Soffits for Heating ducts
 

Does anyone have a suggestion for building a soffit for a heating main trunk?? The problem is I really can't do the traditional 2x2 framing underneath the duct cause it will put me about 1.5 inches below code height of 6'8". The run I need to do is only about 4 feet long and the section of the trunk that I need to do is 2 feet wide. Can I just run the wood support right next to the trunk and not have any support from underneath for the drywall?? I am not sure if that will sag or not. Any other suggestions would be greatly appreciated. I am open for anything except moving the main trunk. Way to labor intensive!!

Easy:

Build a 2x3 wall on each side of the duct. Build it so that it is even with the bottom of the duct work (in terms of their height off of the floor)

Now, purchase what's called 'spring board' (3/4" thick rough boards that are about 16"+ wide) OR:

Better alternative: Get some 3/4" Plywood and cut it into 16" wide lengths (as opposed to normal 2 1/2" strapping).

Attach these to the frame work that you built on each side of the duct work. The advantage of using a wider board than normal strapping, is that over the 24" of area, there will be very little, if any, sagging at all.

So, you will only be taking 3/4" off of your head room + whatever the thickness of the sheetrock is.

Even Better Alternative: If you use the 3/4" plywood over the entire bottom of the duct work, then you could get away with 1/4" sheetrock attached - onto that = Only about 1" loss in head room (Tho, I don't know if that amount will get you the head room that you want)

The Menards by me has some High Strength sheetrock that is supposedly able to span 24" on center and not bend. Anyone use it??

does the code really that strict?
 

I believe normally code say the minimum height in most of the area only, it should allow height lower than minimum small percentage of spaces... this is not avoidable in most basements, there are low spots here or there... I doublt for such relative small area, lower than a few inches will really be an issue, as I remember I read my code before only saying things like "mainly", "mostly", ..etc. not "absolutely"...

Kui****g.....Remember that you are going by your Canadian codes.

Codes vary by region and also by local town or city requirements....

I posted a reply about this on your other post inquiring about the High strength sheetrock....