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Accounts Receivable (Tables)
3 Months Ended
Mar. 31, 2018
Accounts Receivable [Abstract]  
Summary of accounts receivable
  March 31, 2018  

December 31,

2017

 
Billed:      
Block sales $-  $14,038 
Construction services  1,068,477   2,652,496 
    Retainage receivable  388,161   373,576 
Total gross receivables  1,456,638   3,040,110 
Less: allowance for doubtful accounts  (27,006)  (34,235)
Total net receivables $1,429,632  $3,005,875