Tips and tricks for Dansand Top Lock®

Find tips and tricks on this page.


Dansand Top Lock® creates a solid joint between paving stones. Unlike normal joint filling sand, Dansand Top Lock® will remain in place even during a heavy rainfall.

Dansand Top Lock® consists of oven-dried silica sand with a tiny amount of cement dust and a natural binding agent. Once in contact with water the uppermost part of the joint (approx. 10 mm) will harden to a sturdy membrane. This membrane acts as a physical defense against weeds and insects. Seeds will not be able to settle, and ants will not be able to work their way through the hardened joint material. You will not need to use unnecessary chemicals to maintain your joints.

Follow the manual carefully and check the weather forecast before going ahead. Dansand Top Lock® does not tolerate rain during the first 24 hours are laying. Air humidity should not exceed 70 %.

Yes, Dansand Top Lock® is water permeable. During rainfall the joint becomes soft and elastic and will harden again in dry conditions. In areas with abundant water, such as under a dripping gutter, the joint cannot harden.

Dansand Top Lock® does not prevent moss and algae from forming. These will form in joints that are constantly moist or in shaded areas. We recommend the use of a suitable product designed to prevent moss and algae. As an alternative you can scrape out the existing joints with a suitable tool and refill the joints with Dansand Top Lock®.

You can minimise the formation of moss and algae by ensuring that the joints are always filled to the top with Dansand Top Lock®.

All joint filling materials with binding agents can cause discolouring. Always create a test area to ensure that the final result lives up to your expectations.

Binding agents and cement have been added to Dansand Top Lock®. During sweeping some of the material will inevitably
remain on the paving stones. If the stones are rough or have an open, porous surface structure, or if they are of an older date, some filling material will settle in the pores. After watering the joints, once dry a grayish haze may be observed, in particular on coloured or dark paving stones. Remember to sweep the surface entirely clean with a soft broom before watering.


A strong and durable joint must be between 3 and 10 mm in width. If the joint is too narrow, it will not harden sufficiently due to too little material present in the joint. A too wide joint will weaken and may crack or split under pressure.

Dansand Top Lock® requires a joint depth of minimum 40 mm to harden properly – preferably in the entire height of the paving stones.</p

Always mix the content of each bag with a shovel before applying the product. During transportation, binding agents and cement dust may separate in the bag. Never mix the contents of more than two bags at a time.

It is critical that you compact the filling material from the very beginning in order to secure the longevity and the full functionality of the joints. You can test the compactness of the joint by using a spatula – you should not be able to press the spatula more than 1 – 2 mm into the joint.

If you do not compact the filling material with the use of a vibrating plate, the filling material will subside in the joint, and you will need to refill the joints after a short period of time. Joints should always be filled to the top.

Tip: Use a rubber mat under the vibrating plate to protect the paving.

It is critical that you follow the user guide on the bag precisely.

Dansand Top Lock® must only be applied to a dry surface, and the material itself must also be completely dry when being swept in.

Mixing Dansand Top Lock® with water will lead to a joint that will not harden and will also give a marked white haze on your paving. Top Lock® must be allowed to harden slowly in order to create a solid and sealed joint.

No – if you do, your joints will not harden. Dansand Top Lock® needs to “breathe” in order to harden properly. If you cover your newly laid joints, the hardening will stop and the binding agent will become lost. Always check the weather forecast before working.

You will only get the desired weed-control effect if the Dansand Top Lock® is pure and unmixed. Do not mix it with other materials such as cement or other types of sand.

Application tips

The paving needs to be 100 % dry before you begin sweeping Dansand Top Lock® into the joints. Always sweep over a short distance to ensure an even spread. You should never use material from one or two bags at the same time. Sweep lengthwise and diagonally.
Once all the Dansand Top Lock® is swept into the joints, it is important to sweep the paving surface completely clean with a soft broom. This is important in order to avoid having left-over material settle on the surface during watering.

Once the paving is swept clean of all residual Dansand Top Lock®, use your garden hose with the nozzle set to mist.

Water the paving in small areas until you see the water settle on the surface. Then continue to the next area. Once all the surface has been watered, wait five minutes and do it again. Water should not run over the surface, it should only just cover the joints. You can now check if the water has seeped all the way to the bottom of the joints. Use a screwdriver to dig up the filling material – you should be able to observe if the joint filling sand is moist all the way down. If the sand is still dry at the bottom, repeat the watering process. Do not use a watering can – this will not give sufficient water.

Tip! Work in areas no larger than 20 square meters at a time – this makes the process easier to control.

Application areas

Yes, you can use Dansand Top Lock® with clinker tiles and paving tiles! But be aware that Dansand Top Lock® may leave a gray haze on the surface as it contains cement dust and binding agents which will easily settle in the pores in burnt tiles. The darker the stones, the more visible the haze will be. Always test Dansand Top Lock® on a small area in order to verify that the end result will be as desired.

Yes, you can safely use Dansand Top Lock® directly against the plinth. Please note: This is NOT the case with Dansand® joint filling sand, Dansand® stone dust or Dansand Kerama®.

You should only use Dansand Top Lock® on an unbound substrate. An unbound substrate is a layer of sand and gravel on raw soil.

Dansand Top Lock® is water permeable and only works if water can drain from the joint quickly. If your substrate is concrete, recycled concrete or wood, it will retain moisture for longer, and Dansand Top Lock® will not be able to harden sufficiently to create a solid joint capable of withstanding weed seeds or ants.

Dansand Top Lock® is ideal for use in car shelters or in covered patios. The joints will harden in the same way as under open sky without side effects.

Do not use indoors.

No. Dansand Top Lock® is not suitable for areas adjoining swimming pools. The filling material will only work as intended if it can be allowed to dry out on a regular basis, and this cannot be guaranteed in a permanently wet or damp environment.


Joint filling products with binding agents may leave a gray/white haze on the stones known as efflorescence. This is often the result of excessive watering or of the paving not having been swept completely clean before watering. The paving stones are not ruined, however. The haze will normally disappear after rain, wind or snow. You can also clean the efflorescence off yourself. See how here:

White haze or efflorescence on the edges of paving stones:
The white haze is caused by mineral salts. It is a naturally occurring phenomenon that often occurs during warm periods such as spring or early summer. The combination of moist air and heat will draw salts on to the paving. The moisture may stem from wet substrate due to heavy rain. Rain will eventually wash the efflorescence away, but normal traffic and/or cleaning may also remove it.

We may not be able to give a definitive reason for this. We will need to know more about your paving and about the way you have applied the product.  If you believe you have followed the instructions to a point, we would invite you to fill in this  form and mail it to us – we will then be in touch.

Before filling joints with Dansand Top Lock®, you need to eliminate any ant nests with a suitable product. Once the joints have hardened, ants cannot penetrate and will go elsewhere.

Joints must be hardened to withstand new weed seeds. If it has not hardened or has cracked, weeds may sprout freely.

Dansand Top Loc® is not a weed killer and cannot prevent weeds from sprouting from a preexisting root network.

Maintenance and cleaning

Yes! To avoid weeds, you should regularly sweep your paving and repair any dips or cracks in your joints.

If a joint has settled or has developed a crack, remove the joint and refill with Dansand Top Lock® (remember to mix the contents of the bag first). Sweep in and compact the material by tapping the filling material into place using e.g. a piece of wood and a hammer. Now water the joint using a garden hose with the nozzle set to mist. Remember to sweep the paving surface completely clean before watering.

Safety and environment

Yes. All our NO GROW™ filling materials are free from harmful substances. Dansand Top Lock® is made entirely from silica sand, natural high pH minerals and a natural binding agent.
Using a DANSAND® NO GROW™ filling material in your joints means waving goodbye not just to hard work – you can also wave goodbye to harmful chemicals.