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Flat Roofs Core Sampling Surveying

Flat Roofs Core Sampling Surveying

Flat roofs are relatively inexpensive and very efficient to keep your buildings and your internal assets covered and protected from the weather. What can you do to identify flat roof defects?

Defects for flat roofs

 

Whilst their relatively low cost for a good protection plays to their advantage, this type of roof is also notorious for defects that often remain unnoticed until it is too late. As with any part of a building, they will be subject to wear and tear and will receive copious amounts of water.  Regular inspection of the roof is essential to make sure that this essential element is in tip top condition and kept free of defects.

One of the most common defects is water ingress which then leads to a leak inside the building. When water ingress does occur on a flat roof, damage often goes unnoticed for considerable time as water slowly penetrates and soaks the decking, insulation and/or structure beneath. This can lead to extensive damage. If left unattended and no leak detection surveying takes place, it can weaken the whole structure and have catastrophic operational and financial consequences for you.

Other defects can occur too. You can read our most popular blog post about the five common flat roof defects here

 

Flat roofs core sampling to detect water ingress

Core sampling allows the surveyor to see the make up of the roof and locate where water saturation may be.

The image above shows what appears to be a roof in a good condition with no obvious signs of moisture ingress, however;  the tenant has been complaining that there are leaks into his top floor office. 

Imagine, this is your tenant. You arrive on site with a surveyor and  the tools for the job, get onto the roof above the leaking office, but where should you start to take a core sample? You carry core samples, one is wet, two are dry. So we know that the insulation is saturated, but to what extent?

Using the roof image above, grab the slider and drag it across the image to reveal the thermal image, in short, red colours reveal saturated insulation (You can find out more about the meaning of infrared colours in our Understanding Colours post.). This  tells you everything you need to know about the accuracy of core samples. By relying solely on core sampling, your surveyor could mistakenly concludes that the entire roof needs replaced or on the opposite, that the roof is sound. How can you know for sure?

If your surveyor is employed by a roofing company, the impartiality of the advice could well be put into question. It is a matter of trust and reputation.

Flat roofs core sampling technique

The method and process of core sampling is therefore important. The core sample technique should be as follows:

  • take one core sample at a high point,
  • take one core sample at a low point and
  • take one core sample mid-way.

Critically this should be at random locations on the roof, not in a straight line. That way the surveyor can find out if water is coming in at parapets and tracking it down, if the area around the outlet is wet as water loves gravity and then try to ascertain the extent of the damage at the mid-point.

The surveyor will take appropriate notes and photographs. Then of course, they must patch the core sampling holes by resiting the sample and sealing the edges. Often this is made using blow torches.

This technique carries high risks for you and for the surveyor:

For you risk of fire from blow torches. Smouldering the flat roof away and causing extensive damage which could cripple your business,

Again for you invalidating roof construction guarantees by cutting holes through potentially perfect waterproofing.

For the surveyor, the risks are inherent to health and safety: slipping on a wet surface, working at height, stand alone working, fire protection, etc.

It is therefore easy to conclude that core sampling should be a last resort surveying technique, just before the nuclear surveying method.

 

Flat roof defects: infrared is the detection solution

If you are an asset manager, estate manager, building surveyor and are being asked to make a budget go as far as possible, then it is essential you get and give impartial advice to the building owner. By investing in an infrared thermographic survey,  you mitigate risk from a third party advising whichever solution meets their commercial needs and wants.

Thermal imaging can’t tell the difference between polyurethane and fibreboard. Wet is wet and that effects the temperature on the surface. Why? Simply put, wet insulation doesn’t insulate as well as dry insulation – so heat escapes the fabric. Also because water has a high emissivity. This means that water radiates its energy particularly well when it has finished absorbing it from the sun and from the building itself. This high emissivity makes the wet area appear warm to the infrared thermal camera.

Drones  are now extensively used to aide thermal imaging, thus eliminating most if not all health and safety risks for the surveyor as well as improving the accuracy of the surveying results, there is little not to like about infrared.

A thermographic survey may help you save hundreds of thousands of pounds by turning what you had assumed would be a complete “strip and re-new” into a partial strip and overlay. Conversely however the opposite may be true.

The point being: you will get the truth and if you are interested in delivering value to your clients and managing a sustainable portfolio, that’s an invaluable weapon in your armoury.

Core samples have their place of course. We will always advise you hand your infrared survey reports to your roofing company who may then core and confirm the infrared survey findings. More importantly the core sampling will allow them to establish what the roof is actually made of so that they can propose the appropriate solution for your roof refurbishment.

Do you own or manage buildings with flat roofs? We would like to know what surveying method you favour and why. Drop us a line, give us a call, let's talk all things flat roof surveying.

Drone technology for infrared thermography

Drone technology for infrared thermography

You may want to have an infrared survey carried out for a variety of reasons. Infrared thermal imaging technology is ideal for detecting defects and energy deficiencies of buildings and housing stocks. Combined with drone technology, it becomes a limitless tool.

Let's take a closer look at drones.

3 ADVANTAGES OF DRONE TECHNOLOGY FOR IRT SURVEYING

For 16 years IRT Surveys have been surveying buildings using infrared thermographic (IRT) cameras. Mostly on foot. This means that when it is a high building or a flat roof which needs surveyed, equipment  such as cherry pickers have to be hired. This has cost implications for our clients and Health & Safety implications for our certified thermographers and anybody or building in the surrounding area.

There are other technologies available:

  • Radio controlled tethered air balloons: wind and power lines make them impractical.
  • Telescopic pneumatic mast bolted to a van:  a relatively successful technology that IRT Surveys used for years. Ideal then to capture an entire flat roof in a handful of images. The downsides are time-consuming set up, dangerous in windy conditions, and taking images at weird and unexpected angles. Also from a practical point of view, parking the van at the correct location for carrying out the infrared survey can be problematic. The whistling noise created when driving the van is also distracting. Today, masts are largely a thing of the past thanks to other technological advances.
  • Radio controlled helicopters have been around for years, but are difficult to fly and terrifying with the blades and internal combustion engines wiring away.

Nowadays we use drones. IRT Surveys have a small fleet of drones in the UK operated by CAA approved, ITC qualified thermographers with night-time licenses.

ENHANCING IRT SURVEYING: FROM FOOTPRINTS TO DRONE FLIGHTS

Drones are a breeze to fly and present at least three main advantages.

  1. Drones are safe and get the camera to places that are cost-prohibited by any ground based system. From a high vantage point we can also cover large areas in a short window of time.  They are therefore ideal for tall building and flat roof surveying.
  2. They are capable of carrying thermal imaging cameras better than handheld ones to heights that neither a mast nor a cherry picker could reach.
  3. The flight plan can be programmed on a tablet allowing the drone to fly largely autonomously . Since it’s usually us humans that crash the things, this can only be a good thing.

As with any technology, they aren't perfect and and their future will be determined by regulation. Many companies are investing in anti-drone technology now to shoot drones out of the sky. We shall see how this materialises.

CONDITIONS TO USE DRONE TECHNOLOGY FOR IRT SURVEYING

  • The thermographer must have the permission to survey the buildings, the owners/tenants and neighbouring buildings of the activity.
  • An area adjacent to the surveying site must be cordoned off for take-off and landing.
  • A qualified operator has to provide his permissions to operate with certificate from the CAA. Without this the operator will not be insured.
  • They has to carry out risk assessments that are site specific.
  • Finally they also need thermography experience in order to capture the correct data and setting up the correct parameters required for the job in hand.

WHAT DOES THE FUTURE HOLD FOR THE USE OF DRONE TECHNOLOGY IN IRT SURVEYING?

Like all emerging technologies, the sector is full of “give-it-a-go-heroes”. Fast forward 5-10 years they will be gone, the market consolidated and a handful of professionals left doing it properly.

For IRT surveys, it is a nice thing to have available to us. Still 95% of our surveys are still done on foot by thermographers at night in low wind.

Maybe down the line when you call we will simply deploy a local drone to your building and not need the skilled local thermographers to actually take the pictures at all. Their role will become one of convincing you it’s a good idea and to talk you through the findings and recommend solutions based upon technical knowledge and experience.

Looking in the short to medium term, at IRT Surveys, we can’t see the drones replacing a skilled human just yet though. But like the humble hammer, there will come times when you need a drone. It is always handy to have the tool in your box.

Do you have high buildings or flat roofs which require surveyed with thermal imaging? If so, please do contact us for a fast, impartial and clear survey.