Hand Jointing of Recessed Joints
& Back-blocked Butt Joints

Curved or straight trowels may be used for setting recessed and back-blocked butt joints. Under normal pressure, a curved trowel deflects and can assist in the preparation of flatter and more consistent joints. A 200mm trowel is recommended for second coat application, while a 250mm trowel is recommended for the finish coat.

Tape Coat

• Fill recess with compound using a 150mm broadknife.
• Bed in Gyprock Paper Tape centrally over the joint and cover lightly with compound.
NOTE
A minimum 1mm compound is to be left under the tape.
• Cover all fastener heads and fill any surface damage with compound.
• Allow setting-type compounds (Gyprock Base Coat) to set completely, and drying type compounds to harden for 24 hours before proceeding.

Second Coat

• Apply a second coat, about 170mm wide, finishing slightly above the board surface, and feather joint edges.
• Cover fastener heads with a second coat of compound, laid in a different direction, and extending beyond the first coat by about 25mm.
• Allow setting-type compounds (Gyprock Base Coat) to set completely, and drying type compounds to harden for 24 hours before proceeding.

Finish Coat

• Apply a thin finish coat of topping compound centrally over the previous coat, about 250mm wide.
Feather the edges of the compound with the trowel.
• Cover previously stopped fastener heads with a third coat of compound, laid in a different direction, extending beyond the previous coat by about 25mm. Ensure that the edges of the compound are neatly feathered and that there are no trowel edge marks left in the final stopping.
• Allow the finish coat of compound to dry for at least 24 hours before proceeding.

Sanding

• Sand smooth with 180 grit paper or cloth, or with 220 grit sanding mesh. Avoid any heavy pressure which might scuff the linerboard.

Caution: If previous coats of drying type compounds are not thoroughly dry before application of subsequent coats, imperfections can result from delayed shrinkage of the compound.

Attribution: CSR Residential Installation Guide. The RED Book.