I am doing a new furnace install. The funace is on the same floor as the ductwork. THe ductwork is a straight run of 50' (12"x8") and will be run overhead. The ceilings are 12' high. I would like the ductwork at 11'.

Questions
1: How do I connect the plenums together to get the height I want? I am ordering from a supplier that uses Lukjan, here's a link to their catalog.

http://www.lukjan.com/Lukjan2007.pdf

Page 10 has the plenum options. I thought plenums came in 4' sections, do I cut one of them down & attach them with cleats or do I order 1 big custom piece?

2. Are there any code issues with having the ductwork 12" from the ceiling? I heard something about it having to be 1" from the ceiling to be code? I don't want to do this because it would interfere with existing light fixtures.

Thanks

Well first of all 8x12 is only good for about 450 cfm so inless you have a super small furnace, or the furnace is located in the exact middle of the run with the 8x12 going each way. I dought it will work. It is best to get a 2 piece plenum or you will have a hard time getting clear to the celing if you are putting it on a ac coil..

Why not use ductboard? It should fit on the mounting flange on the heater-mine is 14X24, 2800 sq. ft. house. Tape the joints with approved metal tape.

Quote:

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Originally Posted by ma0641

Why not use ductboard?. It should fit on the mounting flange on the heater-mine is 14X24, 2800 sq. ft. house. Tape the joints with approved metal tape.

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People still use that junk?

Very common in Atlanta. Quiet, DIY easy, decent R value without extra insulation. I assume we are talking about the aluminized fiberglass board, 1" thick