Blog

Pipe Butcher in Co. Cork

previous arrow
next arrow
Slider

One might imagine that any new dwellings presented to the market would be compliant with Building Regulations. However, this might not always be the case and some high profile failures such as Priory Hall and Longboat Quay provided more than enough evidence to government that things had to change.

Up to 2014, professionals would only need state, through non-statutory Certificates of Compliance that, in their opinion, the building substantially complied with Regulations. Furthermore, independent inspections were not mandatory. To address this, the government introduced the Building Control (Amendment) Regulations 2014 which introduced new controls including mandatory site inspections and certification.

Some construction (and design!!!!!) during the boom was poor and an embarrassment to our industry to say the least. Substruck were employed to complete a homebuyers drain test at a ‘new’ residential property in Co. Cork. This was in effect completion of units in an unfinished ‘ghost’ estate so BCAR did not apply. However, the Building Regulations still did.

In drainage investigation, you can always judge a book by its cover. Before any testing or CCTV equipment was brought onto site, direct observation showed us that the construction of the drains was pretty poor, both in terms of compliance with current Building Regulations and good practise.

The photos show how the drainage was finished at ground level during more recent patio works. And I think they speak for themselves. It is clear that no test was completed on the drains either during the original drainage works or the remaining completion works. Out of five sections, one passed, while two could not be tested due to the absence of any access points!!!!

This was just one series of defects identified in the survey. Others included absence of access to a WC, trip hazards, a hole in the drain to accommodate a new gully, deformation, open joints and water holding.

BCAR is not without its weaknesses and these were identified in the Oireachtas report ‘Safe as Houses? A Report on Building Standards, Building Controls & Consumer Protection’ in 2017. However, it is still a huge improvement on the previous regime and should help to significantly reduce this type of workmanship.

Cross Connections in Passage, Co. Cork

previous arrow
next arrow
Slider

H1 – A building shall be provided with such a drainage system as may be necessary for the hygienic and adequate disposal of foul wastewater from the building.

H2 – A building shall be provided with such a drainage system as may be necessary for the adequate disposal of surface water from the building.

H3 – No part of a drainage system conveying foul wastewater shall be connected to a sewer reserved for surface water and no part of a drainage system conveying surface water shall be connected to a sewer reserved for foul wastewater.

Above are the three Building Regulations for the design and construction of drainage works in Ireland. The purpose of these Regulations is to provide for the safety, health and welfare of persons and the protection of our environment. They are very broad statements (particularly the first two) which are supplemented by Technical Guidance Document H – Drainage and Wastewater Disposal. Therefore, if works are completed in accordance with this document, that will, prima facie, indicate compliance with these Regulations. However, there is very little other guidance required (you might think) for the third and final Regulation, which simply does not allow cross connections (or mis-connections) in drainage systems. This is where householders and builders inadvertently (I would hope) connect household appliances to the wrong drain, i.e. surface water. On the other hand, surface water entering foul waste water system will increase pressures at sewage treatment plants.

Most properties have two drainage systems – foul wastewater from bathrooms and kitchens and surface (or storm) water from the roofs and driveways. In other words, any dirty water should go to the foul system and any clean water should go the surface water system. Considering that the surface water is drained to local watercourses, the EPA have identified cross connections as a significant contributor to the deterioration of the water environment in our country. Cross connections are deemed an offence under Section 3 of the Local Government (Water Pollution) Act, 1977, and Section 16(7) of the Local Government (Water Pollution) Act, 1977. And, it is up to the homeowner to rectify any cross connections!!!!!

Buildings undergoing renovation works, like this property in Co. Cork, are at most risk of cross connections. The renovation of a garage required the relocation of various appliances. The first cross connection was from a washing machine which was drained to a surface water gully at the corner of the property. The second and third cross connection was where sink waste and condensate from the boiler was drained to a second surface water gully.

If you have any concerns re cross connections, please feel free to contact us and we can survey your drains to ensure that everything is going where it is supposed to go.

Movement Joints in Masonry

previous arrow
next arrow
Slider

Newly constructed buildings will nearly always be vulnerable to cracking for a variety of reasons. However, nowadays we understand much more about why this occurs and what particular controls can be put in place to minimise the effects of movement of building materials and components.

Shrinkage will occur in masonry structures, particularly if blockwork has not cured properly. However, the secondary control to accommodate this shrinkage is the installation of a movement joint.

Movement joints are generally formed to address either contraction (shrinkage) or expansion, whichever will occur first. These terms are used interchangeably in the industry although they are very different. For example, movement joints in concrete footpaths are often referred to as ‘expansion’ joints although they are in effect ‘contraction’ joints as contraction will always occur first as the concrete cures and loses its moisture content.

Unfortunately, buildings can be designed or constructed poorly, with less regard to these controls as identified in the Technical Guidance Documents or Homebond manual.

This crack has formed in the middle of two semi-detached houses in Ballyvolane, constructed in 2005. It is mirrored on the opposite side of the building which is to be expected. The whole building is about 16m in length and 6m in width. It is clear that a movement joint has not been installed and could have been neatly concealed behind the downpipe.

Homebond provide good guidance for movement joints in both brick and masonry buildings. It states that ‘Codes of Practice recommend that spacings of movement joints should be referred to by the building designer. It is not standard practice to incorporate movement joints in semi-detached houses. Based on traditional construction, the minimum recommendation is that in terraces of three or more houses, joints should be built in every two houses unless specified more frequuently by the designer.’ (Homebond, 2008). It also refers to joints at 12m centres or very two houses whichever is less.

Considering the geometry of this building, a movement joint should have been installed. As cracking will normally occur over weak points in a building, it was just unlucky for this homeowner that it occurred on his side.

Incorrectly installed tell-tales in Co. Tipperary

previous arrow
next arrow
Slider

Subsidence monitoring can take many different forms; from simple measurements with a crack gauge to continuous recordings with a wireless crack movement recorder, with built in data logger. Each system comes with its own strengths and weaknesses, which must be considered in order to apply the most appropriate and effective technique.

Crack monitors or ‘tell-tales’ are the most common form of subsidence monitoring used in Ireland. They are easily sourced online so anybody with a VISA card and a drill can install them. And that sometimes is the problem.

The cheaper alternatives do not possess pre-set pegs which allow for quick and easy fixing. However, the pre-set pegs do not always allow the cursor to be square to the grid so accurate recording on installation is paramount. This can occur on uneven finishes such as wet dash or where lateral movement has taken place.

To be fair, standard tell tales (without the pre-set pegs) require a bit more thought and this wasn’t applied on a property in Roscrea, Co. Tipperary where readings from crack monitors would suggest that all cracks have closed by a distance of over 25 mm!!!!!

This is just one example of how poorly installed and recorded monitors provide no data whatsoever and can be a complete waste of time and money for the consumer. Subsidence monitoring should be performed by qualified, experienced professionals for accurate results –

Substruck Ltd. is an approved installer of Avongard crack monitors.

Door Frame Wracking in Cork City

previous arrow
next arrow
Slider

Foundation movement can affect the serviceability of a building. This may include water penetration through cracks and sloping floors. It can also result in distortion of door and window frames. This can be as an indirect result of movement in the external walls or directly through movement of the internal walls. 

Such movement can take the form of ‘wracking’ where the frame loses its squareness (if that’s a word) and is demonstrated by tapered widening at one end of the gaps and a narrowing at the others. This results in the door jamming. The most common cause of doors jamming in older properties is normally temperature and moisture variations during the year.

This door frame in Cork City is about 20mm out of level!!!

But, interpretation of movement needs careful consideration. In this instance, it is evident that the top rail of the door and architrave have been significantly altered over a long period of time and this is disproportional to the cracking. This would suggest that the initial movement began quite some time ago, maybe when the building was constructed, and adjustments were made from or at that point.

Nonetheless, movement was rejuvenated for another reason thereafter and the result was a development of the original movement. This is demonstrated in the cracking. The weak points in the superstructure created during the settlement period will normally be the first to be compromised.

Therefore, it could be argued that the distortion in this situation represents both settlement and subsidence.

Progressive Movement in Cork City

previous arrow
next arrow
Slider

Cracking in walls is the most common sign of foundation movement and may form within or between components. Despite the width of any crack, a key aspect of any subsidence investigation is to determine if movement is ongoing or not.

When an extension begins to move away from a building, a vertical crack will usually form at the interface of the building and extension. This crack will be wider at the top as the extension rotates away from the original structure. The corner of the extension will normally act as the pivot point.

In terms of diagnosing progressive movement, there can be simple signs to suggest that the building is still moving e.g. cracks which have been repaired and re-opened can strongly suggest that movement is not historic. This crack in Blarney St was repaired at some point yet has continued to open and is now in the order of nearly 8mm!!!!!!

The building showed other signs of movement internally in the form of cracked floor tiles and ceiling cracking between the function of both buildings.

The remediation scope was a series of small diameter displacement piles known as Grundomat supporting RC ground beams beneath the foundation.

Cracking in glass in County Cork

previous arrow
next arrow
previous arrownext arrow
Slider

Diagnosing subsidence or foundation movement through a simple present condition survey may sometimes prove difficult without further investigation.

The most common sign of foundation movement is cracking. As a foundation moves, the building will become distorted, particularly around openings in walls.

The construction type of the building can also have an influence on how the building will react to such movement. Foundation movement in this conservatory in Co. Cork has resulted in the window frames becoming so distorted that the glass has cracked!!!!

Extension rotating in Cork City

previous arrow
next arrow
previous arrownext arrow
Slider

Extensions to existing buildings are always vulnerable to cracking where they meet the main structure, normally due to shrinkage or differential settlement. Such cracking is normally superficial and is not expected to deteriorate further.

Nowadays, movement joints are placed at specific locations in order to allow for such movement. Most movement joints in Ireland are in fact contraction joints as concrete blockwork will always shrink first. The degree to which shrinkage will occur will depend on a few factors, but particularly the time and conditions to which blocks are allowed to cure.

These movement joints, normally placed on the external leaf of a traditional cavity wall, are constructed with a proprietary joint bead to allow movement of ± 3mm. Homebond provide good details for the design and construction of movement joints in different forms of construction.

However, this extension in Capwell, Cork city has failed due to an escape of water from a vitreous clay drain at the rear. Services which are leaking over long periods gradually reduce the load bearing capacity of the soils by removal of the finer particles in granular soils.

Although sometimes diagnosing subsidence through a simple present condition survey may sometimes prove difficult without further investigation, the degree of cracking and evidence of a previous repair strongly suggests that movement is ongoing. Note the failure of the traditional ‘toothing in’ below eaves level. Movement of about 15mm was also noted internally.

This cracking is typical of subsidence in an extension where a vertical crack forms between both components; the crack being wider at the top as the extension rotates away from the original structure; the corner of the extension acting as the point of foundation movement.

The approach to this problem is to replace the drain and underpin the rear elevation through micropile supported reinforced concrete ground beams.

Movement joints in superstructure repair in Kilkenny

previous arrow
next arrow
previous arrownext arrow
Slider

Homebond identify foundations as ‘the most important structural element of any building and great care should be taken to ensure that they are constructed properly.’ Design and construction of foundations must be completed by competent persons and supervised accordingly. 

Superstructure cracking is caused by a variety of different reasons but rarely as a result of foundation movement. The measure sought to address this cracking on a commercial property in Kilkenny City by one engineering professional was the installation of a movement joint!!! 

However, most proprietary joints only allow for movement of ±3mm as the building expands and contracts over time. If the building exceeds this movement, then there is a more serious problem.

As cracking continued to deteriorate beyond the scope of a movement joint, the Client became more concerned and a second opinion was sought. Crack monitors were installed and confirmed that movement was progressive in one direction.

Substruck Ltd. was employed to complete further investigation in the form of trial holes and ground investigation. Trial holes revealed poorly formed foundations on non-engineered fill material. Dynamic probing and sampling identified the presence of boulders in poorly consolidated fill material to a depth of 3 metres. Probing to further depths was completed for micropile design.

It was now clear that the building was moving due to poorly designed and constructed foundations and underpinning works was required. This was specified as a series of 12 nr micropile supported straddle and cantilever ground beams beneath foundations along the area of distress.

Direct inspection of drainage systems

previous arrow
next arrow
previous arrownext arrow
Slider

Substruck Ltd. complete many types of drainage investigation, the nature of which will depend on the client brief or requirements. Generally, there are three types of investigation:

reactive – in response to a problem such as a blockage,

subsidence – investigation into a potential cause (i.e. leaking drains) or to provide information to form part of a scope of works where the drainage will have to be removed and replaced, or

general – in response to a recommendation of a house pre-purchase survey.

Our Phase 1 reports document a non-destructive investigation of the drainage system using one or a combination of direct observation, hydrostatic testing, CCTV surveying / inspection and drain tracing techniques.

On arrival to site, direct observation will tell you a lot about the current condition of the drainage and the standard of work applied during construction before any testing or surveying is carried out. We examine the system to determine compliance in relation to construction and siting of access points, ventilation, trip hazards, traps, etc.

Direct inspection of two vitreous clay drainage systems in Pouladuff and Lower Friars Walk in Cork tells us immediately that sections of each system is wholly not serviceable and will have to be replaced.

The photos show fractured and/or collapsed gullies and access junctions.