User Has Full DB Access By Default

I have a DB creation script which starts with the following lines

EXEC sp_addrole 'RAVENROLE'
go
IF NOT EXISTS (SELECT * FROM sys.database_principals WHERE name = N'USER1')
CREATE USER [USER1] FOR LOGIN [USER1] WITH DEFAULT_SCHEMA=[USER1]
go
IF NOT EXISTS (SELECT * FROM sys.schemas WHERE name = N'USER1')
EXEC sys.sp_executesql N'CREATE SCHEMA [USER1] AUTHORIZATION [USER1]'
GO
EXEC sp_addrolemember 'RAVENROLE', 'WS-NOLANKTFSBUILD2'


Basically what I am doing is creating a role, then adding user USER1 to it. The problem is USER1 has full update, insert etc. permissions on all tables in the database by default. Even when I deny that user permissions they can still update, insert etc.

I am using Windows Authentication, User1 also exists as a windows user.

How do I ensure that User1 has no permissions by default? I want to be able to explicitly add them.