InSite | Most common potential defects revealed

Most common potential defects revealed

Published date: 10 January 2024

Just below a third of all potential defects found on the construction of low rise structures relate to external walls.


Potential defects in low-rise (five storeys or fewer) builds between July 2022 and July 2023 saw external walls amount to 30.61% of all those observed by Premier Guarantee surveyors.


Roofs were the second most common at 15.41%.


Since 2018, however, our surveyors have seen a drop in the potential defects relating to external walls, down by almost 15% in five years.


This reflects well on the proactive approach and willingness of our customers to work as a team with us to deliver high quality homes.


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So, where do we see issues in external walls and why?


When it comes to traditional masonry, the following issues are prevalent:


  • Cavity trays missing, full of mortar or being incorrectly installed
  • Fitment of insulation/cavity barriers and closers missing or being poorly fitted with gaps
  • We generally see a lot of comments noting walls out of plumb
  • Excessive mortar build up
  • Weep holes – incorrect specification, missing or being retrospectively fitted but cut in half and for “display only”


With timber frame, the following issues are common:


  • Sole plates – height, packing (missing and type/material used) and overhangs
  • Missing or incorrectly located studs for structural elements
  • A lack of allowance for movement and shrinkage of the frame


Premier Guarantee MD Keith Evans said: "There is no surprise that the external envelope of buildings (external walls and roofs) are the areas where most potential defects are reported by our surveyors.


"External walls are an area that has far fewer operatives nowadays and very little in the way of technical colleges training our future bricklayers."


"This of course leads to a lot of on-the-job training and subsequently an increase in defective work being produced."


What about high-rise?


When we look at high-rise (six storeys or more) external walls make up an even larger portion of the potential defects noted on sites – just below 44%.


Internal walls and roofs amounted to a combined 22% - 11% each.


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The external envelope of high-rise, more complex structures dominates the potential defects reported by our Major Projects warranty surveyors. Unlike low-rise buildings, potential defects concerning internal walls match those for roofs.


reported by our Major Projects warranty surveyors. Unlike low-rise buildings, potential defects concerning internal walls match those for roofs.


So, where do we see issues in external walls and why?

  • Inappropriate specification of windows with regards to wind loading
  • Congestion at the slab edge with conflict relating to the fire barrier, masonry brick support and cavity trays in Brick and SFS build ups
  • Design and consideration of feature brickwork such as rusticated brickwork, feature soldier courses or brick slips in response to meet the requirements of Regulations 7
  • Unplanned material substitutions during construction due to trying to reduce costs in response to inflation
  • Proposal of products of systems being used that don’t have full 3rd party accreditation
  • Bi-metallic corrosion and issues with specification of metals
  • Lack of continuity of waterproofing through and over the parapet and at thresholds
  • Positioning of MVHR intake and exhaust vents causing issues with cross contamination of air, and dispersion of warm, moisture laiden exhaust air which condenses on the underside of balcony soffits


Across all areas of construction, the majority of observations year-on-year has remained steady.


Increases in observations in basements and internal walls have been heightened due to the skill shortage in the industry.


The increases have been minimal due to the proactive, consistent onsite support of our major projects team who advise at all stages when working with our customers over the long term to support their business operation so they can build efficiently and to a good standard.


What are the most common contraventions seen in building control?


Fire safety, at 35%, is the most common contravention found during building control inspections.


The second most common relates to structure at 22%.


Site preparation and resistance to contaminates and moisture made up 8% of the contraventions noted.


Give your site a health check

Premier Guarantee is one of the UK’s leading providers of structural warranties. It also has a growing team of building control approved inspectors who work year round to help builders and developers achieve the very best results.

Our Site Quality Review (SQR) services are designed to assist developers improve workmanship and site practices by analysing 67 inspection areas across 11 inspection sections.

SQRs allow you to have an extra layer of security and peace of mind that the standards on your site are being met and that no unwanted defects rear their head.

You do not have to be a Premier Guarantee customer to take advantage of this service.

If you would like to give your site a health check with an SQR, you can order yours today.

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Every care was taken to ensure the information in this article was correct at the time of publication (January 2024). Guidance provided does not replace the reader’s professional judgement and any construction project should comply with the relevant Building Regulations or applicable technical standards. For the most up to date Premier Guarantee technical guidance please refer to your Risk Management Surveyor and the latest version of the Premier Guarantee Technical Manual.

Ref: MK-3677

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