Does new plasterboard have to be skimmed, or can I just tape it?

A boarded wall is not finished. The board joints, the screw heads and the corners all need covering, and Britain does that in two ways. Skimming is the traditional route and is what most people mean by "getting it plastered". Taping and jointing, imported from North American practice, is now completely mainstream and is the only one of the two that a beginner can realistically do well.

Step by step

1. Check which board you have or are buying.Tapered-edge board has a shallow recess along the long edges specifically so tape and compound sit below the surface — it is made for taping. Square-edge board has no recess and is intended to be skimmed. Using the wrong one produces either a ridge or a hollow along every joint.
2. Judge by who is doing the work.Taping is slow but forgiving: you can stop, look at it tomorrow, sand it, add another coat. Skimming is fast but unforgiving, and there is no correcting it after it sets. For a DIYer the choice is usually made here.
3. Judge by the light the wall will get.Skim gives a continuous, uniform surface. A taped wall has flat compound at the joints and bare board paper between, which are slightly different in texture and absorbency — under a wall light or in raking sun, a poorly executed tape job shows the joint lines. A full skim coat over a taped wall, or a good primer, evens it out.
4. Judge by the ceiling versus the wall.Sanding a whole ceiling of jointing compound overhead is genuinely unpleasant and produces enormous quantities of dust. Ceilings are where paying for a skim is most obviously worth it.
5. Judge by what goes on afterwards.Behind tiles, kitchen units, a wardrobe or a bath panel, a taped finish is entirely adequate and skimming is money wasted. Under a dark, sheened paint in a hallway, the surface quality matters much more.
6. Cost both properly.Taping costs a few bags of compound, tape and abrasive, plus your weekend. Skimming costs a plasterer's day rate plus materials, and it also demands that the boarding is set out and screwed properly, because a plasterer cannot correct a badly boarded wall in 3mm.
7. Board correctly for either.Both need the boards fixed to something at every edge, screws driven just below the paper without tearing it, joints staggered, and a small gap at the floor. Bad boarding shows through both finishes.

Common mistakes

• Taping square-edge board — With no recess, the tape and compound stand proud of the board face, so every joint becomes a low ridge that has to be feathered out over 300mm to disappear.
• Skimming tapered-edge board — It works, but the recesses have to be filled first, so it costs an extra operation. If you know it is being skimmed, buy square edge.
• Assuming a plasterer will fix bad boarding — Two to three millimetres of skim cannot correct board that is out of plane, unsupported at the edges or badly screwed. Expect to be charged to have it put right, or to be turned down.
• Painting jointing compound without priming — Compound is far more absorbent than the board paper around it. Emulsion straight onto it dries to a different sheen and every joint shows as a band.

Alternatives

• Tape and joint: Tapered-edge board, paper or mesh tape and jointing compound in three progressively wider coats, sanded flat and primed. No plastering skill, correctable at every stage, slow, and dusty at the sanding stage.
• Full skim: Scrim tape on the joints then two coats of finish plaster over the whole surface. Fast in skilled hands, gives a hard uniform face, and is the standard British expectation for a room you live in.
• Skim over a taped wall: Occasionally done where a taped wall has to be brought up to a decorative standard. Works, but it is paying for both methods.
• Board and paper: Tape the joints and hang heavy lining paper over the lot. A legitimate and cheap route in a room where a perfect surface is not the point.

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