Plastering: FAQ'S

Plaster is a decorative and protective building material often used for the coating of walls and ceilings. Select headers from our 'Frequently Asked Questions' to learn more about techniques, installation and problems you may encounter.

Cracking: Why is your plaster cracking and what can be done?

Preparation: What to consider when plastering your property

Plaster boarding: Do i need it and what are the benefits?

Surfaces: Precautions

Ingredients: Definitions

 

Cracking: Causes and Solutions

Cracking can occur when your house expands throughout the seasons. When the house expands and contracts it puts pressure on the brickwork (and subsequently plaster) eventually showing in the form of crack in the weakest part of the building, often around windows and doors. 

Cracking can also occur if your house or property is suffering from subsidence. When this happens you should contact a structural engineer or surveyor before any cosmetic works begin. 

 

At Rains plastering we take every measure to prevent cracking from reoccurring. 

  1. Remove any loose plaster inside and around the crack. 

  2. Tie the crack together with a staple gun or similar tool 

  3. Apply PVA to the entire wall and crack, Allow to dry. Filling the crack with PVA with strengthen the wall. 

  4. Apply scrim tape over the crack and PVA again if its a high suction wall. 

  5. Apply two coats of multi finish. 

The best way to prevent cracking on the interior of your house would be to use renderers mesh in the plaster. This is a 1m wide roll of mesh which is applied to the walls and ceilings when plastering. This gives the plaster a fighting chance when your property expands and contracts. At Rains plastering we always recommend you use renderers mesh when any internal plastering works is been carried out. 

Preparation: What to consider

In order for plastering works to be ready to be carried out, you may need to consider some of the following factors. 

Radiators: To ensure the walls are flush, radiators need to be removed and reinstalled by a professional plumber. It's important to ensure these are safely removed before works can begin.

Skirting Boards: if you are replacing skirting boards these must be removed before plastering commences. This allows the plasterer to achieve a flush finish making it easy and quick to install the new skirting boards 

Wallpaper: All wallpaper must be completely removed before any plastering works can commence. Plaster does not stick to wall paper. This can be done by yourself with a steamer and a sharp scrapper or you can hire a professional. 

Protection: Plastering is messy work! At Rains Plastering, we take every precaution to cover all flooring and furniture however we advise that all belongings and clutter are removed from said room to keep this to a minimum. 

Painting: Whether you are painting the plaster yourself, or hiring a professional, you will need to allow a few days for the plaster to dry. You will know this has been achieved when the plaster has turned a uniform pinkish colour. In order to speed up the process, open windows and doors where possible to increase airflow ventilation - have the heating on or try using a dehumidifier. 

 
 

Plaster boarding: Benefits

 
 

Plasterboard is a panel made of calcium sulphate dihydrate (gypsum)

 

Plaster board can be used on a range of back ground including stud walls and existing walls and ceilings. They can be applied with drywall screws and dot and dab adhesive. 

 

Unless your existing ceiling is sound it is advised to plasterboard the ceiling. By doing this you increase the strength of the ceiling and seriously reduce the risk of cracking. Its always advised to plaster board artex ceilings as artex is a difficult substrate to plaster over and can result in a compromised finish or the plaster falling down once plastered. Artex is also known to contain asbestos and so its highly advised that this is disturbed as little as possible. The risk of containing asbestos can usually be determined with the age of the property.

Types of boarding to be used:

 

  1. Standard plasterboard. Used for stud walls and ceilings. Grey in colour, comes in 9mm and 12.5mm thickness. 

  2. Moisture board/Aqua board. Used in bathrooms or any other place required to provide a water barrier. Green in colour, comes in 12.5 thickness. 

  3. Sound resistant board. Does what it says on the tin, this board is used to reduce and block sound. Often used on party ceilings, blocking out the sound of the noisy neighbour or music studios etc. Blue in colour, 12.5 thickness. 

  4. Fire board, This board is used to protect structural parts of your house ie steels and lintels in the event of a fire. Pink in colour, 12.5 thickness 

Surfaces: Precautions

Please bear in mind that different precautions may need to be taken dependent on the existing surface area:

Bare brick work/ block work: Hardwall and bonding will need to firstly be applied to bring the surface level to a smooth finish.

Artex - Its always advised to plaster board artex ceilings as artex is a difficult substrate to plaster over and can result in a compromised finish or the plaster falling down once plastered

Wood - Plaster cannot be applied directly to wood, EML may need to be applied as well as bonding to prepare the surface area. 

Shiny or painted surfaces: sand blast - PVA and sand mixed together then applied to the wall and allowed to dry for 24 hours. the sand in the PVA provides and good base for the plaster to stick to.

Ingredients: Definitions

Perhaps you have already received a quote and want to know what the components are/ what they mean. Please see below summary of commonly used components in plastering. 

PVA: Stands for polyvinyl acetate. Used to seal internal walls and ceilings and control suction. If PVA is not used the plaster will dry very quickly once applied and eventually fall away.

Multi Finish Plaster: A composition of gypsum, lime or cement with water and sand. The plaster is typically manufactured as a dry powder and then worked to form a stiff paste by mixing in water before application

ScrimScrim is a cotton like tape and is applied to the joints between plasterboards. its also applied over and existing cracks. 

Bonding is a backing coat used to repair cracks, chases and holes prior to plastering. 

Angle Beads: Angle beads are used on any edge to achieve a sharp and level finish. 

Hardwall: A backing coat used on brick and block work prior to plastering. 

Renderers MeshSimilar to scrim,  but comes in metre wide rolls. it can be used on internal and external works. it used on severely cracked walls to improve strength and seriously reduce the risk of cracking

EML: Expanding metal lathe is similar to chicken wire. it can be used internally and externally. its most commonly used for when you need to plaster or render over wooden back grounds. its also used for the undercarriage to staircases. 

SBR: Stands for styrene butyl rubber. similar to PVA but used for external works. 

Free flow waterproofer: free flow water proofer is used for the in external mortars. This provides your mortar with a water proof and frost proof barrier. It is also used to control suction. 

Water: sounds obvious like our bodies plaster and render is mainly made of water. the water must be clean and cold to be used.