Internal measured surveys - You have to draw the line somewhere!

Errors or omissions in a drawing can result in serious consequences which can manifest themselves into confusion and disagreement, delays, additional costs and ultimately disputes. These problems can be avoided by ensuring that those who undertake measured surveys are adequately trained and supervised.

Source: www.easyplanbirminghamsouth.co.uk

Drawings are arguably the most effective form of communication within a construction project and are used at all stages.  It is therefore fundamentally important that all of those who are responsible for taking measurements and preparing drawings understand the significance of what they are doing. The 'life' of a drawing will be developed throughout a project and will vary depending upon the complexity and type of project.  For example concept drawings may be required, which can then become initial design drawings, followed by detailed design drawings.  From this stage the drawings could then be developed into construction drawings and used for tendering and also contract drawings.  Eventually, the drawings will become 'as built' and will be included into a Health & Safety File, a requirement under the Construction (Design & Management) Regulations 2015. The above examples of where drawings could be used in a construction project is not exhaustive, however demonstrates their importance.

Errors or omissions in a drawing can result in serious consequences which can manifest themselves into confusion and disagreement, delays, additional costs and ultimately disputes.  These problems can be avoided by ensuring that those who undertake measured surveys are adequately trained and supervised.  It would be very unwise to assume that undertaking a measured survey is a simple process and a skill that everyone should naturally have.  This is because buildings differ significantly in size, construction and form and the amount of information needed will vary depending on the scope of the project. One thing however that is for certain is that undertaking a measured survey is far more than just obtaining dimensions! A common issues I often found with my surveyors when undertaking an internal measured survey would be that they would sometimes miss key information such as floor to ceiling heights, window cill height, joist direction, services intake of a building, diagonal check measurements and sometimes even forgetting to note wall construction. If a re-visit is necessary to collect missing information then this will be a cost to the business and can impact on profitability.

Source: www.puresurvey.co.uk

It is important that the right measuring equipment is taken and used. This will include a folding measure and 5 or 10 metre steel tape (or both) for measuring shorter distances and 25 metre tape and a trundle wheel for measuring longer distances.  Nowadays a digital measure will also be taken which can also be used to obtain, rooms sizes (sqm) as well as single dimension measurements.  When using measuring equipment the 'Surveyor' should be fully aware of the limitations of the equipment and also have an appreciation of distance to be able to discern whether digital dimension are accurate or not.  This is because inaccurate readings can be obtained from a digital measure when the laser comes into contact with reflective surfaces or glass.  If the Surveyor was to write down the measurement without asking themselves if the reading is reasonable, they will have problems when they return to the office and start to prepare their drawings.

Whilst undertaking a measured survey on site the Surveyor must appreciate that either they, or maybe somebody else like an Architectural Technologist will have to interpret the information that has been collected on site in order to prepare the drawings.  Many times I have witnessed Surveyors and Technologists look with complete dismay at a piece of paper in the office that has been given to them by someone who has undertaken a measured survey.  This is because what they are looking at is a rain drenched, smudged, excuse for a drawing that is so 'busy' with lines, dimensions and other information that it is difficult to tell the difference between each!, and they are expected to produce an accurate drawing from this!

To help minimise omissions and errors in drawings there are some simple basic techniques that can be very useful when undertaking measured surveys.  Firstly, I always advised my Surveyors to draw the building footprint (in pencil) first, before taking any dimensions, The pencil could then be overdrawn in pen later.  This would ensure that the drawing was well proportioned and avoid 'squashing' information into a small corner of a piece of paper, because there is no room left on the sheet, toward the end of the survey.  Next, use different colour pens for recording information.  It is much easier to interpret a drawing if say the building outline is in black, dimensions are in red, construction details are in green, sockets, switches and radiators are in blue etc.  Next, when using measuring tapes particularly for longer distances, ensure that there are no twists in the tape and that it is a tight as possible to avoid deflection.  Surveyors must also ensure that dimensions are taken at the same height.  For example is one Surveyor is holding the tape just above the skirting board and at the other end the Surveyor is holding the tape half way up the wall this could result in a significant inaccuracy in a single dimension.

The importance of a comprehensive and accurate measured survey cannot be understated, which can only be achieved through appropriate training and supervision.  Organisations should ignore this at their peril!

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What's the crack? The importance of correct diagnosis of cracking in buildings

Due to the many different factors that can contribute to cracking, this is one of the most easily mis-diagnosed defects that can occur in buildings.

Source: www.eapenvoy.co.uk

When cracking is identified in a building the usual reaction is one of alarm and sometimes panic. Over the years as a Building Surveyor I have learned to be very cautious in diagnosing the cause of cracking, because it is necessary to fully understand the underlying factors that are causing it to ensure that an accurate and appropriate solution is recommended.

Cracking in a building can occur for a variety of reasons and sometimes there maybe a combination of factors that contribute to the problem.  For example drains could be damaged allowing surface or foul water to permeate into the sub-soil below a foundation.  Over time the soil will start to erode and the rate of erosion will depend on the type of soil (e.g granular soil will be more vulnerable than other types of soil), climatic condition, location etc. It is clear that the drainage will need to be rectified to ensure that the surface or foul water, finds its way through the drainage system correctly. However, what has caused the problem to the drains? Are there tree roots in the drains? Are there other trees in close proximity? Has the ground under the drains been affected in some way (i.e nearby excavations)? Is there a damaged rainwater down pipe or guttering in close proximity to the drains that are allowing large volumes of water into the sub-soil, particularly for shallow drainage? etc.etc. 

Source: own

It is therefore fundamentally important that anyone who undertakes inspections or gives advice in respect of cracking in buildings should not make rash judgements and should gather all of the evidence before arriving at a possible cause. In order to aid the inspector, which can be a Building Surveyor or Structural Engineer, it might be necessary to recommend other investigations such as geo-technical surveys to establish ground type, composition, contaminants etc., trial holes to establish foundation depths, CCTV inspection of the drainage system and possibly an arboricultural survey to give advice on any trees that may be an influencing factor. It may also be necessary to undertake monitoring of the crack to establish whether movement is still occurring. For cracking of a less significant nature these types of investigations might not be necessary at all. The choice of which investigations are needed will be decided once the inspector has made an initial assessment of the cracking.

Not all cracking in buildings is serious, which is why it is so fundamentally important to diagnose the cause correctly.  In some situations remedial measures may be as simply as rake out and re-point mortar joints, or possibly a technique called 'stitch repairing', which is basically raking out horizontal bed joints every five or six courses either side of a crack and installing steel bars which are set in epoxy resin (see video below). After the resin has cured the bed joints are simply re-pointed. At the other end of the scale however remedial measures  could be much more substantial and include underpinning or possibly even partial or even full demolition and re-build.  Therefore it is clear that the costs of dealing with cracking in buildings is extremely wide ranging, and mis-diagnosis could result in either undertaking repairs that may not have been necessary (which can be very expensive), or not dealing with the problem appropriately, with the cracking re-occurring.

I sometimes have a rye smile when I watch property programmes such as Homes under the Hammer. It is interesting to hear the presenters talk about defects that 'they have discovered' when they visit the various properties, particularly cracking.  You can bet that they will say, 'that could be serious and needs checking out', they obviously do not have a clue what the cause of the problem actually is. What is even funnier is when they ask the purchaser if they were aware of the cracking when they had bid for the property and they will always say 'yes, but we had it checked out and it is nothing serious!'. In all of the many episodes of that programme that I have seen over the years I have never heard any purchaser be perfectly honest and admit that the cracking was serious and had cost them a fortune! I suppose it is because they do not want to admit too being a complete fool on national television!

The subject of cracking in buildings is extremely wide ranging and it is not the purpose of this article to try to consider every aspect, in fact there are numerous books and other publications that cover the topic extensively.  What is important however is that when cracking occurs that the reasons for it are fully investigated and understood so that appropriate remedial works can be carried out.  Due to the many different factors that can contribute to cracking in buildings, this is one of the most easily mis-diagnosed defects that can occur.  It would therefore seem sensible to seek the advice of a professional at the earliest opportunity. Although this advice may have a cost attached, it could prevent a much higher cost in the future.

Please feel free to share this article and other articles on this site with friends, family and colleagues who you think would be interested

Information/opinions posted on this site are the personal views of the author and should not be relied upon by any person or any third party without first seeking further professional advice. Also, please scroll down and read the copyright notice at the end of the blog.