I'm wanting to have our crawl space dug out and turned into a basement under two of our bedrooms. It was built in the 1970's and they didn't finish the basement. We also would be able to add two bedrooms to the value of the house with an egress window. I'm wanting a ball-park of what it should/will cost per square foot. We would want floor and walls of the new area. I am planning to check with contractors who put a basement under a house down the street to see what they would charge, but I wanted some idea prior to speaking with them.

Thanks for any input!

jkile

Not nearly enough information to enable even a wild guess. If you are smart, you will have drawings done by a qualified design professional, and get at least three bids. Then, and only then, will you know what the project will cost. If you're lucky, you'll find a professional who will be able to provide you with a detailed statement of probable cost also, when the drawings are complete.

If you just get a price from one contractor, with no drawings to become the basis for the contract, you will be at the contractor's mercy all through the process. Even if he is acting completely in good faith, if you have a difference of opinion, without drawings to refer to, you are unarmed for battle, because basically he's going to give you what he figured on, whether it's what you want or not.

Not knowing where you’re located it’s difficult to do. But in NJ area we start around $175 per square foot and that’s low end.

Remember this however. Using a square foot assumption is not the way you should get your final price. If the contractors are using this method as the way they are providing their estimate, Run do not walk away from them.

Reason being. Take a 10 foot by 10 foot square room. 100 square feet right? You need forty feet of sheet rock and enough framing to provide you with forty feet of wall.
Now let’s take that same amount of square footage but change the dimensions of the room.
Let’s make it 1 foot wide and 100 foot long. Still have 100 square feet, but now need 202 feet of sheetrock and 202 feet of framing. Going to cost a whole lot more on materials and labor.

Of course this is not going to happen but you can get the idea of what can happen if the rooms are not square. Your price goes up. And guess what? These prices are often called extras and are typically not included in the cost estimate that the low bidder included.

My suggestion is to get plans done from a professional on exactly what you want. They will be able to help you figure out what the costs will run based on the design. Once you have them, and then ask for bids on them. Do not work the other way around or you will end up loosing a lot of money as each contractor will assume different things when costing out the addition. You want to compare apples to apples when doing such a project.

Do not think adding bedrooms to the basement will add a lot of value to the home. In most cases you will not get your money back. Finished basement rooms oftentimes do not return on investment as do rooms above the grade level. Check with local real estate professionals and get their opinion before you spend lots of cash digging out the crawl space.

Are your on city or private waste system. Septic systems are designed on amount of bedrooms in a home. If you add bedrooms you may need to increase size of septic system. Add another 10 plus grand to cost. Ouch!

I agree with Home Care Club. If you're digging out a crawl space to make a basement with two bedrooms in it, it will be better and probably cheaper to just add two bedrooms above the ground and leave the crawl space alone, and you will end up with desirable space instead of substandard space, and have a chance to get a return on your investment.

Basement rooms are generally considered substandard, and if things are not done perfectly and you get moisture and mold, you will have suffered a huge loss. It is hard enough to make a new basement watertight. It is much harder, and therefore more expensive, to make a watertight basement out of a crawl space.