TECHNICAL DUE DILIGENCE REPORT 019557001 …econtent.tauranga.govt.nz/data/projects/files/civic_space/block_a... · TECHNICAL DUE DILIGENCE REPORT 019557001 Tauranga City Council

TECHNICAL DUE DILIGENCE REPORT 019557001 Tauranga City Council Buildings Block A

Guy Dobson BSc (Hons) Building Surveying MRICS CHARTERED BUILDING SURVEYOR Malcolm Thomas BSc (Hons) FRICS CHARTERED BUILDING SURVEYOR

Chris Phayer BSc (Hons) MRICS MNZIBS MNZIQS REGISTERED BUILDING SURVEYOR CHARTERED BUILDING SURVEYOR

TABLE OF CONTENTS

PROJECT PREFACE 1

IDENTIFICATION PHOTOGRAPH 2

EXECUTIVE SUMMARY 3

1.0 INTRODUCTION 5

1.1 Instructions and Brief 5 1.2 Site Inspection 5 1.3 Terminology 5

2.0 GENERAL DESCRIPTION OF PROPERTY 6

2.1 Generally 6 2.1.1 Roof 6 2.1.2 Windows and Doors 8

2.1.3 Walls and Elevations 9 2.1.4 Internal Finishes 11 2.1.5 Other Defects and Deferred Maintenance 11

2.2 Long Term Robust Remedial Solution 13

3.0 CONCLUSIONS AND RECOMMENDATIONS 15

3.1 Summary Of Report 15

3.2 Recommendations 15

LIMITATIONS 17

Photo Sections

Section 0: Elevations Section 1: Roof Section 2: Windows Section 3: Walls and Elevations

8 April 2015 019557001 Tauranga City Council Willow Street TAURANGA 3110 Attention: Terry Wynyard REPORT ON: TAURANGA CITY COUNCIL – BLOCK A (CIVIC BUILDING) This report has been produced for the strict and sole use and benefit of the addressee and their legal advisor(s). It is not to be duplicated, disseminated or in any other way replicated without the express approval of the writer. This report has been produced in accordance with our letter of engagement incorporating all terms and conditions stated therein. The author(s) of this report where they use the singular phrase “I” or the plural “we”, or similar phraseology, are referring to their role acting on behalf of Prendos New Zealand Limited, not as individuals. PROJECT PREFACE Client Name: Tauranga City Council Client Address: Willow Street, Tauranga Report Prepared by: Guy Dobson Job Reference: 019557001 Reviewed by: Roger Charnock

PRENDOS New Zealand Limited 2 019557001 ___________________________________________________________________________

IDENTIFICATION PHOTOGRAPH Part Front and South Elevations


EXECUTIVE SUMMARY Block A forms part of the original Tauranga Council building (constructed in 1989) which consisted of retail units to the ground floor, offices to the first floor and carpark at roof level. We understand the second floor offices were constructed in 2003 in order to rectify on-going water ingress. The erection of the second floor has eliminated the majority of the original defects and water ingress however there are a number of inherent defects which are continuing to allow water ingress. There are a number of poor construction details and extensive use of surface applied sealants as primary weatherproofing which will fail and cause future water ingress. Sealants will deteriorate, split and fail under UV light exposure and therefore have a typical life expectancy of (maximum) 15 years. As the second floor is approximately 12 years old it is reaching an age where replacement of sealants will be required in the next few years. The majority of flashing/concrete column junctions have not been sealed and will allow water ingress. Although we cannot confirm without extensive opening up work, we believe there is a potential void to the second floor which is between the original concrete deck and 2003 overlaid second floor construction. We believe this is retaining water and acting as a reservoir which eventually leads to water ingress to the City Waters office area following heavy rain. This assumption is on the basis that dyed water easily penetrated into the building, primarily from the Chambers balcony cladding/deck junction, but did not reappear either internally or externally. This void will act as a reservoir for water ultimately leading to water ingress internally if water ingress is prolonged. Once the defects externally have been rectified, water will not be able to access the potential void. It is believed the overlaid second floor structure is in place over the original car park level that was a known source of water leaks. Consequently, water from the ‘reservoir’ void can still enter the building due to the defects in the original car park deck which were not sealed prior to constructing the second floor. The 2003 prefinished aluminium cladding (assumed Alucobond as per the drawings) joints are reliant on sealant for weathertightness. The sealant is starting to deteriorate in places resulting in gaps and unsealed holes which are allowing water ingress, although in most cases small amounts of water. The water will be trapped behind the cladding as there are no weep holes or drainage slots allowed. The weepholes were shown on the original construction drawings but not installed on site. This may result in deterioration of the building and mould growth, and build-up of moisture-laden (humid) air in construction voids which can also lead to corrosion of any concealed fixings. On 16 March 2015 following heavy rain, uncontrolled water was noted to be running off the balcony and onto the wall and window directly below. The office area below the balcony did have confirmed mould growth, including Stachybotrys. Given the amount of cracking to the balcony tiles, the amount of dyed water that penetrated into the cracks, water running off the balcony onto the walls and poor balcony edge detailing, we believe the mould growth and water ingress to the office below is directly linked to the balcony above.


Gaps were noted at several sun shade frame penetrations, the flag pole bracket penetrations, and at the steelwork supporting the atrium glazing. Dyed water readily penetrated into these gaps. We were unable to determine exactly where the dye went without significant dismantling of the wall envelopes. We were unable to inspect the fixings of the Alucobond cladding panels as the cladding cannot be dismantled without causing irreparable damage. The fixings are not visible internally so partial deconstruction of the cladding will be required in order to inspect the fixings. The roof, although generally in good condition has a number of poor details which will be susceptible to failure and water ingress. This includes a downpipe discharging onto a flashing and a lack of proper access to the air conditioning plant. Service personnel are required to access Block C roof through the atrium, jump onto Block A, and walk across the roof. This will result in damaged roof sheets leading to water ingress. The windows are original powder coated “shop front” style which we sealed into the concrete structure. These are failing to numerous areas and are allowing water ingress. All the original shop front type windows will need replacement and proper detailing of the new windows to eliminate the reliance of sealants. The glazing rubbers were also shrunk and split which is allowing water ingress. There are separate canopies to the east and south elevation which gives protection to the bus stops. Although these are linked to the main building they were only partly inspected as they do not directly affect the weathertightness of the building. The membrane finish will be approaching the end of its effective life and should be replaced. The general poor detailing and relying on surface applied exposed sealants for weathertightness has resulted in water ingress due to failures of the sealant and also a high maintenance building.


1.0 INTRODUCTION 1.1 Instructions and Brief

Following previous air and mould testing, Prendos New Zealand Limited were instructed to carry out a building inspection to identify areas of weathertightness issues, likely future defects which will lead to water ingress and prepare a report complete with recommendations, repair options and associated costings. We have not carried out a seismic assessment or structural review of the building. We did note some potential fire safety issues and general maintenance items which, although not the focus of this report, will be commented on in the Other Defects and Deferred Maintenance section.

1.2 Site Inspection The building was inspected over various dates in January and February 2015 as well as a detailed external inspection on 14 and 15 February. Two subsequent inspections were carried out following rain to establish if dyed water when dye tested was visible internally or further ingress had occurred.

1.3 Terminology The front elevation of the Building facing Willow Street is deemed to face East. All references to orientation should be interpreted accordingly. References to left and right should be interpreted as if facing the element or area under consideration.


2.0 GENERAL DESCRIPTION OF PROPERTY

2.1 Generally This report has been broken down into the following sections which should be read in conjunction with the photographic addendum at the rear of the report. The various subsections are as follows: Roof, Windows and Doors, Walls and Elevations. The building is a three storey, concrete and steel framed building with a combination of prefinished aluminium cladding to the second floor (2003) and rendered and painted concrete external walls to the ground and first floors (original). The roof is pitched with asymmetric trapezoidal roof sheet finish. The windows are a combination of original powder coated aluminium and newer aluminium windows. External walls to the second floor are dry lined internally with plasterboard fixed to studs while the finish to the ground and first floors is the internal side of the main concrete walls. The reinforced concrete second floor has a floating timber finish with a carpet finish and the floors below have carpet directly on the concrete floor. The ceilings are a combination of fixed plasterboard and suspended ceiling tiles. The ground floor in the southwest corner is partly below ground level and the external walls are consequently retaining structures. The east elevation faces the prevailing wind direction. The building is vulnerable to wind driven rain and salt laden sea spray, which corrodes any unprotected ferrous metal. Accommodation includes office space, Council Chambers, service areas and Tourist Information on the ground floor. The original two storey building had a carpark to the roof level of the first floor. We understand the current second floor was constructed directly off the car park deck.

2.1.1 Roof The pitched roof to block A forms part of the 2003 building works which we understand was constructed to eliminate previous water ingress problems through the original carpark deck. The roof is finished with asymmetric trapezoidal roof sheets. There is a raised monopitched roof directly over the Chambers which is complete with a membrane roof perimeter section forming the junction between the main roof and the Chambers roof. Large air conditioning plant and equipment has been located on the main roof which is supported on a purpose made metal platform. There is no dedicated access to the plant area which forces service personnel to access block C roof, jump onto block A and walk across the roof. The tiled balcony, which is accessed off Chambers, appears to be original construction and is finished with tiles on a bituminous type water proof membrane (visible at perimeter). The down pipe from the upper roof travels along the balcony and partly


discharges into a rain head. Our inspection on 16 March during rain confirmed that water was discharging uncontrollably off the balcony and onto the wall and windows below. Rainwater at roof level discharges via parapet gutters along the east and west walls, and then to externally mounted down pipes. Rainwater from the ground level canopies along the east and south sides discharges to sumps in the canopy roof and then, via supporting hollow steel sections, to rainwater pipes hidden behind the cladding. The main roof, overall, appears to be weathertight. There are however a number of details and junctions which will be high maintenance and also potential water ingress issues. The current water ingress appears localised in nature to the corridor directly outside the Chambers and Counsellor’s lounge. Photo 1.1 shows a general view of the monopitched roof over the Chambers. This is complete with a section of membrane roof which links the Chambers roof and main roof. Water from the monopitched roof is discharged onto the lower roof and membrane area from the downpipe as shown in Photo 1.2. The concentrated water flow will ‘hug’ the side of the membrane/wall junction. This downpipe also discharges directly onto the ridge flashing which is not considered good practice. The concentrated water flow is then directed onto the vulnerable lower flashing as shown in Photo 1.3. Although there appears to be no current water ingress, this junction is vulnerable and should be re-detailed to prevent potential for future water ingress. The down pipe should also be relocated to eliminate the concentrated flow of water. Photo 1.4 shows the atrium smoke vents which can be accessed from the main roof of Block A. Photo 1.5 shows water run marks internally to the atrium which appears to originate at or around the smoke vents. Although we did not find evidence of water ingress into the offices directly below the smoke vents, we understand water ingress has been experienced through the windows in the atrium. Therefore any water discharging into the atrium will potentially lead to water ingress internally to the offices. Photo 1.6 shows a typical poorly finished flashing at the smoke vent which is allowing ponding water. Water should not be allowed to pond as this can result in windblown water ingress and also premature deterioration of the flashings. Flashings should fall away from the building which will prevent ponding and associated potential water ingress. Photo 1.7 shows corrosion to the painted steel work within the atrium. Although not causing water ingress, it is highlighting the need for maintenance to the building and the need for on-going redecoration and maintenance particularly given the salt laden sea spray environment. Photo 1.8 shows a sealant repaired roof sheet fixing. Over-tightened, defective fixings, burst washers etc. to the roof sheet fixings will allow small amounts of water ingress. Once water starts to penetrate around a defective fixing, this will increase as water is further attracted into the hole.


Photo 1.9 shows the air conditioning equipment to the main roof. Although there was no apparent water ingress attributed to the air conditioning equipment, this highlights the lack of thought for maintenance access. Service personnel are required to walk over other roofs, jump onto the roof of block A, walk over the roof sheets and then access the plant. This poor access will lead to roof sheet damage which will ultimately lead to water ingress. Photo 1.10 shows the main roof downpipe which is positioned across the Chambers balcony and discharges into the rainhead. This downpipe appears to be an afterthought as it is poorly positioned and unsightly. Water from the downpipe is not fully discharging into the rainhead which is allowing water to run down the main wall, as shown in Photo 1.11 and onto the window below as shown in photo 1.12 (taken on 16 March 2015). This balcony is directly over the City Waters office where Stachybotrys and other moulds were identified and water ingress is occurring. Photo 1.13 shows defective pointing to the edge of the balcony tiles. This loose and failing mortar edge is both a maintenance issue, a potential health and safety issue and a potential source of water ingress. Photo 1.14 shows a close-up of the concrete column and balcony slab junction. Vegetation growth was noted which confirms moisture retention at this junction which may lead to potential for water penetration into the structure. Photos 1.15 and 1.16 show split and deteriorated sealant at the junction of the balcony tiles and wall cladding. These cracks were dye tested and water readily ‘disappeared’ into the cracks. The dyed water could not be traced internally and did not show at the edge of the balcony (despite further checks on following days). Photo 1.17 shows the failed sealant below the balcony window. Dyed water also readily disappeared into this crack and could not be traced internally or externally. We believe there is a void between the original car park deck and second floor which is collecting water and is acting as a reservoir. Once filled, water ingress will be experienced to the centre of the building, such as City Waters where water is dripping from the floor slab joints. We understand the original cracked and failing asphalt car park finish was not repaired prior to erecting the second floor. The weatherproofing of these junctions should not rely on sealant and they should be properly detailed using an upstand.

2.1.2 Windows and Doors The windows to block A are a combination of new 2003 aluminium windows to the second floor and original 1989 shop front type aluminium windows to ground and first floors. As with the other blocks, the original windows are leaking and are generally reliant on sealant around the box-section frames for weathertightness. The perimeter sealant has split and deteriorated and is allowing water ingress. Refer to Photos 2.1, 2.2 and 2.3 for examples of defects. These defects are consistent to all original windows to all blocks. The window defects from the other reports are applicable to this block.


2.1.3 Walls and Elevations Photo 3.1 shows a typical junction of the original carpark structure and the 2003 second storey. As can be seen, the top of the concrete column is bare and unflashed. The adjoining flashings have been butt jointed to the concrete. Photo 3.2 shows a close-up of the butt jointed flashing and concrete column. No sealant has been used between the flashing and concrete column which will allow moisture ingress. Photo 3.3 shows the timber support batten directly below the flashing. Moisture staining can be seen on the timber and concrete which confirms moisture ingress is occurring at this junction. Typical examples of this detail were dye tested to try and determine if water is penetrating the building. Water was readily poured into this column/flashing junction however we were unable to track the water ingress internally. This also supports our theory that there is a void at this floor level, or within the building, accumulating water and acting as a reservoir. Photo 3.4 shows a typical two part apron flashing which formed part of the 2003 building works. This flashing covers the original sloped perimeter wall to the original car park. There is a large unsealed gap directly below the flashing as shown in the insert photo. Although the majority of water will drip off the flashing, there is a risk of windblown water entry along this joint. Photo 3.5 shows the junction of the horizontal two part flashing and prefinished aluminium cladding. This junction is heavily reliant on sealant for weathertightness. In a number of places the sealant has deteriorated and split. Exposed sealant will have a limited life span of approximately 15 years depending on UV and weather exposure. This will create a high maintenance junction and will require on-going visual inspections and replacement as found necessary. Photo 3.6 shows the top of the concrete column to the Willow Street atrium entrance. Although similar to the previous detail as shown in Photo 3.1, the flashing is detailed slightly differently. Photo 3.7 shows the junction of the concrete column and horizontal flashing. This junction has been either repaired with surface applied sealant or was originally finished with sealant. A large hole was noted, as shown in the insert photo, which will allow water ingress. Cracking was also noted to the top of the column as shown in Photo 3.8. This may indicate corrosion to the reinforcement, due to water ingress causing expansion of the steel resulting in the concrete cracking. This requires extensive destructive testing to confirm. Photo 3.9 shows the sunshades over the second floor windows which have been bolted with fixing plates into the cladding face. Sunshades have also been installed to blocks B and C however the block B and C sunshade frames penetrate through the cladding and not bolted externally. In this case the sunshades have been bolted through the prefinished aluminium cladding into, we assume, a steel frame behind the cladding. Photo 3.10 shows a large gap at the rear of the sunshades frame. This will allow water behind the fixing face and allow water ingress through the bolt holes as confirmed by dye testing. As we understand there is a frame behind the fixing plate, water penetrating the bolt holes will track into the frame. We believe this is the cause of much of the staining to the ceiling tiles around the perimeter of all buildings, either in the form of condensation drips in colder months or water penetration drips. Photo 3.11 shows where dyed water ingress was achieved around the bolt fixing above the


Council lounge (carpet samples suggest some water ingress has occurred at this point). At the time of inspection the dyed water could not be traced internally and is likely ponding in construction voids behind the cladding. Stained ceiling tiles were noted as shown in Photos 3.12 and 3.13. Cracking at the window sill/wall junction would suggest movement has occurred as shown in photo 3.14. Once water ingress occurs at high level, it will track down through the wall by gravity until it reaches floor level or a clamping point. The original carpet sample as shown in Photo 3.15 suggests that some water ingress, albeit minor, has occurred resulting in bacteria growth. There are no weepholes to the soffit of the Alucobond cladding as shown on the original construction drawings. The omission of these weepholes will prevent any trapped moisture from escaping from behind the cladding. Photo 3.16 shows a bolt fixing which was noted to be loose and could be untightened by hand. Although this only proved to be an isolated finding through random selected checks, all fixings should ideally be confirmed as tight fitting. Photo 3.17 shows the flagpole penetration to the Chambers balcony area cladding. The cladding at the flagpole bracket could ‘flex’ allowing a gap, as shown in Photo 3.18. Dyed water easily penetrated the top bracket and exited from the lower bracket as shown in Photo 3.19. This confirms that water is penetrating at the top bracket, is running down the steel frame or other framing internally, and exiting at the lower bracket. As the internal side of this wall has been lined with acoustic cladding, we could not confirm if any decay and mould growth is occurring in the wall structure. The sealant to the prefinished aluminium cladding is also starting to fail at the horizontal joints. Photo 3.20 shows block A at the atrium entrance. Photo 3.21 shows a close up of the atrium steel penetration through the wall cladding. This area is directly outside the Te Awanui room where bacterial growth was identified in the carpet and directly above the City Waters corner office where Stachybotrys was identified in the carpet. Corrosion was noted on the steel as well as failed sealant as shown in Photo 3.22. This steel penetration was dye tested as shown in Photo 3.23. Some water was noted to be exiting from the lower mitre joint however more water penetrated than exited which would suggest that water is dispersing or is trapped within the structure. This test area is directly above the City Waters office and we believe this defect is the cause of the water damage and mould growth as shown in Photos 3.24 and Photo 3.25. As this office is inside the atrium cladding, we believe that water is penetrating from above and is travelling down through the building causing the decay and mould growth. Photos 3.26 and 3.27 show where repair attempts appear to have been carried out to the parapet capping directly above this test area in the form of an extended parapet capping. The sealant at the parapet capping cladding junction has failed as shown in Photo 3.28. The sealant has also failed at the window frame junction as shown in Photo 3.29. These failed sealant joints will be susceptible and prone to water ingress and are indicative of the high maintenance requirements of sealant reliant joints.


2.1.4 Internal Finishes

From our visual inspection of offices and spaces internally we noted the following damage to walls, ceilings and floor finishes:

Chambers – 2 No. moisture stained ceiling tiles adjacent to east wall.

Circulation area adjacent to Councillor’s lounge – 3 No. small moisture stains on two ceiling tiles, below ventilation trunking.

Second floor office in northwest corner – 4 No. moisture stained ceiling tiles.

We have attributed the probable source of moisture at the above locations to be condensation, forming on the underside of roof sheets and mechanical ventilation trunking.

First floor, southeast corner below roof deck – damp stain at abutment of window and external wall.

First floor, northeast corner, 5m in from east external wall – ceiling tile missing following water damage.

First floor, southwest corner – signs of corrosion and moisture staining at

window/wall/floor junctions; wall paintwork blisters.

First floor, south elevation – corrosion at window/wall junction; wall paintwork blisters.

2.1.5 Other Defects and Deferred Maintenance

During our site investigation, a number of additional building deficiencies, and/or areas of general material deterioration, have been identified. At present these observations are not necessarily of critical significance to the fundamental weathertightness of the building envelope. However, they are considered to be examples of routine building maintenance that provide scope for improvements as they can be designed out during the remediation works. Some of these matters reflect shortcomings in original workmanship and, although not presenting evidence of current failures, they are considered worthy of early attention and/or continued monitoring, due to their potential to cause increased future maintenance problems to the buildings. Neglecting attention to routine maintenance can lead to reduced durability and functioning of building materials and elements. The need for a planned programme of routine building maintenance should be addressed by the Council, together with their professional advisors, to ensure the future durability of the building fabric and to maintain the integrity of the building. The following are not intended to be an exhaustive schedule of maintenance defects for these buildings and more specific comments regarding any general maintenance issues are considered beyond the scope of the current reports. The observations are


not necessarily listed in any order of importance and are intended purely as prudent maintenance observations to assist the council:

Canopy roofing over Willow and Wharf Street frontages (Blocks A & C) have a number of damaged and slipped glazing panes (Note: urgent repairs have been reported and attended to previously for reasons of health and safety of pedestrians).

Membrane linings to all canopy roof areas are showing isolated deterioration of

lap joints and edge details, isolated patch repairs, lifting metal edge trims and isolated sealant repairs. Exposed sealant is prone to premature failure and is considered a temporary repair only.

Build ups of silt, lichen growths and general debris over membrane roof and

gutter linings are indications of ponding and indicate minimal drainage falls. Ponding and silt debris will accelerate deterioration of the membrane material and increase the likelihood of premature failure.

Exterior painted decorations to all block buildings (including cladding surfaces

and metalwork items) are generally showing deterioration and are overdue for renewal. This work will now become an essential part of the recommended longer-term repairs and refurbishment works.

A variety of flashings to joinery, wall junctions and roof-to-wall junctions are

untidily formed and many are reliant on surface applications of sealants. Latter may be associated with ad-hoc repair attempts in response to leak reports. These will be remediated as part of the wider recommended repairs and/or the exterior redecorations.

Numerous roof penetrations over the four buildings are potentially high risk

details that require regular maintenance inspections and provision of permanent access walkways and bridges, to avoid increased damage that may be caused during uncontrolled access.

Numerous roof fixings are over-tightened and causing distortion of rubber

washers. This increases the risk of failures at individual fixings and washers should be replaced as part of an overall maintenance programme to ensure long-term integrity.

Check all rainwater downpipe and overflow outlets from roof areas and internal

box gutters. Silt blockages and a bird nest were observed where randomly selected for inspection. No evidence of outflows being significantly compromised to-date.

A proactive maintenance programme of regular inspections, programmed

cleaning and careful washing down of the buildings is required to extend life expectancies of the various building materials and to reduce risks associated with blockages to drainage outlets and the like.


The proximity of the harbour coastline and the corrosive marine environment make it important to undertake regular cleaning of “unwashed” areas, such as those under atrium roofing and building projections, as well as regular inspection of all exposed metalwork fixings and fittings.

Arrange a specialist fire risk assessment to ascertain the need for fire

separation and continuity of fire cell areas in pitched roof voids throughout the building complex, in particular Blocks A and B.

2.2 Long Term Robust Remedial Solution Roof

1. Overhaul all roof penetrations and fixings.

2. Check roofing underlay.

3. Provide an access platform leading to the air conditioning plant to eliminate foot traffic over the roofs.

4. Adjust the rainwater downpipe from the Chambers roof to discharge directly into a

rainhead and not concentrate flow onto the membrane roof.

5. Take up the balcony tiles and re-lay to falls on a waterproof membrane ensuring a perimeter upstand to direct water into the rainhead.

6. Replace the parapet cap flashings where previously repaired.

Windows and Doors

1. Replace all original brown shopfront type windows with new windows complete with correct flashing details, air seals, weepholes etc.

Walls and Elevations

1. Ensure all steel penetrations are correctly detailed. 2. Provide proper flashing details to the top of all concrete columns, correctly

detailed to protect the horizontal flashings.

3. Remove Alucobond panels to allow inspection of framing behind.

4. Review all horizontal flashings to ensure they are correctly detailed and are not reliant on sealant for primary weathertightness.

5. Replace the cladding to balcony level and provide a nib at balcony level and

proper fixing penetrations for the flagpoles.


Pros and Cons

These remediation works will give a relatively low maintenance building which is not solely reliant on sealant for weathertightness. It will rectify key deficiencies in the original design and will eliminate suspect junctions and details. This is considered a long term and robust solution for the building and is our recommended option. To comply with the New Zealand Building Code all decay material must be removed and replaced.


3.0 CONCLUSIONS AND RECOMMENDATIONS 3.1 Summary Of Report

The building is suffering from water ingress which has led to deterioration and mould growth. The existing building has numerous deficiencies and the materials used have led to a relatively high maintenance building. The building is reliant on the durability of sealant joints to numerous and varying construction details, which increases the on-going maintenance required over the life of the building. The original brown shop front style windows have reached the end of their effective life and should be replaced. The poor detailing and workmanship where windows are fixed into their openings exacerbate the poor condition of the windows. The main roof has a number of defects which will likely lead to future water ingress. This includes no maintenance access to the services plant which requires personnel to walk over the roofs. This will lead to drainage. The balcony has numerous cracks between the tiles and wall cladding which is allowing water ingress into the substructure. The cracks were dye tested however we could not trace the water internally.

3.2 Recommendations We recommend that the long term robust remedial works be carried out to rectify the defects listed in this report. Short term minimal works can be undertaken however these are considered a temporary ‘band aid’ solution to prevent further water ingress and not a long term robust weatherproof solution. They will not meet the requirements of the New Zealand Building Code and are therefore not recommended but can be as part of routine maintenance.

Yours faithfully PRENDOS NEW ZEALAND LIMITED

Guy Dobson BSc (Hons) Building Surveying MRICS CHARTERED BUILDING SURVEYOR Direct Dial +64 7 927 0766 Direct Email [email protected]

Chris Phayer BSc (Hons) MRICS MNZIBS MNZIQS REGISTERED BUILDING SURVEYOR CHARTERED BUILDING SURVEYOR

janelle

Guy

janelle

Chris Phayer


Malcolm Thomas BSc (Hons) FRICS CHARTERED BUILDING SURVEYOR Reviewed by

Roger Charnock BSc (Hons) MNZIBS MRICS REGISTERED BUILDING SURVEYOR CHARTERED BUILDING SURVEYOR Distribution: One (1) by e-mail Enclosures: PHOTO SECTIONS Section 0: Elevations Section 1: Roof Section 2: Windows Section 3: Walls and Elevations

janelle

Malcolm

janelle

Roger


LIMITATIONS The limitations which apply to our inspection are as follows: 1) Concealed structure

We are not able to inspect woodwork or parts of a structure which are covered, unexposed or inaccessible and therefore are unable to report that such parts remain free from defects.

2) Deleterious and Hazardous Materials We did not carry out or commission any specialist investigation or tests to ascertain whether or

not any deleterious or hazardous materials have been used in the construction of or existed in any base building and/or any subsequent refurbishment.

3) Services installation No services installations were inspected. 4) Occupied buildings The property was occupied at the time of our inspection. Notwithstanding this, we do not feel

that our inspection has been excessively limited. 5) Contamination We have not carried out or commissioned any formal enquiries or investigations into the

potential contamination of the site or neighbouring land. In this respect you are advised to make your own arrangements, however, should you require any guidance we would be pleased to help.

6) Liability and confidentiality Our inspection and the report may be relied upon by Tauranga City Council only, to whom we

owe a duty of care. Our report should not be passed to any third party without our prior written consent, but such consent will not be unreasonably withheld or delayed.

PRENDOS New Zealand Limited

TECHNICAL DUE DILIGENCE REPORT 019557001

Tauranga City Council Buildings Block A Photo Section 0

Elevations

019557001


Photo 0.1: Willow Street elevation looking north.

Poorly detailed water run off from deck

Dye ‘disappeared’ at deck/wall junction where sealant has deteriorated

Failing sealant at flag pole bracket

Failing sealant to ground and first floor windows

Water penetration at glazing/cladding junction

Flashing starting to lift

019557001


Photo 0.2: Block A (Civic) and Block B (Library) to south end.

Poor cladding/deck junction

Cladding brought below deck tile level (dye water penetrated at wall/deck junction but could not be tracked internally)

Poor door threshold. Water penetration but no egress

Poor rainhead detail allowing water to run down the building

Poor window flashing and deteriorating sealant causing water ingress

Slipping canopy glass (Willow St and Wharf St)

Partly unsealed sunscreen penetrations

019557001


Photo 0.3: South elevation to Block A and atrium.

Hole in cladding allowing water ingress (dyed water could not be tracked internally) Poorly flashed

and sealed column junction

Ineffective rainhead and edge detail to deck tiles

Partly unsealed sunscreen penetrations

019557001


Photo 0.4: Willow Street elevation.

Penetrations not sealed

Majority of the windows leaking

Direct fixed cladding. Localised rot and mould identified

Holes at parapet level and at control joints allowing water penetration

Poorly detailed overflow

Inward sloping roofs causing leaking internally

019557001


Photo 0.5: Administration building to north end.

Limited rainwater outlets and internal gutter causing water ingress

Failing window seals and deteriorating sealant allowing water ingress to majority of windows

Lack of flashing causing water ingress along parapet level

Poor flashing around the exit door causing water ingress

Cracked concrete allowing water ingress

Confirmed decayed timber to the direct fixed cladding and wall framing

019557001


Photo 0.6: West elevation of the Administration building.

Rot identified in the timber frame and mould growth in the wall

Holes in cladding and poorly formed junctions

Parapet wall/spandral panel junction has failed and is allowing water ingress in various locations

Leaking windows generally

019557001


Photo 0.7: North elevation of Library.

Cladding brought below ground level causing rot and mould growth

Holes and gaps noted to the reclad elevation

Poorly detailed junctions and flashings

Failing window sealant and deteriorating window gaskets to original broken windows

019557001


Photo 0.8: West elevation behind the Library.

Cladding brought below ground level

Sealant has deteriorated

Sealant to the sun screen penetrations is deteriorating




Roof

019557001


Photo 1.1: General view of the roof over chambers.

Water running down the membrane “hugs” the side of the wall leading to a water concentrate at the vulnerable junction

Photo 1.2: Downpipe discharging onto the membrane roof.

Downpipe discharging onto the flashing and cladding junction

019557001


Photo 1.3: Vulnerable roof detail to side of chambers roof.

Water running down the gutter can be directed under the flashing

Photo 1.4: Atrium Smoke Vents.

019557001


Photo 1.5: Evidence of water ingress to the Atrium at high level.

Photo 1.6: Poorly installed flashing.

Ponding water

019557001


Photo 1.7: Roof steel corrosion within the Atrium.

Photo 1.8: General example of roof defects.

Sealant repaired fixing

019557001


Photo 1.9: Air conditioning equipment over the civic offices. All roof penetrations are potential high risk weathertight details.

Poor access to this plant

Photo 1.10: Rain head to the balcony access from Chambers.

019557001


Photo 1.11: Water from the balcony not correctly directed into the rain head.

Run marks

Photo 1.12: Water run marks on wall below the balcony.

Water running off the balcony edge Water from

the down pipe is not fully directed into the rain head

019557001


Photo 1.13: Edge detail to the balcony.

Loose and cracked mortar fillet

Photo 1.14: Vegetation at column to slab joint which promotes water retention and penetration.

Vegetation growth confirming moisture retention

Surface corrosion of fixing bolts

019557001


Photo 1.15: Deteriorated and split sealant at cladding/balcony junction.

Split and deteriorating sealant. Dyed water ‘disappeared’ here

Photo 1.16: Deteriorated sealant to balcony/wall junction.

Crack in grout

Splits in the sealant

Cladding taken below tile level

019557001


Photo 1.17: Split sealant at the balcony window.

Hole in sealant at deck window.

Dyed water disappeared here and could not be traced internally




Windows

019557001


Photo 2.1: Typical 1989 shop front style aluminium window. Box section frames reliant on sealant joints to perimeter and head flashings appear retrospectively added.

Photo 2.2: Typical deterioration of sealant perimeter jointing – see Photo 2.3.

Photo 2.3

Colour finish has faded

019557001


Photo 2.3: Closer view showing UV deterioration of sealant and isolated holes and separators that can allow water ingress; refer Photo 2.2 for location.




Walls and Elevations

019557001


Photo 3.1: Block A – Bare concrete top of original car park columns.

Closer view of surface sealant to lap joint

Wharf St Atrium

Photo 3.2: Blocks A & C (2003) – two piece apron flashings and basic butt joints to columns which are unsealed and allow water beneath the flashing.

019557001


Photo 3.3: Apron flashing lifted to expose bare concrete nib and timber packer.

Moisture staining

Photo 3.4: Typical apron flashing.

Unsealed gap below flashing

Water run marks

019557001


Photo 3.5: Typical surface sealant junction.

Photo 3.6: Willow street frontage at the Atrium.

019557001


Photo 3.7: Junction of column and flashing.

Junction reliant on surface applied sealant

Photo 3.8: Top of concrete column.

Cracks

019557001


Photo 3.9: Block A – Variation of sun-screen support being bolt fixed through parapet cladding.

Photo 3.10: Gap behind the sunscreen bracket.

019557001


Photo 3.11: Dye ingress achieved around lower bolt penetration –corresponding position in Councillors lounge (Photo 3.12).

Photo 3.12: Evidence of water ingress. Corresponds with dye entry to sunscreen bracket.

See Photo 3.14

See Photo 3.13

019557001


Photo 3.13: Stained ceiling tile to Councillors Room.

Water stain

Photo 3.14: Shrinkage/swelling movement.

019557001


Photo 3.15: Carpet sample to Councillors Room.

Photo 3.16: Top bolt was loose (isolated problem from the random number inspected and tested).

019557001


Photo 3.16: Flag pole bracket.

Photo 3.17: Failed sealant joint – similar to sunscreen beams. Flexing of panel adjacent (under finger pressure) leaving a gap.

019557001


Photo 3.18: Dye test to upper bracket led to ingress and egress at the lower bracket.

Photo 3.19: View down to lower bracket showing dye exit but amount did not appear to correspond with amount ingressing above.

Dye and water running out of bracket below

Sealant to the horizontal joint is starting to fail

019557001


Photo 3.20: Block A atrium entrance.

Test area

Photo 3.21: Structural steel penetration into parapet cladding.

Corrosion

019557001


Photo 3.22: Failed sealant joint allows direct dye entry.

Photo 3.23: Minor dye exit noted at mitred joint.

Corrosion

019557001


Photo 3.24: Room directly below water penetration.

Photo 3.25: Close up skirting level framing.

019557001


Photo 3.26: Above structural steel position – sealant joint and repairs to parapet.

Photo 3.27: Wider capping and retrospectively applied surface sealant (reason unknown).

019557001


Photo 3.28: Sealant joint at up-stand junction.

Failed sealant

Photo 3.29: Possible previous ingress adding to steel penetration position below.

Sealant repair to vertical

TECHNICAL DUE DILIGENCE REPORT 019557001 …econtent.tauranga.govt.nz/data/projects/files/civic_space/block_a... · TECHNICAL DUE DILIGENCE REPORT 019557001 Tauranga City Council

Documents