| Cover | May 04, 2021 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Document Period End Date | May 4, 2021 |
| Entity Registrant Name | GCP Applied Technologies Inc. |
| Entity Incorporation, State or Country Code | DE |
| Entity File Number | 1-37533 |
| 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 |
| City Area Code | 617 |
| Local Phone Number | 876-1400 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, $0.01 par value |
| Trading Symbol | GCP |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Amendment Flag | false |
| Entity Central Index Key | 0001644440 |
