dirt floor in a bomb shelter

please help, I need to prepare the floor so that there is no dust, now it is made of clay and a little sand. I was thinking of making it from OSB sheets. but this is a bomb shelter and I would still like to make the floor from non-combustible materials. But I do not want to make the floor from concrete. And so I think maybe use the clay that is already there. Now there are several problems: dust and capillary moisture from the soil. there are windows in the walls and I made additional holes for ventilation and a chimney.

Wetting the clay and then compacting it a little should make the dust problem disappear. The moisture from the soil will be more difficult to remove. You could dig everything out a little and, place a thick plastic sheet and then cover it with the (moist) clay/sand mixture again. Or sufficient ventilation to move the humidity outside.

I am not an engineer, but looking at the roof, I would probably put at least 4 wooden blocks up as columns to make sure it does not collapse in the event something gets hit nearby.

I agree with Sebastian about re-wetting the clay and using it. Maybe check and make sure the mix has enough clay. After it has dried you could probably seal the surface a bit with linseed oil.

I don't think a barrier (plastic) tarp will help. This will just push the rising moisture into the walls instead of the floor.
If you want it to be more dry you probably have to dig up all the dirt, lay down a thick layer of gravel and then put the dirt floor in again on top.

Good ventilation helps. There are special ventilation systems that are programmed to only vent when the outside air is drier than inside. This way you can actually dry out moist basements etc.

Why not make it a tile floor from clay tiles?

https://permies.com/t/26470/Tile-covered-earthen-floor

I have heard of linseed oil on a dirt floor but haven’t done it myself—anyone more experienced?

Linseed oil on clay turns it into a leather like finish. Slows down moisture transfer but doesn’t stop it, probably the best answer at this point. Even a perfectly sealed floor will have moisture problems, the air humidity rises as the air cools I inside. You need as much ventilation and air circulation as you can whenever you can.

Hey R, I’d be careful about as much air whenever possible. Especially in summer the outside air can have a lot of water loaded that condensates when the air cools down on a floor or in a basement. You basically have to calculate the absolute moisture of the air (in SI units it’s given in grams per cubic meter) inside and outside and only vent if the outside is lower than inside.

What about putting down mats, carpets or rugs? That would keep the dust down. Or I suppose, wouldn’t allow the dust to rise in the first place because it isn’t being kicked up.

I'd hesitate before using rugs over a potentially damp floor. Seems like a guaranteed mold habitat to me. Linseed oil would be my first pick because it's somewhat breathable, and a ventilation system that responds to the ambient moisture levels would be a massive help in keeping the space as dry as possible. I'd think a little Arduino setup with temperature and humidity sensors controlling a small fan or two would be the way to go.

Use lime mix with clay to create a breathable floor.. Using lime as a medium will help seal but keep the surface breathing still. Or lay down some cheap stone pack it in good and lay like putty or cement between. If you have the time and money. Plastic vapor barrier is hit or miss depending on your grade of your ground and the walls etc. but that will seal it too. Everything is always breathing pulling and pushing water/air out. Plants, the earth, even the air, it's a divine cycle.

Put some plants in there for oxygen and some cheap lighting system. I don't know how long you plan on surviving in here worst case, if you gonna plan on staying here long you will need tunnels and some sort of vent to outside air.

Study ant and termite tunnel systems.

Honestly though if a bomb ever did go off heaven forbid, at that very moment you won't care a lick about the dirt on your floor.

Thank you for the ideas. At the beginning of the war we had to live here for a month. The most important thing is that the room is below ground level and the temperature is always above zero. To combat humidity, I made three ventilation holes in the wall on the left. One in the far left corner will be used for a chimney. I will put a stove there. The humidity is not critical. There has never been mold here and the stove will give a good effect. The ventilation holes can be used without opening the window. It will have to be closed because a fragment has already hit it. Regarding the floor, I would not like to make a stone floor, since the animals were comfortable lying on it, which means it is not so cold. Although this floor is already a ready-made base for paving stones. Good recommendation regarding wooden supports. Perhaps we should fence off part of the room. Regarding planting, there is exactly such a room on the right with a separate entrance in which I grew green onions right in the floor. Probably the best way is to dig up the clay, wet it and tamp it down, or maybe lay a film on this floor, buy clay and pour some more and tamp it down. Thank you. I will still think about what options there are.  maybe mix clay with lime and cement and for 50 sq. m it will probably take a lot of oil

can be filled with small crushed stone and then washed and compacted

Probably the cheapest and easiest option would be the following: I dig up the entire room, mix the remaining sand with clay. Then I buy several bales of straw and 5 kg of fiber (synthetic fibers that are added to concrete). I chop the straw with a lawn mower and add it to the clay together with the fiber. Then I have an aerator with lawn knives. I thoroughly mix the top layer of clay, straw and fiber, then wet it with water and compact it thoroughly. I assume that the straw and fiber will reinforce the clay, the sand that creates dust and is on top will mix with the clay. When I wet it with water, I can wash the dust off the concrete walls. This will allow the work to be done in a few days. Now the heat is starting and the room will dry out, especially since I have solar panels, I can speed up the drying process. And the second room will allow us to wait out the shelling.  The result will be a level floor that will breathe and which will be stronger due to the straw and fiber. I can also lay out the passages with a geomembrane and fill them with fine gravel.

Hi Bogdan, nice work that you have done!

I understand your concerns about the floor and I also understand why you were considering OSB as a dust cover.  Something was tickling the back of my memory so I did a little research.  It turns out that a borax solution applied to the wood will make it more fire resistant.  Ideally, you would want to apply the borax to both sides of the OSB, not only to assist fire resistance, but also to improve resistance to insect damage.  If I were trying this technique, I would apply at least two and possibly three layers of borax solution to the bottom side of the sheets (include the edges as well).  Then I would apply them in place and liberally cover them with more borax solution.  

The Borax solution will prevent combustion of the outside layer of wood and to the depth that it soaks in.  Now, if it is subjected to extreme heat for long enough, eventually the wood begins to combust inside the sheet, distorting and cracking the surface, leaving gaps where air can get in and more burning can begin.  But by this time, the rest of the building is likely at a loss anyway.

My point is that you just might be able to use the OSB to get exactly what you were looking for and not really incur any more fire hazard.

Use this information as you feel fit.


Eric

the quest is getting more complicated, today I left home and left the basement gate open so that the prepared boards could dry. the storm drain couldn't cope and the basement is flooded. thank god I managed to come and close the gate and at the time made a good water drain from the second entrance where the battery and solar inverter are located. The second room remained dry thanks to this it also remained dry. I don't remember such a downpour in the last 20 years, hail lay like snow. It's good that all this happened in early autumn and now there is still an opportunity to dry the basement. Conclusions have been made, we need to be more careful), and tomorrow there will be a lot of work - we need to drain this part of the basement, after that we need to make the basement gates airtight (they held back a large flow of water well) and make a sealed door to the second room and in the future make a cover over the entrance. drone attacks continue. Therefore, we do not stop and are preparing for winter.

Hey Bogdan,
sorry to hear that the weather got you.
I'm glad to read that you're staying active and continue preparations for winter.

Did all that water come from the uncovered, tilted entrance? Or is it runoff from somewhere else too?

Benjamin Dinkel wrote:Hey Bogdan,
sorry to hear that the weather got you.
I'm glad to read that you're staying active and continue preparations for winter.

Did all that water come from the uncovered, tilted entrance? Or is it runoff from somewhere else too?

Hi Benjamin, there is a drain nearby that has significantly increased the flooding, I already wanted to move it and now this must be done either connect it to the existing drain above the entrance to the basement or bring it out separately. It also helped that I made a ramp from the roadway and it does not allow water to flow down the road, I think that it is necessary to additionally make an elevation so that the water flows down the road. It is good that I did not just put a drain but additionally made a recess in the concrete and cleaned it from debris before the rain, and of course that I made a large container to drain water from the drain. Now I am wondering if I need to make a grate on top?

I drained the room, tomorrow while the floor is still wet I will wash off excess dust from the walls, dig up the entire floor so that the remaining sand in the top layer mixes with clay, then I will chop up the straw with a lawn mower, pour it on top, then add fiber that is used for concrete and mix everything with an aerator with lawn blades, after which I will level it with a building level and tamp it down thoroughly.

Bogdan -

Is it possible to divert water (rain, snow or just surface runoff) away from the ramp entrance, so that the doors have less water they need to keep out?

I don't know what resources you have available there, but some sort of roof structure might help.

My brother has recently built two Gothic arch sheds from construction lumber (nominally 1" X 3" or 19mm X 73mm) and covered with sheet plastic.  These are parallel chord, arc of circle trusses - an outer and inner strap, separated by short scraps of 2x (38mm thick) dimensioned lumber.  Each side subtends about 60 degrees of arc.

The bending jig was very simple, just some sheets of plywood temporarily screwed together, with four blocks screwed down, two on the inside in the middle of the truss span, and two on the outside near the ends.  4 point bending (rather that 3 point) helps to better assure a true arc of circle shape, which will maintain the span and height you've planned for, though the exact shape probably isn't that important for structural reasons.

One shed was a shelter for his portable saw mill, the other is a greenhouse my nephew has been using.  The greenhouse has stood up to a winter with more than 300 inches of snow (between 7 and 8 meters).  The covering was simply polyethylene construction plastic (with reinforcing fibers), though I think he intends to use a more official greenhouse plastic film with better light transmission qualities when it needs to be replaced.

I'll take a photo or two of the greenhouse, so you can see what I mean.  A greenhouse covering the entrance ramp could both keep you dry and provide more growing space, though it won't be substantial enough to sustain projectile impact without damage to the covering.

I think you are on the right track, diverting (perhaps capturing) as much water as possible away from the cellar bomb shelter.

Bogdan -

These are the plans we bought:
https://bow-roof-shed.com/

But, a little digging on the internet should turn up the relevant technical details, or you can probably just lay out by construction, either using a homemade trammel compass and straight edge, or by doing the trigonometry, what are the offsets for the truss jig blocks from the chord of the selected circle.  Don't forget to offset the outer blocks from the inner ones by the thickness of the truss (inner and outer straps, and the scrap wood spacer blocks).

You can use a lesser or greater angle than 60 degrees of arc for each truss, but that seems to be a good compromise between flat-and-wide and tall-and-narrow.  Unless you have a compelling reason to do something different, I think I would start there.

You'll need to tie the arch trusses together down the length of the structure with some additional strapping screwed, nailed or stapled to each truss, and add a few diagonal straps (threaded through the spaces between the inner and outer truss straps, to help stiffen the structure against shear loads.

I'm not telling you what to do in your situation, just offering a suggestion to help divert excess water from the shelter and give you a bit more space out of the direct weather.

I will get a photo or two of the greenhouse, and maybe dig up a link for some building jig details.  In the meanwhile, Mike Haasl's 2nd post in this thread shows what I'm suggesting:
https://permies.com/t/168418/Advice-building-Greenhouse-Cattle-Panels

Kevin Olson wrote:Bogdan -

These are the plans we bought:
https://bow-roof-shed.com/

But, a little digging on the internet should turn up the relevant technical details, or you can probably just lay out by construction, either using a homemade trammel compass and straight edge, or by doing the trigonometry, what are the offsets for the truss jig blocks from the chord of the selected circle.  Don't forget to offset the outer blocks from the inner ones by the thickness of the truss (inner and outer straps, and the scrap wood spacer blocks).

You can use a lesser or greater angle than 60 degrees of arc for each truss, but that seems to be a good compromise between flat-and-wide and tall-and-narrow.  Unless you have a compelling reason to do something different, I think I would start there.

You'll need to tie the arch trusses together down the length of the structure with some additional strapping screwed, nailed or stapled to each truss, and add a few diagonal straps (threaded through the spaces between the inner and outer truss straps, to help stiffen the structure against shear loads.

I'm not telling you what to do in your situation, just offering a suggestion to help divert excess water from the shelter and give you a bit more space out of the direct weather.

I will get a photo or two of the greenhouse, and maybe dig up a link for some building jig details.  In the meanwhile, Mike Haasl's 2nd post in this thread shows what I'm suggesting:
https://permies.com/t/168418/Advice-building-Greenhouse-Cattle-Panels

Kevin, I am grateful for any tips and even more for criticism! Now you have given me a great idea to make a greenhouse with a ramp in front of the entrance to the basement. This will not only drain the water but also use the ramp to grow plants in boxes since the basement is not used for driving a car and this is the sunny side. And plus I will be able to open the doors to the garage and effectively use the sun's heat. Thank you for the great idea!!! If I drain the excess water by rearranging the drains, strengthening the ramp on the roadway that overflow and covering the ramp at the entrance to the basement with a greenhouse, I will completely close the issue.

Hello Bogdan, I see your work as a problem solver continues apace. Kevin and his creativity have proposed a win-win for the home team.  I would love to get those plans myself.

Good ideas helping good people.  Stay strong Bogdan, and please keep us up to date on your many projects.  Remember our family is always with you
Rico

Rico Loma wrote:Hello Bogdan, I see your work as a problem solver continues apace. Kevin and his creativity have proposed a win-win for the home team.  I would love to get those plans myself.

Good ideas helping good people.  Stay strong Bogdan, and please keep us up to date on your many projects.  Remember our family is always with you
Rico

thanks Rico the quest continues)

I have done all the dusty work, cleaned the foam on the ceiling with a float so as not to create dust later, all that remains is to plaster it or just paint it. I tried to dig clay, it lends itself well and then loosens well with an aerator. Today they will bring me 10 bales of straw and I bought 5 kg of fiber. I also washed the walls from dust, I got the idea to paint the entire room white. Concrete walls should not be painted with paint, but treated with liquid glass and painted with lime, I think that this will be good with a clay floor, and the lime itself will also be more useful for concrete walls than paint. Also, wires with light bulbs were stretched along the walls, I think they can be seen on the luminous LED tape. It is also necessary to repair the gate, it has sagged, it will be difficult to remove and put back myself, I will break how to adjust the hinges. And I also need to figure out what to make a door to the second room from, I have oak boards, but the door will turn out to be very heavy

I chop the straw with a lawn mower and scatter it for further digging

Greetings Bogdan, with respect!

You write
"  And I also need to figure out what to make a door to the second room from, I have oak boards, but the door will turn out to be very heavy

Yes the beautiful oak is soooo dense, I concur, but could you use a saw to rip some 2 x 3 inch or similar,  then use steel connector or bolts to make a lighter door?

If possible,   covered with heavy canvas and plywood to cut weight.            Godspeed friend, any way you craft the door will be top notch.  

Untreated cob is dusty.

Two cheap options are painting it with milk paint, with it being a floor it milk pain may need to be reapplied often. Second is wheat paste, if mixed in the top layer of cob it should be able to take some scratches and a little wear, as long as the layer is thick enough.

I finished digging, now I'll pour water well so that the straw absorbs moisture and tomorrow I'll grind everything thoroughly with a lawn aerator, I'm convinced that it's bad to work with a shovel, it's best to use a pitchfork and be sure to wet the straw

Rico Loma wrote:Greetings Bogdan, with respect!

You write
"  And I also need to figure out what to make a door to the second room from, I have oak boards, but the door will turn out to be very heavy

Yes the beautiful oak is soooo dense, I concur, but could you use a saw to rip some 2 x 3 inch or similar,  then use steel connector or bolts to make a lighter door?

If possible,   covered with heavy canvas and plywood to cut weight.            Godspeed friend, any way you craft the door will be top notch.  

Rico, thanks for the tip, I was a little confused with the door, but your drawing gave me a good start, in the spring I dismantled a wooden fence made of boards 15 cm wide and 2.5 cm thick, 4 meters long, I covered the fence with oak from firewood and wanted to make a veranda from the boards. They will come in handy for the door and there is also good 10 cm thick foam left. This will allow you to make warm doors and separate the rooms - a warm bomb shelter, and a cool one for storing food

Rico Loma wrote:Greetings Bogdan, with respect!

You write
"  And I also need to figure out what to make a door to the second room from, I have oak boards, but the door will turn out to be very heavy

Yes the beautiful oak is soooo dense, I concur, but could you use a saw to rip some 2 x 3 inch or similar,  then use steel connector or bolts to make a lighter door?

If possible,   covered with heavy canvas and plywood to cut weight.            Godspeed friend, any way you craft the door will be top notch.  

Alex, thank you for your help. I thought about many options for finishing, but the last flood showed that it was useless. If the hydroelectric power stations are blown up, the room will still be flooded. Therefore, the main thing now is to make the room with less dust. If the idea with the floor does not work out in an emergency, I will simply lay out a large roll of polyethylene. But in the future (after the war), I will definitely try your method. I copied it, but I did not understand what milk paint and wheat paste are. Thank you for your help.

the idea with the lawn aerator was not bad) it mixed the clay well, but unfortunately it managed to process less than half and it broke. Now I will grind it manually and think about what else to mix and mix the clay with.

I hear you about wanting to avoid concrete. In our root cellar we had the same dust problem, so we went with an earthen floor mix of clay, sand and chopped straw. Tamped it really well and let it cure before sealing with a few coats of boiled linseed oil and beeswax. It looks nice and earthy but doesn’t kick up dust like raw dirt. Another option is to put down a layer of pea gravel and pavers – good for drainage and it keeps shoes clean without resorting to cement.

Ted Davis wrote:... we went with an earthen floor mix of clay, sand and chopped straw. Tamped it really well and let it cure before sealing with a few coats of boiled linseed oil and beeswax.

Ted, could you provide more information about the mix you used and how many applications? I have a couple of very dusty earth floors in my Bulgarian house to finish, and I don't want to resort to using concrete.

I removed the shaft, the bearing and the plastic seat were broken, I picked up a larger bearing, heated it up a bit and installed it. The process continues.

Everything was thoroughly dug up, mixed, and compacted. I watered it, let it sit, and then compacted it a few more times. I'll also install fans to increase air circulation. I used 11 bales of straw and 6 kg of fiber.

Bogdan -

Here are the photos of the greenhouse my brother built for my nephew.  The lumber was sawn from a large oak tree in my brother's woods which some of the neighborhood kids cut down with an axe (probably just to see if they could).  So, my brother made lemonade from lemons, as they say, and cut up the trunk of the tree into lumber to make the greenhouse.

It would be better if there were some diagonal boards screwed or nailed to the inner chords of the trusses on each side,  but it has been OK so far, even with more than 300 inches of snow last winter.  The photos of the end look like the trusses subtend a bit less than 60 degrees - the triangle that can be inscribed within the arch is more acute than an equilateral triangle.  I suspect there was more spring back of the trusses when they were removed from bending jig than my brother had expected, so the radius increased and the subtended angle decreased.  But, no matter, it still works just fine.