12' Span between Trusses. How to Prepare for Drywall?

[danieldd]

I want to put up a drywall ceiling in my shop. Unfortunately, there is a 12 foot span between each of the ceiling trusses. If I run a bunch of 2x6 lumber every 24 inches, thats a lot of weight on the bottom chord of the trusses, plus then you have to add the extra weight of the drywall ceiling panels. How do I determine if the existing ceiling trusses can handle the extra weight?

Is there a better way to put in a ceiling?

 

[NUTTSGT]

Better way ? IMHO, I'd be looking at ribbed metal siding.

It still won't span 12', as nothing is going to. But the weight saving will be huge over drywall. It's also "one & done"

 

[danieldd]

Better way ? IMHO, I'd be looking at ribbed metal siding.

It still won't span 12', as nothing is going to. But the weight saving will be huge over drywall. It's also "one & done"

It is a factor I may very well consider. There is the increased noise issue with using metal, plus there is a concern about moisture. I don't know enough about either one at this point to make an informed opinion.

 

[NUTTSGT]

If there is a concern with moisture, I sure wouldn't want to be using drywall.

Increased noise, maybe a little but if you have osb/plywood walls and hang stuff on them, it'll absorb alot of sound.

 

[yeldogt]

Why cover it ?

 

[danieldd]

Cause it ******** hot in there! Not to mention it will be cold in there this winter. Plan on adding insulation once the ceiling is in..

 

[mike93lx]

At 12' OC, my opinion is that those trusses were never intended to have a ceiling on them and are not spec'd for it.

Certainly not drywall.

 

[vavet]

What about some 1x3 firring strips? You could even create a T-section to rude the sag of the 1x3 strips themselves. They'll weight significantly less than a 2x6.

 

[K'ledgeBldr]

Adding additional weight to the trusses- no. It doesn’t appear they were designed for anything else except...
It also appears that they don’t sit on top of the exterior wall- are they set in a hanger?

What’s the overall span of the truss? I’m thinking your only logical and safe process is to add additional trusses (they don’t have to be a roof truss; they could be floor trusses), or maybe I-joists.

 

[Viz]

You mentioned it gets hot in there. Something to consider:

I have a similar configuration. 26'w x 24d', with multiple trusses at each end plus in the middle. I wanted a clear span over each bay for future lifts. Engineer designed to accommodate. The nearly 12' gap will easily handle any lift (with 14' to the ridge).

I insulated during the shelter in place. I used 2" foil backed EPS, doubled the thickness to 4", with the radiant barrier foil facing the 3/4" air gap to the metal roof. It made a significant difference in the interior temperature (in Central Florida), so much so that I'm now confident a DIY mini-split project is in the plans for this coming winter. (Walls were also done).

So, perhaps insulation between the purlins could work for you. Much lighter too on the overall load. I've got pictures if you need them.

Viz

 

[Loose Nut Buster]

I'd go along with Viz and just add insulation between the purlins, they look to be spaced about 2' with a 2x6 top 2x, it also appears to have a sheeting (white) something. If you go that route I'd for sure use venting spacers against the white ? and eliminate condensation issues.
Another method would be (Hi) density Polyiso) rigid foam sheet from a building supplier, it has the highest R rating of the rigid foams and its light in weight. "Dont forget the air space", actually if you go the poly route all you'll have to do is tack some lath strips up n cut the foam (circular or table saw) to fit between the purlins.
Be sure to wear a dust mask n long sleeved shirt since the boards have a fiberglass reinforced fiber blended into it along with the skins for reinforcement... no sagging.
Job done n you'll be happy I'm sure

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[Viz]

I'd go along with Viz and just add insulation between the purlins, they look to be spaced about 2' with a 2x6 top 2x, it also appears to have a sheeting (white) something. If you go that route I'd for sure use venting spacers against the white ? and eliminate condensation issues.
Another method would be (Hi) density Polyiso) rigid foam sheet from a building supplier, it has the highest R rating of the rigid foams and its light in weight. "Dont forget the air space", actually if you go the poly route all you'll have to do is tack some lath strips up n cut the foam (circular or table saw) to fit between the purlins.
Be sure to wear a dust mask n long sleeved shirt since the boards have a fiberglass reinforced fiber blended into it along with the skins for reinforcement... no sagging.
Job done n you'll be happy I'm sure

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Yep, that's what I did. I air stapled 3/4" spacers at the top of the 2x6 purlins, added the 4" of insulation, and stapled 3/4" spacers against the insulation at the bottom of the purlins in case the insulation worked loose.

I tried the power saw route, with the blade backwards, still messy. Hot knife wasted too much product, wound up using a grinder sharpened 4" putty knife to cut along the chalk line - worked like a charm. The biggest hassle on the whole job was the endless trips up and down the scaffold.

Viz

 

[Bigblockyeti]

Drop ceiling? The grid won't care about moisture and doesn't weigh too much. Yes, it's labor intensive to get it up but once up you can spec tiles based on weight, noise absorbsion, etc. Before I added any weight to those trusses, I would know exactly what percentage capacity they're at as is.

 

[Loose Nut Buster]

Another thing is ... if those 8' fixtures aren't LEDs I'd consider switching to them (reasonably priced now days). Not only would you have more output lumens but less heat than the flourescent, lower operating cost and get rid of those mercury vapor lights.
Another thing that'll make you happy and you could do it while having the man lift, do it 1st n you may add a couple more 8' LEDs while your up there.
Good luck!

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[firebirdparts]

At 12' OC, my opinion is that those trusses were never intended to have a ceiling on them and are not spec'd for it.

Certainly not drywall.

I would place my wager on this as well.

I do think that 2 by 6 lumber would be the normal way to hang drywall with a 12 foot span. If you look for ceiling joist span tables you'll find that is adequate on 24" centers. But I don't think the trusses will handle it.

 

[nadogail]

IMHO, the rocket scientist who designed that building was not considering ventilation. Add thrbine vents to the overhead and spray foam on everything.

 

[cdestuck]

Possibility of a drop ceiling in there. Can still put insulation above that if you put in enough support wires.

 

[yeldogt]

Cause it ******** hot in there! Not to mention it will be cold in there this winter. Plan on adding insulation once the ceiling is in..

What is the roof -- are they skylights ?

I would insulate the purlins and box the skylights -- if that is what I am seeing.

Air is cheap to heat -- the key is containment and heating objects. A fan or simple duct to remove heat from peak to ground.

 

[danieldd]

All very good input and thank you for your opinions.

Truss length is approximately 36 feet.. The Flourscent lights will be replaced with LED and the big light will be removed.

I am in agreement the trusses will most likely not be able to handle the weight. I do like the dropped ceiling idea, but boy that will be alot of work. I've done that before in a MUCH smaller area and is labor intensive.

The top of the roof already has some insulation. I believe they used Thermax (maybe an R4), so I have some insulation, not much. There is a ridge vent installed, but when they put in the Thermax panels they didn't cut it to allow the ridge vent to work. I can blame Morton buildings on this. Since I'm not the original owner, I don't have any pull with them. There is also ventilation at the top of the walls, but I agree that some type of attic ventilation is necessary.

It appears my desire for a ceiling may just be out of the question, unless I am willing to put in some posts beneath the trusses to support the extra weight of the ceiling. Since the shop has a tractor, a ZTR and a couple of ATVs and a car, it is probably not in my best interest to go that route.

 

[karoc]

Looks like you have vinyl insulation under your roof metal,I thought that is how to prevent condensation. You could also install chicken wire for your ceiling and roll out some of that foil back insulation on top of the chicken wire. Or take some 2" ridgid foam put between your trusses then install some 1x2's to hold it up keep from sagging.

 

[sberry]

Agree, wasn't made for it. Easiest is to add light insulation to the roof and gentle tuned fan to blow heat down when it's cold and reverse it thru a vent out the roof when its hot. You can contain heat but to cool with simple air movement you got to let makeup air in. Could actually coordinate some of this system like for air cleaning, paint etc.
Ridge vent is for attic. Ideal here would be control able vent for natural cooling.

 

[sberry]

Add some air conditioning and then want vents closed and some wall insulation. A guy can build this himself but the best way is to have a helper most of the te and 2 when if you need them. One of my buds build homes back in the day and said, really takes 3 guys.

 

[sberry]

I woold get/make up some scaffolding that would work thru this whole project, wire and lights and insulation. Get roll of 14/2 and roll of 14/3 and run power to every switch box and 3 conductor to every fixture. 4x4 boxes for switches, use another box even route for recepts. I might splurge and get gfci and recept in the ceiling, make up some scheme out of strap hanGermany for dropping fixtures in center of the building. 14 is super easy, put 4x4 plastic with 2x common recepts in it. Wouldn't have to switch from the same place. Insulate neatly and could skip real ceiling or liner against the roof.

 

[sberry]

I don't have power cooling, I could have a little for not much but we got so few real exhaustive hot days and it's kind of moderated with some doors open if there is a breeze and makes for shade.

 

[kwb]

Best bet is as posted above - Insulate and Fir the Perlins and sheetrock that. Leave Trusses exposed or skin in drywall your call. Not going to get a great R value with 2x6 depth but you will get something like R19 and in your part of the world that is probably better than most.

That was never intended to have a drywall load and I would do my firring strips at 16" and 1/2" drywall rather than 5/8" that would be customary to use on a lid.

 

[buzzworth]

Your skylights will sweat when you get cold weather, make provisions for drippage.

 

[NUTTSGT]

Good thought on the foil faced EPS. I have part of my ceiling foil faced poly ISO. However, it's not fire resistant at all and if it does burn, look out.

Putting it foil faced down will reflect the light and radiant heat during the winter. 2" panels would be a decent R value, maybe 13-15, plus the reflectibility of it.

If you chose to do a dropped ceiling, you could use the same foil faced poly ISO, cut into 2x4 sections rather than ceiling tiles

 

[KnurledNut]

Drop ceiling with lightweight fiberglass tiles?

 

[North Dakota]

at 12' oc, my opinion is that those trusses were never intended to have a ceiling on them and are not spec'd for it.

Certainly not drywall.

this

 

[rburke65]

Why don’t the trusses fall on the posts.....asking for a friend.

 

[mike93lx]

Why don’t the trusses fall on the posts.....asking for a friend.

They don't need to if it was designed and built properly. The beam at the top distributes the load. No different than most houses. Wall stud spacing and truss spacing are usually different

Either that or it was a hack job, but considering the location, there isn't much load on that roof

 

[danieldd]

They don't need to if it was designed and built properly. The beam at the top distributes the load. No different than most houses. Wall stud spacing and truss spacing are usually different

Either that or it was a hack job, but considering the location, there isn't much load on that roof

Pretty sure it wasn't a hack job. This is a Morton built building. Not defending them, but they've been building these things for many years. I really don't understand why they built on 12' centers. Would have much preferred 4' or at least 6' but it is what it is.

 

[mike93lx]

Pretty sure it wasn't a hack job. This is a Morton built building. Not defending them, but they've been building these things for many years. I really don't understand why they built on 12' centers. Would have much preferred 4' or at least 6' but it is what it is.

Not implying it was a hack job, just saying that was the other possibility.

The answer to your question about why 12' spacing is certainly cost.

 

[Loose Nut Buster]

12' centers = lower cost to whomever wishes to go that route and local codes allowing it.
Speaking of lower costs, what about one of those 3-4' diameter barn fans at one end and an open door at the other for a constant breeze through it.
An added benefit could be it'd **** the mosquitos out of it too!!
You could adjust the door or fan to change the velocity of the air moving through also.
Just a thought.

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[captaindiode]

This is a Morton built building

If it is a Morton, I would contact them and get their recommendation for a ceiling. I bet they have the engineering data on the trusses.

 

[LB-1911]

If it is a Morton, I would contact them and get their recommendation for a ceiling. I bet they have the engineering data on the trusses.

He did -

Cut from previous thread

FINALLY got a quote from Morton. I think they're smoking crack because when they told me the quote, I immediately scoffed at their price...

So, to recap.... shop area is 36X36 with an open ceiling. Walls are 12 feet high. Only need 3 walls insulated as the 4th wall has already been done (which leads to a fully enclosed apartment within the building).

The area beneath the roof tin already has Thermax insulated boards that I think is good for R4 at a minimum. Walls and ceiling trusses are on 12 foot centers so they would have to add support to get walls on 6 foot centers and add support for the ceiling joists. Morton would attach an acoustical tin to the ceiling, add R30 insulation batts, add 6 inches of insulation to the walls and cover them with a vapor barrier. As for the 2 big *** sliding entry doors, not much there they can do other than to add the Thermax boards and call it a day.

$20,500 is the price quoted.


Ridiculous!

Here is what I know... Job would take two complete days with a crew of 3. They are renting a lift for the ceiling: $500, Porta Potty rental $150, Dumpster rental: $500. Their hourly labor rate is $51/hour.

So, labor is approximately $2,500. You subtract out the rental stuff and you are left with somewhere around $16,850 for materials.

Yeah, not gonna happen. Closed cell foam is looking a whole lot better for me at this point.

 

[Firebrick43]

Good thought on the foil faced EPS. I have part of my ceiling foil faced poly ISO. However, it's not fire resistant at all and if it does burn, look out.

Putting it foil faced down will reflect the light and radiant heat during the winter. 2" panels would be a decent R value, maybe 13-15, plus the reflectibility of it.

If you chose to do a dropped ceiling, you could use the same foil faced poly ISO, cut into 2x4 sections rather than ceiling tiles

Poly iso is twice as fire resistant as ep/xps

I would put 1” poly iso cut for a tight fit between the purlins with the foil face pointing up with the back flush with the bottom face of the purlin. This will give good heat rejection into the 1/2 air space. I would then put 1” plus poly iso with the foil face pointing down for winter performance. This to be held up with metal cap nail or metal cap screws. This layer should be put up in full 4x8 sheets. Use low expansion foam on the seems and use foil tape. This would provide awesome and light weight performance.

To help install I would either get a pair of Fastcap 3rd hands with connector kit or a pair of their EMT 3rd hands so you can reach up high. Get the 3x3 pivoting head plate and drill some small holes and place some screws that go all the way thru about 1/8- 3/16 of an inch so it will bite the foam and not slip.

Either purchase two sections of rolling scaffold(can normally resale for 80% when done) or rent a mini man lift for the week end. If you have some one cutting foam and handing it up I would have no problems insulating that building in a week end.

https://www.sunbeltrentals.com/equipment/detail/1262/0070030/20ft-single-manlift-s-p/

 

[WesM]

How wide is your building? Could you run LVLs across the building (same direction as the trusses), tying them into the walls (or whatever the trusses are resting on) so they are not putting load on the trusses. Space the LVLs 24" on center and tie the ceiling to them?

I'm suggesting LVLs because they tend to sag less then a similar sizes dimensional lumber. You can also spec out LVLs with a defined amount of belly, so when they are loaded they pull straight. You can look up LVL load tables to figure out what width/thickness you need for this application.

 

[Firebrick43]

How wide is your building? Could you run LVLs across the building (same direction as the trusses), tying them into the walls (or whatever the trusses are resting on) so they are not putting load on the trusses. Space the LVLs 24" on center and tie the ceiling to them?

I'm suggesting LVLs because they tend to sag less then a similar sizes dimensional lumber. You can also spec out LVLs with a defined amount of belly, so when they are loaded they pull straight. You can look up LVL load tables to figure out what width/thickness you need for this application.

He said 36’. That is going to be an 18”+ lvl and have to be doubled at that height at 300$ a piece, or 600$ every 2’ let alone the cost of the header and hangers on the walls

 

[WesM]

He said 36’. That is going to be an 18”+ lvl and have to be doubled at that height at 300$ a piece, or 600$ every 2’ let alone the cost of the header and hangers on the walls

Ouch, yea never mind that idea, I was expecting something closer to 24'.