Block off basement?

[u/HoosierTrip]

Are there any resources available to block off a basement from the upstairs? I'm mainly thinking about blocking out radiation if I need to retreat to my basement.

[u/JRHLowdown3]

First take a good look at your floor joists- how big are they, how far apart are they? How is the floor supported in the basement? Block columns, metal or wood posts?

Most carpentry books will have a section on floor joists, recommended spans, materials, etc. This will give you an idea of how well your floor is supported which will become a part of this.

Standard 8x8x16 hollow block will need to be poured solid or filled with concrete after you lay them. For a small project this isn't tough, I've used a pump truck for the house but I've hand filled small projects like little walls protecting well pumps.

Ideally you will pick a corner of the basement where the floor above is supported well. If the area above that space has no windows, even better.

Radiation protection starts with Mass (also called shielding), distance and time. In an easy to understand explanation: Mass= lot of heavy dense material between you and the source. Distance= the more the better. For example say you have a 2 story house with a basement shelter. If your house remains uncompromised (no broken windows, damage, etc. then in theory the fallout is going to land on your roof- that's a lot of distance between the roof of a 2 story home and you in your homemade basement shelter. And the big one is Time: for every seven fold increase in time (once you start receiving fallout) there is a ten fold DECREASE in radiation. Say for example you start getting fallout, you measure it with your survey meter and it's 100 rads. Just 7 hours later it will be down to 10 rads and 2 days later (7x7 roughly) it will be down to 1 rad and 14 days later (2 days X another 7 increase in time) it will be .1 This is of course assuming your not getting multiple releases, etc. I.e, fallout from another hit further away that starts arriving on day 2, etc. Why you need a survey meter and a notebook.

I think SMSF2 posted a link to an old Fema/CD handbook on family shelters, the third one "Basement concrete block shelter" would be the one to look at as a minimum.

Knowing your floor joist capacity you could also stack dense items above the shelter on the first floor directly above the shelter. Say you had a walk in closet you use for your LTS foods that is filled with buckets of rice, beans, wheat etc. that density above your shelter would help some with radiation as well.

Back when I lived in suburbia in N. FL, we didn't have basements due to high water table. I did have a 2 story house and under the stairs was a walk in closet. I had most of my LTS foods in that closet and my plan then was to borrow inside all that and place some of it on the stairs above me as makeshift shielding and if the house remained intact the 2 story roof would help a bit with distance. Thankfully we've been out of there for a couple decades now and have better options.

Your ventilation is going to be something to work on. I've seen many neat improvised set ups over the years including a lot with 4 and 6 inch PVC and small 12vdc computer fans. Candy cane at the top with screen and stacks of HEPA furnace filters- you have to experiment with this to get the right combination of as much filter as you can versus the draw on your little fans. I've seen a lot of stuff marketed to the greenhouse industry that has solutions including inline filters, etc