Before Concreate Flooring Is Delivered To Site
Before Concreate flooring can be delivered to site all wet trades (e.g. concreting, plastering, and decorating) must be finished, and the building must be weather tight and thoroughly dried out. (Please note that plaster may take several months to dry satisfactorily, concrete and screeds may take substantially longer depending on thickness. The relative humidity must be in the range 45-65%, with ambient temperature in the range of 18°C to 24°C. If necessary, employ a dehumidifier to maintain suitable conditions.
Acclimatisation of Concreate Flooring
As part of your warrantee conditions, it is essential to acclimatise your Concreate Flooring prior to installation. Providing that site conditions are correct before the packs arrive. Packs should be stored unopened prior to installation, in warm dry conditions (i.e. similar to those which will prevail when the floor is laid and in use: 45 to 65% RH). The panels should be stored in the room(s) where they are to be laid for a minimum of three days, to allow them to acclimatise to the ambient temperature and humidity. The flooring must be well protected against damage or marking from other building operations. It is recommended that the panels are kept in the packaging until installation commences.
Concreate must be installed by fully bonding to suitable sub-floors or to Concreate approved 3mm underlay using Concreate Flooring Adhesive or Wood’s Good MS Plus Adhesive (which has been fully certified for use with Concreate floor panels) and appropriate notched trowel. Concreate should be cut with the appropriate fully extracted diamond tipped saw blade.
Provision for expansion
Although it is very unlikely that Concreate will move it is recommended that expansion spaces of 5mm or more must be left wherever the floor meets obstructions including all walls, door frames, thresholds, structural support, fireplaces etc. These expansion gaps can be covered using flexible mastic.
Concreate panels may be installed random or geometric patterns. The diagrams below show some patterns the grey rectangles indicate the cement panels and the brown rectangles the wooden top layer panels.
Concreate is a natural surface with tonal and colour variation. To achieve the desired mix of colours, shades and other characteristics in the final floor, and avoid clusters of similar colour shades, the contents of multiple packs should be mixed during installation. Samples must be taken as a guide only and colour/shade and other characteristics will vary. Before installation commences rack out a small section of boards for the client approval. This product may include up to 3-5% of boards which do not meet the usual tolerances or grade, which should be defect cut or set aside as waste.
The installer is the last line of quality control.
DO NOT INSTALL BOARDS WITH OBVIOUS STRUCTURAL DEFECTS. Concreate must be handled with care and the packs must be opened carefully to avoid damaging the edges and the tongue and groove system. Avoid fitting structurally damaged panels. Minor damages such as chips may be repaired once installed with Concreate repair powder.
Condition of sub-floors
All sub-floors must be dry, sound and of load-bearing strength. It is essential that wood based sub-floors must be of load bearing strength (e.g. Typically 22mm thickness on joist or battens at 600mm centres 18mm thickness if on joists of 400mm centres) and free from excessive deflection under loading.
Moisture condition of sub-floors
Concrete slabs and sand-cement screeds must be sound, and dry. Mineral based sub-floors must not exceed 65% equilibrium relative humidity or <0.3% Moisture content for anhydrite. Sub-floors at ground level or below must contain an effective damp proof membrane to protect flooring from ground water in compliance with British Standards. If there is any doubt that the sub-floor meets the required standard for moisture or the sub-floor does not have an effective integral damp proof membrane, a suitable surface applied damp proof membrane must be installed.
Wooden sub-floors must not be more than 2% higher in moisture than the Concreate (wood) Flooring. When installing wood flooring at ground floor level (or below) above a ventilated cavity (e.g. floorboards suspended on joist), it is essential that a purpose made moisture barrier building paper is installed over the sub-sub-floor before flooring can be installed. The moisture barrier must taken up the walls by 30mm at the perimeter, and all joins overlapped by a minimum 200mm and taped with a water proof jointing tape. Failure to comply with requirements for sub-floor moisture may result in cupping and excessive expansion of the Concreate Wood Panel which is not covered by the warrantee.
Evenness of sub-floors
The maximum permissible departure from the underside of a 2 lineal meter straight edge is 2mm. Failure to keep to these tolerances may result in deflection which may produce undue stresses on the joints, cause gaps between flooring elements, and with fully bonded floors may result in inadequate contact between flooring and adhesive.
If levelling is required over sand-cement screed or concrete sub-floors it is recommended that a rapid curing high strength water-powder mix cementitious levelling compound is employed instead of a powder + liquid latex emulsion which are not as strong and can break up. If levelling wood based sub-floors prior to fully bonding wood flooring, a purpose made fibre reinforced levelling compound must be used. Ensure that levelling compounds are fully cured and thoroughly dried before installation commences.
In some cases such as over suspended floorboards, levelling may be achieved by overlaying the existing sub-floor with a sheet material such as WBP grade Plywood or OSB chipboard. The sheet material must be securely fixed to the wood based sub-floor with the ends of sheet staggered. Ensure adequate provision for expansion between sheets of plywood using washer joints.
If levelling is required above an epoxy resin surface moisture barrier, it is recommended that an additional application of epoxy is applied and a purpose made aggregate is applied onto the freshly applied epoxy. Once the epoxy is fully cured any aggregate which is not fully adhered to the epoxy is vacuumed off. This produces a sandpaper like surface which provides a strong mechanical key between epoxy membrane and levelling compound. Always check the mutual compatibility of moisture barriers, primers, aggregates, levelling compounds and adhesives before installation. See manufacturer’s product data sheet for further information.
Fully bonded installation(eg. Concrete, sand-cement screed or wood based sub-floors) with Concreate Flooring Adhesive or Woods Good MS Plus Adhesive
Concreate Flooring may be installed direct to concrete or sand-cement screed sub-floors, or to suitable wood based sub-floors (e.g. Plywood, OSB) by fully-bonding with a purpose made permanently flexible Concreate Flooring Adhesive or Wood’s Good MS Plus. Concrete subfloors must be < 65% relative humidity.
The adhesive is applied to the sub-floor only using the appropriate trowel, which creates ridges of adhesive which the flooring is bedded into when laid. Always use the correct trowel and replace trowels which are worn.
Tip: When installing flooring uplift occasional panels after placement and examine the residues of adhesive on the underside of the panel to ensue the panel is making full with the bed of adhesive.
- Previous floor coverings and the adhesive residues used to adhere floor coverings to sub-floors (e.g. Bitumen) must be removed before bonding of wood flooring.
- Ensure screeds are of adequate cohesion strength of before installation.
- Avoid accelerated drying of new screeds as this can lead to poor cohesive strength, especially over under floor heating.
- Any residues of adhesive which come into contact with the face of the board must be removed whilst wet, as cured residues are not easily removable.
- When protecting the floor from other trades, apply tape to the protective material. Never apply tape directly on flooring surface as some tapes may react with the oiled surface causing damage once removed.
Installation with Under Floor Heating
Pay special attention when installing Concreate Smoke White Oak which has a real oak top layer
Underfloor heating beneath wood flooring presents special problems because of the wide range of temperature to which the flooring is subjected. During the summer or when the heat is turned off for long periods, high atmospheric humidity causes an increase in the moisture content of wood flooring which has been specially dried for heated conditions. This produces lifting or distortion if the floor has been too tightly jointed at the time of laying. When the heat is turned on again, the moisture content decreases, therefore a greater seasonal moisture content variation is to be expected with underfloor heating than with other forms of heating.
- Avoid accelerated drying of new concrete/screeds over UFH as this may lead to poor cohesive strength of the sub-floor.
- Check the cohesive strength of screeds before adhering.
- Ensure that screeds, concrete, etc are < 65% RH before installation commences.
- Employ a suitable surface applied moisture barrier (e.g. moisture suppressant primer) where necessary.
- If levelling is required above a suitable primer moisture barrier, apply a purpose-made fine graded aggregate over the second coat (on one coat membranes) OR third coat (on two coat membranes) immediately after application. Allow to cure then vacuum off all loose aggregate; (This will aid adhesion between primer and levelling compound). Then use a rapid dry formulae‚ water-mix (i.e. instead of latex mix) levelling compound, as these are typically stronger and develop strength quicker.
- Ensure that levelling compounds are fully cured and dry before installation commences (see manufacturers technical data-sheets).
- Use a purpose made, permanently flexible adhesive as described above.
- Ensure full contact between the underside of the flooring element and adhesive.
- Maintain suitable ambient humidity 45 to 65% RH. (Monitor with a domestic hygrometer).
- Employ floor temperature sensors below the floor with electric under floor heating systems.
- Do not allow humidity below 45% RH, or above 65% RH. (A small domestic humidification unit can be employed to avoid low humidity during the winter heating cycle if necessary.
- Do not allow the floor temperature to exceed 27°C, (including under rugs).
- Do not use thick insulating rugs. (Note: as this will lead to high floor temperatures).
Precautions prior to installation where underfloor heating is to be used
Before floor laying begins, the following procedure should be followed:
The screed should be dried in accordance with BS8201:2011. Once the screed is dry to a maximum level of <75% RH, or <65% RH for floors directly bonded to the screed, the underfloor heating should be commissioned in accordance with the underfloor heating manufacturers guidelines where available.
Where no guidelines are indicated the following protocol should be followed:
Do not commission the UFH for 48 hours after the installation is complete. This gives the adhesive time to fully cure and allows the floor to generally settle.
Do not turn the system straight up to maximum. Gradually increase the temperature 1oc per day until you reach your optimum operating temperature.
And never exceed 27ºC at the surface temperature.
We strongly recommend a dual thermostat system is used to monitor the surface temperature and the ambient temperature of the room. Throughout the life of the flooring avoid any rapid or big temperature changes as fluctuating the heat within the product runs the risk of drying out the timber. This can result in dimensional changes causing the floor to split and crack.
Testing of UFH services
The flooring installer should ensure that all services (not only heating services) running beneath the floor have been tested fully by the services installer before laying starts.
Precautions prior to handover
Means of keeping the flooring dry and stable in the period between laying and handing over should be provided.
Start up schedule
Where underfloor heating is involved, particular attention should be paid to ensure that the top surface temperature of the wood flooring should not exceed 27 °C. Some electrical underfloor heating systems are not compatible with timber flooring and the manufacturer of the timber flooring should always be consulted before installing over underfloor heating systems, particularly regarding the moisture content, species of the timber and specific installation guidelines. It is most important that electrical UFH systems must be overlaid with a fibre reinforced smoothing compound of not less than 5mm no direct contact of any electrical matting should come into contact with the wood floor itself. Please seek the advice of the UFH manufacturer’s instructions to confirm compatibility with wood flooring.
Disclaimer & further information
The combination and order of products used for sub-floor preparation can vary according to specific conditions of the site and sub-floor. This information is not intended to be exhaustive, or a how to guide for the novice, but will serve as a guide only to the experienced installer. Further information is available