Problem: Visible joints, ridging and tape delamination of drywall.
Cause: Lumber shrinkage.
Shrinkage at headers may cause ridging especially at stairways as shown in Figure 67.
Figure 67 - Drywall Header Ridging
Ridging can also occur when studs and joists warp and twist.
- Float board across headers, fastening above and below, but not directly to the header itself. Alternatively, use horizontal control joints and conceal them with a trim or molding.
- Inspect framing before installing the drywall. Straighten or replace warped studs. Use kiln-dried lumber if possible.