Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2017	Feb. 20, 2018	Jun. 30, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	SG BLOCKS, INC.
Entity Central Index Key	0001023994
Trading Symbol	SGBX
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2017
Entity Filer Category	Smaller Reporting Company
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 12,266,807
Entity Common Stock, Shares Outstanding		4,260,041