Fix old ceiling

[Ben Mose]

I am in the process of replacing an irreparable plaster ceiling in my home. The house was built in the 1930’s and has a flat roof with a gable front. The ceiling is in a 12ft by 17ft bedroom and was nailed to 2x4 joists stretched across the 12ft span. These joists were supported by a 2x4 ledger on the adjoining concrete block wall on one side, and sat on the top plate of a load bearing wall on the other. The center (6feet) of these were strapped with 1x4’s to the roof beams 28 inches above – I imagine to control ceiling deflection. The ledger was not even fastened to the wall, it was also held up with 1x4’s
Well, it apparently all held up for 90 years. Mmmm!

My question is, should I use 2x4’s with center straps as before, or 2x6’s without center straps?
Would 2x6 joist handle the weight (see material list) without any deflection problems?

Anyone know the formula to figure this out?


My replacement material list consist of
13 pcs of 2x6x12, @ 24lb/each = 312lbs
6 sheets of 5/8 ultralight drywall @70lb/sheet = 420lbs
Plus insulation batts, joint compound, etc.
I round off the material to about 1000lbs in weight.


Ben

[Paul F Franklin]

I'd go with 2x6. They can easily span 12 ft with that loading. The ledger should be pressure treated and you should isolate the ends of the joists from touching the concrete and ideally, the ledger, so there is no chance of moisture transfer into the ends of the joists. Self adhesive flashing tape would be a good way to provide the isolation.

[Bill Dufour]

I would use blow in fiberglass insulation on the ceiling because it weighs much less then cellulose.

[Bill Dufour]

Has insulation and drywall gone up like wood has in the last 16 months? I have not bought either in over 10 years.
Bill D.

[Rich Engelhardt]

Drywall - on a ceiling - make sure you get one of these:
Buy a drywall panel hoist for a couple hundred bucks - use it - then sell it for half what you paid.
They are worth every single penny.

[Scott Winners]

What is your expected snow load and rafter framing? Can't see our location. Besides stiffening up the ceiling, if you get enough weight on the roof those same sticks could start bearing roof loading into your ceiling.

Can you make a pencil sketch of the crossection and post a picture?

[Ben Mose]

So 2x6 it is.
I used this calculator. ( https://spancalcwasmcdn1.azureedge.net/ )
and span tables ( https://www.awc.org/pdf/codes-standards/publications/span-tables/AWC_STJR2021_20201005_AWCWebsite.pdf ) page 17...ceiling joist.
I don't understand much of it. Does anyone here?

Blown in insulation is somewhat complicated with vapor barrier and all, so I'm leaning towards batts.

I'm familiar with the panel hoist. HD rents it for reasonable fee, plus no where to store it.

Here's a picture of the room. The ceiling hangs at the white edge perimeter 28 inches below the roof beams.
The concerns about the straps (stick ). I'd rather not use them, only if the 2x6 can handle that span without any deflection.

Can't upload picture.

Ben

[Ben Mose]

Here is picture

459270


Ben

[Stan Coryell]

I've used steel 2x4 track as a ledger in the past. It works well, easily attached, attached to, and is straight (smack nail it to the block wall). I'd use 2x6s and notch the ends. Also, I'd strap the top of them together to avoid twisting and nail pops. I wouldn't tie them into the roof joints. Plan the joist placement around the rock. I would use 8' and 10' sheets and make sure you glue it. I would not bother with a lift for six sheets, make two quick deadman. For the first sheet make a offset ledger and screw it up to the ceiling joists, it gives you a square edge to push against. I would probably start the sheets in the middle of the ceiling.

[Gary Ragatz]

Drywall - on a ceiling - make sure you get one of these:
Buy a drywall panel hoist for a couple hundred bucks - use it - then sell it for half what you paid.
They are worth every single penny.

Rental is another option. Around here, Home Depot rents drywall lifts for $38/day.

[Stan Coryell]

So 2x6 it is.
I used this calculator. ( https://spancalcwasmcdn1.azureedge.net/ )
and span tables ( https://www.awc.org/pdf/codes-standards/publications/span-tables/AWC_STJR2021_20201005_AWCWebsite.pdf ) page 17...ceiling joist.
I don't understand much of it. Does anyone here?

Blown in insulation is somewhat complicated with vapor barrier and all, so I'm leaning towards batts.

I'm familiar with the panel hoist. HD rents it for reasonable fee, plus no where to store it.

Here's a picture of the room. The ceiling hangs at the white edge perimeter 28 inches below the roof beams.
The concerns about the straps (stick ). I'd rather not use them, only if the 2x6 can handle that span without any deflection.

Can't upload picture.

Ben

Modulus of Elasticity is somethings ability to bend without permanent deformation. Hence "elastic "

Kiln Dried Douglass Fir is roughly 1,700,000 psi
Kiln Dried Eastern Hemlock is roughly 1,200,000 psi

The dead load on your ceiling is roughly 5 psi

You could use table C1. I'd use C2.

From table C2:
16" OC
10 psf dead load
KD Douglass Fir will span 14'4" while Eastern Hemlock would only span 13'1"