Horizontal vs. Vertical Drywall
Hanging drywall horizontally does place seams at a more convenient height for finishing, resulting in better work, but that’s only part of the story.
Myron R. Ferguson’s book, Drywall: Professional Techniques for Great Results, has many helpful ideas, but as a trim carpenter I was dismayed to see him promote hanging drywall horizontally. When the tapered bevel is placed on the floor, it makes fitting coped corners in baseboard much more difficult, as the baseboard is now “kicked in” at an angle. Also, when drywall is installed horizontally, you end up with an unsupported joint between each stud. If fastened vertically, every edge will land securely on a stud. I know it is easier for drywall installers to install and finish horizontally, but this method adds difficulty for trim carpenters, and I think adds weakness to the wall as well.
x— David Ferrand, via email
Myron R. Ferguson: As far as the tapered edge along the base goes, attaching a shim along the floor is really the answer. Changing the orientation of the drywall will just create poorer-quality finished walls. Hanging drywall horizontally does, as you point out, place seams at a more convenient height for finishing, resulting in better work, but that’s only part of the story. When the walls are 9 ft. high or less, attaching the drywall horizontally can reduce the lineal footage of seams by as much as 25% over vertical attachment. When combined with the longest sheets possible, butt seams are minimized, and those that do appear land between studs where they can be back-blocked to make them easier to finish. The unsupported edges you mention aren’t a problem and are actually less likely to crack than a joint that lands on a stud. All of this adds up to a smoother wall. But the perks go beyond labor savings and quality of finish. Horizontal attachment actually increases the shear strength of the structure.