Before you get quotes
Composite in Wisconsin has to carry a label showing ASTM D7032 compliance under the state deck appendix. The frame under composite is usually wood, so ask how the builder protects the joist tops and ledger from water. Madison’s own deck page reminds owners to use weather-resistant materials such as treated lumber.
- Sample boards in afternoon sun
- The joist spacing printed in the install guide
- Fastener and clip type
- ASTM D7032 label
Sources: Wisconsin Uniform Dwelling Code, SPS 325 Appendix B · City of Madison Development Services Center, Decks. Checked November 9, 2026. Confirm current requirements with your building inspector.
Near Madison
Price check
See the Madison deck cost guide for 2026 published price ranges and permit fees from Madison and Verona.
Related
Questions about composite decks
Are you the deck builder?
An independent builder you hire directly. This is a Madison-area referral site, so we pass your request along; we do not build, price or guarantee anything.
What does composite cost around Madison?
The Wisconsin Homeowners Guide lists mid-grade composite at $45 to $65 per square foot installed in Wisconsin and premium at $60 to $90.
Is composite allowed under Wisconsin code?
Yes, with a label showing ASTM D7032 compliance, per the state deck appendix.
Is a permit needed?
In Madison, yes: the city says you need a permit to build a deck. Fitchburg requires one for decks 24 inches or more above grade, Sun Prairie wants a drawing and site plan, and Verona lists a $300 deck permit. Each Dane County community sets its own rules.