Tape Flat Seams and Inside Corners

A. Finished-Project Specification

Scope: tape embedment across every flat seam and inside corner in the designated room, wall system, or practice area identified in the approved finishing specification, using the specified tape and compound products.

B. Joint Categories (Component Schedule)

Joint Type	Bed Coat Location	Tape Placement	Embedment Method
Flat tapered seam	Full length of the seam, within the tapered recess	Centered over the seam	Single-pass embedment with the 6-inch knife at a controlled angle
Flat butt seam	Full length of the seam	Centered over the seam	Single-pass embedment; wider feathering reserved for later coats
Inside corner	Both sides of the corner before tape placement	Creased tape centered on the corner line	One side embedded, then the other, without pulling tape off center

C. Material Takeoff

• Tape: paper or approved mesh joint tape as specified by the finishing system, in the quantity required to cover every flat seam and inside corner length plus the specified waste allowance.
• Compound: drying-type or setting-type joint compound as specified, in the quantity required for the bed coat across all seams and corners.
• Water: clean water within the compound manufacturer's stated water-addition limit.

D. Reference Conventions

Use the flat seam, inside corner, bed coat, embedment, working time, and full-bond definitions given in the Reference Conventions table above for every joint taped in this chapter.

E. Acceptance Standards

Check	Standard
Tape centering	Tape centered over the joint or corner line with no visible offset at either edge
Bubbles and dry spots	No visible bubbles, air pockets, or dry spots anywhere along the embedded tape length
Wrinkles and tears	No wrinkles, creases outside the intended corner fold, or tears in the tape surface
Loose edges	Tape edges fully bonded to the panel with no lifted or unbonded section
Excess compound	Excess compound removed while leaving sufficient compound beneath the tape for full bond, with no starved or exposed tape
Inside corner alignment	Straight, clean corner line with consistent depth on both sides
Drying or setting	Taped joints fully dried or set per the compound manufacturer's stated time before reinspection

F. Preparation Procedure (Steps 1–5)

1. Review tape type, compound type, joint condition, working time, drying conditions, and finish specification. Confirm the specified tape and compound products match the room's finishing specification before opening any material.
2. Confirm panel fastening, corner bead, gaps, and repairs are ready for taping. Verify the Chapter 6, 7, and 9 inspection records are on file and no deficiency remains open for the area to be taped.
3. Remove dust, loose paper, gypsum crumbs, and protruding fasteners. Wipe or brush every seam and corner to be taped, and correct any protruding fastener before continuing.
4. Pre-fill gaps and damaged areas where the system requires it. Apply pre-fill compound to any gap or panel damage identified by the finishing specification as requiring it.
5. Allow pre-fill material to set or dry. Confirm the pre-fill has reached the manufacturer's stated dry or set condition before mixing taping compound.

G. Flat Seam Taping Procedure (Steps 6–13)

1. Mix compound to the specified consistency using clean water and tools. Mix only the quantity that can be applied within the product's working time.
2. Do not exceed product water-addition limits. Confirm the mixed consistency matches the manufacturer's taping specification before loading the knife.
3. Apply a continuous bed of compound to the first flat seam. Run the 6-inch knife the full length of the seam without leaving gaps in the bed coat.
4. Center paper or approved mesh tape over the joint. Unroll tape directly into the wet bed coat, keeping it centered on the seam as it is laid.
5. Embed tape using a controlled knife angle and pressure. Draw the knife along the tape at a consistent angle to press it fully into the bed coat without lifting either edge.
6. Remove excess compound while leaving enough beneath the tape for full bond. Draw the knife firmly enough to remove surplus material without starving the tape of compound.
7. Avoid stretching, tearing, or polishing the tape surface excessively. Use even, moderate pressure; excessive pressure can burnish the paper and weaken the bond.
8. Repeat for remaining flat seams. Complete each seam in the same sequence before moving to inside corners.

H. Inside Corner Taping Procedure (Steps 14–17)

1. Apply compound to both sides of an inside corner. Coat each adjoining panel face along the full corner length before placing tape.
2. Crease paper tape accurately and place it into the corner. Fold the tape along its center crease and set it into the corner so the crease aligns exactly with the corner line.
3. Embed one side and then the other without pulling the tape off center. Use the corner finishing tool or corner knife to embed each side in sequence, checking that the crease remains centered on the corner line.
4. Remove excess compound and leave a clean corner line. Draw the knife along each side to remove surplus material while preserving a straight, consistent corner.

I. Inspection and Drying Procedure (Steps 18–21)

1. Inspect for bubbles, wrinkles, dry spots, loose edges, excessive buildup, and exposed tape. Check every taped seam and corner under the work light while the compound remains workable.
2. Lift and reset defective tape while the compound remains workable, or remove and replace it after drying. Correct any defect found in Step 18 using the method appropriate to the compound's current condition.
3. Allow the taped joints to dry or set fully. Confirm the compound manufacturer's stated drying or setting time has elapsed before disturbing the joint.
4. Reinspect before first-coat finishing. Confirm full bond, straight corner lines, and no remaining defects across every taped joint before Chapter 11 begins.