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