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FAQs: Screed and Concrete Products

+ Why use aluminium dapple bars on screed and steel dapple bars on flowing concrete?

Aluminium Dapple Bars are used for flowing screed because they are light-weight and easy to handle. Our Dapple Bars also come in a range of widths designed to suit different jobs.

Steel Dapple Bars are typically used for flowing concrete because they need to be more robust. Our Steel Dapple Bars are also powder coated for easy cleaning after use.

Both our Aluminium and Steel Dapple Bars are powder coated for easy cleaning and maintenance.

+ Why use a screed tripod to set a datum level?

Given the nature of flooring materials and construction methods involved it is rare to achieve a 100% perfectly flat surface and small deviations – within set limits – are allowed. However going above the allowable deviations will result in a surface that delivers poor serviceability and introduces the following common issues:

  • Excessive sway or wear and tear on wheeled traffic
  • Pooling in wet areas
  • Degrading of the floor surface caused excessive impact on high spots
  • Trip hazards to pedestrians
  • Problems with installing sensitive or specialist equipment

For these reasons using screed tripods to set the datum level are essential in helping to achieve a surface that is as close to perfect as possible.

+ Why do I need to dapple the screed?

Dappling the screed should achieve two important results:

  • Removing any air trapped within the screed
  • Ensuring a smooth finish to the surface.

+ What are Concrete Dapple Bars?

Concrete Dapple Bars are just another name for Dapple Bars used for laying liquid concrete / flowing concrete floors. These dapple bars will be supplied in powder coated Mild Steel or Aluminium with various dapple bar sizes available (in length and diameter) depending on the type of finish required.

+ What are the Best ‘Liquid Screed’ Floor Laying Tools?

If you are looking for the best floor laying tools when working with Flowing Concrete or Liquid Screed then you’re on the right site. Metex have an extensive range of floor laying tools including;

  • 1 and 2 metre Steel Dapple Bars for flowing concrete – Height adjustable with a comfortable handle and powder coated for longer life and easy cleaning.
  • 900mm and 2 metre Dappling Bars – lightweight powder coated Aluminium for flowing screed.
  • 2 and 3 Bar Aluminium Dapple Bar Sets for flowing screed.
    Dapple Bars with 38mm and ultra thin 15mm bottom bars for highest quality finishes.
  • Liquid Screed Levelling Tripods – Stainless Steel with extra thin 3mm disc.

So if you are laying a Flowing Concrete or Liquid Screed floor equip yourself with the best tools for the job – visit our online shop or call us for more information.

+ What should I look for in Floor Screeding Tools?

If you are planning to lay a liquid concrete or a flowing screed floor you will need the best tools for the job. You will certainly need a Dappling Bar (or Dapple Bars Set). You will also need Levelling Tripods. Here are some things to look out for before you buy anything.

Get the right size – you will need these to get the correct finish for your floor. You need to select the right size dapple bar for the job too short and you’ll be there twice as long – too long and it will be awkward to use and won’t fit into tight areas and through doorways.

Bottom Bar width choices are 38mm or super thin 15mm dependent on the screed thickness you are laying.

Made of the right stuff – for dealing with flowing concrete a steel dapple bar is heavier and more suited to a dense product and is generally more robust. Ideally it will be powder coated for longer life and easier cleaning.

For Liquid Screed go for the lighter weight aluminium dappling bars as calcium sulphate screeds are less dense and easier to dapple – but again look for powder coated finish for easier cleaning and a longer life.

Comfortable to Use – watch your back! You need to make sure that the dapple bars you use are the right height for you – otherwise you could get back ache very quickly. Make sure the dapple bars are either height adjustable or have been manufactured to the correct fixed height and are comfortable to use.

Tripods: Get it Right, Get it Level – Your floor will need to be accurately levelled and for that you will need to use Levelling Tripods. Ideally you should look for a stainless steel finish for long life and easy cleaning.

Thicker legs are good – a greater leg thickness will give your tripod better stability.

So now you know what to look for visit our online shop and make the right choices – great tools – great job! That’s Metex for you.

+ What is Liquid Floor Screed?

Liquid screed is the modern alternative to conventional Sand and Cement screed. It is now widely used in the construction of domestic and commercial buildings and was developed to deliver a level and smooth surface onto which the chosen floor finish can be laid – tiles, wood, laminate etc. Liquid screed lends itself especially well for use with under floor heating.

Liquid screed goes under a number of other names such as; flowing screed, calcium sulphate screed, or anhydrate screed. It has a multitude of beneficial features. Please be aware that this is not the technical notes for cementious flowing screeds. A few of these are listed here:

  • Can be walked on in 24-48 hours.
  • Extremely low shrinkage and Minimal Thermal expansion (0.012mm/mK) so it offers minimal risk of cracking.
  • Significantly reduced thickness when compared to traditional sand – cement screed. This means it can offer a significant weight saving as a result.
  • Dries at a rate of 1mm per day up to a screed depth of 40mm and if necessary it can be force dried as early as 7 days after application.
  • Protein free – cannot harbour harmful bacteria.
  • Excellent thermal conductivity.

This information is from https://www.liquidscreedltd.co.uk/liquid-screed/

+ What is Self Levelling Concrete?

Self-levelling concrete is a modified form of cement that is highly liquid and flows easily. Unlike traditional concrete it does not require the addition of large volumes of water for placement.

Self-levelling concrete is typically used to create a flat, smooth surface with a compressive capability which is similar to or greater than that of traditional concrete.

With growing demand for flatter and smoother floors (often driven by flooring sector as floor coverings become thinner and floor tiles larger) quite understandably self-levelling concrete has become popular, as the degree of flatness and smoothness required from floors has increased.

When self-levelling concrete is poured, it has been described as flowing similar to pancake batter! A tool called a gauge rake is used to move it into place without spreading it too thin. The finishing is then done by lightly breaking the surface tension of the product using tools called Dappling Bars. The polymers in the self-levelling mix keep the viscosity of the concrete the same consistency from top to bottom so the sand aggregates do not sink to the bottom.

To ensure that the finished floor will be perfectly level a useful tool called a Tripod or Spider should be used.

+ What is a Screed Tripod?

A screed tripod is a simple but ingenious tool used to ensure a floor is laid exactly to the correct, desired level. The tripods are three legged devices with a central screw threaded shaft at the base of which is a circular disc. The disc can be raised or lowered to set the perfect required floor level (using a laser level) prior to the liquid screed – or the flowing concrete – being poured.

+ How do I use liquid screed tripods?

Determine the desired level of the finished floor (prior to any floor finishing being applied i.e. tiles, laminate etc.) This level is known as the datum level. You will likely take your datum level from a fixed point such as the final finished floor level or a door sill. Place a Screed tripod next to this datum point and adjust the height of the tripod disc to exactly match the datum level – ideally you’d use a laser level for this.

Leave this tripod in position and place additional tripods throughout the area to be screeded. We recommend a spacing of 1500mm between tripods.

Set a laser level to the datum tripod disc and then transfer this level to all of the other tripod discs in turn, adjusting the height carefully until they are all set to your datum level.
Now it’s a case of simply pouring the screed – or flowing concrete.

Pour in the liquid screed up to the level of the tripod discs, ensure that there are no high or low areas of screed between each tripod. Once the screed has been poured remove all the tripods from site. Top Tip – don’t forget to clean each tripod carefully immediately after it has been removed to prevent any screed setting on the tripod. Pay special attention to the thread which should also be lubricated periodically to ensure a longer life.

+ What should Iook for in a screed or concrete tripod?

A fully stainless steel tripod will last much longer as it will be resistant to corrosion.

  • Good height adjustment is important – our tripods will handle depths of between 10mm & 150mm.
  • Stability is a key consideration – tripods falling over when the screed is poured in are hugely annoying. Metex tripods have thicker than average legs for extra stability, strength & durability.

If working at speed is important we have just introduced a threadless tripod which will dramatically reduce the set-up time. It also reduces the cleaning and maintenance time.

+ What is a Screed Spider?

A screed spider is just another name for a screed tripod – a simple clever tool to ensure a floor is laid exactly to the required level. They are called spiders because they look moderately like one! They are three legged devices with a central screw threaded shaft at the base of which is a circular disc. The disc can be raised or lowered to set the perfect required floor level (using a laser level) prior to the liquid screed – or the flowing concrete – being poured.

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