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I am in the process of placing drywalls on ceiling and walls. I am placing the sheets perpendicular to the studs and joists. I would like to understand better how to prevent cracking and shrinkage at joints. I am looking at butt joints between two studs or joists without support. If sheets are perpendicular there are spots where the butt will not align with a stud/joist, and the tapered joint will never have a support (because perpendicular). From research, I understand that joints can be reinforced with shims or thin wooden boards behind each joints. What is best practice?

Studs and joists are 16in on center.

  1. If butt and tapered joints are not align with studs or joists, do they need to be reinforced to be flush and to prevent cracking?
  2. Does the tape or mesh provide enough in plane strength to prevent temperature shrinkage and cracking?
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    I would cut the drywall to fit. Drywall sheets are 4ft by 8ft to fit on 16in stud spacing. Only need someone just leaning on an unsupported joint to have problems. If needed adding extra studs is an idea.
    – crip659
    Feb 25, 2023 at 16:01
  • Thank you @crip659. Same for ceiling?
    – Max
    Feb 25, 2023 at 16:18
  • And, do you reinforce in the perpendicular direction? If butts are aligned with studs, then tapered joints will not have support.
    – Max
    Feb 25, 2023 at 16:20
  • Go to a place that specialises in plastering supplies and order sheets in the correct size
    – Jasen
    Feb 26, 2023 at 7:56

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You are asking about supporting joints.

Preventing cracks is primarily accomplished by proper firm framing and proper support at edges/butts, and secondarily by tape to withstand framing movement over time.

Cracking from shrinkage is prevented by using curing/setting compound ("Sheetrock 90") for filling, or by using drying compound ("All Purpose") in thin layers only (max 1/8in). Drying compound on edges must be supplemented by paper tape. The purpose of mesh is to hold setting compound in place over wide gaps while applying.

Plan your sheet edges to align with studs edges, not stud centers. That way, one sheet will be fully supported by the 1.5in stud, and the butting edge will get extra backing: nail/screw an additional stud to the existing stud. The add-on stud does not have to be full length or one piece.

With more experience you might get away with aligning the edges "half-on" the stud, but I always find this inferior.

For floating horizontal tapered butts, the stud spacing of 16in to max 24in plus the deeper fill at the taper taper strengthened by tape will provide full support. No backing needed.

For other floating butts (vertical or horizontal) that are not tapered or that span more than 24in between studs, provide additional backing in the form of a strip of ply wood or piece of 1x / 2x lumber screwed at both edges of the butt. Install one sheet, screw-on backing, install second sheet, and use the location of the existing screws to screw to backing. (The second sheet will conceal the backing but the screws reveal its location)

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  • Thank you @P2000. To make sure I understand, there will be only support at the butt joints, but no continuous support behind the tapered joints (just point support at joists). Is that correct? Also, could you please describe what is meant by "beveled butts"? Does bevel mean that the each sheet must be chamfer?
    – Max
    Feb 26, 2023 at 1:23
  • @Max thank you for spotting that, I meant tapered not beveled. Will edit. Yes, tapered joints do not require backing, so point stud/joist is fine. Good luck with your project.
    – P2000
    Feb 26, 2023 at 4:49

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