The challenges follow the UK government's withdrawal of an exemption from affordable housing contributions and vacant building credit for small housing developments after the High Court ruled it was unlawful.
The first appeal decision relate to a development of 121 homes in Weedon. The Council said in a statement that its challenge was based on how the Inspector dealt with its adopted Local Plan policies, which require affordable housing for developments of five or more homes.
In the second appeal, which relates to a five-home scheme in Barby, the Inspector concluded that it would be unreasonable to request affordable housing because the Council did not have a five-year housing land supply. The Inspector said that the affordable housing exemption in the Planning Policy Guidance was a material consideration which he gave "significant weight".
The Council said that the High Court decision and withdrawal of the exemption meant that its Local Plan policy would now carry more weight.
“Having carefully studied the appeal documents relating to these applications and the reasons for overturning these original decisions we have taken counsel opinion and decided to legally challenge these two outcomes," said leader of Daventry District Council Chris Millar. "We never take such action without due consideration of all the implications,” he said.
Planning expert Elizabeth Wiseman of Pinsent Masons, the law firm behind Out-Law.com, said: "When the High Court ruling of Mr Justice Holgate was made earlier this year it was suspected there would be numerous legal challenges due to the uncertainty that was created. So far this prediction appears to be holding true and these challenges are just two examples. It will be interesting to see what the outcomes of these two challenges are and whether they lead to any further certainty for developers of smaller sites."