As you will see, you will also need to notch the center cell of the "A" block so that it will sit flush over the horizontal rebar. The fast block will not need to be notched, only the corner blocks.
If you have enough room between the block walls and the earthen bank where you excavated the hole, so that you can get behind the walls, you can apply the waterproofing material after the walls have been completed. Most jobs do not allow for this so you must apply the waterproofing material by reaching over the block walls from the inside and squeezing between the vertical rebar to apply it. I build the walls to 4 course high, fill them with concrete grout and let em dry for a couple of days before applying any water proofing material. (It is best to fill the blocks up and stop the level of grout at half high in the top course. This lessens the chance of creating a weak spot where the blocks join horizontally) The best results are achieved by using an acrylic cement called PRIMUS which is made by the DRY-VIT CORP. It comes in 5 gallon buckets and is mixed with Portland cement, using a half inch drill motor and a mixing paddle. One bucket will cover approx 350 square feet. I always apply 2 coats on the back walls that are going to get backfilled and have never had a leak or damp wall.
The level of your walls is bound to be a little bit off since we are dry stacking the block. When you have laid the block up to the half way point in elevation, check the level at the corners with your water level and put a pencil mark there. ( Make a water level out of a piece of 3/8" dia clear plastic tube about 15 feet long. Mix up some water with red food coloring and dribble it into the tube. I use electrical wire nuts to stick in the ends and a piece of tiewire tied to the ends so that I can hang both ends over the block. Check and make sure there are no air bubbles or kinks in the tube. Water seeks its own level so set the ends at each corner, take the wire nuts out and put your pencil mark where the water is. Place the wire nuts back in and transfer one end over to the next corner and level with the first pencil mark) This will give you a visual reference to how far out of level your walls are. A half inch is nothing but if you are several inches out of level, then we must correct this by clamping form boards (carpenters cabinet slide clamps work great) onto the sides of the block and leveling them up using the water level and pouring grout into them. This will leave a level top on the walls to continue laying the rest of the block. Stick a piece of horizontal rebar in there too, before clamping, for additional strength. If your walls are relatively level, skip this procedure. Somewhere just below the approximate mid point in the height of the walls, leave the horizontal re bar out and turn the blocks upside down for the next course. This will allow you to tie a piece of rebar horizontally, about one and one half inches above the center webs of the upturned blocks. Then set the next course right side up and you have created a concrete channel or belly band to add additional strength to the walls. This should be grout time as this elevation is a comfortable working height. When you mix the grout, hold back on the pea gravel con agg and use 42 shovels per sack of cement so the grout is good and rich. Visually inspect to make sure that the grout is getting all the way down to the footing and is not hung up on rebar. Mix the grout wet, juke it with a 4' piece of rebar to make sure it does not have any voids anywhere in the wall. Remember, fill to the half way point in the top row of block to eliminate and weak joints in the walls.

The block must be staged inside the area of the room, far enough away from the footings so that you have enough room to turn your body around and to squat down to set the block. You also have to leave a space to gain access at the corners so that you will be able to stretch a tape measure diagonally from corner to corner to check that the corners are square. It may be more efficient to stage the block outside the building and pack them in with a wheelbarrow a hundred or so at a time so that you have room to work inside the room. Stockpile blocks on scrap pieces of wood or pallets and not in the mud.
My room has an outside dimension of 13' 4" long by 9' 4" wide and I am leaving an opening of 32" for my door. These dimensions will work out so that the blocks will fit without any cutting. I have decided to make the room 6'8" in height so that after I pour a 4" thick floor I will have 6'4" of headroom. This will take about 300 block, 50 - 8x8x16 "figure A" block or if those are unavailable, 50 - 8x8x16 "standard" 2 cell block for the corners, 16 8x8x8 "Figure U" block for the door jambs or if these are not available, then get 8x8x8 half blocks instead. You will need about 250 8x8x16 "FAST" block with the open ends and short center web. In the eastern part of the country you may be stuck ordering "BOND BEAM" blocks instead and as a last resort you could use standard 2 cell block with the closed ends. These block will add 25% more labor to the job and they do not give as strong a wall as do the fast block. Also, fast block are a full 16" long whereas bond beam and standard block are 15 and 5/8" long to allow for a 3/8" mortar joint between each block. Since we will be dry stacking our block this will give us a gaping hole in the wall of about 3 1/2 inches. You might want to lay out the first course and scoot the blocks over where this hole is to eliminate it, or, you can install form boards to cover these gaps when we pour the walls solid with grout.
REBAR: We will need about 450 lin feet of #4 rebar for the walls, and another 200 feet for the ceiling. That is a total of 33 - 20' long pieces of half inch rebar. Some people want to have a dirt floor but I am going to pour a floor and you will need to get some # 3 rebar to stub out of the walls and to place in the cement when we pour this floor. This comes to 260 lin feet or 13 pieces of 20' long 3/8" rebar.
Layout: After sweeping off the footing, find the corner stakes and mark them with a magic marker or a piece of keel. Grab a corner "A" block and place it with the outside corner over your galv. water pipe flush with the top of the footing concrete. Start with the long walls and place the blocks so that the open ends face towards each other. Check your diagonal measurements and make sure they are both the same, from corner to corner. You may have to adjust to get it square. Place a fast block with the center webbing up, next to the corner block. Now you must place a string line onto the inside of the blocks to use as a guide to lay the rest of the blocks. If you do not have any masons "chicken legs" then cut 2 pieces of 0ne by about 10 inches long and nail 2 number 8 finishing nails into it, 8 1/2 " apart. You can tie a string to this and place the one by on top of your corner block and stretch the line to the other corner. Pull it tight and then tie the string to the second piece of one by and set it over the top of the other corner block. There should be enough tension on the string so that it acts like a spring and locks the wood 1x onto the block holding it in place. Whew, I hope you get the drift of what I am saying here. Now you can proceed and fill in the first course of fast block in between the corners. Here is where you will find out how level the footing is. If the footing is a disaster, you may have to mix some mortar and set the first course in it to get it level. After setting the first course all the way around, check again to make sure its square. Any bad rockers should be wedged with pieces of chipped block.
If you would like a cement floor break off an inside corner of the fast block and stick a 4' long corner bent type 3/8" dia rebar so that it is hooked behind the vertical uprights. This is to tie your floor rebar to so that the floor won't lift up during a ground shockwave from earthquake or some man made calamity. Another option is to skip this rebar and use a hammer drill to drill holes into the block to accept the floor bars once the walls are grouted. This way your not tripping over the rebar.
After completing the first course its time to cut and tie rebar again. Cut 4 pieces of half inch rebar, 4 feet long and bend them in the middle at 90 degrees for the corners. Set these on top of the block at each corner, then cut pieces to lay horizontally on top of the first course, overlapping the corner rebar. Tie them in place in a vertical position, so that they are tied on top of each other, not side by side. Then cut lenghts of 10 feet and tie them vertically to the vertical uprights coming up out of the footing. Tie them good and tight. Once all the rebar is tied in place you can procede with the next course of block. Turn the corner blocks the opposite direction of the first course so that the ends line up over the center of the blocks in the first course. You will have to knock out a small hole in the side of each corner block so it will sit over the rebar you just tied. Mark where you want the hole, turn the block over and tap your hammer at the center of the blockside, knocking away from both sides of the block untill a large enough hole is made. Hit lightly or the block will break. Keep up this routine untill you have stacked the first 4 course. Keep checking the diagonal measurements and check with your level the vertical plumb of the corners and especially at the door jamb.

Besides the 3 number 5 bars that go under the block, there should also be an outer and inner run of horizontal bar placed approximately 3 inches from the inside of the trench walls on both sides of the center rebar. Prop them up off the ground like before with pieces of broken block so when you pour, concrete will get under the rebar. These should have 4' corner bent bar tied to the straight runs too. When you tie the uprights in place, stagger the placement and tie the bottoms so that they alternate from the inner bar to the outer bar. This will help stabalize the uprights and will also make a stronger footing to wall connection. At about this point in the work your hands should be scratched, banged and bruised, and your patience about gone. Do not despair. The end result will be worth the effort. I usually do all the rebar by myself but a spare set of hands would come in real handy to help hold the uprights while being tied. Where ever you want to put the door, leave out the uprights.
After all the uprights are tied in place, check again to make sure that they start 12 inches from the corner pipes and check that the hollow cells of the blocks will fit over the uprights. Make sure that your temporary 2x4 stakes and temporary rebar supports are secure and will not move on you during the pour. A second check to make sure the corners are square and level to the same elevation is necessaqry before we pour. Now is the time to screw together those 2x6's and at the end of the workday, set them onto, then tiewire them onto the tops of the uprights to eliminate the possibility of someone or some critter falling onto then and getting impailed.
If you are residing in the north and your trenches have to be 4' deep, you will need to change the uprights size to accomodate the extra depth. You should have 22 to 24 inches of rebar protruding above the concrete after the pour. A 4' deep footing will take 10 and one half cubic yards of concrete. That is way too much to mix by hand so get a couple redimix trucks to deliver it. (If you can get them to the site). My footings are only one foot deep and will require only 3 cubic yards. I mixed mine by myself using a one sack mixer and it took 12 hours of pure fanny busting without stopping. But I am more stubborn than most people, and was willing to do it. While dumping the concrete into the trench, take a straight 6'- 2x4 and use it as a straight edge to make sure the mud is level from corner stake to stake. This is critical!! After the truck has washed up and left, you can double check for level from side to side and corner to corner. I took a wood float and rubbed out the cement to give it a rough finnish. If you have any energy left you could steel trowel the footing if you want to. The morning after the pour ( if you can still move) untie the temporary horizontal support rebar and remove the 2x4 stakes and kickers. The concrete needs to set up at least 2 days and a weak would be better. During this time your body can heal up and you can estimate how many block you are going to need, and can have them delivered. Or drag them out in a pick up truck 75 or 80 at a time. There will be no need for sand and cement because we are going to "DRY STACK" these blocks to speed up the project. (Learning to spread mortar takes approximately 30,000 blocks before you are proficient at it, so we will skip the mortar. That is why brick and block laying is considered a skilled trade and you serve an apprenticeship to learn it.)
Once again to determine how many blocks you need, multiply the length of the walls times the height to get the surface area in square feet and then divide by .89. This will tell you how many block you need. Ask for FAST BLOCK for the main walls but you need 2 STANDARD or in some parts of the country they are known as UTILITY blocks for the corners. Get LIGHTWEIGHTS if they have them. At the doorjam you will need a half block every other course, however tall you decide to make the door. A metal masonry door and frame will cost you $1200 unless you can find one in a scrap yard or salvege/ reclamation store. I made a door jamb from 2x6's and the door from a piece of 3/4 inch plywood left over from the ceiling forms.

Phase one; excavating and pouring the footings.
After you have decided what size room you want and where you would like to have it, its time to start digging. The best location is in the side of a hill so that you will be able to cover 3 sides and most of the roof with earth for added insulation and camoflauge. If you know someone with a backhoe, get him to dig a hole in the side of the hill that is large enough to accept the structure. For an example, we will build a 12 foot long by 8 foot wide room with a concrete ceiling. I want my room to have INSIDE dimensions of 12x8 feet, so that makes the outside wall dimensions actually 13 foot 4 inches long by 9 foot 4 inches wide. A good rule of thumb for sizeing the footings is to make the footings twice as wide as the block. So 16" wide for 8" block and 2 feet wide for 12" wide block. (12" wide blocks do not cost much more than 8" but they require more expense in grouting them and also they will require the use of 5/8" dia. rebar. 12"wide blocks covered with earth will give the best anti radiation penetration ratio and will bounce a 50 cal bullet.) I decided to use 8" wide block in my room because they fit together at the corners and are plenty strong enough and easier to stack.
Take the earth that has been removed from the hillside and pile it up out of the way. You can re-use this material to bury your shelter after the roof has been poured. Since the footings will protrude past the block by 4" ( they are 16" wide) this will make an outside footing dimension of 14 feet x 10 feet x 16" wide. In my region we pour the footings one foot thick after digging a trench in the ground. In places like Michigan or Montana where the ground freezes solid, you will have to check the local code for how deep to dig the footings. They must be below the frost line which is 4 feet deep in Michigan. Drive a stale into the ground where you want the corner of the footings to be measure over and drive 2 more on the outside end and then square them up by measuring diagonally from corner to corner untill you get the same measurement which assures a square foundation. Use chalk spray or lime to line out the footings and dig them to the correct depth. I had a backhoe dig my footings even though they were only one foot deep. Take the dug up earth and dump it out of the way. After you have shoveled out and squared up the edges you must locate the corners of where the outside of the block walls will be. Drive a scrap piece of 3/4" galv water pipe approximately 4" in from the corner of your excavation and then go through the process of making sure the pipe stakes are 13' 4" x 9' 4"and then square them up with the diag measurements. These corner pipes should be set one foot above the bottom of the trench and should be set at the same elevations, so as to be used as a reference for how thick the concrete should be. They will remain in place so that you will know where the block corners should start after the footings have been poured. You can use a line level or a long straight 2x6 with a level set on top to check these elevations with. Get them as close as you can to being level.
Cutting, bending and placing rebar is next. I use #5 rebar in the footings to support the incredible amount of weight that they must carry. All the weight from the walls and the concrete ceiling gets transmitted down into the footings so it is very prudent to use enough rebar and place it correctly. Start by cutting 20 pieces that are 4 feet long, using a rebar cutter, chop saw with metal cutting blade, skilsaw etc. Don't cut them with a torch. This will change the temper of the bar stock and make it brittle. Now bend them in the center to a 90 degree bend. I use the trailer hitch on my P.U. truck for this. These will be for the corner turns in the footing. You need 3 horizontal bar which lay directly under the center of the block. Space the first bar about 2" above the bottom of the footing trench and support them up off the ground with pieces of broken block or brick. Do not use chunks of wood or clumps of dirt for this. Tie a corner piece to this bar and make sure it has enough overlap. Drive temporary stakes alongside the first bottom bars every 4 or 5 feet and tiewire the top and center bars to them. Now you will need a piece of #5 rebar , 4'long, that will stick up vertically out of the top of the footing concrete. So, get busy cutting 30 pieces 4' long and put a bend 16" from an end. The short 16" end gets tied to the bottom horizontal bar. Then tie them to the horizontal bars, starting 12 inches from the corner stake. Begin by tying one upright at each end, then take a 20 foot piece of half inch rebar and drive one end into the hillside and tie the uprights to this to hold them during the pour. You may need to drive a 2x4 into the ground outside the end of the footing trench and wire the temporary support bar to this to keep it in place.You can mark the horizontal bar with a magic marker every 16 inches to locate where the uprights should go. This process is a genuine pain in the butt. Be carefull not to let these uprights fall over and hit you in the eye. After completing one side make sure they are all lined up straight like soldiers and are in the centerline of where the block will go. Continue placing temporary wires and stake braces whereever you need them to prevent the uprights from moving.

Materials information sheet;
One 8x8x16" concrete block weighs 30 lbs.
One 12x8x16" block weighs 37 pounds.
Surface area of one block is .89 of a square foot.
One cubic yard of grout will fill 80- 8x8x16" blocks.
One cubic yard of grout will fill 60- 12x8x16" blocks.
One cubic yard of grout or concrete weighs approx 4300 pounds.
Concrete is a 1, 2, 3 mix. One part portland cement, two parts sand and 3 parts 3/4" or under, gravel. Wall grout is mixed with 3/8" pea gravel.
There are 120 pieces of #4 rebar (20 ft long) in one ton. #4 is 1/2" in diameter.
There are 58 pieces of #5 rebar in one ton. #5 is 5/8" dia.
The correct overlap for rebar is 40 times the bar diameter. So 20" for 1/2"bar would be the correct splice overlap.
One cubic yard of concrete will place 93 sq. feet of area at 3 1/2" thick.
One cubic yard of concrete will place 81 sq. feet of area at 4" thick.
One "" " " " " 65 sq. feet " " 5" thick.
One " " " " " 54 sq. feet of area at 6" thick.
In a portable mixer you will mix 48 shovels of con-agg to 1 sack portland cement. Most mixers will only mix a half sack at a time.
Con-agg is sand and gravel mixed at the supply yard with a front end loader. This saves you time, labor and money to haul the stuff.
Eight inch wide block takes #4 rebar and 12 inch wide block take #5. A number 5 rebar is the largest diameter that you can cut and bend in the field and it will wear you out after 7 or 8 hours.
You will need a bundle of 6" bag ties (1000) and a tie twister tool to tie all the rebar together, to hold it in place when you pour the footings, walls and especially the ceiling bar. If your local supply store does not have bag ties then you will be stuck using a roll of tie wire and pliers to tie the rebar. This will take much more time to do it this way.
A word of caution-
Once you excavate the trenches for the footings you will need to layout both the horizontal rebar and a vertical bar gets tied every 16 inches so that it sticks up out of the concrete and will go into the block cells when you stack the block. What you have got at this point is similar to a punji trap. Take some lengths of 2x6 and screw/nail them together at a 90 degree angle and tiewire them over the tops of the vertical rebar to prevent a dog, deer or child from falling onto them.
Another factoid to consider is that the concrete ceiling must be poured all at once so that it is a monolithic structural piece of concrete with no cold joints. This pour may require a small line concrete pump and a redi mix cement truck, depending on how much concrete your ceiling will require. This will compromise security but without a pump you are going to need a platoon of football players to mix and hoist that much mud up onto the roof forms. There is no second chance with concrete; it must be done right the first time or you find yourself in the hurt locker.
We will begin the footing layout and digging next.

This project will consist of 3 phases. First is the excavation and pouring concrete into the footings which will support the block walls. Second phase consists of stacking the blocks and filling them with grout (sand, cement and pea gravel.) The third and final stage will be the building of wooden forms to hold the concrete when we pour the roof.
Materials estimation: Most construction projects are designed based on 16 inch measurements. A sheet of plywood is 4 x 8 feet. This is so the plywood is divisable by 16" increments. Four feet divided by 16 inches is 3. Eight feet gives you 6 sixteen inch increments. Concrete blocks are sold with 3 dimensions. The most common block size is 8 x8 x16 inches, or 8"wide x 8" tall x 16" long. A 12 x 8 x 16 means that the block is 12 inches wide, 8" tall and 16" long. So when you lay out your wall dimensions you should make sure they are designed so that they are divisable by 16 inches. This way you won't end up with any odd sized blocks that have to be cut to fit. I strongly recomend using the 8x8x16 blocks. In the western states we have what is called a "FAST" block, designed for use in reinforced concrete block walls. This fast block is open ended with a short center web that allows you to place horizontal rebar between the layers of block so that when filled with grout you have a hollow channel to be encased in grout. This system produces very strong walls and is used in earthquake zones. In the eastern states you should use "BOND BEAM" blocks which are open ended. The last choice would be to use 8x8x16 "STANDARD" blocks. This will work but standards are designed to be laid up and not grouted. If you are stuck using standards you will have to hammer out a notch in every block so that they will fit over the horizontal rebar, plus you must hoist every block up and over the vertical rebar. This alone makes using standard block a no no. Any non grouted walls built from standard or 3 cell basement blocks will not stop a rifle bullet either.
Lets say you decide on a room 16 feet long and 8 feet wide. How many block will this take? measure the square footage of the walls (length times width) and divide by .89. This will tell you how many block you need. Each corner will take a standard or "FIGURE A" block, also a standard and every other course at the door jambs you will need an 8x8x8 half block or a "FIGURE U" block which has only 3 sides. The height of your walls is up to you. Eight foot tall is just a waste of material and taller walls will break your back when you go to pour the ceiling.
More to come later.

A number of you who reside in rural areas of this country and are not subject to the absurd zoning and construction permit and inspection process conduted by city beaurocrats, may be interested in building a shelter for surviving nuclear radio active fallout, food storage, tool shed etc. Over the years I have seen many people dig a trench in the ground or the side of a hill and bury a 7' diameter corrugated metal culvert and convert this into a survival shelter. These units will leak rainwater and they are hard to heat during the cold winter months. I have built many underground shelters using concrete blocks with a concrete roof and this type of structure will provide a greater degree of surviveability and longevity. Reinforced masonry consists of concrete block walls that have been filled with cement and tied together with the appropriate size rebar.
WARNING: This project will require a great amount of physical stamina, plus it is dangerous for both you and especially little children and they should be kept away from the construction site. If you own a hardhat, WEAR it, and wear steel toed work boots if you have them. Physically, the best approach is to set 3 or 4 courses of block and then fill them with cement the next day.
Tools: You will need a pick and a shovel, wheelbarrow, 4' spirit level, 8" torpedo level, brick hammer, claw hammer, crow bar- preferably 3 foot long, a 15 foot length of clear polly tube to make a water level out of, and a small cement mixer. Some of you people already have this equipment laying around the homestead. If you look in the Weekly Trader you will find a used cement mixer for sale. There are lots of them now due to the nonexistence of new construction via the lame economy. Or, you may have to rent a mixer, but renting will cost you more money in the longrun.
Next, you must decide how big to build this structure. Remember that the concrete blocks are 8" wide so an 8 foot wide outside dimension will measure 6' 8" wide on the inside of the building- a 12 foot ouside measurement will give you a 10' 8" wide inside measurement. Pick a location and scribe lines on the ground to determine what size you want. Think about this overnight and look at it the next day and see if you are satisfied that this area will be big enough. Consider the fact that if you would like a concrete roof it is better to make a long 8' wide structure because if you build wider than 8' you will encounter more expense and difficulty framing forms and pouring the roof.
My batteries are quitting on me so I will have to stop for now.