Unjust EnrichmentConstruction lien action:  A supplier cannot assert an unjust enrichment claim against an owner, particularly if the contractor has asserted a construction lien claim.  The contract between the owner and the contractor is a juristic reason for the unjust enrichment claim being disallowed, and the absence of any dealings between the owner and the supplier and the purposeful decision by the supplier not to participate in the lien action contradict the assertion of any reasonable expectation that the supplier would have a claim in unjust enrichment: Barrie Trim v. Heath et al, 2010 ONSC 2107. See CBC, Chapter 4, part 4. 

Unjust Enrichment-Construction lien action:  If a construction lien claim is struck down because the claim does not meet the technical requirements of the Construction Lien Act, a personal claim in unjust enrichment may be made if it arises out of the same circumstances as the lien: Juddav Designs Inc. v. Cosgriffe, 2010 ONSC 6597  http://bit.ly/ibs1TD