A deck should be a place where you relax, host barbecues, and watch the kids play in the yard. But for homeowners in Cary, a deck that wasn't built for Illinois weather can quickly become a source of frustration and unexpected expense. We've seen too many projects where a few critical mistakes turned a dream outdoor space into a repair liability. This article breaks down the five most common Deck Building mistakes Cary homeowners make in 2026, and how to avoid them before you break ground.
1. Skipping the Permit Process in Cary, IL
The single most frequent mistake we see is homeowners who decide to skip pulling a permit for their deck. They think it saves time and money. In reality, building a deck without a permit in Cary can cost you far more than the fee itself. The Village of Cary requires permits for any deck attached to a house, and for good reason. The permit process ensures that your deck meets the International Residential Code (IRC) as adopted by Illinois, including specific requirements for frost depth, structural loads, and setback distances from property lines.
If you build without a permit, you risk being forced to tear down the structure if a neighbor complains or when you go to sell your home. A home inspection during a sale will flag unpermitted work, and buyers will either walk away or demand you get it retroactively approved, which is a more expensive and painful process. The permit fee for a typical deck in Cary runs between $100 and $300, which is a small price compared to the headache of fines or a forced removal. Burns Carpentry handles the entire permit application process for every deck we build, which means we pull the required permits with the Cary municipal offices so you don't have to think about it.
2. Choosing the Wrong Materials for Illinois Weather
Illinois weather is brutal on outdoor structures. We get humid summers with temperatures pushing into the 90s, freezing winters with snow and ice, and dramatic freeze-thaw cycles that put immense stress on deck materials. Choosing the wrong material is a mistake that shows up within two to three years. Pressure treated lumber is a standard choice for framing, but many homeowners make the error of using it for decking boards without proper sealing or maintenance. Within a few seasons, untreated Wood Decks can warp, crack, and splinter.
This is where the choice between wood and composite decking really matters. For Cary homeowners who want minimal maintenance, composite decking is the stronger choice. It resists moisture, never needs staining or sealing, and holds up to the freeze-thaw cycles much better than wood. Composite decking costs between $40 and $60 per square foot installed in the Cary area, compared to $25 to $40 for a high quality wood deck. But the trade off is that composite will last 25 to 30 years with nothing more than occasional soap and water cleaning, while a wood deck needs refinishing every two to three years and has a typical lifespan of 10 to 15 years. Burns Carpentry installs both materials and will walk you through the pros and cons based on your budget and how much maintenance you want to commit to.
What to Ask Your Contractor About Materials
Before signing a contract, ask your builder what specific brand and grade of lumber or composite they use. Not all pressure treated wood is the same, and not all composite boards have the same warranty. Look for lumber that is labeled "ground contact" rated for the posts and joists, as this has a higher preservative level. For composite, ask if the product has a full co-extrusion shell for better color retention and stain resistance. A quality contractor will have clear answers and documentation.
3. Ignoring Proper Footing Depth and Spacing
Your deck is only as strong as its foundation. In Illinois, the frost line runs about 42 inches deep in the Cary area. If your deck footings are not placed below that frost line, the ground will shift during freeze-thaw cycles. This movement can lift posts, crack the ledger board connection, and cause the entire deck to become uneven and unsafe. We've inspected decks where the footings were only 12 inches deep because the builder wanted to save time. Those decks were wobbling within a year.
The International Residential Code requires footings to extend at least 12 inches into undisturbed soil below the frost line. For Cary, that means digging holes roughly 48 to 54 inches deep. The footing diameter also matters. A standard 10x10 foot deck needs footings at least 12 inches in diameter, while a larger 16x20 foot deck might require 18 inch footings or larger depending on the soil conditions. Getting the footings wrong is not a cosmetic issue, it is a structural safety issue. Burns Carpentry uses a professional survey to mark footing locations and ensures each hole is dug to the required depth before pouring concrete. We also space footings according to the engineered load calculations for your specific deck size, typically every 6 to 8 feet along the beam lines.
4. Overlooking Deck-to-Home Flashing and Waterproofing
This is the mistake that causes the most expensive hidden damage. The point where your deck attaches to your house is the most vulnerable part of the entire structure. If the flashing is installed incorrectly or skipped entirely, water will seep behind the ledger board and into your home's rim joist and siding. Over time, this trapped moisture leads to rot, mold, and structural decay that can cost thousands to repair. We have seen cases where a deck that was only five years old had completely rotted the rim joist of the house because the flashing was just a piece of bent aluminum that didn't extend properly.
The correct method involves installing a metal or rubber flashing that directs water away from the house. The flashing should be integrated with the house wrap or siding, and a gap should be left between the decking boards and the siding to allow airflow and drainage. Never allow a contractor to attach the ledger board directly to the siding without proper flashing. Ask your builder specifically how they handle the ledger attachment. Burns Carpentry uses a corrosion resistant flashing system and ensures that all fasteners are approved for the application. We also leave a 1/4 inch gap between the decking and the house to prevent moisture wicking.
5. Underestimating the Timeline and Budget for a Quality Build
The most common surprise for homeowners is how long a quality deck takes to build and how much it actually costs. Many people see a deck and think it's a weekend project. A professional deck build in Cary typically takes three to five weeks from the initial consultation to completion. That timeline includes site preparation, permit approval (which can add one to two weeks depending on municipal schedules), concrete curing for footings (at least 48 hours), framing, decking installation, railing, and final inspection.
On the budget side, a quality deck in 2026 is an investment. A basic 12x16 foot wood deck with pressure treated lumber and standard railings runs $6,000 to $10,000 installed. A similar sized composite deck with premium materials and aluminum railings can easily reach $12,000 to $18,000. Many homeowners forget to budget for site preparation if the ground is uneven, or for removing an old deck. Add another $1,000 to $2,500 for demo and disposal. The best approach is to get a detailed written estimate that breaks down every line item. Burns Carpentry provides free estimates that include all costs, from materials and labor to permits and cleanup. We also give you a realistic timeline so there are no surprises.
Frequently Asked Questions
How much does a typical deck cost in Cary, IL in 2026?
For a standard 12x16 foot deck, expect to pay between $6,000 and $10,000 for a wood deck and $12,000 to $18,000 for a composite deck. These prices include materials, labor, permits, and standard railings. Custom designs, multiple levels, or premium materials will increase the cost.
Do I need a permit for a deck in Cary?
Yes, the Village of Cary requires a permit for any deck that is attached to the house. The permit ensures the deck meets local building codes for structural safety, frost depth, and setbacks. Burns Carpentry handles the permit process for every project we build.
Is composite decking worth the extra cost in Illinois?
For most homeowners, yes. Composite decking costs more upfront but requires almost no maintenance, resists moisture and freeze-thaw damage, and lasts 25 to 30 years. Wood decks need refinishing every two to three years and typically last 10 to 15 years. If you plan to stay in your home for more than 10 years, composite usually pays for itself in reduced maintenance and replacement costs.
What should I look for when hiring a deck builder in Cary?
Ask for proof of licensing and insurance specific to Illinois. Request a written estimate that itemizes materials, labor, permits, and timeline. Ask how they handle flashing and footings. Check recent references and look at photos of completed projects in the Cary area. A reputable builder like Burns Carpentry will be happy to provide all of this information.
Building a deck is a significant investment in your home and your family's enjoyment of your outdoor space. If you are planning a deck project in the Cary area, Burns Carpentry has the experience to get it right the first time. We handle everything from design and permits to material selection and construction. Give us a call for a free estimate and a no pressure conversation about what will work best for your home.
