christchurch four years on - underfoot services ltd- bevan craig - foundation presenation
TRANSCRIPT
The Reality of damagedFoundations and slab issues
In Christchurch
Pre 1970 foundations
Specification dated 1949
1970 - 1980 Foundation
1980- 2010 Concrete slab foundations
The Elephant in the room is the way the existing home is constructed and the real damage that has occurred
The reality is the way MBIE guidelines are interpreted and used often does not relate to the house or the real damage
The MBIE Guidelines have been written by Engineers but the majority of your houses were designed and drawn up by Architects or Builders.
The practitioner has been cut out of the process and that knowledge of how your houses were constructed, particularly older homes is missing in the Guidelines
Guideline Status
In reality it is not robust or well balanced and is being used as a guide to minimise repairs and mitigate costs not repair your homes correctly
Epoxy crack repair
Jack & Pack
Rebated Bearers
Partial foundation replacement
Manipulation of floor levels
Self levelling floor toppings
No Geotechnical investigation
Assessed as Grind out and Epoxy Fill
It may surprise you that four and half years on that rubble foundation are still not acknowledged as existing in the Guidelines.
Epoxy crack repair
Jack & Pack
Rebated Bearers
Partial foundation replacement
Manipulation of floor levels
No Geotechnical investigation
Minor damage is a judgment call and it can only be quantified by the experience of the person making that judgement
Floor Re-Levels
Jack & Pack
Rebated Bearers
Partial Foundation
Replacement
It should be noted that the Geotechnical profession acknowledges there is a strength loss following a liquefiable event and that the bearing capacity will decrease. Because the residual bearing capacity is unknown and there is currently no simplified or empirical method to estimate this, it is critical that the existing bearing capacity of the damaged foundation is established
River Tailings
The MBIE guidelines Sec 5.3 discusses foundation and floor options and notes that “Poorly graded river gravels (tailings or 20/40 rounded river stone) that have commonly been used in Christchurch as sub grade material should not be used. This type of material is prone to forming unstable stone arrangements (bridges) that may collapse with future vibrations, leading to a localised loss of support to the overlying slab.”
EQC Repair
The Gap is Widening
Insurance Repair
Where does the
responsibility lie
With Yourself
Its your house
The poof of loss is your responsibility
Own your own information
Get independent assessments of the real damage
Get independent advice on your entitlements under the EQC act and your Insurance policy
Peter Sparrow