To answer this question, it is best to look at what plasterboard is made of first of all. Plasterboard is a type of sheet material made from calcium sulfate dihydrate, (aerated gypsum core), often made stucco or plaster of paris which are between facer and backer paper liners. The water resistance comes from the water repellent additives encased in the core and paper liners.
As plasterboard achieves a similar result to wet plaster, it is often referred to as drywall, making moisture boards part of a or moisture resistant drywall system. These drywall green boards should be used in conjunction with other drywall components to create partition and ceiling systems that resist moisture.
This is a type of plasterboard which is designed to be able to tolerate moist and humid conditions such as those found in a bathroom or kitchen. Moisture resistant plasterboard is not waterproof as such but is resistant to atmospheric dampness like you would find in a bathroom. The treatment used to give the plasterboard these properties is green and therefore people will often refer to green plasterboard when they mean MR plasterboard.
We would again emphasise that we don’t have waterproof plasterboard for sale but moisture resistant plasterboard. It is important to make this distinction to ensure that customers know what they are getting. Plasterboard is 100% recyclable and is considered to be an environmentally friendly material as no waste should be required to go to landfill.
There are many applications for moisture board plasterboard and it is often used as an inexpensive structural solution to build internal walls or separators within the bounds of a property. It is popular in the building trade as it can be installed with acoustic insulation in ceiling and partitioning systems.
Many people use moisture resistant plasterboard for bathroom and kitchen projects due to the performance of the material in conditions that are humid but where no water is being directly applied to the surface. Plasterboard can be used in lieu of traditional plastering. If it is not possible to get someone in to plaster an existing wall, it is possible to place plasterboard over existing walls or drylining internal surfaces to get the same effect as just having plastered it. Sometimes things are exactly as simple as they sound and that is the case with plasterboard.
We are often asked when to use moisture resistant plasterboard and the answer is pretty simple. MR plasterboard should be used in situations where there is increased humidity or a reason to expect there to be more moisture around than normal. This would apply to both high moisture areas like bathrooms and kitchens, we would recommend this for use in both of these locations within a domestic property or indeed an office or commercial environment. They have thermal conductivity ratings and surface preparation is important before applying.
At Materials Market we sell Gyproc moisture resistant boards (12.5mm and 15mm), Knauf moisture resistant tapered edge (12.5mm and 15mm), and Siniat moisture resistant tapered edge (12.5mm and 15mm). We don't sell square edge moisture resistant boards.
It is always best to look at the root cause of the problem with the damp before doing anything else to it. Affixing any kind of board to a high moisture damp wall may just be storing up problems for the future. If you do decide to take this step however, the best way is to put batons between the wall and the boards, that way the moisture is not transferred directly into the boards. It is still possible for damp walls to transfer moisture to moisture plasterboard over a longer period of exposure otherwise.
Skimming refers to the process of plastering smoothly over a surface, for example to disguise the fact there are multiple panels of green drywall and present it as a uniform surface for further decoration if desired.
It is indeed possible to skim moisture resistant plasterboard and it is recommended that a bonding agent is used before starting the skimming process, though some people in the building industry believe that it is possible and easier just to skim directly on to the moisture resistant plasterboard, so it is a matter of personal choice how you accomplish the task.
It is possible to apply paint directly to the surface of MR plasterboard and the water repellent liners but it must first be prepared with a plaster bonding agent in order for the paint to adhere to the surface. This is in accordance with the British Gypsum guidelines.
Yes, if you are using it for the purposes for which it is intended. It really comes into its own when used for semi exposed areas like kitchen and bathroom projects where ordinary plasterboard would not be able to cope with the damp conditions and this alone makes it worth the extra cost vs standard plasterboard sheets.
Moisture resistant plasterboard is not fireproof but there are different types of treatment that can be done to plasterboard to give it more of a fire resistance and you can find our own selection of fire resistant plasterboard here. While these are not fireproof per se, they add significantly to the amount of time that it will take for a fire to spread and therefore increase the safety of any home or building they are installed in.