Here are the most common questions that we are asked about Moisture Detection Probes and RotStop timber treatment. Please contact us if you have any further questions.

Frequently Asked Questions

We are Auckland based experts who find weathertightness issues in plaster clad houses. We use unique, patented technology to find leaks and decay, and provide a range of solutions to solve leak and rot problems cost effectively. 

  • Home-Owners – to keep their houses safe and dry, 
  • House Buyers – to find out potential problems before they buy, 
  • House Sellers – to prepare their plaster clad house for the best sale price
  • Real estate agents – to help their vendors sell their homes and to help purchasers make good buying decisions
  • Builders – for timber treatment testing
  • Property Managers / Body Corporate Managers – to keep their buildings in tip top condition
  • Is the timber treated and if so, how well treated?
  • Are there any leaks?
  • Is there decay in the house?
  • What are the risk features of the house, i.e. where could leaks be happening now or in the future, and what features will make it harder for me to sell the house to someone else?

In this hot real estate market, it is tempting to get carried away and buy a house without taking enough time to inspect it properly.  This is very risky and there will be a lot of buyers falling into this expensive trap.

You should obtain an independent pre-purchase inspection report from a reputable inspector.  However, these reports will nearly always recommend further invasive weathertightness testing, because a pre-purchase inspection is only visual and cannot tell you what is happening behind those nice freshly painted walls. 

Without mores testing, you could be paying too much and have expensive repairs coming up that you didn’t expect.  In some cases, we see buyers being stuck with houses that really require full reclads or rebuilds.  With the right information, you can either walk away from a lemon, or reduce the price you’ve offered to allow for the repair costs. 

MDC offers weathertightness inspections from the basic visual investigation up to full Moisture Detection Probe system installation (highly recommended).

We find major unknown or undisclosed weathertightness defects in the house that are either going to cost you a lot of money to repair, or will devalue the house when you decide to sell.

This means that you need to buy the house with your eyes open – you need to know what you are getting so there is less chance of an expensive surprise.  

The hard evidence that we gather allows you to negotiate a fairer price for the house – why should you have to pay to fix someone else’s problems? 

There are many factors involved in determining if your house is at risk.  The main ones are:

  • Whether the framing timber is properly treated
  • Whether the cladding is direct fixed or has a cavity to allow the timber to dry out
  • Whether the building is designed, built and maintained well enough to keep the water out 

The biggest risk though is not knowing what is happening in your house because expensive damage can be spreading unseen inside your walls. MDC’s proven and inexpensive investigation process will find out all the answers so that you can make the best decisions.

MDC help owners to find leaks, fix the leaks, and then keep the home leak free.  We find out if there is any decay and whether the house is made from treated timber and design a maintenance programme so you can keep living in the house for as long as you want. 

Every plaster clad house should be monitored with probes to keep it dry, prove that it doesn’t leak and help prevent the need for a reclad in the future.

Every seller of a plaster clad house should know that there is a ‘stigma’ that keeps many buyers away and reduces the selling price.  Many owners struggle to even get an offer above land value.  Often when an offer does come in, the pre-purchase inspection finds problems and the buyer pulls out or expects to buy your house for peanuts.  It can be very discouraging for sellers of plaster clad homes and many end up virtually giving them away.

MDC recommend that they are engaged at least a year before putting a plaster clad house on the market.  This gives us time to find and fix leaks, repair decay if necessary, treat any untreated timber and alter details that may deter buyers.  

We will never promise to get rid of the plaster house stigma completely, or make the house worth as much as a non-plaster clad house, but we will get more buyers interested, avoid nasty surprises in the pre-purchase inspection report and therefore increase the likely sales price.

We can measure the real moisture levels in the framing in all the places that leaks are likely to show up.  Our patented discrete Moisture Detection Probes are installed into small holes drilled through the skirting.  We then read these with our moisture meter.  From 40 to 80 probes are used depending on the size of the house, and how it has been designed and built.  The probes stay in the house as a permanent leak detection system to pick up any leaks that develop in the future and provide proof that the house is dry.

When we install a Moisture Detection Probe into the skirting board, we also save the timber samples and analyse them in our laboratory using scientifically based and peer reviewed techniques.  This clearly shows whether decay is present and how bad it is.  If necessary, we can then take further samples to see how far the decay has spread from the leak point. 

It takes less than a day to install the probes and there is very little disruption to the occupants.  Once they are in place, all you see is what look like small buttons on the skirting boards.

Houses built between 1992 and 2005 are at the highest risk of being built with untreated or badly treated timber. 

You can’t usually tell by looking at it, unless it has some label or printing giving this information. Newer houses may be built using treated timber that is dyed pink. 

The only way to tell conclusively is by testing samples for boron, tin or CCA treatment.  

MDC can collect samples from your house, or you can send them to us.  Beforehand, however, please ask us for instructions on how to gather samples.

Once you know how well treated you house is, you know how quickly you need to react to leaks. 

Untreated timber – you need to react quickly as decay can set in as soon as the timber becomes wet.

Boron Treated timber – depending on the strength of treatment you may have more time to react to a new leak.  Boron leaches out of wet timber leaving it unprotected and we see many houses, with well treated timber, showing signs of bad decay – all because the leak has been allowed to go on for year after year.

Tin – this was only used for a few years but gave good protection if it was strong enough.  However, the treatment level was often inconsistent in strength and coverage throughout the wood.

CCA Treated timber – this is much more decay resistant and is the best treatment available. 

By making decisions based on real evidence.  We make sure that we spend your money on the actual problems.  We have developed cost effective repair methods for the common defects in plaster clad houses.  We avoid recladding and major rebuilds by treating timber with RotStop, wherever possible, instead of replacing it. 

The Mdu Moisture Detection Probe System is a series of small moisture measuring probes installed through your skirting boards and deep into the framing timber around the base of the wall (called the ‘bottom plate’).

The probes allow the real moisture level of the timber to be read at the locations where water from leaks is going to show up.  The full system includes decay and timber treatment analysis so the end result is real, scientifically based evidence about where your house is leaking, where decay may have started and how well treated your timber is.  

Once any problem areas have been repaired, the probes are monitored regularly to check for any new issues.  Houses, like cars, need regular maintenance and the probe system warns you when this is needed.

The history of the probe readings, your timber condition and timber treatment information is stored and available on-line as a permanent record protecting your investment by proving that your house isn’t a leaker – vital information to share with potential buyers when you want to sell.  Read more here.

MDC has been helping owner and buyers of plaster clad homes since 2005.  In the early days, we were mainly engaged in helping owners to find out where their homes were leaking and decayed, so they could make a claim against the councils or builders.  Now, the claim process is closed to nearly all owners, so MDC now help owners repair, protect and maintain their houses for the minimum cost.