Sand Wall Seams for Fabric Wallcovering: Check the Covered Sample

Fabric wallcovering can soften the look of a room without hiding a raised drywall seam. The fabric follows the wall beneath it, and a pale weave may also reveal a contrast between joint compound and the board face. Flatness and a uniform background are separate requirements. More sanding addresses only one of them.

For directly adhered textile wallcovering over new gypsum board, prepare and inspect a representative seam before committing to the whole wall. This is a substrate-preparation task; stretched fabric over tracks or padded panels has a different construction and should follow that system's requirements.

Read the wallcovering specification before choosing the last grit

Look for the required substrate, primer, adhesive and wall condition. Do not translate “smooth” into a polishing-grade abrasive or assume that any paint primer will do.

For example, Symmetry Resources' woven wallcovering installation instructions call for a sound, dry, smooth wall with uniform color and an appropriate opaque acrylic wallcovering primer. They also require surface blemishes to be smoothed and sealed to avoid showing through the covering. Those requirements concern the prepared wall as a whole, not simply the grit used on a seam.

Confirm that the drywall joints are properly finished and dry. A joint that moves, loose tape or a damaged board edge needs repair before surface refinement. Sanding should remove small high imperfections from sound joint compound, not expose the tape or grind the board faces down to meet a low seam. Preserve the broad, feathered build that conceals the joint; the aim is a visually smooth transition, not sanding all the compound flush with the board paper.

Work on the high compound, preserve the paper

Use a movable side light to locate ridges, then compare the area in the room's normal lighting. Run a clean hand lightly across the seam and use a straightedge where necessary to distinguish a raised shoulder from a depression. Mark the locations on a sketch rather than leaving heavy pencil marks that could show through a pale covering.

Fit fine abrasive to a flat hand block. Support the abrasive across the ridge and use light passes; avoid scrubbing with fingertips directly on the narrow line. Stop periodically to remove dust and check the transition. At the edge of the compound, reduce contact with the board's paper face.

USG's gypsum-panel finishing guidance cautions against roughening that paper, using abrasives so coarse that they leave visible scratches, and leaving sanding dust before subsequent surface treatments. A finer abrasive cannot restore torn paper. Repair damage using the board and finishing system's instructions before carrying on.

Where the joint-compound instructions permit 150 grit, eQualle 150-grit sheets in a 25-sheet pack provide cut-to-fit paper for a hand block. Use a fresh piece of the 150-grit sheet abrasive when it loads; pressing harder to make a spent piece cut increases the chance of digging into the repair. Keep sanding dust contained and use the protection specified for the compound.

A low area calls for an appropriate additional skim of compound and drying time. Do not sand an ever-wider ring around it until the wall face becomes a shallow dish. After correcting high and low areas, remove the dust before applying the specified wallcovering primer.

Judge the seam with the covering in place

Prepare a representative area with the actual primer, adhesive and fabric, following their application and drying instructions. Choose an area that includes the joint and adjacent board face. A loose swatch held against the wall can suggest color show-through, but it cannot reproduce the appearance or bond of an adhered sample.

Inspect the dried trial in the lighting the room will use. A ridge or hollow visible through the material points back to surface shape. A change in background color with no corresponding relief calls for checking the specified opaque primer and its coverage. A line at the fabric's own join needs a wallcovering-installation assessment; it may have nothing to do with the drywall seam underneath.

Woven coverings can have visible seams and optical shading even over a properly prepared wall. Symmetry's instructions acknowledge both. Do not keep sanding the substrate to erase a characteristic of the fabric. Accept the sample for its flatness, background coverage and intended appearance, then use the same preparation on the remaining seams.

Short tip: refining joint compound