Indy Total Construction

The main problem when plastering corners, whether external or internal, is getting a good, sharp angle. You will face a similar problem at the junction between the wall and ceiling. However, the techniques for dealing with both types of corner are not difficult to master.

There are two forms of guide you can use for forming an external corner: a timber batten or purpose-made metal beading.

The wooden batten is used as a thickness guide for the floating coat then the finishing coat on each wall. Nail it on to one wall so that it projects by the right amount beyond the other and use as a ground for that wall. Then, when the plaster has set, move it round the corner and repeat the process. Any sharp ridges on the apex of the corner should be sliced off with the trowel blade and then the corner rounded off with a block plane or rasp. With wallboard you must tape the angle first.

Two depths of metal beading are available to deal with masonry or gypsum board-clad walls and they can be fixed in place with plaster or galvanized nails. On wallboard, nails must be used. The beading acts as a ground for the floating coat on masonry walls. Before this hardens, cut back the level to allow for the finish coat. Trowel off flush with beading, leaving the nose exposed to provide a knock-resistant corner.

For dealing with internal corners, you need a long wood rule. Use this to rule the floating coat outwards from the corner.

After keying the floating coat, cut out the angle by running the corner of the trowel blade up and down it, holding the blade flat against each wall in turn. This will produce a sharp angle. The finish coat should be treated in the same manner. The final job is to hold the short side of the blade against one wall so the long side is just touching the fresh plaster. Hold the blade at 30′-40° and gently run it down the corner.

For finishing corners where both walls have been plastered, use a special V=shaped angle trowel. This produces a constant right angle in the fresh plaster. Load a small amount of plaster onto the angled blade of the trowel and run it lightly down the angle.

Directions:

1. Reinforcing the external corner of a masonry wall with angle-bead; set it into blobs of plaster, 12in apart.

2. Plastering one wall; work away from the corner, using the nose of the bead as a thickness guide.

3. Plastering the adjoining wall in the same way: leave the nose just visible. Score the surface of both walls.

4. Applying the finishing coat, this time covering the nose: round off the corner by running a wet finger along the bead.

5. Securing angle-bead to the internal corner with galvanized nails; nail through the drywall into the stud.

6. Applying a coat of finishing plaster, working away from the corner; the nose should be left visible in this case.

The idea of an architrave is to hide the join between a door or window frame or lining and the surrounding plaster

A loose architrave can be nailed back in place to the door frame, or even screwed to the surrounding masonry if you drill right through it with a masonry bit and insert wall- plugs to take the screws. But removal and fixing are both easier than for skirting, so replacement is usually the sensible alternative to major repairs. You just lever the existing architrave off, and nail the new one on.

On a brick or block wall, you usually nail through the molding’s inner edge and into the doorframe, lining or ‘wrought grounds’ with 25 mm (1 in) oval nails; lost-head nails or panel pins can also be used. But if necessary you can nail through the middle of the molding and into the wall itself, using cut nails for medium-hard blocks if you like, and masonry nails for bricks and hard blocks. If you find that there are rough (concealed) grounds between the plaster and the frame or lining, then nail into those. On a stud wall, nail into the studs.

At the bottom, the upright pieces butt against the floor and the ends of the skirting. At the_ top the corners are mitred. A good idea is to start by cutting off three pieces of molding which are manageable but still slightly too long. Then you can mark off the heights of the two upright ones (which may of course differ a bit, depending on whether the floor is flat or level), mitre their top ends and fix them loosely to the wall.

This makes it easy to mark off the exact length of the top piece. Mitre its ends, position it, and make any adjustments – by moving the uprights slightly, and even shaving the mitred ends with a sharp chisel or block plane if necessary. Then nail all three pieces finally in place, and pin the mitres from the top as for skirting boards.

When mitring, always make quite sure you’re cutting the right way round. That sounds silly, but you’ll find it’s all too easy to waste whole pieces by mistake

Failing that, a hacksaw should do the job.

In certain places — eg, the backs of alcoves — the skirting board is held in position by the two pieces at right angles to it. So, unless you remove at least one of those first, sawing the board out is your only option. A flooring saw may work. Otherwise drill a series of holes in line dOwn the face of the skirting, and use a chisel to chop out the waste between the holes so you can prise out the two ends of the board. Pipework and other obstacles sometimes force the same solution.

If a length of skirting refuses to come away completely, you may still be able to make sawing easier by levering enough of it out to push timber wedges behind it. In all cases, it’s best to saw at an angle of 45° across the thickness. If you’re just removing a section, cut the new piece to the same angle when you come to fix that in place.

Always use 45° cuts, rather than butt joins, if you have to make up a long piece from two shorter ones. They’ll be less conspicuous, especially if you site the join near an out-of- the-way corner.