EXHIBIT (a)(3) NOTICE OF GUARANTEED DELIVERY To Tender Shares of Common Stock of Chemfab Corporation Pursuant to the Offer to Purchase dated August 2, 2000 by PPLC Acquisition Corp. an indirect wholly owned subsidiary of Norton Company an indirect wholly owned subsidiary of Compagnie de Saint-Gobain This Notice of Guaranteed Delivery, or a form substantially equivalent to this form, must be used to accept the Offer (as defined below) if the shares of common stock, par value $0.10 per share, of Chemfab Corporation and all other documents required by the Letter of Transmittal cannot be delivered to the Depositary by the expiration of the Offer. This Notice of Guaranteed Delivery may be delivered by hand or facsimile transmission, telex or mail to the Depositary. See Section 3 of the Offer to Purchase. The Depositary for the Offer is: ChaseMellon Shareholder Services, L.L.C. By Mail: By Overnight Delivery: By Hand: P.O. Box 3301 85 Challenger Road 120 Broadway, 13th Floor South Hackensack, NJ 07606 Mail Drop-Reorg New York, NY 10271 Attn: Reorganization Atn:tReorganization Department Ridgefield Park, NJ 07660 Department Attn: Reorganization Department By Facsimile Transmission (for Eligible Institutions only): (201) 296-4293 Confirm Facsimile By Telephone: (201) 296-4860 ---------------- DELIVERY OF THIS NOTICE OF GUARANTEED DELIVERY TO AN ADDRESS OR FACSIMILE NUMBER OTHER THAN AS SET FORTH ABOVE WILL NOT CONSTITUTE A VALID DELIVERY. This Notice of Guaranteed Delivery is not to be used to guarantee signatures. If a signature on a Letter of Transmittal is required to be guaranteed by an "Eligible Institution" (as defined in the Offer) under the instructions thereto, such signature guarantee must appear in the applicable space provided in the signature box on the Letter of Transmittal. Ladies and Gentlemen: The undersigned hereby tenders to PPLC Acquisition Corp., a Delaware corporation ("Purchaser") and an indirect wholly owned subsidiary of Norton Company, a Massachusetts corporation, which is an indirect wholly owned subsidiary of Compagnie de Saint-Gobain, a French corporation, upon the terms and subject to the conditions set forth in the offer to purchase dated August 2, 2000 (the "Offer to Purchase"), and the related Letter of Transmittal (which together with any amendments or supplements thereto constitute the "Offer"), receipt of which is hereby acknowledged, shares of common stock, par value $0.10 per share (the "Shares"), of Chemfab Corporation, a Delaware corporation, pursuant to the guaranteed delivery procedure set forth under "Procedures for Tendering Shares" in the Offer to Purchase. Certificate Nos. (if available) SIGN HERE ___________________________________ ___________________________________ Signature(s) of Holder(s) ___________________________________ ___________________________________ Name(s) (Please Print or Type) If Shares will be tendered by book-entry transfer: Name of Tendering Institution ___________________________________ Address ___________________________________ ___________________________________ Zip Code Account No. _______________________ ___________________________________ Area Code and Telephone No. at The Depository Trust Company Dated: _____________________ , 2000 2 GUARANTEE (Not to be used for signature guarantee) The undersigned, a firm which is a member of a registered national securities exchange or the National Association of Securities Dealers, Inc., or a commercial bank or trust company having an office or correspondent in the United States, guarantees (a) that the above named person(s) "own(s)" the Shares tendered hereby within the meaning of Rule 14e-4 under the Securities Exchange Act of 1934, (b) that such tender of Shares complies with Rule 14e-4 and (c) to deliver to the Depositary the Shares tendered hereby, together with a properly completed and duly executed Letter(s) of Transmittal (or facsimile(s) thereof) or an Agent's Message (as defined in the Offer to Purchase) in the case of a book-entry delivery and any other required documents, all within three New York Stock Exchange trading days of the date hereof. ___________________________________ ___________________________________ Name of Firm Authorized Signature ___________________________________ Name: _____________________________ Address (Please Print or Type) ___________________________________ Title: ____________________________ Zip Code (Please Print or Type) Area Code and Telephone Number: _________________ Dated: ______________________, 2000 DO NOT SEND SHARE CERTIFICATES WITH THIS NOTICE OF GUARANTEED DELIVERY. SHARE CERTIFICATES SHOULD BE SENT WITH YOUR LETTER OF TRANSMITTAL. 3