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Framing basement ceiling

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  • Feb 21st, 2021 8:52 am
[OP]
Member
Sep 20, 2010
217 posts
235 upvotes
Hamilton

Framing basement ceiling

I'm planning out my basement for finishing into a rec room. It will be a complete open space, mainly for just hanging out.

How would I frame over the AC line as seen in the attached picture. The ceiling has I-joints and the AC line is running under the joists. I don't want to lose too much height. What options are available? Would furring boards work?
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9 replies
Deal Addict
Jan 19, 2011
2922 posts
1161 upvotes
Either reroute your AC line through the joists (not a viable option)...

or use 2 x 2 or 2 x 3 furring attached to the base of the joists crosswise to accommodate your ceiling.

You are going to lose height, two inches including drywall from the base of your joists
"The truth is incontrovertible, malice may attack it, ignorance may deride it, but in the end; there it is."
Just a guy who dabbles in lots of stuff learning along the way. I do have opinions, and readily share them!
Member
Jan 21, 2011
388 posts
157 upvotes
You need to build a bulkhead to enclose A/C line and duct work.
[OP]
Member
Sep 20, 2010
217 posts
235 upvotes
Hamilton
lamin wrote: You need to build a bulkhead to enclose A/C line and duct work.
Thanks, I'll be building a bulk head for a larger section with the main heat and cold air returns, but this was a small section of the ceiling where the AC lines ran lower than the joists. It's a bit annoying as it's about 2-3 inches lower. It's a long run and the other side isn't as bad as it goes above a metal beam. I guess I could keep that section lower as there are some other bulk heads on that side I'll have to deal with.

Just don't want too many level changes and would want to keep it simple.
[OP]
Member
Sep 20, 2010
217 posts
235 upvotes
Hamilton
fieldhousehandyman wrote: Either reroute your AC line through the joists (not a viable option)...

or use 2 x 2 or 2 x 3 furring attached to the base of the joists crosswise to accommodate your ceiling.

You are going to lose height, two inches including drywall from the base of your joists
I might have to do this. Still in the planning stages, but don't want to use furring all across the basement because of this. I'll see if there's a way to somehow incorporate this into a bar design.
Deal Addict
Nov 18, 2005
4981 posts
1358 upvotes
Kitchener
Can you push that ac line up between the floor joists?
Deal Addict
Jan 19, 2011
2922 posts
1161 upvotes
I think re routing it might be worth your while. if not, you essentially have to drop a huge chunk, perhaps all of your basement ceiling.

Furring out a basement ceiling is a great idea if you have multiple stupid things that cross joists below them. I helped a friend with a basement years ago that had the AC line run diagonally across a chunk of it, but also had a few homeowner added wires stapled to the bottom, and the odd pex line, so we dropped the whole thing with 2 x 3 boards laid on edge.

but if it is just the one line, you could have it re routed... Just don't do what one idyut I know of who notched the bottoms of his joists 2 inches to push the line up into, lol
"The truth is incontrovertible, malice may attack it, ignorance may deride it, but in the end; there it is."
Just a guy who dabbles in lots of stuff learning along the way. I do have opinions, and readily share them!
Member
Dec 6, 2020
279 posts
251 upvotes
You will definitely need to build a bulkhead around your air ducts -- they certainly can't be rerouted through the joists.

Since you have engineered I-joists, re-running your AC refrigerant lines through the joists may not even be an option. Some I-joists have very strict limits on acceptable hole size and placement. Even if the hole requirements can be satisfied, I would be very reluctant to run any piping that could attract condensation through the webbing of an I-joist. Getting any water in the OSB webbing will compromise the strength of the joist.

As for what will work for the refrigerant lines, you could potentially re-route the lines on the outside of the house (this may require moving the AC unit to stay within its line length limits) but this isn't a DIY job and will be expensive.

Building a furring is probably your best option even though you will lose some ceiling height.

If you do fur out the ceiling, install the furring strips perpendicular to the joists. This will leave you with a very useful cavity space that will make running new wiring much easier if you need to do that in the future.
Newbie
Mar 13, 2006
83 posts
54 upvotes
fieldhousehandyman wrote:
or use 2 x 2 or 2 x 3 furring attached to the base of the joists crosswise to accommodate your ceiling.
This is what I did. If your house is relatively new you really won't lose much noticeable height. Finger jointed point 2x2s are cheap at Home Depot.

For framing the bulkheads, might i suggest taking a sheet of OSB and ripping it into four or five equal strips. You should get just under 12" width (or just over 9" if five strips). The 9" was sufficient for my ductwork's drop. Frame one side of these strips with 2x2 and use these pseudo-beams to frame your ductwork. You don't have to put anything across it besides the drywall. Just make sure it runs parallel to the ductwork... Simplified framing without losing more height than necessary.
Deal Guru
User avatar
Nov 18, 2005
11283 posts
2730 upvotes
Kingston
From the pictures, it looks like the AC lines follow the ductwork fairly well so just enclose it as part of enclosing the ductwork.

When I was doing similar work in my basement I saved a couple of inches of headroom by not running any 2x framing under the ductwork. I installed framing on either side of the ductwork using 2x3 that reached just below the depth of the ducts (if the ducts hung 8" down, my framing hung 8.5" down). Then I ran drywall under the ducts fastened to the framing on either side. So the drywall was just a 1/2" below the ducts rather than 2" below. Where I had ducts running side by side I was able to install framing in between so that the span between the framing that supported the drywall wasn't too far (24" is the normal maximum span).

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