Screed You Must Read
Good preparation of subfloors and screeds is vital if installations are to be successful:
BAL states that its levelling compounds are fast, strong, smooth and reliable.
The range includes: BAL Solidbase, Thickbase, Rapidbase, Fibrebase and Acrybase. Every product in the range is designed to flow quickly and smoothly, delivering a consistent flow rate throughout a 15-minute period after mixing.
The products are supplied in 20kg sacks, giving typically 5sq m to 6sq m coverage at 2mm depth.
BAL levelling compounds are all polymer-rich to provide strong bonding. They are said to offer minimal shrinkage and excellent self-healing properties, which are standard across the comprehensive range.
All are protein-free formulations designed to eliminate possible future bacteria growth. BAL levelling compound all have a 25-year guarantee.
Solidbase is a contract-grade levelling compound for everyday levelling of solid core substrates, including concrete, sand:cement screeds and existing quarry tiling.
The single-part powder mixes with water, and may be used at bed depths of 2mm to 12mm. It is said to be ready for tiling after four hours.
Rapidbase is for faster drying and may be used from feather edge to 15mm. It can be employed on all the same backgrounds as Solidbase, but can also be used on floors with underfloor heating.
It dries sufficiently to accept ceramic tiles just two to three hours after application and is ready to take foot traffic after only 90 minutes, according to BAL.
Thickbase may be used from 2mm to 50mm and is also said to be sufficiently flexible for underfloor heating applications.
Tiling can begin within three to four hours after application. It can reportedly also be used as a patch and repair to spot-fill holes.
Fibrebase is for levelling timber floors, being both flexible and having a high tensile strength. It gives a bed depth of 3mm to 30mm and is reputedly ready for tiling after four hours.
The powder incorporates special fibres enabling it to deliver a smoother, stubble-free finish. Timber substrates should be primed with BAL APD.
Tongue-and-groove flooring and single layer plywood will also require covering with a 4mm fibreglass mesh before levelling for added reinforcement.
These are all single-part products, requiring only that the powder is mixed with water.
Acrybase is an acrylic-based, two-part product, comprising a 23.5kg sack of powder and a 5 litre bottle of liquid.
It is recommended for external use and for heavily trafficked areas, is said to be suitable for both wet and dry areas and can be used with absorbent and non-absorbent substrates.
It offers a bed depth of up to 10mm, with feathered edges if required, or from 10mm to 20mm depth if mixed with 3mm granite chippings.
BAL has also completely re-engineered its established Quickset Cement, with fixers and contractors nationwide trialling and providing feedback to the development team.
The new formulation is reportedly appreciated for its versatility and on-site performance. It is suitable for all key applications, including underfloor heating, with resilient and wooden floor finishes and in total immersion areas as swimming pools.
Its rapid strength development reputedly means better setting performance, especially during colder weather, when it cuts the delay of waiting for a screed or render to set.
In normal conditions, the screed will reportedly bear foot traffic after three hours. Tiling onto bonded screeds or renders can begin after four hours, or 48 hours for floating or unbonded screeds.
Quickset Cement is also claimed to cut project costs, having a 60-minute pot life, enabling projects to be completed with fewer, larger mixes for faster completion.
It is also pumpable and has greater flexural and compressive strength, says the manufacturer. This allows the use of leaner mix ratios, reducing project material costs. It is also claimed to offer 80% less shrinkage than a standard OPC screed.
The product is available in 20kg sacks suitable for 1:5 mix ratios. The valve sack packaging reportedly also enables easier machine loading. It also carries a full 25-year guarantee.
Bostik offers a full system of products for preparing subfloors and screeds. Screedmaster Rapid DPM is a single part surface membrane for cementitious subfloors which dries in up to one hour.
It is designed to protect adhesives, floorcoverings and smoothing compounds from residual moisture in power floated concrete slab or sand/cement screed, with a two coat application suitable for up to 95% RH.
Also available now is Bostik Screedmaster One Coat Membrane, a solvent-free two part epoxy surface membrane for up to 97% RH with a one coat application.
Bostik also produces a range of smoothing underlayments designed to meet the demands of different professional flooring applications.
The company recently introduced Screedmaster Flow, a self-smoothing compound developed for its high strength performance, excellent flow characteristics and ease of preparation.
Also available is Screedmaster Speed a two-part, high strength polymer modified cementitious underlayment for smoothing uneven floors before laying decorative floorcoverings. It has been developed for fast-track application, and reputedly sets in as little as 30 minutes.
Screedmaster Smooth is a single-part cementitious underlayment developed for applications where an ultra-smooth finish is required. It is said to be suitable for application by trowel and mortar screw pump.
The Bostik Laybond range of professional flooring adhesives combines high quality with specialist performance.
It claims to offer an adhesive for virtually any flooring application from carpet tiles to underlays, fibre bonded to linoleum and vinyl sheet to LVT products.
Products in the range include Bostik Laybond Carpet, a high tack low-VOC acrylic adhesive, Vinyl and High Temperature, a high strength adhesive for luxury vinyl tiles and highly plasticised products. www.bostik.co.uk
Flowcrete UK says its comprehensive selection of floor screeds includes a number of heavy-duty, self-smoothing and environmentally friendly surface underlayments, including the award-winning Isocrete K-Screed range, which contains a plasticising and accelerating admixture to enhance the system’s performance.
K-Screed reportedly exhibits high strength, excellent moisture control and rapid installation times to provide construction projects with a reliable screed layer that also allows for earlier follow-on work to speed up construction schedules.
Many high-profile, large-scale projects around the world, including the Dubai International Airport and Singapore’s Marina Bay Sands, have used K-Screed to ensure that the final floor finish is effectively supported and bonded to the substrate.
K-Screed can incorporate additional elements into the floor. Recently both the Western Hailes Healthy Living Centre in Edinburgh and Ryhope General Hospital combined K-Screed with Flowcrete Isowarm system for an efficient, targeted and space-saving underfloor heating solution. www.flowcrete.co.uk
Kerakoll UK products were used when New Forest District Council and PT Contractors needed reliable screeds and adhesives for the pool and surrounding deck areas at Applemore Leisure and Health Centre, Southampton.
The council had used Kerakoll products in another major project and appreciated the technical back up and range of solutions the product range addressed, as well as the low level of VOC emissions and the lifetime warranty on the products.
The 900sq m project was challenging as the pools were situated on a raised platform at first floor level giving rise to problems with thermal shock.
There were also issues with the steel reinforcement in the concrete under the pool, solved by using Geolite 10, a high grab geo-mortar designed for restoring reinforced concrete structures.
The pool and decks had a bonded Keracem Eco screed applied which was dry one day after laying, and Keralevel Eco LR was used to level walls which were out of true.
This is a high performance rendering system with very low VOC emissions and is said to be ready to tile on after about two hours.
Once dry, everything was tanked with Nanoflex Eco, a breathable membrane which is anti-alkali and chlorine resistant as well as being water repellent.
Tiles were then applied to all surfaces with adhesives from the H40 Eco range and Fugalite liquid grout. www.kerakoll.co.uk
Mapei’s range of smoothing and levelling compounds now includes two new high performance, fast-dry products.
New Planiprep Skimcoat is a fine polymer-modified cement-based mortar designed for patching and smoothing imperfections.
It features a quick-cure formulation for skimming uneven subfloors and joints, filling screw-holes in plywood surfaces and repairing other minor surface defects.
Floorcoverings can be bonded as soon as the product has dried.
Mapei one-application rapid subfloor levelling and smoothing compound, Latexplan Trade Fast is a new two-component cement- based screed for use on new and existing substrates and can be applied from 3-10mm in one application. It is foot-traffic ready within an hour and floorcoverings – including PVC, carpets and ceramics – can be bonded after just three hours, says Mapei.
It is also said to be suitable for use with underfloor heating systems and to pre-smooth damp subfloors (max 97%Rh) before the application of a surface applied damp proof membrane.
Its low odour, protein-free formulation is said to ensure safe application in health and education environments, confined spaces and occupied areas. www.mapei.co.uk
Pallmann Pall -X Extreme is described as extremely versatile, able to be used as a one or two component wood floor lacquer for flexibility and offers a range of uses to satisfy different requirements.
This water-based lacquer is fast curing even in the most extreme conditions and suitable for extremely heavy wear areas, says Pallmann.
As a two-component version (with the hardener component B) it can reputedly be used for very high traffic areas, such as shops, restaurants or schools without any problems. In normal to heavy areas the lacquer can be used without the hardener.
Training courses from experts at Pallmann will reportedly walk you through the five steps for the installation, renovation and maintenance of wood floors.
The training sessions provide hands-on experience for all aspects of wood floor installation including the new Pall -X Extreme lacquer.
The training sessions are run at Pallmann’s technical forum in Rugby and are free to attend.
Pallmann wood floor installation systems are claimed to be fail safe when used correctly.
That’s why the company offers a two years warranty for those who attend each of its Five Steps Training courses. T: 01788 530 080
Ronacrete products were specified for Terminal 2 at London Heathrow Airport as part of a £4.8bn development programme at the airport.
The Terminal 2 project, estimated to cost around £2.5bn, includes the main building, a 522m satellite pier, a 1,340 capacity car park, an energy centre, cooling station, and road refurbishment.
The terminal covers a floor space of 185,000sq m, extending into the existing Terminal 1 site.
The floor will take heavy traffic from the 20m passengers a year plus associated trolleys and airport vehicles who cross it annually.
RonaScreed eight-day overlay fast drying screed manufactured by Ronacrete was specified to cover the 185,000sq m of floor space. The product is a screed additive which when added to a screed enables earlier access by following trades and reduces drying time.
Available in pre-packed form, it is described as economical and suitable for fast-track projects where early access is required and is therefore suitable for large scale education, commercial, hospital, and retail projects. www.ronacrete.co.uk
tremco illbruck offers customers a selection of flooring products, including ones claimed to achieve the highest environmental standards and capable of overcoming problems of irregular or damp substrates.
One of the latest additions to tremco illbruck’s range, which includes DPMs and a selection of adhesives, is SX500 rapid drying smoothing compound designed to facilitate fast-track installations for a variety of situations.
SX500 is a two-component, 40%-recycled content product compatible with all Tremco’s products but well-suited for use with ES600 moisture vapour suppressant for a fast-track flooring installation.
The versatile, fast-curing smoothing compound is supplied in 22kg bags of the (Part A) dry powder, to be mixed with the 4.4kg of activating liquid (Part B).
Once blended, SX500 is said to have a working time of around 10 minutes and can usually be walked on in half an hour while installation of most floorcoverings can take place after approximately 90 minutes, says the company.
The system is said to be well suited to retail re-fits, office refurbishment and social housing, where getting the building back to use in the quickest time is paramount.
In situations where the existing substrate is particularly uneven and it is necessary to apply a smoothing coat before installation of a DPM, the contractor may well employ Tremco SX300 NA.
This has been developed to be moisture-tolerant and contains no ammonia to minimise odour. It is also protein-free and conforms to HTM 61 requirements.
SX300 NA comprises a dry cementitious powder and a white latex liquid which are mixed together to offer a pot life of 20 minutes.
It can be usually walked on in two hours, says the company. The high performance underlayment can be trowelled out at a thickness of up to 6mm but, where there are greater irregularities to be tackled, the mix can be bulked by adding 3mm granite chippings at equal volume increasing the allowable depth to 30mm.
Where it is applied over a DPM, SX300 NA reputedly does not require a primer provided the maximum thickness is 6mm and there is no underfloor heating.
Also available in the range is SX200 smoothing compound which is BREEAM- compliant and reportedly offers many beneficial performance characteristics.
Like SX500, SX200 is made from a blend of reclaimed and natural materials and can be used in combination with other products from the tremco illbruck range to help achieve an environmentally-friendly installation.
These include pressure sensitive adhesives and carpet tile tackifiers.
Whether the final floor surface is a sheet vinyl, carpet tiles, a rubber sports floor or another floorcovering, achieving a sound, flat surface prior to laying is essential to the final success of the installation, says the company. www.tremco-illbruck.co.uk
Ultra Floor Level IT TWO and Prime IT AR have been used to refurbish office premises at Liverpool’s famous waterfront attraction, Albert Dock.
Liverpool based contractor, Carpet Design and Flooring recently finished subfloor preparation and Hospi-Loop II pile carpet installation of 200sq m of office area using Ultra Floor products.
The work was carried out over a two-day window while the office was closed to facilitate a speedy installation.
Existing floorcovering and adhesive residue was removed before Prime IT AR was applied to the concrete substrate.
Prime IT AR is a water-based acrylic primer said to be suitable for absorbent subfloors and as a barrier primer, prior to applying a smoothing underlayment.
It helps stop the moisture from the wet underlayment passing through to the porous subfloor which can cause pinholes, prolonging the life of the installation.
It was used to prepare the area prior to levelling with Level IT TWO.
Level IT TWO is Ultra Floor’s recently enhanced two-component smoothing underlayment.
Claimed to be the ‘easiest’ latex to apply, it offers superior flow and handling. It is reputedly now 30% faster and can be overlaid in just 12 hours. Once smoothed and cured it was ready to receive the bonded Hospi-Loop II carpet.
Carpet Design and Flooring completed the job within the allotted timeframe, stating that it chose Ultra Floor because it is a ‘trusted brand.’
Ultra Floor recently rebranded its entire range to include new products, performance enhancements and vibrant new packaging. Ultra Floor is a brand of the Instarmac Group.
Weber has a comprehensive flooring products range, comprising industrial, commercial, design floor and marine screeds, developed for optimum speed, durability, strength and smoothness and technically advanced.
All are manufactured under the BSI Quality Assurance Schemes ISO 9001 and ISO 14001. Weber’s flooring screeds also meet the latest Part L and Part E requirements of current Building Regulations.
Developed for optimum speed, Weber’s high-performance commercial screeds reportedly achieve a smooth surface that is ready for foot traffic after only a few hours and can be covered with a soft floorcovering in 24 hours.
This range consists of products for use as floating, un-bonded and bonded screeds including insulated, acoustic or heated floors.
Weber’s high performance industrial screeds offer the key factors for a successful floor installation allowing the creation of stronger, smoother, longer lasting floors with minimal down-time, says the company.
Speed of application is claimed to be up to 10 times faster than traditional screeds and the fast drying/curing properties allow forklift traffic or resin finishes to be applied within 24 hours.
Weber’s decorative Design Floor range reputedly opens a new design concept for architects, designers and specifiers with durable and low-maintenance coloured floor finishes.
Design Floor is said to provide a hardwearing, seamless, super-smooth floor finish to complement any environment, whether in the retail sector, commercial developments or domestic settings.
Weber says its product range enables users to create practical floors with eye-pleasing aesthetics, with the advantages of self-levelling screeds that are quick, simple and cost-effective to install.
This article has been reproduced from the Contract Flooring Journal. You can find them at www.contractflooringjournal.co.uk.