Asbestos in New Zealand buildings has been common for around 70 years. While we’ve covered at length the factors behind this surge in asbestos-containing materials in construction, how can asbestos be best managed in a property?

Despite its hazardous nature, asbestos had many unique properties for building materials, but it can break down over time. Asbestos roofs, for instance, tend to deteriorate on the outside, mostly due to harsh UV rays, pollution, or a lack of upkeep - moss and other growth can break down the protective roofing cover around asbestos-containing materials.

Often, if your asbestos roof can be salvaged, you might consider encapsulation. There are benefits to encapsulating asbestos on your property, though it’s not a one-time fix like some people might think. Whether you’re in a home or office, you’ll need to maintain regular monitoring of the area, and encapsulate it using a waterproof, durable material. If you’re encapsulating asbestos in a roof, you’ll require excellent UV tolerance as well.

Why choose encapsulation?

It doesn’t matter if you’ve just bought a house, or moved into a new office after years of running a successful business; the cost of renovating and the disturbance to your life is never an option you consider lightly. While cost and business downtime are arguments against renovation and removal of asbestos, it’s also not always necessary. You’ll need to consider the health of the asbestos present, where it is in your building, and the quality of the surrounding materials.

Unfortunately, the answer you want isn’t often the one you’ll receive, so before spending a lot of money on any decision, speak to an asbestos specialist and get a qualified, professional opinion.

The benefits of asbestos encapsulation, if it is a viable option, are considerable. You won’t have to remove large sections of your building, you’ll experience minimal downtime around the property, and it will be far cheaper than total reconstruction. However, any encapsulation must be performed by a professional, and only using high-quality materials suitable for the target area. As mentioned above, exposed areas such as roofs are at risk of decay if not regularly cleaned and properly maintained.

What asbestos encapsulation covers

Asbestos encapsulation is designed to protect the asbestos from external damage, so if it’s not reasonably practicable to remove asbestos or the asbestos is in good condition, the preferred method of dealing with it is often encapsulation or enclosure.

When you decide against removal, asbestos is usually encapsulated in a robust, resistant material such as reinforced plastics, resins, plasters and cements. If the asbestos is surrounded by material where there is little chance of corrosion over time, and an equally low chance of asbestos fibres becoming airborne.


If you’re at home, you’ll want to immediately call in the professionals to recommend the next course of action. If you’re running a business it’s your responsibility to enclose non-friable asbestos if you’re not reasonably able to remove it, and only if any asbestos present in the building will avoid being damaged by employees or work activity.

Enclosing any asbestos on your property is done through creating a physical barrier between the asbestos-containing material and any access points. Although this option helps to minimise the potential for airborne fibres, any enclosure must also allow for the asbestos to be regularly inspected as part of any ongoing asbestos management plan.

Maintaining the asbestos encapsulation

Due to the need for ongoing monitoring, it’s realistic that enclosure or encapsulation should be an interim measure for any long-term asbestos management in a building. You’ll need to regularly inspect any affected areas---assuming you are trained in doing so. Otherwise, you’ll require the assessment of a competent person to decide whether asbestos needs to be removed due to any incurred damage or exacerbated deterioration.

Asbestos does not corrode due to salt-water exposure, does not create condensation, nor catch on fire. Its durability is, in part, due to thermal expansion, so applying a coating that is too rigid could cause the area to crack under heat. Likewise, it’s important the encapsulated area is checked every six months, and re-encapsulated every two years. This is a reasonable timeframe to monitor and record any environmental wear-and-tear.

Part of your ongoing monitoring will require air sampling. Quite self-explanatory, you’ll need an asbestos professional to take a sample of the air in either your home or workplace and test it for asbestos fibres. Air sampling is important, as it must be conducted before any removal work as a measure of the present conditions, and afterward to ensure no asbestos is present.

It’s recommended that when approaching any asbestos management or removal project, you consider speaking to your asbestos specialist about the following: 

●      Background sampling of the property.

●      Ongoing testing following encapsulation to identify leaks.

●      Post-removal asbestos sampling after it has been removed.

This is done for a few reasons, with the most obvious being to test for any asbestos present. However, taking air samples before and after work is done identifies any areas that may have been missed, while sampling as part of a maintenance plan can help spot any leaks in the enclosure that could be a hazard to your health or those around you. 

Sampling and monitoring your asbestos removal

When it comes time for full asbestos removal, you’ll want to take just as much care as you did during the encapsulation process. Although you’ll be preparing for a reasonable amount of renovation, you’ll gain increased peace of mind, and will no longer have to worry about maintenance checks of such regularity.


Ideally, air sampling should start before the removal process begins, with background monitoring to establish existing asbestos fibres in the air. Once all asbestos removal work has been completed, your asbestos specialists will clean the area and take another reading to ensure the air is healthy and breathable.

Any dust present in the removal area must be treated as if it contains asbestos, and if you notice any dust still present following a procedure, contact your asbestos removal team as soon as possible. In the event that any asbestos cannot be removed from an area due to lack of access, you will need to speak with your consultant about options for ongoing encapsulation.

Long-term planning

If you’ve discovered asbestos in your home or business, you’ll want to know about its presence and ensure it’s taken care of. While encapsulation is one reliable option to prevent any asbestos fibres from entering the breathable air, there are certain conditions required to make it worthwhile in the long-term. Alternatively, you can opt for full asbestos removal, which, while a lengthier and more intrusive process, will ensure your building is asbestos-free for the future.

If you have any concerns about asbestos in your home or business, have already encapsulated asbestos in your home and are concerned about the quality of the job, or just need to speak to the expert team at Chemcare about how to take an asbestos sample, contact one of our asbestos specialists today.