Lath, solid plaster and gyprock: plastering Inner West terraces and semis

Tap it. Plasterboard sounds hollow and consistent, and the fixings usually show as faint rows once you look along the surface. Lath and plaster sounds duller and denser, and if you look closely at an old ceiling you can sometimes see very slight ripples running one way where the timber laths sit behind it.

The other giveaway is the edge. Where a light fitting or a vent has been cut in, plasterboard gives a clean paper-faced edge around ten to thirteen millimetres thick. Lath and plaster gives a thicker, crumbly edge with timber behind it.

Sometimes, and sometimes not. Attached houses move against each other, and a fine, stable crack along a party wall that opens and closes slightly with the seasons is ordinary and can be raked out, reinforced and re-set.

What is worth taking seriously is a crack that is stepping through the brickwork, widening over a single season, or appearing at the same time as doors starting to bind. That is a builder or an engineer question first. We would rather tell you that than fill it and watch it reopen.

It is worked out at the quote. We need somewhere to unload sheet and compound, and full sheets cannot go far by hand down a narrow terrace hallway, so the delivery point and the timing get planned before the first day.

In practice it often means an earlier start, a shorter unloading window, and sometimes cutting sheet down so it can be carried in. That affects the quote, which is why we would rather see the street than guess at it.

Often yes, and it is usually worth it. A rose and a run of moulded cornice are what make the room read as original, and losing them is the kind of thing you cannot undo.

Whether they can stay depends on how they are fixed and how sound they are. Sometimes the ceiling around them can be replaced while the detail is supported and kept in place. Sometimes a section has to be taken off, repaired and reinstated, which is the work described on the ornate and heritage restoration page.

Whether approvals are needed for internal work is a question for your council or your heritage adviser, not for us, and we would not tell you otherwise. Plenty of internal maintenance is ordinary repair work, but we are not the right people to advise on what needs consent.

What we can say is that where original fabric is involved, it is better to repair and match than to strip and replace. If you tell us the house is in a conservation area we will scope the job that way, with the original detail kept wherever it is sound.

Most of it, but the framing is the job rather than the plastering. Lining masonry means framing off it or fixing furring channel to it, and in a tall space that framing also has to carry whatever services and lighting are going in.

Two things usually come up in conversions. Bulkheads to hide ducts and services, which sit on the bulkheads and pelmets page, and sound between spaces, which is acoustic walls and ceilings. Both are decided before sheeting, not after.