Questions and answers

Dansand® polymeric bloc paving fix

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

Effect

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How does Dansand® polymeric bloc paving fix work?

Dansand® polymeric bloc paving fix is similar to joint filling sand but is able to withstand sweeping. You can certainly even call it walk-proof. In other words, unlike common joint filling sand, this sand will not accumulate on the paving after a heavy rain.

We have added some harmless binders and a little bit of cement to the Danish kiln -dried silica sand. When it gets wet, the curing process begins and the sand hardens to a solid joint. It actually forms a solid surface, hardening from the top to approx. 1 cm down.

Once the joints have hardened, there will be no more weed growth or ants nesting in the joints. This way you will avoid using a lot of unnecessary chemicals.

Remember to follow the instructions very carefully. And check the weather forecast in advance because Dansand® polymeric bloc paving fix is not rain-proof during the first 24 hours after application. The air humidity should not exceed 70% either.

Is Dansand® polymeric bloc paving fix water permeable?

Yes, Dansand® polymeric bloc paving fix is water permeable. In rainy weather the joint becomes soft and elastic. When it dries, it turns solid again. At places constantly exposed to water, for example, from a dripping gutter, the joint cannot harden.

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.

Application

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Why do I always have to try the material on a test area?

Always try a test area first, mainly in order to see whether the result meets your expectations. For all cement-containing products, you should try the product on a test area to find out how much film you can get on your stones.

We have added a little bit of cement and binder to Dansand® polymeric bloc paving fix, which inevitably accumulates on the stones. If the stones are very rugged, have an open surface or are old, some of the material will seep into the pores.

When wet, the surface will have a greyish film, which is most clearly visible on coloured stones. Remember, therefore, to sweep well with a soft broom before watering. With a test area you will be able to see whether the job you have done is to your satisfaction.

Read more under "Smudging - my paving is all grey after using Dansand® polymeric bloc paving fix".

Why are the joint width and depth specified.

In order for the joints to last, it is important to make sure that their width is 3-10 mm. If a joint is too narrow, the material will not harden well because the material is not enough whereas if the joint is too wide, it will be weaker and when load is applied, it might crack or break off. In other words, stick to the specified range for best results. Best hardening of Dansand® polymeric bloc paving fix is achieved with joint depth of at least 40 mm.

Why do I have to mix the contents?

We have added some binders and cement to the sand, 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.

It is not a good idea to pour the contents of the bag straight into the joints.

See "Sweeping"

Why vibrate the joints when the stones are already set?

You will discover that the joint filling material compresses and it will be necessary to sweep some more material into the joints after vibrating the surface. By vibrating you ensure compact joints and prime curing results.

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

Why shouldn’t I mix Dansand® polymeric bloc paving fix with water in advance?

It is important to follow the instructions on the bag or on our website about sweeping in dry Dansand® polymeric bloc paving fix on completely dry paving. If you mix it with water before application, the joint will not harden completely and a thick film will form on the surface. The binders in Dansand® polymeric bloc paving fix will simply go to waste (drown) if they get wet. The material needs to harden slowly for a sealed surface to form.

Do I have to cover my newly jointed paving with plastic in case of rain?

No, because if you do, your joints will not harden. Dansand® polymeric bloc paving fix needs wind in order to harden.

If you cover your newly watered joints, the curing process will stop and the binder will go to waste.

Always check the weather forecast before you start working with Dansand® polymeric bloc paving fix.

When will my joint harden?

Well, it depends entirely on the weather. The colder it is, the longer it takes for the joint to harden.

At approx. 20 degrees, the joint will be hard enough for you to walk on the stones in 48 hours and in 72 hours you can easily drive on the paving. In general, the soil temperature must be at least 10 degrees day and night before and after sweeping the material into the joints. If it is colder, there is a risk that the curing process might fail.

When it comes to the other end of the temperature scale, the temperature in the joint should not exceed 30 degree because in that case the surface of the joint might harden so fast that the curing process in the rest of the joint would stop. In other words, a thin and not very durable shell might form. You probably know well that if the air temperature is 25 degrees, the paving stones can certainly be much hotter, especially if it's been hot for many days in a row.

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.

Application advice

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Sweeping

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

It is important that you sweep the material into the joints over a short distance to avoid sweeping in the binders only at one end. Therefore, you should only work with a few bags at a time. Sweep the sand into the joints lengthwise with diagonal movements. Once you have swept Dansand® polymeric bloc paving fix into the joints, clean up the paving, preferably using a soft broom. This way you can very easily remove all material from the surface so it does not stick to it once you start watering.

How can I best water my Dansand® polymeric bloc paving fix joints?

Once you have brushed your paving clean of any excess Dansand® polymeric bloc paving fix, use a water hose with spray nozzle and set it to mist.

Water the paving step by step until you can see that the water starts accumulating on the surface. Then go to the next spot. Once you have watered the joint filling material, repeat the process in 5 minutes.

The water should not run on the paving but rather should be evenly spread.

After that, inspect a joint to see if the water has reached all the way down to the bottom of the joint. You can stick a screwdriver into the joint and scrape up some sand. If the sand at the bottom is dry, water again.

Do not use a watering can or a garden sprayer since it does not provide enough water.

Good to know: Work only within an area of max. 20 m² at a time in order to have more control over the process.

Area of application

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Can I use Dansand® polymeric bloc paving fix on bricks or block paving?

You can certainly use Dansand® polymeric bloc paving fix but you should be aware that a greyish film may form on your stones.

Our product contains binders and some cement and since hard-burnt stones like these often have open pores, some material can accumulate on top, forming a greyish film. The darker the stones are, the more visible the film will be.

It is absolutely necessary to try the product on a test area to see whether such “staining” is acceptable.

Dansand® polymeric bloc paving fixright next to the outer wall base?

You can sweep down the material right up to the base. (NB! This is not the case with Dansand® joint filling sand and Dansand® stone dust for paving).

What happens if I use Dansand® polymeric bloc paving fix 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, and Dansand® polymeric bloc paving fix might not harden up properly. In addition, your stones might also appear wet and with patches of white.

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.

Can I use Dansand® polymeric bloc paving fix in close proximity to my swimming pool?

No, Dansand® polymeric bloc paving fix is not suited for areas in close proximity to a swimming pool. The unique qualities of the product will only work in full effect, if it fully dries on a regular basis. The effectiveness can simply not be guaranteed in a constantly moist environment.

Troubleshooting guide

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Smudging - my paving is all grey after using Dansand® polymeric bloc paving fix.

If there is a film on your paving, do not despair. Your stones are not ruined. The film will normally disappear by itself, when your paving is exposed to some rain, wind and maybe snow. This is why we recommend trying the material on a test area first to see how much the stone can take up.

You can remove the film with water and common liquid detergent as well as by scrubbing hard with a scrubbing brush. Neither the joints nor the paving stones will be destroyed by the detergent. Remove the film as soon as possible but you have to do so without coming into contact with the joint itself.

There are white rims on my joints.

Is it only the joints that are white? 

You might have watered a spot too much too quickly so binder accumulates at the top.

Should the top layer peel off, you can repair it.

See more in "How to repair joints?".

Do only the stones have rims?
It might have something to do with the stones. If not, look at the kind of substrate you have and whether it is bound.

See "What happens if I use Dansand® polymeric bloc paving fix on a bound substrate?".

Or 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, these salts are pulled to the surface. 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.

Dansand® polymeric bloc paving fix would not harden.

There can be so many different reasons for this that we need to know something about your paving and how you have applied the product. If you believe that you have followed our instructions on the bag and on our website, we suggest filling out a contact form and sending it to us so that we can help you further.

Click here for a contact form.

Ants

Before using the joint filling material you should get rid of the ant nest with a suitable ant repellent. Not until the joints have hardened, will ant activity in the joints stop. The ants will simply move their route elsewhere.

I have weeds in my joints.

The joints must be hard in order to be able to resist new weed seeds. If a joint has flaking or for one reason or another has not hardened up, weed seeds can sprout freely.

Dansand® polymeric bloc paving fix is no poison and cannot combat weeds from existing root systems. You have to remove the weeds before sweeping the material into the joints. You have probably also seen a dandelion growing through the asphalt. It is important to remove all existing weeds before filling and it is just as important to maintain the surface and the joints. Then you will get the best looking result.

Maintenance and cleaning

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Do my joints need maintenance?

Yes, if you want to avoid weeds, you should regularly sweep your paving. If there are any scratches or pockets in the joints, you need to repair them.

How to repair joints?

You can easily repair your joints. If there is a crack or a hole in your joint, scrape it up and fill it in with new Dansand® polymeric bloc paving fix (remember to mix the content first). Fill in the joints, then pound them using e.g. a large stone in order to compact the sand in the joint. After that, water with a hose set to mist, just like when you have filled new joints in the entire paving.

Environment and safety

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Is Dansand® polymeric bloc paving fix environmentally friendly?

The material consists primarily of common quartz sand from Denmark with safe binders and a bit of cement, 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 as hard to combat and burn off weeds. You can say goodbye to a lot of unnecessary chemicals.

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