Site search

you can join words with quotes eg. "solar collectors"



Plasterboard

Problems of disposal

Plasterboard has been something of a problem for eventual disposal because of the high levels of sulphate and the plasterboard industry has generally been slow to implement a recycling strategy.

Indeed the plasterboard manufacturers can hardly be said to be transparent about their policies and in the past and the almost national monopolies of these companies have come into question. In 2002 the four main plasterboard manufacturers (BPB, Knauf, Lafarge and Gyproc) were given enormous fines by the EU for price fixing through a cartel extending throughout most of Europe. This gives an indication of how some of the largest materials suppliers work together and may be too entrenched in their manner of operation to want to see change.

In England and Wales, since the 1st of April 2009, high sulphate wastes sent to landfill must go to a ‘high sulphate monocell’ specifically designed for sulphate wastes,

There are, however, government initiatives afoot in the form of the Plasterboard Sustainability Action Plan to encourage industry to recycle more of the million tons a year of plasterboard waste, or alternately some suppliers have put in place their own recycling schemes, eg Siniat whose web site says “Scheme available to merchants, distributors and contractors” so it’s not clear whether small amounts would be collected.

The Plasterboard Sustainability Partnership page on recycling says:

but this does not make clear whether small batches of plasterboard would be collected from a self build site.

The other alternative is the local authority recycling centre but it is very difficult to get clear information about whether they send it to a high sulphate monocell or whether they send it for recycling. Best to check with them.

Other environmental issues

There are several ways in which internal walls impact on environmental issues –

Other factors to consider are

  • fire resistance (if it is a separating wall) and spread of flame
  • sound resistance
  • running of services

Whether to use plasterboard

The main uses of plasterboard are:

  • Providing fire resistance to walls and ceilings. The Building Regulations, Approved Document part B (sections B2 and B3)  stipulates how much fire resistance different parts of a building require and what the Spread of Flame limitations are. It is very often possible to achieve the requirements by adding one or more layers of plasterboard.
  • Creating a flat smooth surface which can be plastered or decorated directly. Plasterboard is paper faced with one side being of relatively good quality so that it can take paint directly. This is the method of finish being adopted by many of the SIPS manufacturers and by Walter Seagal self builders. The more traditional method is to hand apply two coats of plaster (undercoat of browning, top coat of finish) and then decorate. If the former method is used then joints are normally feather edged and taped and filled (or simply covered with a timber cover strip); if the traditional method is used then they are simply taped.
  • Adding acoustic insulation
  • Adding thermal mass.  This is a slightly controversial subject because it has been and still is somewhat difficult to quantify although upcoming software is getting better at it. Thermal mass is normally a very useful component in stabilizing temperatures in a building because excess heat goes into the walls and ceilings and is stored there until the temperature drops. What is difficult to calculate is how deep it goes into the surfaces before it starts coming out again. See Thermal Mass. Arguably the diurnal temperature cycle is the most important one in this context and although the layer of thermal mass provided by plasterboard (and plaster) is relatively thin, it is situated in the optimum location to have the maximum effect (on the surface). For instance the total mass of plasterboard used in a two storey four bedroom timber frame house (as required for fire protection) may well be around 3 – 5 tonnes, which gives considerable thermal mass

One of the deciding factors with internal wall construction is whether, and to what extent the wall needs to be load bearing. The qualities of high thermal mass and acoustic insulation tend to work together with heavyweight materials. Of the traditional methods for internal wall building, both concrete block and brick rate quite poorly in terms of embodied energy, sustainability and adaptability though they both score well on fire, thermal mass and sound reduction.

Plasterboard walls are relatively easy to alter and remove, providing the floor level is consistent between rooms. Plasterboard is low in thermal mass (and not so good for sound insulation unless it is filled with acoustic mineral fibre). BASF has been developing gypsum based wall boards which incorporate microcapsules of phase change (eutectic) wax substances (PCMs) which increase the effective thermal mass very considerably. See Knauf Comfortboard. Plasterboard can achieve high fire resistance if extra layers are added.

With stud walling there may sometimes be a risk of compromising air tightness, especially with timber frame construction (see Air Tightness). This can occur if the joints with the adjoining external walls, floor and ceiling are not properly sealed and the joint also hides a break in the external construction thus allowing cold air to move straight into a ‘cooling fin’ within the house.

Alternatives to plasterboard

There have been several fairly recent developments in dry lining boards for internal walls. Traditional plasterboard is being challenged by other variations of gypsum based boards and also by clay based lining boards. Lining boards usually have to have a degree of fire resistance both structurally and with regard to the spread of flame (Building Regulations: Linings and Structure) and this limits the materials that can be used.

An added factor driving the change is that plasterboard has so little strength before it is fixed and damaged boards tend to litter many a building site so some of the newer boards tend to be less brittle and also tend to have a better finish. Most of the newer boards come from northern Europe and are still being imported which adds to the embodied energy and cost. Another factor is thermal mass; the newer boards help maintain thermal stability.

Suppliers

There are more eco-friendly alternatives to plasterboard such as:

 Fermacell is a gypsum/cellulose lining board made in Germany to a high ecological standard using recycled materials.

 

Heraklith wood wool

  Heraklith BM is a wood wool based building board which can be used as an all-in-one solution.

 

  Breathaboard by Adaptavate.  “All components are natural and sustainable. Breathaboard is completely biodegradable and non-toxic and the waste or off-cuts can even be used as a fertiliser!”


Building regulations

Structure

The Building Regulations part A covers the structure of a building. This Approved Document goes into a lot of detail for traditional masonry buildings but almost none for timber frame, steel frame, earth building SIPs etc. For these you will need to consult a structural engineer (while SIPs structures are usually handled by the manufacturer)

Fire safety

With most forms of construction there will be implications concerning fire safety. These are covered in the Building Regulations and you can see examples of how to conform with these in Part B (Fire Safety)

Resistance to the passage of sound

The degree of sound insulation required within and between houses and flats is covered in Part E of the Approved Documents.

Leave a Reply

You can use these HTML tags

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>

  

  

What is 11 + 9 ?
Please leave these two fields as-is:
IMPORTANT! To be able to proceed, you need to solve the simple calculation above. (so we know that you are a human) :-)