We want to finish our garage (drywall, insulation, and carpet tiles) so we can use it as overflow living space but still have it able to function as a garage when we want to move. Currently, there is a 15' X 18' ceiling that is just exposed joists, and the garage door tracks and motor (as well as some fluorescent lights) are installed on the joists. The joists look to be about 4' apart.

We want to install a drywall ceiling and then blow-in insulation above that. Right now, we are thinking we need to add studs running parallel to the joists (in order to have more places to attach the drywall), and other info we've been able to find online says that we need to just butt the drywall up against the hardware for the garage door, since we shouldn't attempt to disconnect the hardware, drywall over the joists, and then reattach the hardware to the joists.

Also, there are two beams at a 45 degree angle (parallel to the floor, see last picture) that we would need to remove in order to install the drywall on the joists. Would the drywall serve the same purpose as those beams, and so would it be okay to remove them?

ANY advice is greatly appreciated! I was also hoping someone could expound on the text below (found on an Internet search):

Truss Lift
If you are applying drywall to a ceiling that is directly under truss framing for a roof, be aware of the phenomenon called Truss Lift. A roof truss is a framework that is assembled in a factory using pressed-on gang nail plates and the truss assemblies are installed on the walls on the building site. The bottom chord of the truss becomes the ceiling joist. The truss will expand/contract differently than you would expect of non-truss framing, and this seasonal event will cause the bottom chord to rise and fall in the center portion of the chord. An interior wall - one near the center of the truss - cannot be fastened solidly to the bottom chord or structural damage will occur. More importantly to you, the drywall joint between an interior wall and the ceiling will crack if it is fastened in the usual manner, and this crack can be as much as 1/2". What you need to do is fasten the ceiling drywall normally except for about 2' out from the interior wall. This portion of the drywall will "float". The corner joint between the ceiling and wall drywall can be taped and filled in the usual manner and it will flex enough to keep from cracking. This seasonal rise and fall of the ceiling is usually not obvious if the ceiling drywall floats properly. Since the truss rests on the exterior walls, nothing special needs to be done at that point; fasten the drywall as usual.

 

Those are trusses, they can not be altered without an engineer signing off on the plans.
Those diagonals look like they may have been used to square up the wall when it was built.
To convert from a garage to living space you really should remove the over head door and add a row of concrete blocks in it's place so water will not be able to come in under the wall.

 

Joe, Sarah specifically stated she wanted to keep the ability to use it as a garage for when they sell the house.

It reads to me like you mainly want to close in the ceiling and insulate. Joe IS correct that you cannot add anything to the trusses but I see no reason why you could not install independent ceiling joists away from the trusses. You would have to temporarily remove the brackets holding the door track and in the process could frame up more substantial support that would be hidden by the drywall ceiling. To that end you would have to disable the door for a period of time.

It is a fairly big job and you would have to have most, if not all, the materials in the garage before disabling the door. Definitely doable and would definitely be worth doing but it won't be cheap or quick.

Hopefully Chandler and X will weigh in.

 

Thanks for the info. I would LOVE to fully convert the garage and remove the door! However, this is just temporary. My husband doesn't want to eliminate the garage all together because of resale value. We were going to add an insulated garage door blanket and add weatherstripping around the door in the mean time. Fortunately, our driveway slopes downward away from the garage door.

My understanding from the info I pasted at the bottom of the original post is that the bottom chord of a truss is the ceiling joist. Would it be altering them if we were just adding more joists? Is it because it would affect the load on the roof and the original trusses ma not be able to support it?

Thanks again for your response!

 

So we would have to remove the brackets (and that is something that is safely done, if we just unplug the garage door motor?), and we would be able to add additional joists? Would 2X4 lumber work?

The only thing we need to get into the garage would be the drywall lift, which I understand breaks down and so can probably fit through a standard doorway.

Thanks for your input! While we are definitely DIY-ers, my husband has gained substantial experience remodeling our house (replacing the siding and windows, gutting and replacing the kitchen and bathrooms, installing tile flooring and tub surrounds), this will be the first major drywall job he has had to do. Fortunately, almost half of the garage already had drywall up, so the 18X15 ceiling is pretty small (10 pieces of sheetrock).

 

ANYTHING attached to the truss other than an electrical cable stapled in place or the ceiling drywall nailed/screwed to the bottom is not allowed. You could add additional ceiling joists in the same plane as the bottom of the truss and nail/screw the ceiling to the truss.

You may need to use fire-rated drywall depending on your local code.


I am not a carpenter and I do not off hand know the span distance allowed for 2x4 ceiling joists nor do I know the span that you would have in your garage. Just out of the blue I would say that 2x6 joists may be required. Since I do not know the size or location of any other door into your garage I cannot state with any authority that you must have all materials inside before starting the job. What I AM stating is that once you disconnect the door opener and remove the brackets and horizontal tracks you will not be able to open the big door. Careful framing before setting the ceiling in place will allow you to re-install the tracks and opener directly to the drywall ceiling, actually, the fasteners going through the ceiling into the framing. This will make a nicer installation but during the construction you will not have the door.

 

It is 5/8" fire-rated sheetrock. And thanks for the tip about not attaching the drywall to the existing joists. So we'll just add a bunch of joists, then. How far apart should we space them?

 

Standard joist spacings is either 16 or 24 inches on center. For your purposes 24 inches on center with 5/8 inch fire-rated drywall should be adequate. Again, I am not a carpenter and I defer to others with more knowledge than I.

 

Thanks for all your advice!

 

I sent a PM to XSleeper and also to Chandler asking them to look at this thread.

 

Sarah. I am not at my computer and these small keypads on phones are laughable.

What is the span across the garage parallel to the joists? What is the spacing on the trusses? Adding parallel lumber to the trusses is good and you have adequate support at the ends. My thought is to use 9 1/4" LVL to span across, possibly 11 1/2" but we'll wait on numbers. I'll look back in when I get to my big boy computer.

 

The span parallel to the joists is 18 feet. There are three total trusses, with 4 feet in between each. The span perpendicular to the trusses is 15 feet.

I couldn't get an exact measurement, but it looks like about 4 inches or so of space between where the room comes down and meets the board running parallel to the ground/perpendicular to the trusses (only a problem on one side, as the other side has plenty of clearance, see picture). Would we just cut the joists at an angle to fit it in? And I haven't been able to find anything online about how we would actually add the extra joists. Finally, what are your thoughts on the original post at the bottom regarding truss lift and securing the drywall 2 feet in from the edges? Does the drywall still "rest" on top of the wall drywall?

 

Last first. Yes, your ceiling sheetrock rests on your wall sheetrock. Truss/joist lift is minimal, and yes, you start your screws 2" in from the edge, doubled, then single across the rest of the board. Double screws at the edges will help with movement of the sheetrock.

Using LVL for ceiling joists may be necessary since you don't have any central support wall/beam to take the pressure off in the middle. You can taper the ends of the LVL, but you must adhere to their specific guidelines. The taper will allow you to slide the joist over the top plate and fasten it in place, since the roof line tapers down more than 9 1/4" at that point. Where you must taper the LVL, you cannot taper it more than 3 times the depth of the LVL. So if you have a 9 1/4" LVL, you can't begin your taper any earlier than 27 3/4" from the end, and that taper cannot take up more than 1/2 the depth of the LVL, or a little over 4 1/2".

Confused yet?

For reference, LVL is Laminated Veneer lumber. It is specially made for spans and is much stronger than lumber it's equivalent size or larger. It will give you a good place to put your sheetrock without fear of sagging in the middle over time. I would place one between each truss so you will have a 24" center and use 5/8" fire rated rock.

Now, the fun part. Everything has to come off the ceiling. GDO, straps, lights. It can all be replaced once the rock is in. Have you thought about drop down stairs for access, or at least a scuttle hole so you can install your insulation?

 

So if we taper the last few inches of the LVL to a minimum depth of at least 4 1/2" we should be okay? I will take another look at where the roof meets with the wall.

How would we secure the new joists? I'm assuming there is something more to it than just using screws at the end. We were planning to do one on each side of each truss, (1 foot away from the truss), plus one more on each end, for a total of 8 new joists to span 15 feet. Unless it IS okay to screw the drywall into the existing joists (the bottom chords of the trusses). A previous replier said we should NOT attach anything to the trusses.

And would it matter which direction we hung the 4 X 8 sheets (parallel vs. perpendicular to the joists)? And we do need to stagger the seams, correct?

We were already planning on taking everything down from the ceiling. Actually, now we're thinking we'll secure the doors and remove the tracks and motor completely, and just replace them when we're ready to sell. We probably should replace the garage door anyway, so we'll just do that all at once (and that is years in the future). Then we won't have to deal with those ugly tracks and motor in the middle of a living space.

Thank you so much for taking the time to reply!

 

Use screws at the end to stabilize them, then put 22 1/2" lengths of 2x4 on top of your top plate between the truss and LVL, flat, then nail them down. It will be an angle nail, but sufficient. Adding hurricane ties to the rafters and top plates will also give a good warm and fuzzy. Attaching sheetrock to the bottom chord of the truss is fine, as long as you have the LVL in there as additional support. I think they may have been referring to adding additional lumber/weight to the bottom chord as a no no.

Hang your sheetrock lengthwise, perpendicular to the joist run, and stagger your joints. Rent a sheetrock hoist and you can thank me later. Also you will be placing these LVL's TWO feet from the truss, not one foot, unless you want one foot centers.

 

As you want to convert a garage to living space, there are certain requirements you will have to meet. In CA, I think you need a permit and supply additional vehicle parking for the lost garage space. Also needed; seismic hold-down hardware for the trusses to the walls, ventilation for the newly insulated area- ridge exhaust/soffit supplies, electrical/structural inspections to meet your very own CA State Code, possibly wall hold-downs to the foundation, more gable-end bracing, smoke detector, egress window/door (appears you may have), required short wall to elevate siding at vehicle door hole (as said), anything else to satisfy your Building Department/ H.O. Insurance carrier- if ever a future claim.

2x8, Hem/Fir (#2) or Doug./Fir will span the 18’ and a lot cheaper than LVL’s with no storage above: Chapter 8 - Roof-Ceiling Construction

If you need more height above plate at 1-1/2" back from room side to meet code bearing with a tapered joist, you could add 2x2's to the bottom of existing trusses and notch the new joists to gain height- meeting code requirements. Use nails as fasteners unless the screws are rated structural (eg. Simpson); Chapter 6 - Wall Construction Use blocking if code requires it in CA, others don't; under 2x10 c.j. only (as in your case).

Hire the removal/installation of the garage door to a professional; those torsion bar lift systems can maim you. You can attach drywall to the underside of trusses; they are probably designed as such to use the ceiling as a diaphragm to hold the building in check laterally (hence the corner braces, as said). The lack of a vapor barrier under the slab may cause problems, be sure to grade the dirt away from siding and keep plants back as the water could wet your floor once you block the outside air from drying any wetness as it is now.

Your Building Department will have your State guide-lines; STATE INFORMATION

Gary

 

Good call on the torsion bars, Gary. Pix was so small I didn't notice. For sure hire that done!

 

Thanks so much for the advice, and especially the tips about alternatives to LVL! We aren't technically converting the garage, as we are leaving in the garage door. I will check about installing additional vents, though, because it is probably a good thing to do either way. And additional smoke detectors never hurt anyone.

 

Thanks, Chandler! You've been a real help! We were planning on renting a drywall lift (totally worth the small rental fee), but do you think my husband will be okay doing it himself? Or should we get someone to help him?

I was planning on the one foot spacing on either side of the truss if we couldn't attach drywall to the trusses. But if we can, then two feet spacing is just fine with us!

 

One foot on either side of the trusses will give you a 12" on center spacing and twice the number of joists. That is fine, but overkill, IMO. You can attach drywall to the truss bottom chord. I used to install ceiling drywall alone with my friend (drywall lift), but that was last century. Depends on how "peppy" he is. It is always better with two people, to do heavy stuff like that.

 

Thanks, chandler.
Sarah, if using the garage for living space, you are converting it, get a permit, if just for safety. Many jurisdictions double the permit fees and require any work removed; if caught....my 2 cents. Gary

 

I definitely concur that a permit should be obtained. However, since this is only going to be used as a temporary or "overflow" living space I would NOT tell the permit people the usage. Simply tell them that you want to install a ceiling in the garage for a more finished look.

If you change your mind (before starting) and DO decide to make the old garage into a permanent addition of living space then you most definitely should tell the permit office this AND permanently remove the garage door as Joe mentioned in the first response.