Pyrite Presentation to CIF - Tuesday 12 th August 2014

1. Pyrite Presentation to CIF - Tuesday 12th August 2014 Paul Forde BE CEng MIStructE EurIng FIEI RConsEIDBFL Consulting Engineers

2. Summary Topics to be covered today • What Pyrite Issues am I dealing with today • Involvement from 2006 / 2007 to date • What are the Manifestations • Remediation • What Guidance Existed in 2006 / 2007 • What Steps were then taken • What Guidance now exists • What Quality Control Procedures should now be Adopted by Engineers & Contractor • What still needs to be done (Personal Opinion) Summary

3. 1. What Pyrite Issues am I dealing with today • Pyrite in Hardcore • Pyrite in Blockwork • Not dealing with Effects of Pyrite in Concrete, Cement, Mortar or Natural Ground although there are issues there. • How damage manifests • How to protect against the threat posed by Pyrite by Adequate Quality Control Procedures Note : I would emphasise that there is now no insurance cover available against pyrite. 1. Pyrite Issues Covered. Summary

4. DBFL Involvement from 2006/2007 to Date Stone Hardcore Infill • My own initial ‘baptism’ in 2006/2007. • What Damage we were seeing over the years. • My initial conclusions. • Significance of Progression of Damage and Time-Line. • My conclusions now. 2. DBFL Involvement to Date. Summary

5. 2. DBFL Involvement to Date. Observed Damage - Wall Cracking

6. 2. DBFL Involvement to Date. Observed Damage - Floor Rising

7. 2. DBFL Involvement to Date. Observed Damage - Bowed Internal Walls

8. First introduction -400 homes in 2006. • Typical damage - wall cracking over internal doors and minor floor cracking. • Normal snagging to Contractor • Misdiagnosis • Recurrence of cracking confirmed misdiagnosis 2. DBFL Involvement to Date. Initial Misdiagnosis

9. 2. DBFL Involvement to Date. Cracking in concrete floor slab

10. 2. DBFL Involvement to Date. Cracking in concrete floor slab breaking tile joint

11. 2. DBFL Involvement to Date. - Initially misdiagnosed as settlement with ‘solution’ to pressure inject the voids

12. Timing • In our experience damage normally manifests approximately 1½ to 2 years after the floor slabs have been poured. • However, both earlier and later instances have been found. 2. DBFL Involvement to Date . Significance of Progression and Time Line

13. 2. DBFL Involvement to Date . Significance of Progression and Time Line Photo taken 20th August 2007

14. 2. DBFL Involvement to Date. Significance of Progression and Time LinePhoto taken 13th January 2010

15. Summary of conclusions • Complex interaction • Stone very confined – Party walls – high frictional forces • Stone less confined – external walls – stresses relieved 2. DBFL Involvement to Date. Conclusions

16. 2. DBFL Involvement to Date. Conclusions

17. The floor slab itself provides very little resistance to the expansion. • The upward pressures are transferred from the expanding stone infill through the insulation to the underside of the slab. • The upward pressures cause the slab and also any walls built off the slab to rise. These walls subsequently crack. • When the slabs and stone are removed the wall cracks reduce and often fully close. • The fill does not behave isotropically 2. DBFL Involvement to Date. Conclusions

18. B Before Removal of Infill After Removal of Infill 2. DBFL Involvement to Date. Closing of cracks

19. Rising Walls • Frictional forces develop • Horizontal cracking and gaps in walls can occur • Some can extend around the full periphery of the property • Frictional forces can lift entire house. • The required forces to cause this are not ‘huge’ – a force in the order of 100kN/m2 can cause it. 2. DBFL Involvement to Date. Conclusions

20. 2. DBFL Involvement to Date. Gaps in rising walls

21. 2. DBFL Involvement to Date. Conclusions

22. Blockwork • My personal experience with pyrite in blockwork commenced earlier this year (2014). • Horizontal and vertical cracks were noted in rendered walls of houses and we found the cracking patterns difficult to explain. • Eliminated usual causes e.g. settlement, shrinkage etc. • Queried whether pyrite could be a factor. • Following removal of areas of render we found cracking within the concrete blocks themselves. • On further inspection we noted delamination, crumbling and further cracking. 2. DBFL Involvement to Date - Blockwork

23. Cracking first viewed in external wet dash, once drylining was removed internally cracking was noted reflected through the wall in the blockwork and along the mortar joints 2. DBFL Involvement to Date – cracking in render and blockwork

24. Vertical cracking at rear wall junction 2. DBFL Involvement to Date – cracking in render

25. What are the Manifestations • Swelling of sub-floor hardcore causing effects (already described). • Swelling of hardcore used externally • Sulfate attack from hardcore • Cracking and disintegration of blockwork. 3. Manifestations

26. Cracking of concrete pavings, lipping between adjacent pours, gaps under kerbs and general lifting and differential movements in paved areas. • Possible damage to underground services from swelling stone is also a concern. • Horizontal gaps have been observed in many manholes and service chambers. 3. Manifestations. External Areas

27. 3. Manifestations. External Areas. Manhole chambers and Footpaths

28. 3. Manifestations Internal Rising Wall – Sulphate attack

29. 3. Manifestations Sample of Blockwork

30. 3. Manifestations. Cracking & Disintegration of Blockwork

31. 4. Remediation • Stone within buildings - remove and replace • Blockwork – remove / demolish Remediation

32. Method Statement / Remedial Works Plan In order to provide certification Engineer to supervise and sign off at various stages through the works. Works cannot proceed without sign off. Remediation – Stone within buildings

33. Remediation Works Remediation – Stone within buildings

34. Remediation Works Remediation – Stone within buildings

35. Remediation Works Remediation – Stone within buildings

36. Remediation Works Remediation – Stone within buildings

37. Remediation Works Remediation – Stone within buildings

38. Remediation – Blockwork

39. Remediation – Blockwork

40. Remediation – Blockwork

41. 5. Guidance in 2006/2007 • BRE Digest 1 – first published in 2001 & mainly concerned with sulfate attack on buried concrete from soils in contact with the concrete. • SR 21:2004 – this was amended in 2007 as SR 21:2004 + A1:2007 to reflect the problems being experienced in Leinster with pyritic hardcore. • At this time stone used in civil engineering projects was tested – usually to confirm compliance with Clause 804 material. • However, stone used as sub-floor fill inside buildings was rarely, if ever, tested. • Issues with “traceability” of stone due to extensive use of “hackers”. • Structural concrete was tested, both for workability (slump) and for strength (cubes). • Structure blockwork was sometimes tested for (compressive) strength. 5. Guidance in 2006/2007

42. 6. What Steps were then Taken • Initial Government response was sluggish and each Contractor and homeowner affected was left to deal with the matter on his own at a time that the economy was entering recession • Eventual Goverment Intervention in the form of setting up the Pyrite Panel who issued their Report in June 2012. • Drafting of IS 398: Parts 1 & 2 • Setting up of Pyrite Resolution Board • Updating NRA Specification for Roadworks (600 & 800 Series) • Updating S.R. 21 (2014) 6. Steps Taken

43. How has Industry responded? Development of existing and new standards 6. Steps Taken – Amended / New Standards

44. 7. What Guidance now Exists • The Problems with Pyrite parallel the introduction of the Eurocodes • Eurocodes take Declaration of Performance (DoP) approach • National Annexes and Standard Recommmendations (for the use of the Annexes) for various aggregates and cement. • The problem for most Engineers and Contractors and Suppliers is the sheer volume and variation of the guidance. • It can difficult to interpret each standard and decide if the anomolies that exist between the various standards are of any significance. 7. What Guidance now Exists

45. How has Industry responded? Current relevant standards 7. What Guidance now Exists – Current Relevant Standards

46. It can also be difficult to determine if the results of testing are properly describing the source material (not to mention if the sample tested is representative). • IS 398-1:2013 gives guidance and methodology for achieving a Category A status (Green Cert) 7. What Guidance now Exists

47. 7. What Guidance now Exists – “Green Cert”.

48. 8. What Quality Control Procedures should now be Adopted by Engineers & Contractors • Should the Contractor and Engineer be doing more? • Judicious random sampling on site • Does not relieve the supplier of his responsibilities. • The supplier clearly has a duty to comply with the current regulations and a duty in law to supply material that is fit for purpose. • The Contractor should insist that he receives evidence that his supplier is fully compliant with relevant QA certification under the EU Construction Products Regulation. • Nevertheless, I still have my own reservations even if the Construction Products Regulation certificates are in place. 8. What Should we Do now

49. 9. What still needs to be done (Personal Opinion) • Current Regulations not clear and unequivocal • Clearer guidance required • Regulations not robust • Difficult to regulate • Number of suppliers and subcontractors on any project 9. What still needs to be done