Questions to ask a siding, window or deck contractor before you sign

Updated November 10, 2026 · KeystoneProGuide editorial team

Which questions matter most?

Ask the ones whose answers you can check. A registration number can be looked up, a lead certificate can be seen, a product line can be priced elsewhere and a payment schedule can be measured against the law. The questions below are grouped by the stage at which to ask them, and each comes from a rule or a piece of official advice. Use them alongside how to choose a contractor, which covers the checks you make on your own.

About the business

What is your Pennsylvania registration number? It should be on the estimate already, as PA followed by digits. Any hesitation here ends the conversation.
Is this the exact name you are registered under? The registration, the contract and the name on your check should match.
Who will actually install the job, and are they registered? Under the Home Improvement Consumer Protection Act, subcontractors must register too, and the contract must name the ones known when you sign.
Can I see your insurance certificate? The contract must state the current amount of coverage, and registration requires at least $50,000 for personal injury and $50,000 for property damage.

About an older house

Is your firm EPA lead-safe certified, and who is the certified renovator on this job? Required for paid work that disturbs paint in a pre-1978 home. The EPA's rule covers window replacement at any size.
Will you give me the Renovate Right pamphlet before you start? The EPA requires firms to hand it over before renovation in a pre-1978 home and to document that they did.
How will you contain dust and clean up? The EPA's lead-safe practices include containing the work area, no open-flame burning, no power tools without HEPA exhaust control, and a cleaning verification at the end.
What happens if you find material that might contain asbestos? The EPA says it generally cannot be identified by looking and should be assessed by a trained, accredited professional. Ask how that would change the price and the schedule.

About the product and the work

Exactly which product, size, color and finish are you quoting? The act requires specifications that cannot change without a written change order signed by both of you.
For windows, is this an ENERGY STAR model for our climate zone, and will I get the labels? ENERGY STAR says to look for its label for your climate zone next to the NFRC label, and to keep both labels as documentation.
Are your installers trained or certified for this product? ENERGY STAR notes some warranties require an installer certified by the manufacturer.
How will you flash the windows and doors? The International Residential Code, which Pennsylvania adopts, requires corrosion-resistant flashing at exterior window and door openings, installed to the manufacturer's instructions or, failing those, with pan flashing at the sill.
For a deck, how will it attach to the house? The code sets a minimum 2-by-8 treated ledger, galvanized or stainless fasteners, and forbids hanging a ledger on stone or masonry veneer.

About permits and the schedule

Does this job need a permit here, and who will get it? The answer is local. An uncovered deck no more than 30 inches above grade needs no state permit; a higher or covered one does. The FTC warns that asking you to get the permits yourself is a sign of a scam.
What are the approximate start and finish dates? The contract must give both.
What will you do if you find rot behind the siding or under a window? Get the answer, and the price per unit of repair, in writing before signing, so that a discovery does not become an open-ended change order.

About money and paperwork

What is the deposit, and what is in the special order line? On a contract over $5,000, the act caps the deposit at one-third of the price plus named special order materials, and the two must be listed separately. The Attorney General suggests paying the rest as the work progresses.
If you are arranging financing, who is the lender and what are the terms? The FTC says never to agree to contractor financing without shopping around. A home equity loan on your main home can be cancelled within three business days of closing.
What does your workmanship warranty cover, for how long, and who honors it? The FTC says to read the warranty before you buy and to get any spoken promise in writing.
What must I sign at the end? Do not sign a completion certificate until all the work in the contract is done to your satisfaction, as the Attorney General advises.

What answers should worry you?

An offer to start today at a special price, a deposit request before anything is in writing, a contract with blank spaces, a product described only as "premium", or a reluctance to name the installer. The FTC lists pressure for an immediate decision, requests to pay everything up front or in cash, and lenders the contractor knows among the signs of a scam. The full set of patterns, with cases, is in scams to avoid. Businesses are listed on the exterior remodeling directory page.

Sources

2008 Act 132 (Home Improvement Consumer Protection Act), Pennsylvania General Assembly
Frequently Asked Questions: Home Improvement Contractor Registration, Pennsylvania Office of Attorney General
Renovation, Repair and Painting Program: Contractors, U.S. Environmental Protection Agency
Renovation, Repair and Painting Program: Work Practices, U.S. Environmental Protection Agency
Residential Windows, Doors, & Skylights, ENERGY STAR (U.S. Environmental Protection Agency)
How To Avoid a Home Improvement Scam, Federal Trade Commission
Warranties, Federal Trade Commission
34 Pa. Code 403.62. Permit requirements and exemptions., Commonwealth of Pennsylvania (Pennsylvania Code)
Chapter 7 Wall Covering, 2021 International Residential Code, International Code Council
Chapter 5 Floors, 2021 International Residential Code, International Code Council
Protect Your Family from Exposures to Asbestos, U.S. Environmental Protection Agency
Home Equity Loans and Home Equity Lines of Credit, Federal Trade Commission