Common Snags in New Builds

New build homes come with a variety of warranties, and each one is important in its own right, although the snagging list should be carefully monitored by the purchaser. The NHBC (National Housebuilding Council) is the largest provider of consumer protection for homebuyers with its 10-year Buildmark warranty, even offers the consumer a snagging list template which can be found here. The snagging or new home checklist mentions checking for leaks, and sometimes water leaks can be notoriously difficult to find, although, to our thermal imaging cameras, leaks appear like warning beacons in the pictures. The snagging list also mentions checking for missing insulation which can also be difficult to survey, as the insulation is usually in the loft space and buried in the walls. 

Home Snagging using Thermal InfraRed Imaging

Using the infrared spectrum for building inspections has many benefits. The thermal images, especially when the images are “thermally tuned” allows us to see amongst other things

• Missing, wet, or poorly installed insulation. 
• Heat loss. 
• Failed damp-proof membranes.
• Evidence of thermal bridging.
• Dot and Dabbed Plasterboard. 
• Air leakage generally around doors and windows.
• Moisture including water leaks and damp detection.
• Underfloor heating installations.

As well as internal home inspections, we also carry out external building envelope thermal surveys using our specialist drones equipped with thermal cameras. This gives us a whole overview of the property, with interior and exterior pictures we can also confirm or deny any thermal anomalies highlighted. 

Why Insulation is so important in New Homes

Insulation keeps your home cold in the summer and warm in the winter which will give you a high level of thermal comfort. If installed poorly in new homes it can be notoriously difficult to identify without a thermal survey. The correct type of insulation well-fitted will reduce your energy bills and your carbon footprint. 

Thermal snagging surveys can identify issues with continuity of insulation, identifying areas of incorrect installation, areas where it may have failed or be missing altogether.

Insulation Missed by Design
Whether by oversight, deficiency in the design, or intentionality due to differing construction standards, it is possible that areas of the building have been left uninsulated at the time of construction.
Insulation Missed During Construction
While insulation and insulation features may have been part of the design, they may not have been properly incorporated, unintentionally missed, or wilfully inactioned to make savings.
Insulation Damaged During Construction
Insulation damage could occur during construction, whether damaged by lumps of mortar falling within a cavity or discarded items left within the structure during the build, such as empty pots of paint which can lead to compression of the insulation.

According to Which and the Energy Saving Trust, a well-insulated home can save around a tonne of carbon expulsion into the atmosphere. 

Best Conditions for Internal Thermal Inspection 

The optimum conditions for carrying out an Internal Infrared snagging survey of your new build home are as follows

• • Turn up your heating – ideal conditions are a minimum of 10 degrees temperature difference between inside and outside air temperatures, this environment gives the most accurate thermal images for analysis and thermal tuning. 
  • Turn off any fans and artificial sources of air circulation (unless using Air Testing conditions).
  • Furniture should be moved away from external walls prior to the survey with enough time to allow the temperature to normalise across the areas exposed.
  • External surfaces should be free of moisture (no rain for at least 36 hours prior to survey).
  • External wind speed should be less than 5m/s.
  • The exterior of the building should be free of solar radiation.

As with all thermal envelope surveys, according to the standards set out in BS EN 13187, the required conditions for carrying out the inspection are a minimum 10° C difference between the internal and external ambient temperature. The easiest way to achieve this in the UK is to turn the heating up inside the home and carry out the inspection 2-3 hours after sunset (in order to mitigate for the next factor).

Reduce the effects of the Sun – Solar Gain

During daylight hours, the effects of solar gain can greatly skew any results gathered during a thermal survey so all surveys should be carried out once the sun has gone down and the building surface has had a chance to cool down, and the solar gain effects removed. It is often recommended to carry out the survey just prior to sunset to allow the building as much time as possible to reduce the effect of solar gain, however, in the UK this could often mean that the exterior of the building would then be affected by moisture due to condensation as the warm air cools, which would, in turn, affect the survey results as discussed below.

Wind Speed

Wind speed should be 5m/s or less. Higher wind speeds will affect the thermal boundary layer on the building surface creating a cooling effect impacting the survey results.

All surfaces should be dry prior to the survey being carried out and throughout the duration of the survey. 

All surfaces should be dry

Prior to the survey being carried out and throughout the duration of the survey, all surfaces to be surveyed should be kept dry. Moisture on the building surface can have a reflective effect and lead to incorrect readings.

Finally, it is important to note that the environmental conditions, as described above, should not vary greatly during the period of the survey being carried out.

While you may see thermal surveys carried out in different conditions elsewhere in the world, with some lucky thermographers even using high external temperatures and lower internal temperatures to create a 10° C difference (air conditioning systems inside buildings on hot days outside), the perfect conditions to carry out an external building thermal survey in the UK would be a cold, dry night with low humidity.

Once images are captured and analysed by our qualified thermographers, we are able to highlight any areas of snagging that are invisible to the naked eye without you having to undertake any invasive work on your property.

Why you should use a Qualified Thermographer

Our thermographers are British Institute of Non-Destructive Testing Level 2 Qualified. This means they have been trained to ensure the correct conditions are met to carry out the inspection and are then able to analyse and comment on the images taken in a report format. Hopefully, your home has been built to give you a high level of thermal comfort but if mistakes have been made in the build process, a thermal survey gives you a chance to identify and rectify these thermal anomalies with your builder. If you are unable to reach an agreement on repairs required, a report issued by a Level 2 qualified thermographer can be used in legal proceedings as supporting evidence to any claim you may have. 

Our reports are not just for homeowners, we also work with many housebuilders who will use our service to show that the properties they have built are up to the standards that they set. 

Thermal Chimney Survey

If your newbuild property has a chimney installed, a thermal survey of the chimney can ensure all installation works have been carried out according to building regulations. 

Carrying out an internal and external thermal inspection of your chimney could highlight issues with your chimney stack and pot, and any discrepancies in your chimney flue and liner. 

Drone Site Surveys also carry out thermal solar panel surveys if you have this energy system installed, you can read more about this on our solar panel survey page here.