How many coats of jointing compound do I need?

The standard approach is three coats: a bedding coat (50mm wide) to embed the tape, a filling coat (150mm wide) to build up the joint, and a finishing coat (250mm wide) feathered to a smooth edge. Two coats can suffice for non-critical areas where skim plaster will be applied over the top.

How long should I leave between coats?

Setting compounds (e.g. Gyproc Easifill or Knauf Fill & Finish) set chemically and can be recoated after 60-90 minutes regardless of humidity. Ready-mixed compounds (e.g. Gyproc Ready Mixed or Knauf Ready Mixed) need 24 hours drying time between coats. Always check the manufacturer's data sheet.

Should I use paper tape or mesh tape?

Paper tape (e.g. Gyproc Joint Tape) is stronger, better for internal corners and gives a flatter finish — it is the industry standard for most flat and corner joints. Self-adhesive mesh tape is quicker to apply and works well with setting compounds on flat joints, but it is weaker and not recommended for internal corners or where movement is expected.

What coverage rates should I expect?

Setting compound (powder) covers roughly 0.65-0.70 kg per linear metre of joint over three coats. Ready-mixed compound uses around 0.80 kg/m due to higher moisture content. Finishing compound is lighter at around 0.60 kg/m. Actual usage varies with joint quality, board gap width and operator experience.

Which jointing compound brands are best for UK plasterboard?

The main UK brands are Gyproc (by Saint-Gobain), Knauf and Siniat. Gyproc Easifill 60 is popular for bedding and filling coats, while Gyproc ProMix or Knauf Ready Mixed are convenient for finishing. For high-performance joints to BS 8212, use the board manufacturer's recommended system (e.g. Gyproc tape with Gyproc compound on Gyproc boards).

Jointing Compound Calculator — Plasterboard Tape & Filler

Calculate how much jointing compound and tape you need for plasterboard flat joints and corners. Covers bedding, filling and finishing coats.

Wall / Ceiling Area

Total plasterboard area to be jointed

Board Size

Determines joint spacing

Compound Type

Setting compound is most efficient

Number of Coats

3 coats is standard for a smooth finish

How We Calculate This

This calculator estimates the jointing compound (filler) and tape required for plasterboard (drywall) installation. It uses your total area to work out the number of boards, then calculates joint lengths for both flat (board-to-board) and internal corner joints.

The 3-coat system

Bedding coat (50mm wide): A thin layer of compound is applied along the joint and paper tape is pressed into it. Uses ~0.15 kg/m.
Filling coat (150mm wide): Once the bedding coat has set, a wider coat is applied over the tape to build up the joint level with the board face. Uses ~0.35 kg/m.
Finishing coat (250mm wide): A final thin coat is feathered out to blend the joint seamlessly into the surrounding board. Uses ~0.25 kg/m.

Corner joints

Internal corners (where walls meet walls or walls meet ceilings) require paper tape folded along its centre crease. The calculator adds vertical corner joints (perimeter × ceiling height) plus horizontal ceiling-wall junctions (perimeter length) when enabled.

Compound types

Setting compound (powder): Mixed on site, sets chemically. More efficient coverage and faster recoat times. Brands: Gyproc Easifill, Knauf Fill & Finish.
Ready-mixed (tub): Pre-mixed, convenient but higher moisture means ~10% more product needed and longer drying. Brands: Gyproc ProMix, Knauf Ready Mixed.
Finishing compound: Lighter formula for the final coat only. Lower coverage rate but smoother finish. Often used over a setting compound base.