A method is presented for constructing mechanically stable fins. The method includes forming a fin stack including a plurality of sacrificial layers, recessing the fin stack to form channel fins, depositing a first type epitaxy between the channel fins, depositing a dielectric region over the first type epitaxy, depositing a second type epitaxy over the dielectric region, and removing the plurality of sacrificial layers resulting in formation of a plurality of gaps. The method further includes filling a first set of the plurality of gaps with a p-type work function metal (WFM) to form a p-type field effect transistor (pFET) structure and filling a second set of the plurality of gaps with an n-type WFM to form an n-type field effect transistor (nFET) structure, where the nFET structure is stacked over the pFET structure.