Cover - shares	6 Months Ended
	Jun. 30, 2020	Jul. 29, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2020
Document Transition Report	false
Entity File Number	1-37533
Entity Registrant Name	GCP Applied Technologies Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3936076
Entity Address, Address Line One	62 Whittemore Avenue
Entity Address, City or Town	Cambridge
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02140-1623
City Area Code	617
Local Phone Number	876-1400
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	GCP
Security Exchange Name	NYSE
Entity Common Stock, Shares Outstanding		72,974,610
Entity Central Index Key	0001644440
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Amendment Flag	false