Synthetic resin based pavement fixing mortars are modern, high quality building materials. The following instructions and application tips will help to prevent damage by providing good planning and correct application.
Planning is the be all and end all
The most common cause of damage of paved surfaces with loose foundation and jointing materials e.g. sand or gravel, is heavy truck, car or bus traffic as well as cleaning using aggressive street cleaning machines.
Damage such as grooves, loose upended stones and movement of the paved surface are the result. Pavement fixing mortars are not able to compensate for any settling of the subsoil.
Contraction joints need to be laid according to the relevant construction guidelines. Any existing contraction joints in the foundation need to be incorporated into the surface to be paved. The foundation needs to be sized according to the expected traffic loads. The following statement always applies: "The joint is only as strong as it’s sub- and superstructure. That is why it is imperative that during planning, the correct foundation for the paved stone surface is determined.
Preparation before jointing
To carry out the job properly the correct tools are required. A new, clean sponge-rubber squeegee should be used to work in the jointing mortar. A clean, coarse street broom is used to sweep off excess mortar residue. A soft coconut hair broom is recommended for final cleaning.
Especially during the winter months, always take note of the weather report so as not to be caught in a rain shower. Heavy rain can cause the binding agent to be washed out of the joint, thus causing the joint to become sandy after hardening. Precipitation such as dew or rain can also result in the paving joint mortar not hardening properly or achieving it’s final strength. When using the systems DRAIN, D1 and TRAFFIC V2, if insufficient surface protection is used when jointing and hardening during rain or dew, then grey or white discolouration can occur on the stone surface.
For the repair of old paved surfaces, clean the gaps with compressed air or water jet (high-pressure cleaner) so that the minimum joint depth of 30 mm is reached, any residual mortar sticking to the stones needs to removed completely. The joint width must be at least 3 mm, in order to ensure a stable, longlasting result. For joint widths from 15 mm, the joint depth needs to be at least double the joint width, in case of medium traffic loads, at least 2/3 of the height of the stone.
The stone surface needs to be cleaned of all soiling such as cement residue, dust, bedding material, oil etc. as these may otherwise become sealed under the synthetic resin film. Tape-off adjacent surfaces which are not going to be jointed. Taping off the edges of the surface to be jointed, means that adjacent areas such as curbstones, curb surrounds, house walls etc. will not be at risk of being marked by the synthetic resin.
Because you are working with natural materials, it is recommended to always use material from the same delivery / batch on each construction site. If jointing is carried out on a site after work has been interrupted for an extended period of time, then you should always lay a test surface first. Longterm, the new surface will adapt to the old surface due to weathering.
During application suitable protective gloves and goggles should be worn. Avoid skin contact with jointing mortar, especially the binding agent. When using in sealed rooms, ensure sufficient ventilation.
Mortar that has already hardened should not be mixed with water or fresh mortar to try and make it usable again.
The paving joint mortar should be spread over the entire surface. If the mix is poured out onto one spot, in order to spread the material from there, then it is possible that dark synthetic resin marks will be left on this spot. These marks will disappear in time and through weathering.
At higher temperatures the pavement fixing mortar will harden more quickly. At temperatures above 20°C, small areas should be jointed and brushed off one at a time before starting on the next area, in order to prevent hardening and sticking of mortar residue on the stone surface.
Individual grains of sand on the stone surface will disappear during the weathering phase and through abrasion.
If the surface needs to be protected against rain, the plastic covering sheet must not be laid directly on the surface, as this can cause grey or white discolouration. Air must be able to circulate between the surface and sheet. Fine expansion cracks in the joint or at the stone edges, can always occur; these have no negative effects on the usage properties or frost resistance of the surface. Expansion cracks do not affect walking on the surface or use of sweeping machines.