17:44 -0500, Goedjn wrote:

On Fri, 02 Feb 2007 10:55:59 GMT, Mike E. Fullerton
wrote:

We recently bought a 25 year old house. It uses gas heat. When it got
cold and the heat came on I noticed a very loud cracking sound when
the heat came on and again when it turned off. This is from the
expansion and contracting of the galvanized heating ducts in the
basement. The ducts are on metal hangers so they are not touching the
floor joists.

Are these round or rectangular ducts?

Rectangular.

sometimes creasing the panels in those in
a big X will reduce the booming.

How do you crease the panels?