That slab is where their house sat until April last year when an electrical fault started a fire that gutted the building, leaving their 6-year-old son "traumatised".
The slab is also meant to be the foundation for the Mōrungas' replacement home, but after $30,000 worth of flooding, sewerage and geotechnical checks and assessments by experts, their building consent application has hit a major snag, they say.
In Paora's opinion the Whakatāne District Council keeps "shifting the goalposts".
The latest news - that there now needs a $10,000 survey because of outdated Māori land maps - "has been the straw that broke the camel's back", Karen says.
They've been told the building site sits on the border of two Māori land titles.
The couple has had three hui with council staff about their application and Karen said unexpected needs and costs came up each time.
The toll on her mental health has been heavy.
"I couldn't even look at the emails anymore because it was just too much."
Paora has had to take stress leave from work, due to the frustration and disappointment.
In his opinion, a lack of cultural understanding by council, of Māori land titles and succession of kaitiaki, has led to a lot of the "inconsistency" during the application process.
"A lot of this could have been avoided if they'd just told us what was needed right from the start ... We are just building straight on top of our old house site."
Whakatāne District Council's general manager of planning and infrastructure, David Bewley, said the council acknowledged Mōrunga's frustrations.
"Through the building consent application process, some matters have arisen with determining the property boundary line. Council staff have requested to meet with Mr Mōrunga to work through these matters in a practical way."
He said the council wanted to meet again with Paora Mōrunga before commenting further on the matter.
Karen and Paora raised six children in the home and it was full of memorabilia.
They're spending the winter in two caravans with their youngest son, Rangiaua Broughton-Pile and two teenage mokopuna.
They had insurance leading up to the blaze and had to fight "tooth and nail to get anything out of it".
The materials for a kit set home sit in a container on the section but even if they get building consent, they risk losing their builder due to lengthy delays.
They'd originally hoped to be in a new home by last Christmas.
One of the few things lifting their spirits is their "great" community.
"They're willing to come and help us with anything we need," Karen says.
"We were at a tangi this week ... People asked how we were going and offered to protest outside the council."
Retelling that gets a rare giggle out of her.
"You hear so much negative stuff about our community but when the s*** hits the fan they're there. They've been there for us."
Waiariki MP Tāmati Coffey said he was "a strong supporter of any opportunity for local Māori to build on Māori freehold land".
He said a survey of the boundary line would be more constructive than a survey of an entire land block.
"I will be contacting the council to advocate exploring this possibility, in the hopes that this whānau can move forward and continue to achieve their whenua aspirations."