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Calcium sulfate screeds


The purpose of this standard is to provide the delegates with knowledge and skills relating to calcium sulfate screeds.


2 days of 6 learning hours per day.


The purpose of this standard is to provide the delegates with knowledge and skills relating to calcium sulfate screeds.


  • introduction to calcium sulfate screeds 
  • interpretation of contract information 
  • personal protective equipment (PPE) 
  • screed selection 
  • equipment & delivery methods 
  • laying methods 
  • coverage rates 
  • test methods 
  • screed repairs 
  • waste disposal & cleaning of equipment.

Occupational relevance

Training delivered against this standard would be relevant to the following occupational group(s): 

  • operative and craft.

Delegates pre-requisites

There are no delegate pre-requisites as part of this standard.


As a minimum, course trainers must be able to demonstrate that, in relation to this standard, they have: 

  • an award in education and training (or equivalent, as per requirements for approved training organisations)   
  • successfully completed training to this standard 
  • at least 2 years relevant industrial experience 
  • a verifiable CV.


Delivery may be in an on or off the job environment. 

All materials and equipment must be of a suitable quality and quantity for delegates to achieve learning outcomes and must comply with relevant legislation. 

The class size and delegate/trainer ratio must allow training to be delivered in a safe manner and enable delegates to achieve the learning outcomes.  

The following delivery methods may be used in the delivery of this standard: 

  • classroom / practical learning 
  • e-learning 
  • a blend of classroom and e-learning. 

This standard is considered to contain 51% or more practical training. 

This standard is considered to be set at an intermediate level. 


For the successful completion of training, delegates must complete an end of course practical assessment or knowledge test that measures all learning outcomes and has a pass or fail criteria. 

Where this training is assessed using multiple-choice questions, a minimum of 10 questions must be asked and delegates are required to achieve an overall pass mark of at least 80%.

Quality assurance


Quality assurance against this standard will require initial approval of the training organisation and their content mapped to the standard.  

CITB will also conduct an approval intervention, either desk-based or centre visit, to ensure the training organisation can meet the requirements of the training standard.  

Approved training organisations (ATOs) will be required to present information on records of training and assessment upon request to CITB for desk-based analysis. They will also be visited annually by the CITB quality assurance team.


Refresher every 3 years

Buffer/grace period 

3 months


Recommended Refresher

Approval date

May 2021

Review cycle

On request or 3 years from approval date.

Learning outcomes

Learning outcomes

The delegate will be able to: 

Additional guidance to support learning outcome

interpret and understand guidance and information relating to the work specification 

Contract information: 

  • job sheet, method statement and risk assessment 

  • site induction 

  • company policies 

Product/system information: 

  • product datasheets (store materials on site in a secure location to meet manufacturer’s specified storage conditions) 

  • safety (COSHH) datasheets 

  • delivery notes (check material type, quantity and batch numbers) 


  • roles and responsibilities 

legal obligation to protect yourself, the area and members of the public. 

select and use appropriate PPE for the work 

  • Function of PPE 

  • Correct fit 

  • Storage, maintenance and cleaning 

  • Replacement 

  • Equipment manufacturers’ operator’s manual 

  • Risk assessment 

Including: eye protection, head protection, safety footwear, gloves, ear defenders, respiratory protective equipment, high visibility clothing 

explain the legal obligations to protect themselves, the area and members of the public 

  • Establish a safe area of work 

  • Use of barriers and signage 

  • Provision of suitable ventilation if required 

  • Risk assessment  

  • Hazards including use of hazardous materials and equipment 

explain the composition of calcium sulfate screeds 

  • What is anhydrite and where does it come from 

Components of a calcium sulfate screed (anhydrite, aggregates, water & admixtures) 

describe the benefits and factors affecting the choice of calcium sulfate screed 

Selection factors: 

  • project type 

  • thickness required 

  • surface finish required 

  • underfloor heating 


  • sustainable 

  • minimal cracking & curling – self-curing 

  • reduced need for construction joints 

  • rapid strength development 

  • design flexibility 

  • fast application 

  • cost competitive  

  • protein free - will not harbour bacteria 

  • weight saving due to low design thickness 

outline screed delivery and installation methods 

  • Site mixed or ready mixed 

  • “site batching” systems 

  • Site delivery of ready mixed screeds 

  • Screed pumps 

recognise the importance of subfloor quality and be aware of common preparation methods including bonded, unbonded and floating construction 

Including but not limited to: 

  • Mechanical removal of laitance (if necessary) 

  • Scabbling of in situ concrete 

  • Shot blasting pre-cast units 

  • Coarse aggregate exposure 

  • Vacuum removal of dust and debris 

  • Substrate moisture content < 75% RH 

Primers and bonding slurries (including polymer and epoxy primers  


describe the importance of priming the substrate 

  • Risks and mitigations  

  • Types of primers and bonding agents e.g. epoxy, polyurethane, acrylic 

  • Preventing out-gassing/pin-holing from the substrate 

  • Mitigating the effects of moisture in the substrate  

  • BS8204:7:2003 

describe methods used to install calcium sulfate screeds 

  • Manual installation 

  • Pump installation 

  • Use of stands/tripods and laser levels 

  • Typical thicknesses 

explain curing and drying requirements for newly installed screeds 

  • Curing 

  • Assisted drying 

  • Underfloor heating systems 

  • Drying out periods 

identify common screed repair methods 

  • Crack repairs (static and live cracks) 

  • Screed strengthening 

  • De-bonding (stitch pinning/resin injection) 

describe factors to be considered when planning an installation 

Layout including: 

  • starting point and how to progress 

  • movement joints 

  • site conditions and building envelope 

  • daywork joints, terminations and continuing from previous day’s work 

  • number and position of mixing stations – pumps or missing units 

  • lighting 

  • disposal of waste 

  • protection 

mix calcium sulfate screed (bagged) using appropriate mixing equipment under supervision  

  • Following manufacturer’s recommendations 

  • Mixing methods and equipment 

  • Ambient temperature requirements 

  • Dust extraction requirements 

  • Hazards associate with mixing (dust, noise, splashing, fatigue) 

apply calcium sulfate screed using appropriate equipment (pump) and method of application to achieve required thickness, levels and surface finish under supervision 

  • Following manufacturer’s recommendations 

  • Check thickness achieved 

  • Delivery methods 

  • Hazards  

  • Importance of discharge maintenance on site 

describe inspection and testing methods during and after application 

  • Quality and preparation of base 

  • Priming of the base 

  • Ambient conditions during application and cure 

  • Mixing of materials 

  • Applied thickness 

  • Levels and surface regularity (SR1, SR2, SR3 etc.) 

  • Departure from datum 

  • Screed workability - flow testing 

  • Compressive strength 

  • Flexural strength 

  • In situ crushing resistance 

  • Moisture content 

  • Curing 

explain how to achieve joint and edge details 

  • Movement joints 

  • Restraint 

  • Mechanisms of cracking 

  • Daywork joints 

  • Acoustic joints 

  • Edge joints 

  • Crack control joints (door thresholds, constrictions, corridors, corners etc.) 

  • Thermal bridging 

protect floor area following installation 

  • Manufacturer’s recommendations 

  • Signage 

  • Barriers 

clean tools and equipment and understand the safe use of solvents and other cleaning materials in line with health & safety guidelines 

  • Manufacturer’s data sheets 

  • Waste material hazards 

  • Control of Substances Hazardous to Health (COSHH) 

  • Risk assessments 

dispose of waste in a responsible manner  

  • Hazardous and non-hazardous waste disposal 

  • Handling of waste material 

  • Handing of waste packaging 

Additional information about this standard 

Industry guidance: 

  • Proprietary Screed Manufacturers Guidance 
  • BS 8204:7:2003 – Code of practice for Pumpable Self Smoothing Screeds  
  • BS8204:1:2003 – Code of practice for Screeds, Bases and In-situ Floors 
  • BS EN 13454  - Binders, composite binders and factory made mixtures for floor screeds based on calcium sulfate 
  • BS EN 13813 - Screed material and floor screeds — Screed material — Properties and requirements 
  • FeRFA Guide to the Specification & Application of Screeds, The Resin Flooring Association

The Resin Flooring Association (FeRFA) website


Health and Safety Executive (HSE) guidance

Control of Substances Hazardous to Health (COSHH)

Chemical safety data sheets







Related standards

Flowable screeds 

Thermal and Acoustic Insulation and Underfloor Heating 

Prepare Background Surfaces to Receive Screed Flooring 

Screed Flooring and Equipment Introduction 

Traditional Screeds 

Work Practice and Project Planning for Screed Flooring