Who is the vdw 840 plus suitable for?

The 12.5 kg bucket is aimed at builders and tradespeople who grout smaller terraces, paths or entrance areas; for larger areas, the mortar is available in a 25 kg bucket in basalt .

Areas of application and test points

According to GftK product information, these are the following use cases and requirements:

• Natural stone and concrete paving on garden paths
• Paving slabs and clinker bricks at house entrances and on terraces
• Coated concrete block and ceramic terrace elements
• Joint width consistently 3 to 20 mm, joint depth at least 30 mm
• For joint widths of 15 mm and above, the jointing depth must be at least twice the joint width.
• Stable, load-bearing and permanently water-permeable substructure
• Application at air and substrate temperatures of 5 to 25 °C
• For pedestrian traffic only, not for indoor spaces, ponds or fountains

Your advantage during grouting

The mortar is mixed with water, compacts itself according to GftK and can also be applied in light rain; what remains is an almost binder film-free surface.

Check the joint and substructure correctly

The joint mortar cannot absorb settlement from the subsoil; the substructure and bedding must be adequate for the load.

Bedding and joint depth

A stable, well-draining sand or gravel bed is sufficient; according to GftK, a well-draining mortar bed reduces cracking. For slabs laid in a mortar bed with a bonding agent, the joint depth in pedestrian areas may be reduced to 20 mm.

Calculate consumption

The manufacturer's values ​​apply per 10 mm joint depth: 600 × 400 mm slabs with a 5 mm joint require 0.4 kg/m², at 30 mm depth approximately 1.2 kg/m² – the bucket is theoretically sufficient for about 10 m².

Processing and limits

First, create a test area, as some stones may discolor. The area can be walked on after 24 hours, is fully approved after 7 days, and is not resistant to high-pressure cleaning; for areas subject to vehicular traffic with joint widths of 5 mm or more, GftK offers the vdw 800 paving joint mortar .

Product features at a glance

Technical data: GftK vdw 840 plus Basalt, 12.5 kg

The values ​​are taken from the GftK product information from September 2024; strengths were determined in accordance with DIN standards.