Know Anything About Concrete?

[Hunter12]

If your serious about building a secret room. I would start simple check with City and County and Public works to make sure you are clear of all utilities and right of ways. Then once that is all in the clear see if building permits apply and how that will effect the value of your investment "house". Then you should probably contact and engineering firm to ask them for advice on the "type" of concrete needed or other building materials. Because the concrete in your basement is extremely dense. This is to help prevent water and other things that go through the ground. You will also need to consider vent ports. Because, you will need to fresh air! Your best bet is to seek a professionals help when taking on a task like this. You can also look into different bomb structure designs from the "Cold War" era. You can do alot of this research on your own if funds are tight. But, with new technology and materials. You will probably find it cheaper to get it done by hiring someone in the field with reputable references. For something like this. You are gonna want to get it done right the first time around.

[Eric P]

Talk to a licensed geotechnical or structural engineer and find the plans for your floor. You are right to be concerned about doing this. If you have swelling soils, the slab was engineered to float and move uniformly. Adding the weight of concrete walls (145 lbs per cubic ft) can cause the slab to shift in ways you may not want. Even enough to shift the wood frame to keep windows and doors from opening.

[HoneyBadger]

If your serious about building a secret room. I would start simple check with City and County and Public works to make sure you are clear of all utilities and right of ways. Then once that is all in the clear see if building permits apply and how that will effect the value of your investment "house". Then you should probably contact and engineering firm to ask them for advice on the "type" of concrete needed or other building materials. Because the concrete in your basement is extremely dense. This is to help prevent water and other things that go through the ground. You will also need to consider vent ports. Because, you will need to fresh air! Your best bet is to seek a professionals help when taking on a task like this. You can also look into different bomb structure designs from the "Cold War" era. You can do alot of this research on your own if funds are tight. But, with new technology and materials. You will probably find it cheaper to get it done by hiring someone in the field with reputable references. For something like this. You are gonna want to get it done right the first time around.

"Okay"

[def90]

You will need footings period.. You cannot build a concrete wall on top of a floating slab.

[HoneyBadger]

You will need footings period.. You cannot build a concrete wall on top of a floating slab.

Thank you. This is the kind of stuff I need to know.

[HoneyBadger]

I wanted to do as much of this as possible by myself to keep costs down and keep it low key, but it's looking like it might not cost a whole lot more to excavate and add a room to the basement... which is still a lot more project than I can afford at the moment.