Do a mechanic lien documents need to be notarized?

No, Pennsylvania mechanics liens and related documents, such as the Notice of Intent to Lien are not required to be notarized in order to be valid. However, Pennsylvania liens must be accompanied by an Affidavit of Service which does need to be notarized. 

For additional information, see: To Notarize or Not? A Guide to Common Construction Documents 

If you mean a lien claim, then the answer is no:

https://www.levelset.com/mechanics-lien/pennsylvania-lien-law-faqs/

Pennsylvania Mechanics Lien must contain:

1. Name of claimant;

2. Notice of whether claimant is contractor/subcontractor;

3. Name and address of property subject to lien;

4. If subcontractor, name of the contractor;

5. Claimed amount;

6. Description of work/contribution to the property;

7. Last date on site/work completed;

8. Date of formal notice (if required as subcontractor);

9. Description of property to be liened.