Double DPC?

[foxford2021]

I hope someone can explain exactly what a Double DPC is?

We are in a new build timber framed property, After lots of issues we had a snagger in to inspect our property and one point listed was the air bricks (see photo)

Our developer's response was it's ok as we have a double DPC?
The snaggers said if this is the case then it should be fine but they found no evidence to support (or deny) it.

I would like to understand exactly what a Double DPC is in relation to a timber-framed building (if it's relevant?)

[New Home Expert]

A DPC or Damp Proof membrane under the concrete floor.
Then another DPC is placed under the sole plate that your timber frame is fixed too.
Standard practice.

What did your snagger say about the replaced bricks above the air bricks?
Looks like they either forgot the dpc tray above the airbrick ducting OR they had to clear a lot of mortar from it.

There are lots of possible defects with timber frame. I hop your snagger knows what to look for.