What is the best way to determine the thickness of drywall to use in a house? Is it based on the stud spacing or ceiling vs wall application?
I have new windows installed and they are for 2×4 walls. The window jambs are (I believe) 4 and 7/16 inches. If I add that up, I have 3.5 inches for the stud, 7/16 inches for the exterior sheating. That brings us to 3 15/16″. Half inch drywall would bring it to 4 7/16″, so I suppose I should use half inch? Most of the studs are on 16″ center, but some are 23.
I suppose I answered my own question here, but if windows are sized for half inch sheetrock, when do you use 3/8″?
Thanks,
Jon
Replies
1/2" drywall is pretty much
1/2" drywall is pretty much the standard on interior walls and ceilings. 5/8" is normally used for firewalls such as the adjoing wall of a garage to house. 3/8 might be used when wrapping a curved wall but hardly anywhere else unless weight is a concern and you wouldn't want to use it on 24" centers.
Window trim moldings are hollowed out on the back and they can span small differences when drywall and window jambs aren't perfectly flush, and they aren't. If the framer wasn't keeping studs, jacks, headers, sills and trimmers flush, you may have to bevel the edge of the drywall with a utility knife or tap it with a hammer so the moldings sit flat. When the difference gets to be 1/4" or more, either filler strips or extension jambs are attached to the window jambs to bring them out flush with the walls. This is typical when framing with 2x6 studs and in some old house remodeling situations, you may have to make tapered fillers to compensate.
Standard windows and doors are made for walls constructed as you described, 7/16" -1/2" sheathing, 2x4 or 2x6 studs (3 1/2" or 5 1/2") and 1/2" drywall. Doors are made for either 4 9/16" or 6 9/16" many windows are made 4 9/16" only and manufacturer made extension jambs bring them to 6 9/16". If you stray from the standard construction sizes in framing and sheathing thickness, you have to make, or have made, custom fillers or extension jambs. Doors are made in 6 9/16" because extension jambs would prevent them from opening 180 degrees. Adding to windows is easy, cutting them down isn't, you want to avoid that situation.
Standard jamb and window frame thickness is 4-9/16" to allow dor finishing mud and other variables.
1/2" SR is standard. 5/8" for ceilings where framoing is 24" OC
3/8" SR is used for under cheap paneling
Changes
I assume they have engineered plywood now to be able to use thinner pieces and save $$ on material while achieving the same strength rating, I guess that is the reason.
More like lobbying efforts with the code authorities, but basically you are right. The changes came about to save the manufacturers money and strectch the resources to produce more goods with the same of less material. Codes changed to meet the thinner material thicknesses. IMO plywood suffered the most , because they did not reduce the number of allowable voids in the plys and over all you get a weaker sheathing material. OSB is not as bad and does not delaminate , making it the choice of most builders for both wall and roof sheathing.
3/8 drywall is used to cover old walls quite frequently. It's also used in curved applications because it will bend to a sharper radius than 1/2", but it would be installed in two layers. It's also handy for matching up to old plaster walls, if you need to have 3/4 or 7/8 etc thickness.