In a perfect world, rooms would have corners that were truly square and truly vertical, and it would be possible to hang a wall covering all around the room in a continuous operation, simply turning the lengths that ran into the room corners straight on to the adjoining walls. In reality, corners are seldom square or true, and, if the covering were hung in this way, lengths would be vertical on the first wall but could be running well off the vertical by the time they returned to the starting point. This would be visually disastrous, with vertical pattern elements out of alignment are corners, and sloping horizontal pattern features.
The way to avoid these problems is to complete each wall with a cut-down strip that only just turns on to the next wall. Then hang the remainder of the strip with its machine-cur edge against a newly drawn vertical line on the second wall, so that you can trim its other edge to follow the internal angle precisely. Any slight discontinuity of pattern will not be noticeable except to the very closest scrutiny, and the remaining lengths on the second wall will be hung truly vertically. The same applies to paperhanging around external corners
PAPERING AN INTERNAL CORNER
1. Hang the last full length before the corner of the room, then measure the distance to the corner front the edge of the length and add about 12 mm or 1/2 in.
2. Use a pencil and straightedge to mark a strip of the required width, measured from the relevant edge (here, the left one), and cut it from the length.
3. Paste the strip and hang it in the usual way, allowing the hand-cut edge to lap onto the adjoining wall. Trim the top and bottom edges as usual.
4. Brush the tongue into the internal angle. If it will not lie flat because the corner is out of true, make small release cuts in the edge and brush it flat.
5. Measure the width of the remaining strip, subtract 12 mm/1/2 in. and mark a fresh Vertical line on the adjoining wall at this distance from the corner
6. Hang the strip to the marked line, brushing the wall covering into the angle so that it just turns on to the surface of
.the first wall.
7. Use the back of the scissors blades to mark the line of the corner on the wall covering, then cut along the line and smooth the cut edge back into the angle. Use special overlap adhesive when using washables and vinyl on all lap joints.
PAPERING AN EXTERNAL CORNER
1. Plan the starting point so that lengths turn external corners by about 2.5 cm/1 in. Brush the paper on to the next wall, making small cuts so that it lies flat.
2. Carefully tear off a narrow strip of the wall covering along the turned edge to leave a ‘feathered’ edge that will not show through the next length.
3. Mark a vertical line on the next wall surface, at a distance from the corner equal to the width of the wall covering plus about 6mm or 1/4 in.
4. Hang the next full length to the marked line, with its other edge overlapping the feathered edge of the strip turned from the previous wall
5. Brush this length into position, trim it at the top and bottom as before, and run a seam roller down the overlap(do trot do this on embossed or textured wall coverings).Again, use a special overlap adhesive with washable and vinyl coverings.