The traditional way of finishing off masonry walls, and one still favoured by many, wet plastering involves using either a cement-based render or a gypsum backing which is trowelled directly onto your bricks or blocks.Initially, a scratch coat is applied, also known as a ‘key’ coat. This is the base coat which is lightly scratched while the plaster is still wet to form a good key for the next layer of plaster – the ‘skim’ coat – to bond to.
In addition to cement-based and gypsum plasters, lime and clay plasters are favoured by many traditionalists and those wanting a wall that can breathe. Lime and clay plasters are more expensive than ‘conventional’ wall finishes and it is a good idea to only use a plasterer with experience of such materials.
Something to note though: if you are planning on using the method of wet plaster on an outside wall, do bear in mind that you cannot add insulation as you can with plasterboard — unless you are happy to use external insulation on your property. So, if you have solid brick walls – as opposed to cavity walls – you should consider the impact that a lack of insulation will have.
- Gives an even, hardwearing finish
- Suits traditional properties perfectly
- Easy to apply around tricky areas such as windows and doors
- Offers superb airtightness and soundproofing
- Cannot add insulation internally behind this type of plaster
- Takes longer to dry out than other methods
- Hairline cracking can occur
- High skill level is required — a skilled plaster can be hard to come across and will often charge more for this type of work.
Costs: Approximately £15/m²
Those after a traditional look and breathability in their wet plaster should investigate the new wave of chalk and lime putty-based plasters. They come ready-mixed and contain hairs or fibres which are very flexible compared to sand-based plasters, meaning they can cope better with background movement — particularly common in timber frame buildings.
Those wanting a level of insulation should take a look at Thermalime from Angliamix. It contains lime putty, chalk and fibres and has the addition of an insulating component.
British Gypsum’s Thistle Magnetic Plaster
For those who pride themselves on their creativity, British Gypsum has developed Thistle Magnetic Plaster. Installed in the same way as traditional plaster, Thistle Magnetic Plaster turns any wall into a magnetic surface (a minimum of 3mm is required to enable magnetic attraction).
Not only does this allow you to easily attach pictures, mirrors or photographs to the wall, but the plaster can also be painted over with blackboard paint to create an interactive board. This is perfect to be used in your children’s playroom to inspire their creativity, or in home offices to inspire your own!
This homeowner updated a hallway and incorporated a magnetic wall which enables her to move artwork around and create a multitude of looks
Thistle Magnetic Plaster is available to buy from DIY stores such as Wickes and B&Q, or available to order directly from builders merchants such as Jewson. Prices start from around £80, see stockists for details.
Plasterboard with Skim Coat
There are two standard board thicknesses of plasterboard — 9.5mm for 400mm spacings and 12.5mm for 600mm. There are also several different ways in which plasterboard can be fixed to a wall: ‘dot and dab’ or ‘board on dabs’, and plasterboard that is screwed to timber battens fixed to the wall.
With dot and dab, sheets of plasterboard are stuck to either brickwork or blockwork walls using dabs of adhesive and leaving just a small cavity between the plasterboard and the wall. With the batten method – ideal for those wishing to add insulation to a solid wall – timber battens, usually measuring 38mm wide and with a depth to accommodate the thickness of insulation you are using between them, are screwed to the wall.
Rigid board PIR (polyisocyanurate) insulation is then inserted between the battens before the plasterboard is fixed over the top. A vapour control layer is also necessary in the case of solid walls.
Finally, the joints between the boards are covered with scrim tape – usually in the form of a self-adhesive tape – before a skim layer of plaster is trowelled on to the plasterboard.
- Hairline cracks – which are often associated with wet plaster – are unlikely
- Faster drying out time
- Possible to carry out on a DIY basis
- Insulation can be fitted behind plasterboard
- The cavity created can eat into room space
- Can be hard to fix shelving, radiators and pictures
- Offers little in the way of airtightness
- Scrim does not always mask the gap between the sheets of plasterboard and these can be evident through the skim coat.
Costs: Approximately £14-16/m²
Rather than adding insulation and then plasterboard, new insulated boards make this a far quicker and easier task. Celotex’s PL4000 is made up of PIR insulation bonded to tapered-edge plasterboard and comes in a range of insulation thicknesses. This is a great option for those wishing to add insulation to solid walls and can be used either with dot and dab installation or whereby boards are screwed to the wall.
There are also products on the market which aim to overcome the problems associated with fixing items such as radiators to the wall. Fermacell, for example, is made from cellulose, which is tougher and stronger than most plasterboard — but it is twice the price too. Another option is British Gypsum’s Gyproc Habito, which has a high-strength reinforced core.
There are also boards that are specifically for wet areas, such as Aquapanel, and which are designed to take the weight of heavy stone tiles.
Hang Art With Ease with British Gypsum’s Gyproc Habito Plasterboard
Gyproc Habito is a plasterboard with a reinforced core that can support up to 15kg with a single no.10 woodscrew. Gyproc Habito is a stronger, more durable plasterboard option ideal for self-builders and renovators wanting to upgrade the specification of their home.
Gyproc Habito is available to buy through builders merchants such as Jewson.
Rather than having a skim finish applied to plasterboard, it is quite possible to have the plasterboard itself as your final finish — in 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 usually chosen. Joints are taped and then filled over, as are any screw or nail holes. The whole surface is then sanded before it is painted. It is quick, relatively cheap and crack-free.
- Quicker and less messy than the other methods
- Works out a little cheaper as no plasterer is required
- Can be carried out on a DIY basis
- The final finish is rougher and a little dull, even when painted
- Walls feel hollow when tapped and lack the solid-feel of plastered walls (particularly when used on stud walls)
- Plasterboard is easily damaged and hard to repair
- Very poor soundproofing.
Costs: Approximately £12-16/m²
Drylining Innovations: Soundproofing
If soundproofing your property is an issue for you, take a look at British Gypsum’s Sound Solutions product range. The range uses acoustic plasterboard to achieve high levels of soundproofing that is suitable for both new builds and retrofitting. In order to choose the right solution to your problem, it is important to first diagnose where the noise is coming from which may mean addressing sound problems not only in the walls, but also floors and ceilings.
If the floors of your home appear to be the biggest problem, take a look at British Gypsum’s Silent Floor system. If you are building from scratch, the Silent Floor system works by fixing RB1 Resilient Bars to the underside of the joist. Isover acoustic insulation is then placed between the joists and two staggered layers of Gyrpoc SoundBloc is fixed to the resilient bars.
If you are installing the system as part of a retro-fit, the first step is to remove the existing ceiling. The ceiling structure can then be refitted and decoupled from the floor joists using Resilient Bars. Silent Floor retrofit again comprises two layers of 15mm Gyrpoc SoundBloc, 100mm acoustic insulation and Gypframe RB1 Resilient Bars.
British Gypsum’s Low Space Liner system is a great solution for a property or a room where space is at a premium, as it only loses 55mm from your room. British Gypsum offer an installation service with fully trained installers who are backed with a two year guarantee*. For any questions on sound insulation in your home, you can arrange for one their experts to visit you to help assess and solve the problem — just visit the roomsmadeforyou.co.uk for more information.
*T&C’s apply. See website for details.