The UK practice of mudding drywall, that is skimming the whole surface of plasterboard with about 3mm of plaster, is one that most other countries would consider a bit over the top however there is some method in this seeming madness other than keeping armies of plasterers gainfully employed and physio and shoulder surgeon’s at the top of their game.
Plasterboard or Plaster
Drywall board or plasterboard, otherwise known as Gyprock or Sheetrock, has made the installation of internal linings quicker and of a consistent quality as the dry lining is made flat and smooth.
Like any trade, you pay your money and take your choice when it comes to finding a plasterer but there are some best practice rules that can guide you. The USG (US Gypsum) the worldwide authority on such matters has distinct levels of finish which can be summarised as follows:
Taping Drywall – Always use a commercial paper tape which when bedded into base (hard) plaster provides an extremely strong bond as the joint takes on similar characteristics to the wallboard which after all is paper and plaster. Fibreglass or adhesive tapes are not recommended and should not be used – ever.
There are five different levels of finish ranging from 0 with no plaster (for places that will not be seen) Levels 1 & 2 for cupboards and or textured services and areas to be tiled.
Levels 3, 4 & 5 are of the most interest as they can be specified for quoting purposes and will dictate the quality of finish achieved.
Level 3 – Paper tape bedded and covered with 1-2mm base coat plaster with subsequent second coat of premix (soft plaster). This can be adequate if the job is done with care and second coat is applied to width of 300mm and sanded paying special attention to edges. Other considerations with this method are that this may not be suitable if there is a light-source (window) highlighting the plaster ceiling or plaster wall. Suitable only for FLAT finish paints.
Level 4 – This is the level of finish most widely specified in Australia and the USA. As per level 3 but with the addition of a third coat of finishing plaster (usually premix) brought out to approx 350 – 390mm (edge to edge) and sanded.
Level 5 – This level is for critical applications like high gloss and glazed surfaces and is as per level 4 but in addition a skim coat is applied across and between the previously plastered joints.
Important Pro Tips;
In critical applications always use rebated edges on plasterboard and avoid butt joins. Always try and install a plasterboard ceiling with the joints running toward any light source – not across it. Always used high quality paper tape. Pay special attention to any fat edges of plaster on each side of your join as these always show up most but can be sanded.
Conclusions – As you can see, Drywall plastering is a step by step process which can result in the best finish possible. I can assure you that skimming is not required to get a perfect finish for most normal situations and no – you will not be able to see the joins. If you live in the UK and feel more comfortable mudding drywall thats ok – just make sure your plasterer is a perfectionist. More information on how to plaster can be found here or at www.how2plaster.com
How To Paint Drywall
Warning: It is absolutely vital that you seal your finished plasterboard (plaster) with plasterboard sealer. Dust off sanded plaster with a broom (I know its messy – don’t forget your mask) then apply a coat of premium sealer. Sealer will also form a more solid substrate for wallpaper.
I have done work over the years in multi million dollar properties where the builder has accepted the lowest price for painting and the specification (if there was one) did not include a plasterboard sealer. This is an very expensive mistake as the paint will start to flake off over a period of several years creating an ongoing maintenance nightmare for the owner.
Try and roll out ceilings toward any light source – not across it.