Wallpaper installation guide: wall preparation, hanging standards and acceptance

A project installation runs in eight steps, and the first three, all preparation, decide most of the finished quality. SEAMATER surveys and measures the walls and installs the wallpaper, for projects in Vietnam and overseas export projects; the designer and project manager still confirm inputs and accept the result.

1. Approve the wall: moisture, flatness, primer.
2. Check materials: code, batch, quantity, hanging direction.
3. Set out: start point, seam positions, pattern placement.
4. Mark a plumb line for the first drop.
5. Cut drops with top and bottom allowance, matching pattern.
6. Paste to suit the product and hang, smoothing from the centre out.
7. Finish seams, corners, reveals, switches and sockets.
8. Clean off paste, control room conditions while drying, and inspect.

Walls must be dry, flat, sound, clean and primed. Wallpaper does not hide defects; it exaggerates them under raking light.

Drying time for new plaster depends on thickness, weather and ventilation, and it stretches considerably in rainy or humid seasons. Measuring moisture, rather than counting days, prevents many lifting and mould failures.

On uneven walls, the usual remedies are re-skimming and sanding, or hanging a lining paper first so the decorative paper sits on a uniform base.

Non-woven papers usually strip dry in full sheets. Paper-backed and vinyl products need the paste softened with water, a stripping solution or a steamer; score water-resistant faces lightly so moisture reaches the adhesive. Isolate power before wetting walls, limit water on plasterboard, then wash off old paste, patch, sand and re-prime. In refurbishments, allow time for wall repair, because the real wall condition only appears once the old paper is off.

Hang wallpaper after ceilings, painting and dusty work are complete, and before switch plates, wall lights and loose furniture go in.

• Before: ceilings and curtain pockets finished, adjacent paint and joinery painted, walls skimmed and primed, air-conditioning installed and tested, floors protected.
• After: switch plates and sockets, wall lights, wall-fixed curtain tracks, artwork and mirrors, final clean.

Agree in advance where the paper stops at skirting level so it does not need re-cutting later.

Wallpaper survey and installation, curtains and chandelier hanging can be booked together so the sequence between trades is agreed in one place.

Three points matter most for project teams: checking batch numbers, a plumb first drop, and the correct pasting method. The rest is crew skill.

• Batch: check the batch number on every roll at delivery and before opening, and hang each wall from rolls of the same batch where possible; keep labels for the handover file.
• Direction: some plains require reverse hanging of alternate drops, shown on the label.
• Plumb: set the first drop to a vertical line, not to the corner.
• Allowance: cut drops about 5 cm long at top and bottom and trim after hanging.
• Paste: paste the wall for non-woven; paste the paper and observe soak time for paper-backed products. Use fungicidal adhesive in humid areas.
• Seams: butt joints, not overlaps (except double-cut seams on wide vinyl); roll gently.
• Paste on face: remove immediately with a clean damp cloth.
• Switches and sockets: isolate power, remove plates, cut back neatly, refit.

Stop after two or three drops to check shading and pattern match under room lighting. A fault found here costs a few drops; found at completion, it costs the room.

Inspect once dry, under normal room lighting, from a normal viewing distance. Raking light is for checking walls before hanging; used at acceptance, it makes every seam look worse than it reads in use.

Local damage can be repaired by double-cutting a patch from retained offcut paper, matched to the pattern.

In tropical, humid markets across Southeast Asia including Vietnam, three moisture-related defects recur: edge lifting during humid spells such as northern Vietnam's nồm season, mould spots on external walls, and seams opening when air-conditioning dries the paper too fast. Prevention starts with waterproofed walls, appropriate adhesive and stable room conditions; typically, keep direct airflow off the walls for the first one to two days, following the manufacturer's guidance. See wallpaper in humid conditions and materials for humid tropical climates.

• Wallpaper codes by room, with batch numbers and photos of roll labels.
• Any leftover paper, with its batch number and where it is stored.
• Adhesive and primer used.
• Cleaning guidance by product type.

Plan the roll quantity before ordering; see how to calculate wallpaper rolls and types of wallcoverings. SEAMATER checks the roll quantity for the customer and handles survey and installation, so the handover file can be built with the installation crew.