In this article we are looking why plasterboard manufacturers recommend the use of paper rather than fibre tape for internal corners to walls and ceilings.

These articles reflect defects which are currently and commonly picked up by FCM’s Clerks of Works during their site inspections.

Our Clerks of Works are your "eyes and ears on site", helping to get it right first time.

Paper or fibre tape for jointing internal corners to plasterboard?

Fibre scrim at wall ceiling junction

Paper jointing tape should always be used for internal angles. That is wall to ceiling and wall to wall.

The photo above shows fibre tape which is not suitable for these locations.

Extract from the British Gypsum White Book shown below.

Fibre Scrim at ceiling wall junction

Fibre scrim incorrectly used instead of paper tape.

Operatives use fibre tape instead of paper because it is self-adhesive and so quicker and easier to fix.

This causes cracking at the internal joints.

The joints should be fully filled with joint filler before the paper tape is folded along the centre to give a sharp corner and applied to the compound.

When the paper is covered over with a second layer of jointing cement you are left with a solidly filled joint with a sharp edge, ready for decoration.
 

Voids behind jointing tape

The photo above demonstrates one of the main problems of using fibre scrim tape.

There are often voids between boards at corners.

These joints are rarely filled prior to the fitting of the fibre scrim, as the scrim is being used because it is self-adhesive, and quicker to apply in order to save time and effort.
 

The fibre scrim has no inherant strength so the boards will move due to expansion and the joint will crack

No sharp arris for decorations

The photo above clearly shows that fibre tape will not give a sharp internal corner for decorations.

The fibre scrim has no inherent strength so the boards will move due to expansion and the joint will crack.

Fibre tape will give uneven internal corners which are unsightly and will never give a quality finish.

Fibre tape is only suitable for repairing small patches.

Trying to get a sharp line between a white ceiling and a different coloured wall will be almost impossible.

The only way to ensure sharp corners is to use paper tape folded along its centre line and embedded in jointing paste.

If you want to hand over high quality projects to your clients:

• Make sure that your spec has the correct clauses specifying paper tape and do not allow contractors to get away with using fibre scrim.
• Ensure that all joints to plasterboard are finished with paper tape and not scrim tape.
• Ensure that the operatives are fully filling joints before applying the paper tape and following the manufacturers installation instructions.

Below are 2 videos on paper tape jointing.

The first is 7 minutes long and shows in detail how an internal corner should be formed.

The second is only 1 min 30 secs and shows jointing in flat surfaces. It is a good video to show the basics if you do not have the time for the longer one.

Steve Farrell
T: 07714234380
E: stevefarrell@fcmltd.co.uk
L: linkedin.com/in/stevefarrellfcm

Fox Curtis Murray are a building consultancy specialising in providing Clerks of Works services and Quality Control inspections.