Plasterboard rules for partitions and ceilings: fire and sound

Why there are different types of plasterboard at all

Standard plasterboard is the grey-faced board used for most internal walls and ceilings in dry rooms. It is inexpensive, easy to cut with a utility knife, and fine for a bedroom, hallway or living room partition where nothing unusual is happening on either side.

Moisture-resistant board, usually green-faced, goes in bathrooms, kitchens and other rooms with regular damp or splashing. It resists swelling and mould better than standard board but is not waterproof on its own, and it is not the subject of this guide.

Fire-rated board, usually pink or red-faced, contains glass fibres that hold the board together longer when exposed to heat. It costs more per sheet than standard board, so it is worth using only where there is a real reason for it, not as a blanket choice for the whole flat.

When you actually need fire-rated board

The clearest case is a wall or ceiling section around an electrical switchboard, distribution panel, or the riser pipes for central heating that pass between flats. These are places where a fault or overheating is more likely, and standard board burns through faster than fire-rated board does.

In panel-built blocks from the Soviet era, the switchboard is often set into a corridor wall shared with a neighbouring flat, and any plasterboard built around or over it should be fire-rated for at least that section, not necessarily the whole wall.

If your partition has nothing to do with wiring, heating risers or a kitchen hob wall, standard board is normally enough. Fire-rated board around a switchboard is sensible; fire-rated board through an entire hallway because it sounds safer is usually money spent without a clear reason.

Sound insulation between flats

A single layer of standard plasterboard on a simple metal stud frame stops very little sound. If the wall you are building separates your flat from a neighbour's, rather than two rooms inside your own home, sound performance is worth planning for from the start, not fixing afterwards.

The usual improvements are a double layer of board on each side, mineral wool inside the stud cavity rather than an empty void, and staggered or double stud frames so the two faces of the wall are not rigidly connected. Sealing the perimeter with acoustic sealant where the wall meets floor, ceiling and adjoining walls matters more than people expect.

For a ceiling below a flat that will have footfall, similar logic applies: resilient bars between the joists and the board, and insulation in the void, cut down impact noise noticeably compared with board fixed straight to the joists.

Basic rules for stud spacing and screw layout

Metal stud partitions are normally set at 400 mm or 600 mm centres depending on the board thickness and the wall height, with a track fixed to floor and ceiling and vertical studs slotted in between. Wider spacing on a tall wall leads to boards flexing and joints cracking later.

Screws go in at roughly 200-250 mm spacing along each stud, driven just below the paper surface without tearing it, and joints between boards should always land on a stud or joist, never floating in mid-air between them.

Vertical joints on opposite faces of the same partition are usually offset from each other, and horizontal joints in a ceiling are staggered row to row. This spreads any movement across the whole surface instead of concentrating it along one line, which is where cracks tend to show up first.

• Stud centres: 400 mm or 600 mm, closer for taller walls or thicker board
• Screws every 200-250 mm along each stud, seated just below the surface
• Board joints always on a stud or joist, never unsupported
• Offset vertical joints between the two faces of a partition
• Stagger ceiling joints row to row rather than lining them up
• Fire-rated board only where wiring, panels or risers are involved
• Mineral wool in the cavity for any wall shared with a neighbour

What to check with the apartment association first

A partition wall inside your own flat is usually your decision alone, but changes that touch shared building elements are not. Anything that affects a load-bearing wall, a shared electrical riser, ventilation ducting, or the building's fire compartmentation is worth raising with the korteriühistu before you start.

Ask the board or property manager whether the change needs their written consent, whether it needs to be recorded in the building register, and whether there is a fire safety plan for the building that specifies particular requirements around switchboards or risers on your floor.

We do not touch load-bearing walls and we do not do gas work, so if a wall you are planning turns out to be load-bearing, that job needs a structural engineer or the relevant specialist, not a plasterboard fitter.

When it is worth having this done rather than doing it yourself

A single non-structural partition in a dry room, built with standard board on a simple stud frame, is a job many people manage themselves with basic tools and a weekend. The risk is low and the material forgives minor mistakes.

Anything involving fire-rated board around a switchboard, sound insulation between flats, or a ceiling that needs resilient bars is less forgiving. Getting stud spacing, joint layout or insulation wrong means redoing the whole section, and by then the board and materials already bought are wasted.

Our plasterboard work starts from 28 € per job for smaller partitions and repairs, and general odd jobs are charged from 39 € per hour with a 25 € call-out in Tallinn that comes off the bill if the work goes ahead. For anything larger, we give a fixed quote after seeing photos or a description, valid for 30 days.