Using PowerShell

Step 1. Export Sub Site using Export-SPWeb command.

Export-SPWeb -Identity http://intranet.company.corp/site1/subsite1 -Path "C:\Exported Sub Site\subsite1.cmp" -IncludeUserSecurity -IncludeVersions all

Step 2. Create new Site Collection to host the exported Sub Site. [Select template Collaboration > Blank Site]

e.g. http://intranet.company.corp/site2

Step 3. Import the Content Migration Package (CMP) using Import-SPWeb command.

Import-SPWeb http://intranet.company.corp/site1 –Path "C:\Exported Sub Site\subsite1.cmp"

Using STSADM

Step 1. Export Sub Site using stsadm –o export command.

stsadm.exe -o export -url http://intranet.company.corp/site1/subsite1 -filename c:\Exported Sub Site\subsite1.cab -includeusersecurity -versions 4

Step 2. Create new Site Collection to host the exported Sub Site. [Select template Collaboration > Blank Site]

e.g. http://intranet.company.corp/site2

Step 3. Import content to new Site Collection

stsadm.exe -o import -url http://intranet.company.corp/site2 -filename c:\Exported Sub Site\subsite1.cab -includeusersecurity