This forms the base coat that is lightly scratched while the plaster remains wet to form a good key for the subsequent layer of plaster - the 'skim' coat - to bond to.
In addition to cement-based and gypsum plasters, lime and clay plasters are preferred by lots of traditionalists and people desiring a wall that can breathe. Lime and clay [http://limeplasteringdevon.co.uk/ plasterers in devon] are higher priced than 'conventional' wall surface finishes and it's also a good idea to use only a plasterer with expertise of such materials.
Something to note though: if you are planning on applying the method of wet plaster upon an exterior wall, do take into account that you can't add insulation as you're able to with plasterboard - unless you are happy to utilize external insulation on your home. So, if you currently have solid brick walls - in contrast to cavity walls - you should be thinking about the effect that a lack of insulation may have.
Pros
Provides an even, hardwearing finish
Suits traditional properties perfectly
Straightforward to apply around challenging areas for example windows and doors
Offers exceptional airtightness and soundproofing
Cons
Can not add insulation inside behind this kind of plaster
Takes longer to dry out compared to other methods
Hairline cracking may appear
High skill level is essential - a skilled plaster is usually difficult to encounter and will regularly demand more for this particular sort of work.
Plasterboard with Skim Coat
There are a couple of regular board thicknesses of plasterboard - 9.5mm for 400mm spacings and 12.5mm for 600mm. Additionally, there are several different ways wherein plasterboard could be fixed to a wall: 'dot and dab' or 'board on dabs', and plasterboard which is screwed to timber battens fixed to the wall.
By using dot and dab, sheets of plasterboard are adhered to either brickwork or blockwork walls applying dabs of adhesive and leaving simply a modest cavity between plasterboard and the wall. With the batten method - perfect for individuals looking to add insulation to a solid wall - timber battens, typically measuring 38mm wide together with a depth to accommodate the thickness of insulation you are employing between them, are screwed to the wall.
Rigid board PIR (polyisocyanurate) insulation is subsequently inserted between the battens prior to the plasterboard is set over the top. A vapour control layer is also needed in the case of solid walls.
Finally, the joints between the boards are covered with scrim tape - usually in the style of a self-adhesive tape - right before a skim layer of plaster is trowelled on to the plasterboard.
Pros
Hairline cracks - which can be associated with wet plaster - are unlikely
Faster drying out time
Achievable to carry out on a DIY basis
Insulation may be fitted behind plasterboard
Cons
The cavity made can eat into room space
Can be difficult to fix shelving, radiators and pictures
Provides little in the way of airtightness
Scrim won't always mask the space between the sheets of plasterboard and they can be evident through the skim coat.
Drylining
As opposed to using a skim finish applied to plasterboard, it can be quite possible to use the plasterboard itself as the final finish - in actual fact, this is very common in the US and in more and more developer houses in the UK too.
In the case of taping and jointing, tapered-edge board is typically preferred. Joints are taped and subsequently filled over, as are any screw or nail holes. The whole surface is then sanded before painting. It is swift, somewhat cheap and crack-free.
Pros
Quicker and less sloppy as opposed to other methods
Ends up a little cheaper as no plasterer is required
Can be accomplished on a DIY basis
Cons
The final finish is rougher and a little dull, even if painted
Walls feel hollow if tapped and lack the solid-feel of plastered walls (in particular when employed on stud walls)
Plasterboard is easily damaged and difficult to restore
Inadequate soundproofing.
