All posts by Drainage NZ

Subsoil Solutions For Aucklanders

Since the deluge in 2017, Auckland’s problem with its ageing stormwater drainage pipes came to light. The city’s population growth, coupled with the rise of multi-unit blocks of flats, is putting too much strain on stormwater facilities.

While the Council is already building a multi-million dollar central interceptor to address Auckland’s water woes, many can be done on the private property owners’ part to help the situation. This includes improving their home’s drainage system to minimise runoff to the streets and prevent debris from funnelling into stormwater inlets. Silt and debris blockage was one of the major contributing factors to the massive flooding and damage in New Lynn during the storm.

Installing structures such as subsoil drainage can help to maintain flow conveyance and remove litter and excess sediments that block hotspot inlets during heavy rainfall events.

The problem with old pipes and clay

About 16,000 households or 2 per cent of Auckland’s wastewater network use combined stormwater and sewage pipes. Many of the pipes in older parts of the isthmus were installed a century ago and have not been replaced or “separated.” In heavy downpour, stormwater can easily overload the pipes and backflow into the sewage system.

The stormwater dilutes the wastewater. And when it overflows on private property, it does not only cause a smelly problem but also poses a bigger issue from a public safety perspective. This usually happens on parts of the network that weren’t separated. In some areas, like Hauraki Gulf Islands, there is no formal stormwater system and natural land drainage isn’t sufficient to deal with stormwater.

The problem is exacerbated by Auckland’s clay-dense soils formed under a warm and moist climate. Clay accumulations are particularly high in western suburbs and the inner city areas have soils.

Clay particles accumulate in the layer of the earth below the surface soil, hence called the subsoil. This layer is made up primarily of minerals and leached compounds, and lacks most of the organic elements and the rich soil fauna and flora found in the top soil. Clay has low-porosity and impedes the land’s natural ability to absorb and drain away stormwater.

So when the rain pours, stormwater tends to pond on low-lying areas around homes or run off to the roads, overloading the public wastewater infrastructure. If the flooding reaches the foundation of a house, it can compromise its structural integrity and safety.

This video shows the usual drainage problems that Aucklanders are facing.

What can be done?

The Auckland Council is in charge of stormwater management, but property owners are responsible for maintaining private stormwater assets that run to their property. These private stormwater assets include drains, catchpits, grates, pipes, roof gutters, rain gardens, permeable paving, ponds and soakage pits.

Soak hole repairs and inspections

Stormwater is typically directed to a soak hole rather than led directly to the stormwater network. In areas with no stormwater reticulation facilities, soak holes allow water to percolate to the ground.

Soak holes are basically manholes with boreholes ranging from 5 to 20 metres deep. Over time, soak holes get blocked by the silt, vegetation and litter they trap, and this can cause flooding. These devices require annual cleaning and maintenance, which can include flushing the bores, disposing the waste properly, and checking the inlet pipes.

Soak hole inspections may also be done at any time to ensure the device is functioning as it should and complies with the required health and safety standards.

Subsoil drainage

If your existing stormwater assets are not sufficient, consider incorporating a subsoil drainage system. It can be as simple as digging a trench and filling it with gravel or rock (called a French drain or weeping tile). Modern subsoil drainage uses a specialised perforated pipe covered with geotextile material, which is laid around the foundation or in low-lying areas within the property.

As well as minimising flood risk, installing an effective drainage system can give your property’s market value a boost. In fact, part of the process of property valuation is a thorough inspection from little things such as materials quality and efficiency wiring and plumbing, to general details like the location, the lot and the house itself.

Nobody wants to buy a house that gets flooded every time it rains. So things like upgrading old plumbing fixtures or installing an efficient drainage system are good investments with greater potential reward. Even if you don’t plan to sell, these projects can increase your quality of life and protect your home from costly water damage.

 

Hiring qualified and experienced drainlayers

Below are some of the important benefits of hiring an authorised drainlayer for the job:

  • Compliance. Drainlaying is generally a restricted work because it involves sanitary fixtures that concern public heath safety. There are also minimum requirements, specifications and standards to keep in mind when building subsoil drainage, especially for subdivision construction. For instance, the subsoil drainage must have a cesspit or holding pit before overflowing into an approved point of discharge. The pipes must also be laid deep enough into the subsoil, otherwise it will simply drain away the surface water and flooding will persist.
  • Real value for money. The right people will provide the right solution for your property. You get quality results that prevent expensive problems from recurring.
  • Professional insurance reports. A standard home insurance typically includes water damage cover. If you want to make a claim due to sewer backup, overflow and discharge, or flood, a licensed drainlayer can provide you with a detailed and professional insurance report to serve as proof. If you are taking out an insurance policy, a professionally written report for your new drainage system will increase your chances of getting coverage for drainage emergencies.

To learn more about subsoil drainage solutions in Auckland, talk to us.

Have You Been Instructed By Watercare To Do Sewer Repairs?

If you are working on a public or private site near public utility pipes, you will most likely need a resource consent and engineering approval from the Auckland council as well as a Works Over approval from Watercare. As per Water Supply and Wastewater Network Bylaw 2015, the design of a structure shall protect the public water supply network and wastewater network from possible damage, misuse and interference. It also must not harm the environment or the safety of the people using the water supply.

Typical projects that need said approval are subdivisions, major developments and multi-lot projects. But in general, this requirement covers any project that includes building over a pipe, working close to a manhole and trenching of services.

The Works Over approval is given on the basis that the owner acknowledges all risk associated with repair or replacement works on the pipeline and future maintenance. On the other hand, Watercare assumes no risk or responsiblitity concerning the building, engineering or legal work associated with the application, the work itself and any consequences arising from future works (if any).

So if upon review of your application, Watercare finds any damage to the pipeline within your site plan, you will be asked to carry out sewer repairs or replacement. You may need to provide an initial CCTV inspection survey along with your application, for this purpose.

As the owner, it is your responsibility to pay for all repair/replacement costs and to ensure the following steps are undertaken:

  1. The work must be carried out by a licensed/registered drainlayer certified by the Plumbers Gasfitters Drainage Board (PGDB). A certified drainlayer would work to comply with Watercare’s requirements for your particular building project.
  2. The drainlayer must secure an authorisation from Watercare to work on the public utility network. The approval to access and/or connect to the wastewater network must be applied for and granted prior to commencing work. To apply for this authorisation, you will need to provide a copy of your approved Works Over pack.
  3. Once some or all of the work have been completed, your drainlayer should provide a CS3 form with an as-built plan of the completed work. These will be sent to compliance @water.co.nz.
  4. One all works are complete, a final CCTV inspection must be submitted to ensure that the pipe has been repaired and none of the other pipes were affected.

Under normal circumstances, building over or adjacent to a public drain isn’t permitted. Nevertheless, dispensation is given as along as specific conditions are complied with and the building work is completed according to the approved plans.

The following are the specific conditions stipulated by Watercare:

  • Existing asset/ wastewater connection

The property owner is responsible for identifying the exact location of all Watercare pipes and structures (including connections) onsite to ensure all clearance requirements are met as per Watercare Engineering Standards. Any blockages and/or damage resulting from inability to identify and protect these assets will be shouldered by the owner at his own cost.

As service connections are not allowed under the building footprint, the owner must see to the relocation of existing connections to a minimum 1m clearance from the building. Moreover, all work involving the existing wastewater service connections must be compliant with Watercare’s compliance statement policy. A separate ‘new connection application’ is required for all new wastewater connections.

  • Foundation

To protect the wastewater pipe, foundation design must provide adequate support and protection for the structure on top of the pipe and the bridging piles must absorb the structural load of the building. All excavated sites within the 45o filed of the influence must be shored or retained properly to avoid damaging the sewer pipe line. The bottom of the foundation slab or beam must be compliant with Watercare Code of Practice Drawing WW 27. At any time throughout the works, Watercare’s ability to maintain and/or replace the pipe must not be impeded.

  • Piles/retaining wall posts

There should be at least 1 metre horizontal clearance between the foundation piles and the face of the pipe. The piles must be in a predrilled hole and founded below the 45o zone of loading influence. Driven piles are not allowed unless they are over 5 metres horizontally from the face of the pipe.

For keystone retaining wall foundation, a minimum vertical clearance from the top of pipe is required as per Watercare Code of Practice Drawing WW 27.

A council structural engineer must inspect bridging details and calculations before issuing a Building Consent and/or EPA.

  • Driveway/vehicle crossing

A minimum of 900mm vertical clearance must be maintained from the top of the driveway slab to the top of the water and wastewater pipes. Heavy machinery must NOT be parked or operated directly above Watercare assets.  Surface mounted assets must be cordoned off to avoid traffic movement over them or must be protected with 30mm steel road plates at construction vehicle crossing points. Any exposed mains must be cover with 150mm layer of SAP7 cushion prior to backfilling. Backfill must be compacted in 200mm layers to achieve maximum density.

  • Manholes

During the course of the work, the owner must ensure all manholes are accessible at all times. The minimum clearance from any structure is 1 meter from the outside edge of the manhole chamber.

  • Damage to Watercare asset

If in case the public water or wastewater line is damaged during construction, the owner must immediately advise Watercare and seek approval for repair work.

  • Post construction CCTV

A final CCTV inspection survey and log must be submitted to Watercare once all of the works have been completed. This is to ensure that no defects/damage to the sewer pipes have been incurred during construction. If any issue is found on the post construction CCTV, the repair and all associated costs must be borne by the property owner.

If you need a reliable drainlayer to carry out Watercare compliant sewer repairs, get in touch with Euro Plumbing on 0800 832 638. We have the expertise and equipment for the job, and we’ll take care of your repairs so you can proceed with your building project ASAP.

Wet Carpet Flood Tips

A wet carpet is more than just a nuisance. It may be a symptom of a more serious underlying residential drainage problem such as basement flooding. Not only that, it may also become a cause for serious health risks, i.e. the growth of moulds or mildew.

There are many possible scenarios that can lead to basement flooding. Houses built on wooden pilling with external block walls on foundation are prone to this issue. On the other hand, below-ground-level entryways or long steep driveways invite surface water into the home.

Regardless of the cause, basement flooding is something that needs urgent attention. Wet carpets harbour moulds, including a particularly dangerous one, Stachbotrys, that can cause severe illness in adults or death in infants. In ideal conditions, moulds can grow on wet carpet within a span of 48 to 72 hours

Before you panic, read this handy guide for dealing with a flooded basement. Doing these steps will help prevent permanent damage to your property and belongings:

  • First of all, turn off the circuit breakers to the flooded areas and remove any small electrical devices. For your safety, wear rubber boots and gloves. Or call your local electrician for help.
  • If safe to do so, remove small furnishings immersed in the water to prevent rotting or rusting. Metal furniture may also leave stains on the carpet if left standing on it too long.
  • Hang draperies or other furniture skirts that are in contact with water. This will prevent water stains.
  • Remove valuable items, paper goods, potted plants and breakables.
  • Do not attempt to use a vacuum or shop vac to remove water from the basement. This is a potential electrical shock waiting to happen.
  • Make sure to thoroughly wash your hands after removing important items from your basement.
  • If you suspect that the flooding is sewage related, do not handle any of the items. Also, do not use a fan or turn on the air con unit to dry up the wet floor. This will only help to spread the contamination.
  • Plan for flood restoration professionals to dry and disinfect the flooded area.

Ultimately, the best solution in this situation is to solve basement flooding permanently, not just to deal with the effects.

If left unresolved, it can cause considerable damage to the flooring, furniture and even the structural foundation of your home. You’ll likely run into the same problem in the future as well, so it’s like a never-ceasing headache.

Fixing the root of the problem is the best route. Once you got that sorted out, you should call in flood restoration experts such as Auckland Steam ‘n’ Dry to get your basement back to its original state. You can call them on 09 376-7007.

We recommend doing it the professional way because it guarantees proper drying and restoration methods that will prevent the growth of moulds and eliminate any contamination issues.

 

 

Boggy / Soggy Lawn Solutions

Boggy lawns are a pretty common problem for homeowners in Auckland, where many areas have clay soils. High-density soils such as clay soil and compacted soil have low percolation, which means they drain water slowly. As such, they tend to get waterlogged easily in a flash rain, resulting in a soggy lawn.

 

Having a boggy lawn can be problematic in a number of ways. For one, it can cause flooding. In the event of a heavy rain, the surface water from your lawn might find its way into your basement. Things can get really messy and costly to deal with. If you are growing a garden, poor drainage can drown your flowers and vegetation.

Fortunately, there are a number of subsoil solutions for soggy lawns. The right method will depend on how big your lawn is, how often it gets wet and how long it remains wet.

If the lawn is relatively small, it might be easier to eliminate the problem rather than solve it. In other words, you might want to consider altering your lawn. A well-draining soil needs air in it. In the case of clay, the tiny soil particles are compacted so they don’t allow much room for air. To manage this, you can introduce lots of organic matter such as compost and aged manure to lighten the soil. Organic matter will force the tightly packed soil particles apart, resulting in improved drainage. If you are growing a garden, another option for you is to build raised beds on top of the clay. Planting a cover crop with a deep root system, such as clover, turnip and alfalfa, can also aerate the soil.

If altering your lawn isn’t an option or if your soil is heavy clay, a more effective solution is to install underground drainage pipes or tiles. This is done by laying clay or plastic pipes beneath the ground to create a soakaway that will drain the water off your lawn.  A soakaway is a hole dug in the ground that’s filled with coarse stones, gravel or any material that will allow the runoff to percolate back into the ground faster.

 

It might sound like a project you can DIY, but it’s a lot of physical labour and can become costly if you make even a small mistake. It also requires precise engineering to ensure proper water runoff and percolation in even the heaviest rains.

We know this very well and we’ve seen a lot of botched DIY attempts at managing a clay lawn, which is why Drainage NZ offers affordable, engineered basement and garage flooding solutions for Auckland. We remedy boggy lawns by installing compliant garden drainage. The process involves soil assessment and percolation tests, so we can determine exactly how to work around your lawn.

Once we have determined the ground slope, percolation rate and the proper location for the drainage pipes, we’ll build a trench filled with loose soil or gravel that will receive the surface water. This is also where the drainage pipes will be laid. The width of the drainage area will depend on the rate at which water must be absorbed back into the ground. If the lawn tends to get waterlogged relatively fast, the trench will have to be larger and filled with gravel instead of loose soil. The drainage pipe used here has special holes in them to allow the water in the trench to enter and be swiftly carried away to a catch area.

The good thing about this solution is it can be integrated into your garden design. It doesn’t have to be an odd line of gravel around your lawn as the drain can be covered by turf or made into an attractive footpath.

Flushing Tampons Down The Drain, What A Pain!

Flushing a used tampon seems like the most convenient course of action – it’s totally mess free and you won’t have to go looking for a nearby rubbish bin. However, in this case, the easiest option isn’t the best.

It’s not a secret that flushing tampons down the loo can clog up the plumbing system and harm the environment. Even tampon brands have these warnings explicitly written on their product packaging.

The problem with flushing tampons

Tampons are designed to be super absorbent. Once they go down the drain, they absorb all the water they can hold and expand like crazy. In fact, they can expand up to ten times their original size. And since they cannot be processed by wastewater treatment facilities, drains are bound to get clogged up by years’ worth of used tampons. Need proof? Have a look at what we found on our recent drain unblocking and CCTV drain inspection work.

Sure they are ‘flushable’ in the sense that they go down the drain without any problems. But the truth is tampons don’t break down in seconds like tissue paper does. Even the biodegradable options take months to break down, so they remain practically intact while they’re making their way through the pipes or the sewage treatment system.

When all those tampons accumulate in the pipes, they can cause blockage which is both problematic and costly. This costs utilities billions of dollars in repair and maintenance costs each year. And you can bet it will cost you a fortune if it happens on your property. If you have a septic tank, the tampons will sink to the bottom and impede the tank’s ability to function.

The result? Blocked drains can cause flooding, health risks and damage to property. It can be very costly to fix these problems.

Aside from causing blockage, flushed tampons can get into clean water sources when the sewer pipes back up and the wastewater overflows into our creeks, rivers and streams. In some instances, they bypass sewage treatment facilities altogether and end up directly in waterways. They not only become an eyesore but can also harm wildlife. In fact, thousands of marine animals and seabirds die from ingestion of marine litter, which include tampons.

Now, if you think flushing tampons down the drain instead of throwing it in the bin is keeping them away from landfills, hold that thought. Any waste that gets caught in the sewage are eventually strained out and sent to – you guessed it – a landfill. So that’s basically just taking the longer route.

What can you do about it?

For starters, follow the 3P’s rule, which is to flush only pee, poop and paper (sparingly). Wrap your used tampon in tissue and throw it in the rubbish bin where it belongs. It’s that simple.

How about the ones that are already down the drain? If water from your pipes is starting to back up or if your drains aren’t working as well as they should, call our team for a drain unblocking and CCTV survey. During inspection, we’ll send a tiny camera down your pipes to locate the source of the blockage before attempting any treatment. This saves a great deal of your time and money, since we can provide the right solution based on concrete evidence and diagnosis. It also means we won’t have to go digging around in your property to find the problem.

For more information, don’t hesitate to call us on 0800 DRAINLAYER (0800 372 465).

What To Do If Your Drains Are Not Draining

Are your drains slacking on the job? Maybe you’ve noticed that your drains are not draining as quickly as they used to, or maybe they are even flooding! If that is the case, you most likely have a blocked drain, and this is not as uncommon as you may think.

Why do drains block?
Common caused for drains getting blocked include:

  • Rubbish stuck in pipe
  • Leaves or other substances blocking the pipe
  • Damage or collapsed pipe
  • Tree roots which have grown into the pipe and blocked it
  • Silt and dirt build up after years of drainage service

Blocked drains are actually a common problem and can cause serious issues if left untreated. Blocked drains can cause health issues and property damage. If you have noticed a blocked drain, you would be wise to act on it.

What to do if you notice a blocked drain
If you notice a blocked drain, you should pick up the phone and call a drain unblocker. The best and fastest way to see what is causing the blockage is by means of a CCTV drain inspection. The drain unblocker will put a CCTV camera down the drain to see what is causing the blockage, and once this is known then appropriate action can be decided.

Here is an example of a CCTV drain inspection:

Once the blockage has been identified, it can now be decided how to best tackle the problem. The solution will depend on whether it’s a blockage or whether the drain is damaged.

If the problem is a blockage, the most likely course of action wiull be to unblock it by means of Hydro jetting. This involves putting a jetting hose down the drain, which sprays water through a water jet at very high pressure to clear any blockages. This method is faster and cheaper than all other drain unblocking solutions, and can be used on all sizes of drain pipes.

If the drain has been damaged, whether it’s by tree roots, burst pipe or otherwise, the solution will involve repairing the broken section of pipe. This is more complicated than a drain unblocking but is necessary to get sorted.

If you are having drainage issues, contact us today by calling 0800 372 465 and let us solve your drainage problem!

 

Hynds Streetware Product Range

When it comes to streetware castings, there is one brand name that quickly comes to mind: Hynds.

Hynds Pipe Systems Limited is New Zealand’s premier supplier of water and water-based waste management systems for civil, rural and infrastructure applications. This massive family business has built a name and a strong culture through innovation and partnership, which evidently shows in the quality and durability of their products.

To date, Hynds has a nationwide network of 32 merchant branches and over 40,000 product lines, including a full range of innovative Streetware products.

Hynds Streetware

The brand offers a comprehensive range of spun and precast products that include:

  • Traditional cast iron manhole cover and frame sets
  • Cast iron manhole grates, inspection covers, carriageway covers
  • Stormwater grates
  • Safety grilles
  • Surface boxes
  • Kerb and channel grates

All of their products meet currently recognised Australian Standards AS3996-2006 and European Standards EN 124, as well as the loading requirements specified in Transit NZ’s HN-HO-72 standards.

Hynds’ castings load rated for a wide range of applications, from light duty pedestrians to heavy duty carriageway locations, and extreme heavy duty and trafficable airport runways. For your reference, here are the internally approved load classifications:

Cast iron is traditionally used for manhole covers for its robust and reliable nature. Hynds use Gray (Flake Graphite) Grade T220 cast iron in most of their infrastructure castings, making sure the design and quality meets both municipal and regional specific standard requirements. Currently, they are supplying manhole access covers and frames specifically to the council standards of Napier, Palmerston North, Christchurch, Queenstown and Invercargill regions.

Among its product lines are:

  1. Cast Iron Access Covers (Class B and Class D loads)
    With a 450-500mm clear opening, these access covers easily retrofit into existing concrete manhole tops, with a choice of flat or spigoted frames. There’s also a complementary range of circular manhole grates for these access covers.
  2.  

  3. Hytech Manhole Cover and Frame Sets
    NZ’s local authority called for cast iron streetware products to be manufactured to a recognised standard and tested by an independent third party. Hynds responded with its Hytech range, which carry the NZ Standards Mark and accredited by OPUS International Consultants. Each product in the range is load tested to Australian Standard AS3996.
  4.  

  5. Cast Iron inspection Covers (Class A load)
    This range consist of light duty, non trafficable inspection covers and frames for grease traps, electrical pits and other areas where regular maintenance is required. The inspection covers can be made watertight and airtight by adding a silicon sealant. It’s locked down with stainless steel allen head screws to prevent theft or unauthorised access.
  6.  

  7. Cast Iron Storm Water Grates (Class B to D loads)
    These grates are suited to the standard range of concrete cesspits and sized to suit standard sump range. For 675x450mm sump sets, you can have the option for adding anti-theft brackets and screws.
    This particular range is compatible with all regional council requirements for Whangarei, Bay of Plenty, Hamilton, Palmerston North, Napier, Wellington, Christchurch, Queenstown, Dunedin and Invercargill.
  8.  

  9. Non Slip Heelguard Grates (Class A and Class D loads)
    Particularly suited for pedestrians and areas with expected heavy foot traffic, this range features non-slip epoxy coating and long-lasting galvanised steel construction. Hynds’ Heelguard grates have a flat-edged frame to ensure ease of use with concrete/asphalt pavers, and are compatible with standard concrete sumps.
    Grate and frames sets are available for trenches and cesspits.
  10.  

  11. Manhole Safety Grilles
    Hynds supply two Watercare-approved brands of stormwater and manhole safety grilles: Caliber and Impact. Both can be retrofitted into existing and new manholes, but Impact grilles can be adjusted to suit a wide range of opening sizes.
  12.  

  13. Surface Boxes
    A full range of surface boxes made for hydrants, lampholes, pressure sewers, valves and Toby boxes, all of which meet regional and municipal council requirements.
  14.  

  15. G.A.T.I.C Range
    Sourced from internationally recognised manufacturers, the products in this range are gas, water and airtight with load ratings from Class B (Pedestrian) to Class F/G (Airports/Ports).The Infilled/Solid Top Covers and Decorative Edged Covers feature machined mating surfaces and decorative edge (on request). It comes in either a single or a multiple-part cover and frame set. There are also options for square, rectangle, tee or cellular frames.Meanwhile, the Xpave Infilled Covers are designed with a deep recess to accommodate thicker pavers as well as to make access points discreet and unobtrusive in pedestrians and trafficable areas. The covers are laser-cut for utmost precision.
  16.  

  17. UBER
    Made with Spheroidal Graphite Grade 500/7, the ductile iron access covers in this range are lightweight and robust but 30% lighter than traditional cast iron. Personalisation is the hallmark of this range, with specific council designs already in supply. The system features bolt down security that meet the HN-HO-72 requirements for sewer and stormwater lids.
  18.  

  19. Di-Hinged Carriageway Covers
    Manufactured in France for high intensity traffic environments, these ductile iron-hinged access cover system exceeds expectations in terms of strength, performance, stability and protection against water ingress.The range features 360-degree EPDM sealing rubber for non-rock stability, cover locks that open at 90 degrees and personalisation options.
    There are four models in this range: MAESTRO, TWINO, MAXIMO and SOLO. The first three models are load rated to 400kN, while SOLO is designed to suit higher loadings up to 900kN in industrial settings.
  20.  

  21. Ductile Iron Stormwater Grates and Frames (Class D240)
    Designed with improved hydraulic capture, higher loadings, cycle friendliness and greater aesthetic appeal in mind, these stormwater system features side-locking frames and anti-theft hinge and bolt. It fits standard concrete sumps.
  22.  

  23. Stormwater Kerb and Channel Grates (Class C260)
    Manufactured in France, Hynds stormwater grates are cycle friendly and meet special requirements associated with smaller subdivision streetscapes.

For the full product specifications and information, see the Streetware product catalogue.

Is Basement Waterproofing (Tanking) Paint-On Membrane The Solution?

In theory, a basement built in decent, free-draining ground conditions will stay dry. But if there’s a build-up of water in the ground surrounding the basement, the water will penetrate the floor and walls through any cracks, joints or structural weaknesses in the basement. This water ingress can lead to mould growth, decay and leaking.

For obvious reasons, a basement needs some form of waterproofing to prevent damp-related issues that could lead to more serious structural problems.

Waterproofing Membranes

The easiest known method of basement waterproofing is applying an external membrane or liquid coating on the outside and/or inside of the wall to create a hydrophobic barrier.

Some waterproofing membranes are “stick-on” plastic sheets that are inexpensive and quite simple to apply. However, these membranes can easily lose adhesion when things get wet on site or when there is high humidity during application. These can also be damaged during backfilling operation or incorrectly installed by the contractor. A better option is a “paint-on” waterproofing membrane, which has less room for builder error and last a long time. These tanking membranes can be easily applied using a paint brush, roller or trowel.

Just like paint, there are different types of waterproofing membranes made for different structures and soil conditions.

For example, Cemix Crystalproof is a crystalline material which waterproofs and protects concrete in-depth. It can be used for both internal and external waterproofing of any structurally sound concrete (new or old), including moist or green concrete. Its ultra-strength bond ensures long-term protection even when subjected to high water pressure.

On the other hand, Aquastop is best used for concrete, block and masonry surfaces. It’s most suited for inside concrete block basements as it can withstand pressure from a head of water (hydrostatic pressure) and keeps internal areas dry, though it can also be applied externally.

For concrete block walls, retaining walls and timber posts, a stable flexible bituminous emulsion like Bituproof Plus works best as it does not creep under heat or slump in vertical surfaces. However, this product is only suitable for use on the positive side of the wall where water or moisture can enter the structure.

Elastomeric membranes like Cemix Rubberguard are an innovative waterproofing solution that offers the best durability. When applied systematically and allowed to cure completely, these membranes make basement walls impermeable to water, chemical vapours and subterranean gases. Rubberguard, in particular, has excellent adhesion properties over concrete, masonry, cement sheeting, renders, plaster board and wet area sheet surfaces.

Sealants and Joint Treatments

Other considerations in using basement tanking membranes are sealing active leaks or cracks and ensuring the corners and joints are also protected.

Crystalproof and Aquastop can both be used to seal minor cracks up to 0.4mm. Bigger cracks can be filled with the Cemix Quick Patch repair mortar. Block walls and floors with rising damp can be cured instantly using a nano-technology sealer like Cemprotect, which penetrates hydrophobic protection treatment for all cementitious substrates including natural and artificial stone. It’s designed to protect concrete from gradual water damage and enhance the effectiveness of the waterproofing membrane.

For the corners, pipes and joints, there are elastic bands and seal tapes specifically made for these volatile areas. The ones from Cemix Safeguard range are high-strength and tear resistant, offering long-term sealing protection.

Are Paint-on Tanking Membranes the Solution?

Paint-on membranes have the advantage of low in-place cost, quick application and excellent elongation. When applied correctly, they can last for decades. The chief disadvantage to them is the possible inconsistency in coverage. It takes careful application to achieve the minimum coverage thickness of 60mils.

Moreover, it’s good to remember that these cheap methods only manage the symptom rather than treat the cause. If you don’t solve the root of the problem, groundwater will still seep into anything that’s not 100% structurally perfect, including a tanking membrane that has not been applied properly.

So what’s a good basement waterproofing design?

It should include a system for removing excess water from the soil surrounding your property. An effective yet unobtrusive method is to install subsoil drainage, wherein drainage pipes are installed underground to intercept and convey subsurface or seepage water.

Benefits of subsoil drainage:

  • Protection from water damage
  • Increases stability of the ground and soil strength
  • Reduces foundation movements caused by the variations in the soil moisture content

The subsoil drainage system is ideally installed around the perimeter of your home so that the water gets drained before it reaches the foundation. If you have a retaining wall, it’s a good idea to locate the drainage pipe behind it to relieve hydrostatic pressure. The important thing to remember is to place the system above the natural water table so you’ll drain away the surface water, instead of groundwater.

The most common type of subsoil drainage is a special geotextile-covered pipe. The pipe has a number of perforations which allows water to be drained away to enter. The geotextile covering stops soil and other particles from going into the pipe and clogging it up. A simpler type of subsoil drainage is buried rocks or pebbles, which acts as a free draining system. The subsoil drainage must discharge water into a cesspit or holding pit, where any debris is cleaned out, before overflowing into an approved point of outfall such as soakholes, a curb discharge or an existing stormwater system.

To prevent clogging, the drain pipes should be at least 7.5mm in diameter and the trenches should be 300mm-wide at the very least. Drain envelopes are installed around a subsoil drain to provide structural bedding for the pipe and increase the effective surface area of the drain.

The Verdict

Basement waterproofing membranes are great if you need a quick fix that is inexpensive. But the fact is they don’t solve the problem at all and there’s still a risk of running into bigger problems later that costs more to repair.

Installing a subsoil drainage system should tackle the problem at its roots. If you need more information about it, call us on 0800 372 465.

Stormwater Galv Kerb Outlet Installation

What is a kerb outlet? They are essential parts of drainage systems which serve to remove the excess water from your property by directing it to the kerb on the street, which will then flow into the stormwater system.

Firstly, kerb has two spellings, also being written as curb. “Curb” is the American spelling of the word, where as “kerb” is the correct English standard as has been used since the mid 17th century. Since in New Zealand we use the English standard, we will go with the spelling “kerb”.

Kerb outlets can be used in conjunction with driveway channels, gutters and other types of water removal drainage systems.

We just completed a job for a customer which involved installing a kerb outlet for their stormwater drainage system.

For this job, we had to remove part of the footpath as well as some ground from their property in order to run the piping for the outlet. Once the ground was removed, we could lay down the pipe which was 100mm diameter uPVC in this case.

In this system the kerb outlet was used in conjunction with a 5,500L stormwater above ground detention tank. The outlet was connected to the gutter drain as a means of escape for the stormwater.

Once the pipes were laid, we reinstated the concrete on the foot path and to the neighbouring property that had to be removed. The road and driveway were then cleaned up from all the left overs of working there.

Why would you need to replace a kerb outlet?
Kerb outlets are crucial part of stormwater drainage systems that ensure that water being drained can be removed from the property onto the road, where it can then drain into the main drainage system. If your kerb outlet is blocked or damaged, you could find yourself with a flood in your yard, which could even cause damage to your home.

Do you need a kerb outlet for your drainage system? Contact us today to discuss your drainage needs.

Basement Flooding Problems Solved

Basements are inherently prone to flooding due to the fact that they are built partly or entirely below ground level. And thanks to gravity, water easily finds its way from high to low ground. If the water level around your home rises above the basement floor, then gravity will naturally move that water into your basement.

There are a number of reasons why basements flood.

  1. Surface inflow

Basement flooding is common during wet weather. During heavy rains or rapid snowmelts, surface water may accumulate around the house and find its way into hard surface depressions such as driveways or basements.

  1. Structural issue

If you notice a tiny wet spot in your basement, don’t assume it’s nothing. It could be a sign of a structural issue, like a crack in the foundation floor, that will allow groundwater to seep in. If left unresolved, that tiny spot could turn into full-on flooding that may cost you thousands in carpet damage, basement repairs and restoration.

  1. Foundation drainage failure

The foundation drainage system of your basement works to keep the ground water level lower than the basement floor, either by gravity or by pump.

Gravity foundation systems (weeping tiles) may get plugged by fine sediments or degrade over time. As a result, the system will cease to drain water by gravity. On the other hand, a sump pump built into the basement, which pumps out water around the foundation and discharge it into the lawn, could fail if they are plugged or can’t keep up with the incoming water.

  1. Sewer backup

By design, sanitary sewers have a path to the home called the sanitary sewer lateral. This allows domestic wastewater to flow from your home out to the sewer pipes. But when the sanitary lateral fails, sewage could backflow into your home.

The sanitary lateral fails if it is blocked by what is being flushed down the toilet, it is damaged due to aging or if the sewers are full. You’ll need a licensed plumber to carry out an assessment and resolve the issue properly.

  1. Broken or malfunctioning pipes

Plumbing failure can sometimes be to blame for basement flooding. A flood could break into the home’s internal water supply line in many ways – burst pipes, damage to aging plumbing equipment or failure of the hot-water tank.

What to Do When Your Basement is Flooded

  • First thing to do is switch off any power around the area. Never step into a flooded area before doing this. Call a qualified electrician if you’re not sure how to turn the power off.
  • If it’s not due to rainfall, it’s best to call in a licensed plumber to help you check the drains, sewers and pipes for the cause of the flooding.
  • Once the issue has been resolved, act fast in removing water from the basement. The longer the water sits, the more damage it will cause. Make sure to wear protective gloves and boots (and a nose plug if the smell is rank).
  • Remove all the stuff in your basement and allow everything to dry for 48 hours. If they remain wet after that, it’s best to discard those items to avoid mould or mildew. Don’t be tempted to keep soggy carpets or rugs, as they may carry bacterial contaminants.
  • Scrub and disinfect every inch of your basement, from floors to walls, cabinetry and hardware. Then allow to air out until totally dry.
  • If you have flood insurance, you may need to take photos of the damage for documentation purposes. Confirm your coverage and claims process.