Hi Experts in this forum,
I have build my new home last year, after handover I have done concrete around the house and also landscaping done. After few months internal wall cracks came and this is reported to builder. Builder did visual inspection and then said this is due to paving around the house was not done properly and due this cracks are coming and need to do engineering report to see level of surface is graded away from the house. Engineering report is came through and it was clearly mentioned as fallows:
Report#1:
Our observations found that the perimeter pavement at the east, west and south faces all grade away from the dwelling (refer figures 1, 3 & 5, Appendix A). These sections of pavement are graded away from the dwelling, at grades ranging from 1:29 to 1:57 (refer figures 2, 4 & 6, Appendix A). No sections of pavement were measured to grade towards the residence.
The minimum grade required for pedestrian only areas as stipulated by ‘CSIRO – Foundation Maintenance and Footing Performance: A Homeowner’s Guide’ is 1:60 away from the from the foundations. All sections of pavement are within the advised grade tolerance.
Based on the above, the pavement system is graded adequately to effectively direct rainwater and surface flows away from the residence.
The pavement is not directed towards any form of surface drainage, and so even though the grade of the pavement is compliant, the surface runoff could still be penetrating the residence’s founding soils.
After above report came through, builder had meeting with me and he discussed like even though paving is graded away from the building and water runs of from paving t garden bed, where does the water go eventually it will accumulate water to pool as there is no surface drainage to discharge the water into drains and it will penetrate into the foundation and make slab to heave and then cracks will come up and also he mentioned paving need to cut and connect to drainage pipes around the house to dischargee the water.
I said as per report is fine as paving is done and water is draining away from dwelling, then he said the way report was given by engineer he did not like and he will go back and speak with them to update? then I was shocked and said not sure what you are talking no where mentioned in engineer report about drainage surface water is the issue as already report was send out, again he said leave it with me I need to speak engineer about report and sends you email. He send below email along with another same report(refer Amended Same Report#2)
It clearly states that ‘The pavement is not directed towards any form of surface drainage, and so even though the grade of the pavement is compliant, the surface runoff could still be penetrating the residence’s founding soils. Stormwater which travels over the end of the pavement is not connected to the Legal Point of Discharge or any drainage points and as such has no way of being discharged from the subject site. This allows water to pool and can potentially percolate into the foundation soils of the building over time.’
Due to above reason, builder is not required to take any further action.
Amended Same Report#2:
..............
Based on the above, the pavement system is graded adequately to effectively direct rainwater and surface flows away from the junction between the pavement and the residence.
The pavement is not directed towards any form of surface drainage, and so even though the grade of the pavement is compliant, the surface runoff could still be penetrating the residence’s founding soils. Stormwater which travels over the end of the pavement is not connected to the Legal Point of Discharge or any drainage points and as such has no way of being discharged from the subject site. This allows water to pool and can potentially percolate into the foundation soils of the building over time.
Now I don't know what to do, when cracks reported , builder said due to paving issue need to get engineering report, when paving is good as per engineer report now builder is referring to surface drainage is not connected to point of legal discharge. Seems builder does not want to fix it and just push back to me, I need expertise how can resolve the issue.