Polymeric sand has amazing advantages when it is installed correctly. It locks paving units together permanently, prevents weeds from growing, and remains tough whether it is dry or wet. However, for polymeric sand to serve these purposes, it must be installed correctly.
There are a few inherent problems and a whole lot more mistakes that people make when using polymeric sand for paving. While it is a really great generic product, polymeric sand can result in major problems if it isn’t used correctly. It is also important to use a quality brand.
2 Inherent Problems of Polymeric Sand
The most obvious inherent problems of polymeric sand relate to when and how it is used. It’s that simple.
1. Bad Weather Conditions
It is vital to ensure that the weather isn’t going to count against you when you use polymeric sand for any project.
Rain is an inherent risk of any polymeric sand project. For instance, if it rains before the sand has set, the sand won’t create a decent bond and the joints will lack strength.
If the weather forecast changes, either postpone the job or cover the paving with a tarpaulin or plastic sheeting to protect the surface finish. Just make sure you remove the protective cover as soon as possible so that the curing process isn’t compromised.
2. Skills Needed to Work With Polymeric Sands
Without knowledge and experience, polymeric sand can be relatively difficult to use. It hardens quickly, which is a clear advantage, but if it hardens on your top surface, it can be a disadvantage because it will wreck the overall appearance of your paving.
4 Common Polymeric Sand Mistakes
Like everything in the building industry, if you don’t follow the rules, your mistakes can be costly. These are four of the most common mistakes users of polymeric sand tend to make. Cutting corners and not following the manufacturer’s instructions tops the list.
1. Cutting Corners
Many installers cut corners to speed up paving processes. This may be to save time or to cut costs, sometimes both. DIYers also cut corners, and because they are doing the job themselves, it’s usually because they want to cut costs.
If you’re tackling a DIY project, it stands to reason that you should always follow the manufacturer’s instructions when working with any products. After all, the performance of any product depends on this.
When working with polymeric sand, this means doing your installation while following the guidelines from A to Z. Use the tools that are recommended, and follow the procedures as specified.
If you cut corners and don’t follow the instructions properly, there’s a good chance that your project will fail.
For example, instead of using a roller or compactor to flatten the bedding sand, DIYers sometimes think that it’s acceptable to jump up and down on the surface to flatten it. This isn’t appropriate and it simply doesn’t work.
Similarly, installers sometimes ignore the importance of compacting the laid paving after they have swept polymeric sand into the joints. The problem is that if there are pockets of air within the joints, which will eventually settle and cause cracks over time.
Another example is when people use regular sand to half fill joints and then top it off with polymeric sand. Unfortunately, water can easily work its way into the joint, causing the top polymeric layer to fail.
Yet another example of cutting corners is failing to clean the paved surface thoroughly. If you leave any particles of polymeric sand on the surface, when the surface gets wet they will harden and remain on the surface.
Finally, never install polymeric sand on a damp or wet surface. This will affect the stability of the polymers used in its manufacture.
2. Using the Incorrect Jointing Sand
Before the advent of polymeric sand in the early 2000s, professional paving companies and DIYers used various types of fine building sand to fill paving joints.
Alternatively, a professional paving approach often was (and sometimes still is) to use regular fine-grained building sand mixed with cement, making mortar to fill the joints.
One of the biggest disadvantages of using mortar is that the cement can leave a haze on the surface. If you try to hose it off, you risk hosing out the mortar from the joints. Ironically, this is also a disadvantage of using polymeric sand!
Now that polymeric sand is widely available, there’s no doubt that one of the biggest mistakes people make when filling paving joints is to use regular sand.
3. Using the Wrong Type of Polymeric Sand
There are various different types of polymeric sand available. So, it is critically important to choose the right product for each job. Important differences include the maximum joint size as well as the wetting or watering process. Some types call for a single watering step, while others require a three-step process.
Examples include:
- High-performance polymeric sand that is designed for concrete, natural stone, and wet-cast pavers with joints up to one inch.
- Different types that are suitable for pavers with joints up to two inches or four inches thick.
- A product designed to strengthen joints up to six inches thick.
Additionally, some manufacturers offer specialized sand with a formula that enables a simplified installation process. There are also products that are designed to neutralize polymeric sand haze and dust during installation.
On the other end of the scale, some polymeric sand products are inferior because manufacturers use cheap ingredients to minimize their costs. For instance, by adding Portland cement, they can also minimize the set-up time of installation.
4. Under- or Over-Watering Paving
We’ve said how hosing water over a mortar joint can have disastrous results. Using too much or too little water during a polymeric sand joint installation also comes with risks.
If you use too much water it can wash away the polymers that strengthen the polymer mix. If you don’t add enough water, the joint probably won’t be strong enough. This is a common risk when using mortar in paving or laying bricks and blocks for walls.
Another risk is that if you don’t water right through the joint, a crust can form at the top of the joint, and it’ll be just as likely to wash away when it rains.
Summary
It’s always important to identify possible problems and failures when working with new products. So, if you’ve never worked with polymeric sand before, make sure you know the parameters required for correct installation.