The problem Level 5 solves
On a Level 4 wall, joint compound covers the seams, fasteners, and beads, while the paper face of the board remains exposed between them. Compound and paper absorb paint at different rates.
Under flat paint in normal light, nobody sees the difference. Under a satin sheen, or under light grazing the wall from a window, the joints reflect differently from the field and read as visible bands.
When you actually need it
Three conditions each push toward Level 5, and any two together make it necessary.
- The wall is smooth, with no texture to disguise variation
- The wall receives raking light from large glazing, skylights, or wall washing fixtures
- The paint sheen is satin or above
How to verify you actually got it
Before priming, turn off the room lights and hold a bright flashlight almost flat against the wall, then sweep it along the surface.
On a genuine Level 5 the plane reads uniformly. If you can see where the joints are as slightly different bands, only the joints were skimmed and the field was not. That check takes two minutes.
Where not to pay for it
A secondary bedroom with one small window and textured walls receiving eggshell paint genuinely does not need Level 5. Specifying it throughout a whole house is a common and expensive mistake.
It is worth pricing per room. A great room with a wall of glass needs it. Most bedrooms do not.
