Is 18 inches of clearance enough for an 8x28 foot deck?

Eighteen inches of clearance is technically enugh for airflow, but the existing water pooling near that window is a major red flag. If you build over that without fixing the grade, you're essentially creating a humid crawlspace that will rot your rim joist and siding within a few years. You need to regrade the soil under the deck footprint so water flows away from the house before you even think about framing. Laying down a heavy-duty weed barrier topped with a couple of inches of **crushed stone** or gravel will help prevent moisture from wicking up into the structure. Since you're going over a concrete pad, you'll have to account for the height difference in your joist layout. Using a ledger board against the house is standard, but make sure your flashing is perfect, especially since you've already seen water issues there. I'd recommend using a high-quality **joist tape** on top of all your framing. It costs a bit more upfront but adds a decade to the life of the wood by preventing water from sitting in the screw holes.

As for the price, $15k to $20k is right in the ballpark for an 8x28 deck using composite materials or high-end cedar. If that's for pressure-treated pine, it's a little steep, but labor costs vary wildly by region. Just make sure that quote includes proper footings for the section extending over the grass. Don't let them just throw blocks on the dirt. For tweaks, consider adding some low-voltage LED lighting into the stair risers or the perimeter posts while the frame is open. It’s way harder to retro-fit that later. Also, if you’re worried about the 18-inch drop, check your local codes; you might be able to skip the railing entirely if it’s under 30 inches, wich would save you a few thousand dollars and keep the view open.

Def gotta agree on the drainage. If it's allready pooling, it'll only get worse once it's covered. Have you thought about where you'll put the stairs? With an 8-foot depth, they can eat up a ton of your usable space if they're not tucked to the side. Also, for that price, I'd push for hidden fasteners. Way cleaner look than having screw heads everywhere, and it's easier on the feet if you're out there barefoot.

I built a similar 8-foot wide deck last year and 8 feet gets narrow fast once you put a table out there. I ended up bumping mine to 10 feet in one section just so people coud acutally walk behind chairs without falling into the yard. If you stick to 8 feet, go with a 'picture frame' border. It makes the whole thing look pro and hides the cut ends of the boards. Also, since you're so low, don't close the sides with solid wood. I used a dark mesh screen behind wide-spaced horizontal slats—it keeps the air moving so it doesn't get swampy but still hides the dirt and concrete underneath.

That budget seems okay for a basic build, but have you ruled out the possibility that the existing concrete pad is already sinking or sloped toward the house? If that's where the water is pooling, building on top of it might just hide a foundation disaster until it’s too late. Also, with only 18 inches of clearance, have you considered how you'll handle pest control? Skunks and rodents love a low-profile cavity like that, and once the boards are down, you're basically locked out of the area.

I'm super new to this, but reading about the water pooling is making me nervous for you. Since everyone is saying to regrade the soil, how do you actually do that if there's already a concrete pad there? Do you have to rip the concrete out first, or can you just add dirt around it? Also, I keep hearing about joist tape—is that something a beginner can put on themselves to save money, or is it better to let the pros handle it so it doesn't leak?