Summer can be a great time to start home improvement projects, but you may not be able to tackle them all on your own.

Hiring a contractor may be helpful, but it’s important to do your research before you begin! In 2017, consumers nationwide filed more than 5,000 complaints on general contractors with BBB.

Common complaints for contractors include sales practices, followed by refunds. Consumers also submitted complaints related to contractors performing work and being unable to reach customer service or get a refund.

Follow these tips to ensure you are hiring a trustworthy contractor:

– Find a contractor you can trust. Start with trust and find a contractor on bbb.org. There you can see their rating, complaint history, reviews from past customers, and whether they’re a trustworthy BBB Accredited Business. Ask for references from friends and family as well.

– Research their track record. You can search for a contractor’s business profile at bbb.org to see if they are a BBB Accredited Business, get free information on their history of complaints, and read verified Customer Reviews. Also ask for local references, and speak with those customers about their experience with the vendor and the quality of work. If possible, inspect the contractor's work yourself. Ask if the contractor is a member of a professional association that has standards or a code of ethics.

– Watch out for contractors who have: high upfront payments, cash-only deals, high-pressure sales tactics, “handshake” deals without a contract, and on-site inspections. Learn more at www.go.bbb.org/generalcontractors.

– Always double check licensing and insurance. In California, any contractor working on a project that is valued at $500 or more for labor and materials must hold a license from the Contractors State License Board. CSLB licenses contractors in 44 different classifications, so verify that the contractor holds a license for the work you are having done. You can check the status of a license on CSLB’s Web site. It’s also important to verify that they’re insured – ask to see a copy of their Certificate of Insurance, or ask for the name of the insurance carrier and agency to verify independently.

– Inquire about a lien waiver. A lien waiver is a statement from your contractor that says all suppliers and subcontractors have been paid for their work.

– Get it in writing. Always get estimates in writing and never let any work begin without a written and signed contract. Do not be pressured into signing an agreement before you are ready, and make sure you read and understand everything before signing. The contract should include contact information, start and completion dates, and a detailed description of the exact work to be done, any material costs, payment arrangements, and warranty information. Specify who is to obtain necessary building permits and who is responsible for clean-up. Make sure all verbal promises are included in the contract. It’s also important to ask questions such as information on the subcontractors, how much work will be subcontracted, and any other questions you may not understand on the contract. Never sign an incomplete or partially blank contract.

– Ask for multiple quotes. You should always shop around and get at least three quotes from different businesses. Make sure all bids consider the same set of criteria. Remember that the lowest bid may not necessarily be the best bid; if one bid is significantly lower than the others are, the contractor may be cutting corners or may not understand your work requirements.

If you’re exposed to a home improvement scam, report it to BBB Scam Tracker at www.bbb.org/scamtracker to help warn others.

If you work with a great company on your home improvement project, leave them a Customer Review.

And if you’re not satisfied with an outcome, you can file a complaint with BBB.

Evan Arnold-Gordon is with the Better Business Bureau serving the San Francisco Bay Area and Northern Coastal California.