Over the years I have enjoyed using 4x2 floor trusses like Brawler shows in his second picture. However, I have learned that all framing crews do not understand how important it is to keep the HVAC chases aligned. I instructed a crew one morning about installing the floor trusses and when I returned in the afternoon enough of the chases did not align that we had to run ducts overhead instead. The framing crew did not grasp that HVAC chases can be ordered off center and one has to pay attention as to which way a truss is turned before it is installed.
Another problem I have had with using HVAC chases in floor trusses is that the HVAC installers had to cut a hole in the OSB sheathing to insert the pre-made large ducts from one end of the house to the other. |