Questions and answers

Dansand® stone dust for paving

Find the answers to our frequently asked questions as well as info about our NO GROWTM products.

Effect

/

How does Dansand® stone dust for paving work?

The washed and kiln-dried product consists mainly of common Norwegian granite to which we have added some minerals. As a result Dansand® stone dust for paving has a high pH value that makes it difficult for weed seeds to germinate. They are simply deprived of nourishment.

Moss/algae

Our joint filling materials cannot prevent the occurrence of moss or algae. These two botanical phenomena love wet surroundings. You will see them in periods after much rain or high humidity and also typically in partial shade areas.

Use a suitable agent against moss or algae control agent to prevent their spreading.

You can minimise the occurrence by always keeping the joints filled.

Application

/

Why do we specify the width and depth of the joints.

We know from experience that if the joint is too wide, the stone dust will roll out when the paving is being used or when it rains. In other words, for best results you should stick to the specified limits.

Dansand® stone dust for paving: 1 – 20 mm

The depth of the joint also affects its durability. We recommend at least 40 mm.

In case of repairs, we have some solutions where it is up to you how long the joints will be able to withstand the weed seeds that fly in.

Find out more under our 3 solutions.

Why do I have to mix the contents?

We have added some minerals which, together with the larger grains of sand, can settle to one side of the bag. For this reason, give the sand a good stir with a shovel for optimal effect.

Sweeping

The paving must be 100% dry before sweeping the material into the joints.

In the past, joint filling material used to be left on top of the stones so that people could walk on it and thus settle it into the joints.

Today, in places that have to look good, the excess material should be swept away, partly because new stones are coated ex works and partly because lime stains can develop on the stones. Since we have added minerals to the products, it is important to sweep your paving clean, preferably with a soft broom in order to avoid efflorescence on the stones.

Why vibrate the joints when the stones are already set?

You will discover that the joint filling material collapses and that it will be necessary to sweep some more material into the joints after vibrating the surface. The joints must always be filled up to the edge.

Tips! Use a rubber mat on the vibrating plate compactor to protect the paving.

Use the product alone.

The weed-inhibiting effect can only be achieved when the product is used on its own. That is, you cannot mix it with other materials such as cement or another sand type.

Area of application

/

Can I use Dansand® stone dust for paving on bricks or paving tiles?

No, unfortunately you cannot use Dansand® stone dust for paving, because then you would risk white efflorescence developing on the stones. Such efflorescence cannot be removed.

Dansand® stone dust for paving has a high pH value (approx. 10.4) and these hard-burnt stones will absorb all moisture from water/rain and with that also the moisture from the sand and the surroundings. Due to the high pH value, white lime stains can also develop.

No stone dust right next to the outer wall base.

You should never use Dansand® stone dust for paving right next to a foundation or any other brickwork. Instead, you can spread some kiln-dried quartz sand or another type of sand.The stucco applied to the foundation is more porous and can in some cases suck salts from the joint filling material which show as white efflorescence on the base. And these cannot be simply washed away.

Weeds are rarely seen at the base.

Can I use Dansand® stone dust for paving in close proximity to my swimming pool?

No, Dansand® stone dust for paving is not suited for areas in close proximity to a swimming pool. Because of spray water the material could get onto the paving or into the water. This should be avoided.

Covered areas

Our products are most suitable for open environments exposed to the elements, i.e. where there is a little bit of everything - sun, wind and rain. Dry environments absorb the moisture and when the dry stones suck moisture from the surroundings, white efflorescence (from salts) may develop on the paving stones. This will most often occur in the spring or when it gets extremely hot in the summer. It is the other way round with the outer wall base where the efflorescence on the stones can be brushed or washed away. Therefore, we just simply recommend not using the product in the carport for aesthetic reasons.

The product cannot be used indoors.

What happens if I use Dansand® stone dust for paving on a bound substrate?

Let's just make it clear that you can only apply our products on an unbound bed, i.e. sand foundation/base gravel on top of subsoil.

Our product is permeable to water so that the water can be quickly drained off from the base layers and the joint.

In case of concrete and aggregate, or wood base layer, moisture stays a bit longer and white patches might develop on your stones and joints.

Troubleshooting guide

/

Why do I still get weeds in my paving?

There are 2 types of weeds: Weed spreading through the root system and weed seeds that fly in and set in the joint.

Before adding stone dust, all existing weeds (and roots) must be eradicated. Our stone dust do not poison the existing weeds, but are a poor growth medium - that is, any new weed seeds cannot strike roots in the sand. Because of the high pH value (about 10.4), the roots will simply dry out.

Weed seeds are wind-borne: You prevent them from striking roots by making sure that you have filled the joints with at least 4 cm joint filling material. And the joints will be more durable if you keep your paving free from dirt and leaves. If the joint filling material compresses in the joint, you need to refill. It is important that the joints are always filled to the edge.

There are white rims on my joints.

 

And are there also individual rims at the edges of your paving stones?
The white rims are salts and this is actually a natural phenomenon, which may occur especially during periods when the air is very hot, most often in the spring and early summer. When moisture and heat meet, the salts are pulled to the surface forming these white rims. The moisture can come from a wet foundation, for example, as the result of a heavy rain. These rims dissolve by themselves and will be washed away by rain, normal wear on the surface or normal cleaning.

Do only the stones have rims?
It can have something to do with the stone. If not, look at the kind of substrate you have, it may be bound.

See "What happens if I use Dansand® stone dust for paving on a bound substrate?".

Maintenance and cleaning

/

Do my joints need maintenance?

Certainly, because this way you get the nicest and most durable joints.

Tips: When the gardening season starts in the spring, you can figure out how much you would need.

Do you want to just refill the joint or carry out more extensive renovation? Therefore we have designed three solutions for you. They are not so complicated :)

Find out more under our 3 solutions.

Environment and safety

/

Is Dansand® stone dust for paving eco-friendly?

Dansand® stone dust for paving consists primarily of crushed granite from Norway and sustainable natural minerals that give a high pH value.

If you have first used Dansand® joint filling sand, Dansand® stone dust for paving or Dansand® polymeric bloc paving fix between your stones, you do not have to work so hard to combat or burn off weeds. You can say goodbye to a lot of unnecessary chemicals.

Dansand