GENERAL SPECIFICATION FOR SCREEDING / LEVELLING AN INTERIOR FLOOR USING TAL SCREEDMASTER SELF LEVELLING SCREEDING COMPOUND (5mm THICK) PRIOR TO INSTALLING RESILIENT FLOOR COVERINGS
Please note that ‘general’ specifications are issued for information purposes, and should not be used as project specifications.
As each and every project needs to be assessed individually on its own merits and characteristics please contact the TAL Technical Advice Centre for a project-specific detailed materials and methods specification for specific projects. TAL SCREEDMASTER does not contain casein or other protein bearing additives, making it ideal for hygiene applications such as hospitals, clinics and food preparation / storage areas.
TAL PRODUCT REQUIREMENTS
The TAL products required for this installation are as follows
TAL RAPIDFIX
TAL FLOOR PRIMER
TAL FLOORKEY
TAL SCREEDMASTER
TAL 10mm NOTCHED FLOOR RAKE / TAL ADJUSTABLE FLOOR SPREADER
TAL SPIKED SHOES
TAL 12mm SPIKED ROLLER
TAL PROFIX PLUS
Special note must be taken of the following :
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TAL SCREEDMASTER is only suitable for underlayment applications. If a durable floor covering is not going to be installed over the TAL SCREEDMASTER application, then a protective coating must be applied over the cured SCREEDMASTER.
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Although TAL SCREEDMASTER was developed as a self-levelling product, it must be noted that the success of the installation is dependent on the correct background preparation and correct mixing and application procedure. Very low or very high ambient conditions can also have an adverse effect on the installation.
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ALL SURFACE BEDS SHOULD HAVE A DAMP PROOF MEMBRANE, AND ALL SUBSTRATES MUST ATTAIN MOISTURE LEVELS OF 5% (75% RH) OR LESS BEFORE THE APPLICATION OF TAL SCREEDMASTER, A POLYMER-MODIFIED UNDERLAYMENT, CAN COMMENCE. Should there be no damp proof membrane below a surface bed, or should prevailing moisture levels not attain 5% or less then TAL X-CALIBUR X-SHIELD VAPORSTOP HB must be applied before the application of TAL SCREEDMASTER. TAL X-CALIBUR X-SHIELD VAPORSTOP HB is a moisture tolerant, 100% solids epoxy barrier coat that prevents the passage of water vapour and moisture through concrete slabs into the underlayment layer. Please contact TAL X-CALIBUR for a specification for the application of X-SHIELD VAPORSTOP HB if required.
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FOR OPTIMUM PRODUCT PERFORMANCE THE SLAB, WATER AND AMBIENT TEMPERATURES SHOULD BE AROUND 20°C. HOWEVER, IF THIS IS NOT POSSIBLE, THE INFORMATION BELOW SHOULD BE USED AS A GUIDE FOR PRODUCT INSTALLATION:
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Ambient temperatures between 10°C - 30°C must be maintained throughout installation and curing.
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Item 2c
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The Floor Slab must have a minimum temperature of 10°C during the SCREEDMASTER application.
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The temperature of the water must be between 15 - 25°C when mixed with SCREEDMASTER.
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Low floor slab and/or ambient temperatures and water temperatures will have a detrimental effect on the curing of the TAL SCREEDMASTER, ie full cure will never be achieved.
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High floor slab and/or ambient temperatures and water temperatures will result in flashsetting of the TAL SCREEDMASTER and the product will not be workable.
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1 BACKGROUND PREPARATION
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1.1. |
Allow all new concrete work and screeds to cure for at least 6 weeks and 4 weeks respectively before proceeding. All concrete work and screeds must have a moisture content of 5% or less before the levelling application can be commenced. |
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1.2. |
When screeding directly onto concrete, ensure that the surfaces are clean and free of all traces of curing agents, laitance and any other surface contaminants, by mechanically abrading the substrate. The floor surface must be thoroughly scabbled or scarified in cross-directions to a Concrete Surface Profile (CSP) value of 6 (Medium scarification), or to ensure that the aggregate in the concrete is fully exposed and open. |
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1.3. |
The substrate must be structurally sound, clean and dry and free from all traces of surface laitance and contamination such as dust, dirt, waxes, oils, bitumen, old adhesives, paint, grease, weak cement screeds, shutter release and curing agents, sealing compounds, etc. All damaged, defective, deteriorated, friable (powdery) and hollow sounding areas must be removed until a sold background is achieved. These areas can be made good before proceeding, using TAL RAPIDFIX or TALCEM. All holes or voids in the floor must be identified and filled with TAL RAPIDFIX, and all “highs” or trowel marks must be identified and ground down. |
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1.4. |
The surface must be clean and dry and free from all traces of dust, debris, loose particles and surface contaminants before proceeding. |
2 EXISTING JOINTS
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2.1. |
All construction/cold joints and structural joints in the background, as well as structural cracks which may be subjected to movement after the SCREEDMASTER installation, must be extended through to the surface of the screed application in the form of voided joints. With regards to these existing joints already in the concrete slab, the full width of the joint should be maintained and extended through the screed to the surface. |
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2.2. |
All joints in the substrate, including saw cuts, must be filled with TAL SEALMASTER CORD prior to the TAL SCREEDMASTER application to prevent these joints from being filled with screed. |
3 FLOOR LEVEL SURVEY/ FLOOR TOLERANCES
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3.1. |
The success of an installation is highly dependent on the background conditions and the quality of the background preparations before pouring the TAL SCREEDMASTER. |
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3.2. |
Since these installations are normally 3 – 5mm in thickness, it is important to ensure all highs and lows are identified and addressed before applying TAL SCREEDMASTER. |
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3.3. |
The use of a 3m straight edge is recommended. In identifying the highs and lows the straight edge should be placed down and rotated through 360° around the centre point. This ensures that valleys and ridges are identified together with occasional highs and lows. |
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3.4. |
Floor Preparation Example. |
(Fig. 1) (Fig. 2) (Fig. 3)
Floor Level datum point Rapid Fix (5mm)
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The illustration (Fig. 1) above shows a maximum and a minimum of 5mm in the levels. Thus between A and B a minimum of 10mm of product has to be poured to get the floor to the level of the highs at A and B. Fig. 2: must be applied where there are limitations in the final levels.
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3.5 |
Enough product should always be applied to cover the lows and highs in the existing screed as these manifest themselves as undulations once floor coverings, especially vinyl sheeting, are applied. |
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3.6. |
Experienced personnel normally use the TAL ADJUSTABLE FLOOR SPREADER which reduces the amount of work required in the preparation stage, since with the spreader thicknesses above 10mm can be achieved in one application. The bubble bursting stage is eliminated in this case. |
