5/8” drywall ok for cathedral ceiling with 2x4” rafters?

[MerlinsBeard]

I’m planning for 5/8” Sheetrock for walls and ceiling in my 10x16’ shed, but wondering if I need to use furring strips for support or can I use the rafters directly when the ceiling is a cathedral style with 2x4” rafters?

 

[rayra]

Furring strips are northeastern garbage left over from the era of lath & plaster, as a means of leveling early uneven ceilings in settling homes. Nobody else uses them.

5/8" may be a little heavy for your flimsy 2x4 rafters.

What sort of roof deck and fasteners did you use?

What is the rafter spacing?

what sort of roof pitch / rafter spans? shallow 'shed' slope, or a peaked roof? 12:12 gives you 7' rafters to the peak.

/mildly curious why you are drywalling a shed interior

/literally just finishing a 10'x6' shed extension

 

[Renegade1LI]

Never seen a shed with dry wall, I would go with 1/2" light weight, skip the furring strips if it's a storage shed, unless your spacing is over 24" oc. If it is I would consider adding more 2 x 4s than.

 

[MerlinsBeard]

It's an amish built, 16" rafter spacing, wasn't explicit but looks like 7/12 roof. Not sure exactly what they used for fasteners. Ridge beam and gussets for support.

Finishing shed because it's going to be a hobby workshop area, and I like the look of drywall as far as finished space. On 1/4 acre lot, so not looking to go too big with the shed.

The ceiling is a little more complex since I have a dormer. Still prefer to try to keep the ceiling space but have it finished with drywall. If there are structural issues with that, that's what I'm trying to find out.

Here's a couple pictures for reference.

 

[mike93lx]

That's not a ridge beam. It's just a board for nailing to. A ridge beam is structural and is used to transfer roof load to the gable walls.

5/8 is crazy heavy with little to no gain. Just use lightweight 1/2

 

[racecougar]

I'd suggest bumping down to 1/2" for the ceiling in that.

 

[zc15]

1/2" gets my vote

 

[MerlinsBeard]

Roger that, feedback much appreciated!

 

[Lynden]

Check out Ceiling Board.

Interior Ceiling Gypsum Board - American Gypsum

1/2” Interior Ceiling Board is specifically formulated to meet the need for a lower weight ceiling panel with increased integrity in its gypsum core.

www.americangypsum.com

 

[billconner]

Is the difference even a pound per square foot? Seems not significant as far as dead load on structure.

 

[Zeke]

Whatever you do, I like it. I even like it as it is. The dormer makes a boring shed a winner.

 

[CombatNinja]

I concur on the 1/2" but you are insane for putting drywall in a shed. So many better options that will be infinitely more durable and forgiving in a hobby space.

 

[jshillin]

1/2" if you are going to go with drywall. I put 7/16" OSB on the walls and ceiling of my 12'x20' shed/wood shop and painted it.

 

[mike93lx]

Is the difference even a pound per square foot? Seems not significant as far as dead load on structure.

The load on the structure isn't why I advised against. It was the installation. Handling sheets in that little space will be less than fun anyway, and making them more than twice as heavy will make it a lot worse

 

[Ricky Joe]

I would rethink drywall at all in a shed. Mold can really make a presence even in the so-called mold resistant gypsum board.

 

[demarpaint]

I'm working that 5/8" sheetrock now to enclose a bump-out extension to my attached 2 car garage. Code says it has to be 5/8" because the garage is attached to the house and 5/8" has to be used to slow or contain a fire. Given a choice I would have gladly used 1/2" board because it is lighter and easier to work with. I'd use 1/2" if I were you.

 

[kmacht]

Unless that shed is setup to be completely sealed from the outdoors that drywall is going to be soft and moldy in short order. Things like doors, windows, soffit, etc are not designed on a shed to keep moisture out. They may keep rain out but not moisture. You need a different sheathing material for those walls than sheetrock.

 

[strutaeng]

I did a large addition to our house and used 5/8" sheetrock. Mostly for sound and strength (kids bouncing off walls.)

For the ceilings I did use 1x4 furring strips. Ceiling joists were 2x12s at 24" and a few had variations, but furring strips (also at 24" o.c.) helped.

Unless it's specific (I've seen some architectural homes), furring strips are not used around here.

 

[jkuro]

I can't tell from the photo if that's a window or gable vent. Don't forget to put in some sort of ventilation.

 

[MerlinsBeard]

The reason for the 5/8" drywall consideration is largely for the sound impact that it has in reducing noise in the neighborhood. I'm not very far away from my neighbors and if I can go a little thicker on the drywall to gain some dB reduction I make in the shop, I'm going to strongly consider it.

Currently, I'm leaning towards 5/8" drywall for sides and 1/2" for ceiling.

For those questioning about moisture issues, I do plan to air seal wall cavities and insulate with the intent to install a mini split. Planning rockwool for walls and 2" polyiso for ceiling, with smartvent to provide shingle soffit airflow to ridge vent.

Sound is an important factor to me as if I can get away with doing more in the evening/early morning hours without waking up the neighbors, it's a big win for me.

 

[billconner]

Good thinking. Ultimately your windows will be acoustic weak point, and certainly not the roof. You can help neighbors and yourself with some acoustic "fuzz" inside - absorption. Rugs or carpet, fabric wall hangings, anything porous and soft.

 

[Showkey]

If you insist on drywall in a shed ………at least use “green-board” drywall.

What You Should Know about Water-Resistant, Greenboard Drywall​

Your Guide to Water-Resistant Greenboard Drywall - Modernize

Here is your guide to water-resistant greenboard drywall to help you decide if it's something that you'll want to use instead of standard drywall

modernize.com

 

[Sumboodie]

I'm working that 5/8" sheetrock now to enclose a bump-out extension to my attached 2 car garage. Code says it has to be 5/8" because the garage is attached to the house and 5/8" has to be used to slow or contain a fire. Given a choice I would have gladly used 1/2" board because it is lighter and easier to work with. I'd use 1/2" if I were you.

Only for the firewall. The other walls can be 1/2"

 

[billconner]

By basic IRC, 1/2" except for habitable spaces over the garage, then 5/8. It is a section that gets amended by adopting jurisdictions more frequently than others.

SEPARATION​	MATERIAL​
From the residence and attics​	Not less than 1/2-inch gypsum board or equivalent applied to thegarage side​
From habitable rooms above the garage​	Not less than 5/8-inch Type X gypsum board or equivalent​
Structure(s) supporting floor/ceiling assemblies used for separationrequired by this section​	Not less than 1/2-inch gypsum board or equivalent​
Garages located less than 3 feet from a dwelling unit on the same lot​	Not less than 1/2-inch gypsum board or equivalent applied to the interiorside of exterior walls that are within this area​

 

[demarpaint]

Only for the firewall. The other walls can be 1/2"

Not in my case, the garage is attached to the house and the master bedroom was dormered above the garage. I was told the bump-out had to be finished with 5/8" drywall. I spoke with the building inspector as well as the architect who drew the plans that I needed to get the permit. I live in an incorporated village and they can and have busted balls of a lot of people I know.

 

[Sumboodie]

Not in my case, the garage is attached to the house and the master bedroom was dormered above the garage. I was told the bump-out had to be finished with 5/8" drywall. I spoke with the building inspector as well as the architect who drew the plans that I needed to get the permit. I live in an incorporated village and they can and have busted balls of a lot of people I know.

That's a firewall.

 

[demarpaint]

That's a firewall.

And why I used 5/8" on everything. Had the bedroom not been built over the garage then 5/8" could have been used on the common wall between the house and the garage. In all honesty I would still have used the 5/8" boards.

 

[billconner]

That's a firewall.

Not by usual building code definition however, just to be precise.

 

[mike93lx]

I dont think you would be able to notice a difference at all with 1/2vs5/8. The insulation will matter, as will the quality of the windows.

 

[CombatNinja]

You'll be money ahead spending the difference toward rock wool insulation for noise abatement if that is a priority. There is virtually zero detectable difference to the human ear between 1/2" and 5/8' in that realm.