Confused about ceiling weight trusses can support

[Anotherguy]

I have my truss engineering sheet but I'm still confused about how much weight I can add for a ceiling. I've searched around but I can't really wrap my head around it. Hopefully someone can help me.

I want to hang OSB, lighting and insulation. The specs are:
TCLL 30.0
Snow (Pf/Pg) 29.8/43.0
TCDL 7.0
BCLL 0.0*
BCDL 10.0

Trusses are 4' oc. The garage is 30x52x13

*"this truss has been designed for a live load of 20.0psf on the bottom chord in all areas where a rectangle 3-6-0 tall by 2-0-0 wide will fit between the bottom chord and any other members" Whatever that means

Thanks in advance

 

[ddurrett896]

BCLL is storage. Sounds like attic trusses and anything in the 2-2-0, 3-6-0 can handle 20lb/ft.

BCDL doesn’t more (osb, lighting, insulation). These will handle that.

 

[Anotherguy]

With it showing 10/psf, does that mean they will support a total of 15,600 pounds over the entire garage?

 

[jbwilkins]

T

*"this truss has been designed for a live load of 20.0psf on the bottom chord in all areas where a rectangle 3-6-0 tall by 2-0-0 wide will fit between the bottom chord and any other members"

3'6" Tall, 2' Wide

 

[mcbane]

With it showing 10/psf, does that mean they will support a total of 15,600 pounds over the entire garage?

Yes, assuming you have 1560 sq ft. And it can support a concentrated dead load of more than 10 lbs but you would need to ask the truss engineer for that spec.


Sent from my iPhone using Tapatalk

 

[bad_idea]

I would call the truss manufacturer and ask your questions. Before you call them I would figure up the weight of the OSB and insulation you plan to use per sq ft.

 

[Zen]

Don't worry, you'll be fine.

 

[Innovate1]

TCLL - top cord live load. This is the upper load and is variable load like snow.
TCDL - top cord dead load. Again upper load but constant load like sheeting and shingles.
BCLL - bottom cord live load. Variable load like stuff stored on top of bottom members.
where there is more room to put stuff they sometimes have higher load capability.
BCDL - Bottom cord dead load. Fixed load like ceiling sheeting, insulation, lights, etc.

The concentrated loads like garage door tracks and such no one seems to worry too much about and most are small enough to not matter much as there are margins built into the design.

 

[joe--h]

OSB is going to sag on 4' centers.

You'll have to strap it with 1x4 or whatever you can get cheap.

Joe H

 

[NUTTSGT]

OSB is going to sag on 4' centers.

You'll have to strap it with 1x4 or whatever you can get cheap.

Joe H

I was going to mention this as well and needing to add that weight factor in to. Personally, I'd skip the OSB and put up ribbed metal siding. No strapping, no priming and no paint, one and done.

 

[b-boy]

Another vote for metal for 4' OC.

Easy on, easy off if needed.

 

[firebirdparts]

With it showing 10/psf, does that mean they will support a total of 15,600 pounds over the entire garage?

That's right.

 

[Anotherguy]

Thanks for all the input. I never considered metal siding as a ceiling material. Nor did I think about sagging from osb.

 

[3rdgendslmech]

If you go the metal ceiling route try to find a local-ish distributor and get some prices. They'll be a lot cheaper and could probably have what you want the next day.

 

[WNYflyer]

TCLL - top cord live load. This is the upper load and is variable load like snow.
TCDL - top cord dead load. Again upper load but constant load like sheeting and shingles.
BCLL - bottom cord live load. Variable load like stuff stored on top of bottom members.
where there is more room to put stuff they sometimes have higher load capability.
BCDL - Bottom cord dead load. Fixed load like ceiling sheeting, insulation, lights, etc.

The concentrated loads like garage door tracks and such no one seems to worry too much about and most are small enough to not matter much as there are margins built into the design.

^^^^ Good Info

To elaborate:

Allowable bottom chord dead load (BCDL) = 10 psf, therefore with trusses 4' o.c. the bottom chord can have linear vertical load applied to it of 10 psf x 4' o.c. = 40#/foot of bottom chord length

10 psf x 30 x 52 = 15,600# as already noted.

*"this truss has been designed for a live load of 20.0psf on the bottom chord in all areas where a rectangle 3-6-0 tall by 2-0-0 wide will fit between the bottom chord and any other members" Whatever that means

This means basically wherever a box 3'-6" tall x 2'-0" wide can fit on top of your bottom chord the truss and thus bottom chord can support a box weighing up to 2' wide x 4' o.c trusses x 20 psf (really a BCLL) live Load = 160# spread over a width of 2'.

The 3-6-0 etc. as noted equals Feet - inches - 1/16th's, 1/8th's, 1/4th's?can't remember which of those though.

 

[ckyle29]

With a 10 pound/sf BCDL you can easily support the ceiling, lights and insulation. A 4 X 8 sheet of OSB is approximately 46 pounds, but it is spread out over a 32 square foot area, so that's 46 pounds hanging from an area rated for 320 pounds. I have the same 10 pound/sf BCDL on my shop, with 2X4 strapping every two feet, 1/2 inch plywood, R38 blown in, 15 8' fluorescent light fixtures, 3 mini-splits mounted in the ceiling, two garage door openers, three pendant lights, a pool table light and a ceiling fan in a 30 X 60 shop and I'm still way under the rated load.