Technical information

There are two methods of applying Premjoint, depending on whether the bedding material below the paving is permeable - often referred to as free draining, or whether it is impermeable meaning non-draining. See the Mixing & Application instructions for more details. All paving joints should be a minimum width of 3mm and up to a maximum width of 20mm. Joint depths should be a minimum of 20mm (a deeper depth will increase the strength of the jointing compound). Deeper joints may extend drying times. You should always ensure that Prem-Joint penetrates the full depth and width of the joint, without voids, to provide maximum stability. Voids left in the body of the jointing will cause a permanent weakness in the joint. Prior to applying Prem-Joint ensure all mortar is raked free from the joints to ensure that they are clean and to the full depth. Once Prem-Joint has been freshly installed, unless the moisture has completely drained free from the joint, the material will remain soft. It needs to drain free of moisture before it will begin to cure.

Premjoint Wet Application Method (permeable bed)

The most popular method of applying PremJoint is the 'wet application method' this is generally used for patios & walkways, when the paving is fixed using permeable bedding materials, such as UltraScape Perma-Bed. This method uses lots of water during application. The fixed paving is hosed down with plenty of water initially and throughout the application of Premjoint, this saturation process prevents the oils in Premjoint penetrating the paving causing staining or picture framing, whilst also assisting the brush-in grout to fully penetrate the joints and aid the removal of excess material. The water used during the application process needs to freely drain from the jointing compound before Premjoint will fully cure and harden. It will only harden and cure when all traces of moisture have been drained from the full depth of the joint. It's crucial with the ”Wet Application Method”, that the base of the new paving area is permeable to allow the remaining water to drain feely through the brush-in grout into the ground below. If any moisture or dampness remain in the PremJoint brush in paving grout after application, it will delay the curing of the product. Once the jointing has cured and hardened it will be unaffected by further rain water.

Premjoint Dry Application Method (impermeable bed)

The dry application method is used to apply Premjoint where either the bedding materials used to fix the paving are impermeable and therefore will not allow the drainage of water, or where the temperature conditions drop below 3 degrees, with concern if the wet application method is used it will freeze and expand within the joint before it has had chance to drain away. Once the paving is firmly secured and has set, gently pre-wet the surface using a fine mist spray of water, avoiding completely soaking the joint - this prevents PremJoint brush in grout from staining the paving. Open the PremJoint and pour the material along the length of the joint, brushing it into the joint at the same time. Rather than using water to wash the product into the joint, use a pointing trowel and jointing iron to strike off the joint and to enable the material to be compressed into the joint.