356

Plas

ter s

kim

min

gPlaster skimming

May 2008

Plaster skimming to plasterboardsand Gyproc MultiBoard is a popularmethod of providing a smooth,seamless surface ready to receivedecorative treatment, combinedwith a quick turnaround on site.Surface preparation simply involvesjoint reinforcement using GyprocPaper Tape in accordance withrecommendations. The plaster istrowel-applied to the wall or ceilingto a nominal 2mm thickness.

www.gypsum.ie

10

plaster skimming_120408:Layout 1 26/05/2008 16:08 Page 356

357

Plas

ter s

kim

min

g

Key facts

May 2008

● Traditional plaster finish

● Provides uniform surface

● Resilient and scuff-resistant

● Applied to 2mm thickness

● Finished in one visit to site

2

1

Plasterboard

Plaster

1

2

Technical support: T 01 629 8400 E technical.enquiries@gypsum.ie

10

plaster skimming_120408:Layout 1 26/05/2008 16:08 Page 357

ComponentsPlaster products

Gyp

Wal

l™ CL

ASS

IC

358

Plas

ter s

kim

min

g

Gyproc Paper Joint Tape

For reinforcing plasterboard joints and

internal angles.

Roll length 150m

ThistleBond-it

For pre-treatment of MR grade board surfaces and 6mm

Gyproc Multiboard.

Tub contents 10 litre

Gyproc Thin-Coat Angle Bead

Length 2400, 3000mm

Gyproc Thin-Coat Mini Mesh Bead

Length 2400, 3000mm

Gyproc Thin-Coat Plaster Stop Bead

Length 2400, 3000mm

3mm thickness

Gyproc Skimcoat, Gyproc Carlite Finish

or Gyproc Board Finish

To provide a plaster skim finish.

May 2008

Plaster accessories

Plaster accessories

www.gypsum.ie

10

plaster skimming_120408:Layout 1 26/05/2008 16:08 Page 358

Gyp

Lyn

er™

UN

IVER

SAL

359

Plas

ter s

kim

min

g

Construction tips

● Ensure the background is prepared properly, e.g. board fixed the correct way round (skim onto the front face of Gyproc plasterboards and the smooth face of Gyproc MultiBoard), and reasonably clean and dry

● Select the right plaster system for the background, normally:- Gyproc Skimcoat or Carlite Finish where the job also involves finishing undercoats- ThistleBond-it for skimming of moisture resistant boards, 6mm Gyproc MultiBoard and some low suction

backgrounds- Gyproc Board Finish for Gyproc plasterboards and Gypoc MultiBoard

● Sequence the work - approximate setting time is between 2 hours and 3 hours, but finishing times can be extendedin low temperatures by 30 minutes or more

● Check manufacture dates and use oldest material first

● Ensure environmental factors are suitable:- Plaster should not be applied when the background temperature is less than 5oC- In very hot / dry conditions take precautions to avoid rapid loss of water- Finished plasterwork is suitable for locations where the temperature does not exceed 43°C- Avoid excessively polishing the surface- Apply plasters in accordance with:

IS EN CEN/TR 15124:2005: Design, Preparation and Application of Internal Plastering Systems

IS EN 13914-:2005: Design, Preparation and Application of External Rendering and Internal Plastering - Part 2: DesignConsiderations and Essential Principals of Internal Plastering

May 2008

Technical support: T 01 629 8400 E technical.enquiries@gypsum.ie

10

plaster skimming_120408:Layout 1 26/05/2008 16:09 Page 359

Gyp

Wal

l™ CL

ASS

IC

360

Plas

ter s

kim

min

g

May 2008

3

• Gyproc plasters are suitable for mixingby hand or mechanical whisk of a slowspeed, high torque type. A range ofsuitable mixers and paddles is available inthe Gyproc Tools range. While mechanicalmixing speeds the process up, there is noneed to continue mixing after dispersinglumps and achieving the right consistency– over-mixing wastes time and energy,can affect setting times, lead todeterioration in workability and createdifficulty in achieving a flat finish.

Application to board backgrounds

• Gyproc Drywall Metal Angle Bead orGyproc Drywall Plastic Angle Bead is fixedto the plasterboard angle by embeddingin the finish plaster. Before this plastersets, any surplus should be wiped fromthe corner, as scraping it away later maydamage the zinc coating. If the bead isfixed to the board 'dry' the adhesion maybe reduced because it is difficult tosqueeze plaster between the bead andthe plasterboard.

Installation

Mixing

•The plasters are pre-mixed. Add onlyclean water prepare them for use. Do notuse any additives.

• Gyproc plasters should be mixed byadding to clean water in clean mixingequipment. Contamination fromprevious mixes adversely affects thesetting time and strength. Freshcontamination has more effect than old,so equipment should be washed justafter mixing.

1 2

www.gypsum.ie

10

plaster skimming_120408:Layout 1 26/05/2008 16:09 Page 360

Gyp

Lyn

er™

UN

IVER

SAL

361

Plas

ter s

kim

min

g

• Apply finish coat plaster after the jointtreatment has set.

• Build out to 2mm thickness in twoapplications, wet-on-wet and trowel toa smooth matt finish. Use water spar-ingly and only in the latter stages oftrowelling.

May 2008

Decoration

• Ensure that the plasterwork isthoroughly dry before final decorating.

• Consult the paint manufacture foradvice on applying a suitable coat ofpermeable paint in the interim.

• Plaster surfaces can be decoratedwith most proprietary paint finishesand will accept the majority of wallcovering adhesives.

Always follow the manufacturers’recommendations in respect of applieddecorative treatments.

Technical support: T 01 629 8400 E technical.enquiries@gypsum.ie

10

4

plaster skimming_120408:Layout 1 26/05/2008 16:09 Page 361