The most important types of substrates are: cement screed, anhydrite screed, concrete floors, poured asphalt screed, magnesium oxychloride screed, wooden chipboard, prefabricated floor screeds etc. If fitting on double floors, please consult our specialists or our Applications Technology department under the fax No. +49 521 9245936.
Inspecting the substrates
Before laying textile floorcoverings, the contractor (fitter) must inspect the substrate carefully to verify whether the covering can be processed. After inspection, the fitter must submit to the client any objections in writing according to VOB Part B § 4 No. 3.
unevenness exceeding the evenness tolerance according to DIN 18202
cracks in the substrate
closed movement joints
insufficiently dry substrate
surface of the substrate is too rough and porous
surfaces of the substrate are soiled
surface of the substrate is insufficiently firm
no heating-up report in the case of underfloor heating
no screed markings for measuring moisture
adjacent components at an incorrect height
unsuitable temperatures of the substrate and climatic conditions (Minimum temperature 18 °C with a maximum relative air humidity of 65 %. These atmospheric conditions in the room must be maintained 72 hours before and after fitting, day and night.)
edge insulating strip does not project
Non-observance of the substrate inspection may lead to damage during or after fitting.
With the exception of asphalt constructions, substrates evidence household moisture. As soon as these key values are exceeded, i.e. the substrates are still too damp, the increased moisture present at the time of fitting can have a harmful effect in the period thereafter. For this reason, the substrate must be inspected before fitting by means of a suitable moisture measurement process, e. g. the CM method. The respective values must be checked against the state of the art. In the case of underfloor heating, the owner must present a heating-up and cooling-down report. In addition, the floor layer must carry out a moisture check at marked places (without heating pipes). During and after fitting, the floor temperature must be ± 22 °C.
Primers and stoppers
Substrates with which stoppers will not bond permanently must be primed with suitable primers, e.g. very thick, very smooth or very porous and highly absorbent substrates. A primer is always required in the case of anhydrite and magnesium oxychloride screeds.
Fitting on old substrates
Floors to which a wearing covering had already been glued in the past must be freed from adhesive residues and other soiling so that a firm, smooth surface is created. It must then be primed and stopped with absorbent stopper. Please refer to the processing guidelines of the stopper manufacturer for the suitable stopper, the thickness of the application and the water-cement factor. It is recommended to use materials from one manufacturer which are co-ordinated.
The insulating underlays available on the market are invariably offered as suitable for private and/or public, commercial and industrial buildings. The insulating underlays are often identified as suitable for chair castors and B 1. Please remember that the indentation behaviour, the chair castor suitability and the fire behaviour of textile floorcoverings can be impaired. To protect yourself against losses, please consult our Applications Technology department. A fitting on underlays requires the explicit consent of our Applications Technology department. Underlays must be fitted in such a way that their edgings and seams do not coincide with the seams of the floorcovering. An offset of more than 20 cm is absolutely necessary.
Processing the carpet
Before being cut to size, the carpet supplied must be inspected for faultlessness, its colour and all other identifiable defects. The general and usual production-related tolerances (e. g. colour of a batch according to grey scale ≥ level 3) should not be reported in this inspection. Any defects must be notified to Carpet Concept immediately before individual runs are cut. Visible defects might no longer be accepted once the carpet has been cut or fitted.
Processing several rolls
When fitting several rolls, ensure that the roll tags correspond and that the production or batch number on each roll is the same. If no cutting plan is provided, begin with the smallest roll number and work to the largest roll number. If a cutting plan is provided by the factory, this takes precedence. Each roll must be fitted in the specified order so as to avoid colour deviations at the seams. Only lay the outside edges (original edges of the carpet) against one another.
In order to ensure perfect fitting, the textile floorcoverings and the adhesive to be used must be conditioned for about 48 hours before processing. Ensure a floor temperature of at least 15 °C and a room temperature of at least 18 °C at a relative air humidity of no more than 65 %.
Attention! Needlefelt floorcovering in runs
As polyamide fibres absorb humidity from their environment, an expansion of the product can be noticed in the case of an increased air humidity, which may lead to shrinkage when the needlefelt floorcovering becomes dry. For this reason unpack the needlefelt floorcovering for conditioning only when you start the fitting. Make sure that the gluing of the individual runs is made immediately upon the rolling out of the runs to avoid expansion.
Laying out the runs
In the absence of any specific arrangements, the division of the runs and the direction of fitting of the individual runs are left to the fitter. However, the direction in which carpet runs are fitted must not change within one spatial unit. To avoid any discrepancies later on, it is advisable to coordinate the direction of fitting with the site engineer or the owner before fitting.
Trimming at columns and pillars
Insofar as the room contains columns, pillars and similar, the cut for the respective carpet run must always be made lengthwise. Crosswise cuts sever all pile yarns, which has a permanent negative visual impact.
Trimming the run edges in the case of needlefelt floorcoverings
Once checked the runs are laid out beside each other and overlapping approx. 6 cm in the seam area. The seams can be cut either with a special knife (Stanley knife) or with a large hook-type blade or a special seam cutter. Make sure that both edges of the run are trimmed with a double cut (cutting the lower edge is not permitted).
After the seam has been cut, the runs are folded back lengthwise (or crosswise in smaller rooms). It is essential that the runs do not slip out of position. In the case of longer runs, we recommend that the individual runs are weighted or tacked down (e.g. with clamping rails). Be careful, though, not to put tacks through pipes etc. in the screed.
Make sure to use glue which achieves high stabilities very quickly and has rigid glue joints. For instance, the product Multi-Coll of the company Wulff or the product UZ 88 New of the company Uzin would be suitable. For the application of the glue we recommend to use a screed with B1 dents or larger. After the gluing do not use a hammer or similar metal instrument for rubbing down. The friction heat generated could lead to bright patches that cannot be removed.
Trimming run edges in the case of tufted one-colour cut-pile and looped carpetings
The trimming of the run edges is always required. Depending on the pattern, at least 4 cm must be cut off. In the case of cut-pile and looped carpetings, the run edges have to be cut, if possible, along the tuft channel, each run separately, using a special pile channel cutter or hooked knife. No perfect seam cut along the web can be made with the articles that are tufted on a stitch racking device. Once the two runs have been cut to the exact dimensions, the carpetings can be folded back and glued (see the section on glueing individual runs).
In the case of looped carpeting, the edges must be additionally reinforced with a colourless fixative near seams, rails, power supply units and adjoining stone floors etc.
Trimming run edges of woven carpetings
The trimming the run edges is essential in principle. The selvedges have tuft lines made up of different-coloured yarn. When the runs are laid out, two edges of the same colour should never be laid side by side, as otherwise the pile direction will not coincide. Each run edge is cut along this tuft line. Please make sure that the light-coloured binding thread and the filling warp are neither trimmed nor cut at the run edge. If a hooked knife is used, we recommend that you cut from the rear along the tuft line. The tuft line forming the pattern must never be cut or trimmed.
In the case of looped carpetings, the edges should be additionally stabilized near seams, rails and adjoining stone floors etc.
Patterned and printed carpetings
It always takes longer to fit patterned carpetings than it does to with plain carpetings. This has to be taken into account already when making the calculation. Take the following into consideration when determining the amount to order: The first run must be ordered in the original length plus an additional allowance for trimming of approx. 10 cm. All other runs must be ordered with a full repeat allowance. This is the only way to guarantee that all runs will be supplied in the required length.
Before gluing, lay the runs loosely against each other. Here too, you must follow the ascending order of runs or rolls. Refer to 4.6 for processing woven carpetings. In the case of tufted floorcoverings, the run edges are cut individually along a steel ruler at the edge of the pattern. Both Stanley knives and hooked knives have proven to be useful. If the runs are laid out loosely beside each other, it is possible to see where planted designs occur (for technical reasons these cannot be avoided, see general terms and conditions). The dimensional accuracy of several runs to each other can be achieved if each run has a maximum deviation of 0.35 %. With a length of 10 m, for instance, a maximum deviation of 3.5 cm per run is permissible. Deviations from the horizontal of up to 4 cm over a run width of 4 m are allowed. The trained carpet fitter can compensate these tolerances by stretching. This can be achieved by using double-headed tensioners or the like. To do so, proceed as follows:
Matching the pattern
The cut run edges are laid adjacent to each other and faithful to the pattern in the middle of the room. Depending on the spatial unit, the runs are folded back and subsequently glued with a sufficient quantity of high-grade dispersion adhesive (of class EC 1) by means of a notched spatula as prescribed by the manufacturer of the adhesive. Once the adhesive has been applied, the runs must be placed into the adhesive base (see the section on gluing individual runs) immediately or after a short waiting period (airing time), depending on the climatic conditions and run length.
In the adhesive base you can now go on aligning the pattern at the run edges using double-headed tensioners. This means that the runs can be adjusted to the exact pattern in both directions up to the walls. This alignment of the pattern must be done relatively quickly, because the adhesive should not set during this period as otherwise it will no longer be possible to stretch the carpet. After stretching, the entire surface must be rubbed down before you can begin fitting other runs. Thus all the runs are aligned in the same manner until the complete dimensional accuracy of the pattern for the particular spatial unit is achieved.
Gluing individual runs
A full-surface gluing is recommended. The appropriate adhesive must be chosen according to the back of the carpet, the substrate and the required purpose. Always ensure that high-class "very low emission adhesives", e.g. of class EC 1, which comply with all legal requirements, are used, such as Mapei Ultrabond Eco 170, Mapei Ultrabond Eco V4 SP, Henkel Thomsit T 410 or Bostik Power Tex.
Applying the adhesive
The quantity of adhesive will depends on the properties of the substrate, the specific weight of the adhesive and the back quality of the floorcovering (roughness). The adhesive is applied over the full surface by means of a notched spatula. The form of notching is specified by the adhesive manufacturer. When applying the adhesive, make sure that no adhesive accumulates in the indents of the substrate. Depending on the type of adhesive, the carpet can be placed in the adhesive base after application and once the airing time has elapsed (the excess water in the adhesive must escape into the air). Always ensure sufficient glue on the rear of the floorcovering. The entire surface of the carpets must be rubbed down after being placed in the adhesive base. Depending on the room conditions, it may be necessary to rub down or roll the entire surface again after about 30 - 45 minutes. Final inspection and any further rubbing down/rolling must take place after approx. 60 minutes.
To avoid indentations, slipping out of position of the pattern and damage of seam edgings, a setting of the glue of at least 24 hours has to be observed. During this period the freshly fitted areas must not be weighted with additional construction work or with furniture, etc.
The protection covers should only be applied after setting and once the glue is thoroughly dry.
Fitting recommendations for conductive carpeting
The last few years have seen an increasing number of conductive carpetings being laid without any special conductive fitting. However, we recommend that conductive fitting is carried out as follows.
The substrate to be covered must be inspected and prepared as described above. The entire surface of the fully stopped substrate is primed with a conductive primer after it has dried out.
When this primer has dried, a copper band flag (10 x 0.08 mm) is glued on every 30 m2 or every 7 m of axis length in the area of the intended earthing point with conductive adhesive. The copper band flag should reach about 1 m into the room and be of sufficient length at the earthing point.
Attention: connection should always be executed by an electrician. Further fitting is carried out according to the type of manufacture or pattern of the carpet as described in these recommendations. When carpet runs are glued, of course, a sufficient quantity of conductive adhesive (EC 1) must be used.
Seam edge fixing
In the case of highly used areas and revision openings, round cuts and seams, etc. a permanent seam edge fixing is necessary. According to DIN 18365 (characteristic properties) this has to be made properly and professionally with a transparent glue. Smearing at the pile of the carpeting has to be avoided.
The suitability for stairs must be ensured already when buying the carpet. The corresponding quality must be chosen according to the expected wear and tear, taking into account the anticipated frequentation. If necessary, a special stair rail (nosing) must be fitted on the edge of the riser. When determining the quantity required, always make sure that the pile direction goes downstairs, i.e. with cut-pile qualities the pile direction on the step leads towards the nosing. The radius of the nosings must be rounded off at least 10 mm.
Because of the large variety of different materials and stair versions, we cannot go into detail here about preparation of the substrate.
The carpet must be matched roughly to the individual steps, i.e. there should be a projection of at least 1 – 2 cm all round. Gluing to the step can be done using a suitable dispersion adhesive of class EC 1. If the carpet has to be led around the nosing, however, dispersion contact adhesive is indispensable in certain cases.
The dispersion adhesive is applied to the step in sufficient quantity by means of a notched spatula. After the airing time has elapsed, the floorcovering must be laid and then trimmed to the exact dimensions according to the stair contours once the adhesive has set.
If contact adhesives (dispersion-based) are used, the dispersion contact adhesive must be applied in sufficient quantity to both the step itself and the back of the carpet. After the airing time or after the two adhesive surfaces have dried, the carpet is laid and rubbed down. Only then is the carpet adjusted according to the stair contours.
Suitability for chair castors
Office chairs must have suitable castors for the use of the respective floorcovering. DIN EN 12529 distinguishes between two types. On textile floorcoverings, only the use of castors of type H (for hard) is to be envisaged. If unsuitable castors are used, increased signs of wear can be expected. The technical information we provide is limited solely to the suitable chair castor according to the above DIN standard.
Limitation of fitting recommendations
The information provided in these fitting instructions can only be of general nature.
Recourse claims in this respect are excluded.
In case of doubt, we recommend that you perform your own tests and carry out test or trial fittings.