Building the Shelter

BUILDING THE SHELTER

oncret has long been recognized as a suitable barri- T h e re are no special tricks invo l ved. A regular crew can Cer against radiation. In fact, considering its cost and build the shelter without the services of a “fallout spe- convenience, concrete surpasses all other materials for ci a l i s t . ” Any concrete contractor can tackle the j ob with general-purpose shielding. The concrete shelter is easy c o n f i d e n c e. He has all the skill and re s o u rces that are to build and is virtually free of maintenance pro b l e m s. needed to deliver the finished prod u c t . It there f o re is not surprising that many shelters are Few trends in recent years have placed the building made of concrete. c o n t ractor in a more responsible position than has the Many concrete shelters are adaptations of existing fa- dri v e for the construction of fallout shelters. New s p a p e r s cilities (basements, for example). But for maximum pro- and genera l-c i rculation magazines have taken up the tection the concrete fallout shelter is an independent cause in recent weeks with great vigor and with a cru- s t ru c t u re especially designed for civil defense. The un- sading spirit. Engineers and professional builders mean- d e rg round concrete shelter not only shields its occu- while have looked with alarm on the way many shelters pants against radiation but also furnishes some prot e c - ar e being constructed. They have warned that a shelter is tion against blast and heat. Properly constructed, it useless unless it is properly construc t e d . pr ovides comfortable quarters for a bombed-out family. Many shelters have failed to pass the inspection of An experienced concrete man will have no trouble in municipal building authorit i e s . Professional engineerin g building a fallout shelter. He merely applies the same g roups have cited numerous instances of stru c t u ra l pr inciples of good concreting that apply to the construc - weaknesses and poor job prac t i c e s . Thus the res p o n s i b l e tion of basements, foundations, walls, and floor slabs. builder faces a challenge. If he is called upon to build a

Shown here is a fairly monolithic undergroud survival shelter being constructed in Excelsior, Minnesota. The walls and roof of this underground shelter, photographed while the water sheen was still plainly visible on the slab, were cast all at one time using prefabricated forms.

sh e l t e r , he should do his best to achieve the maximum in affluent persons have put thousands of dollars into lux- wo r kmanship and engineering standards . Oth e r wise he ur iously appointed shelters. casts a shadow on the entire industry. A typical OCDM six-person shelter has an inside mea- T h e re are many kinds of fallout shelters, but the pre- su r e of 12 feet by 9 feet. Stru c t u r al walls are eight inches fe r r ed material by a wide margin is concret e . Some shel- thick—the standard thickness for a concrete ra d i a t i o n ters are tucked into basements, others adjoin gara g e s, shield. Hal f -inch rei n f o r cing rods run through the walls and some are placed in their own locations under- ve rtically and hori zo n t a l l y. Co rner re i n f o rcing bars are gr ound. Many shelters are dual-purpose roo m s . That is lapped two feet three inches. The rods extend to within they provide fallout protection but also can serve as fam- th r ee inches of the outside face of the walls. ily rooms or basement playrooms until the awful day Box outs and sleeves for ventilation pipes are inserte d when the bombs begin to fall. b e t ween the forms before the concrete is placed. Tw o The concrete undergr ound shelter in its own location pipes extending no more than three feet above the surpasses all others in many re s p e c t s. It provides ab- gr ound ventilate the shelter. One pipe brings fresh air in- solute protection against radiation. The cost is re a s o n- to the shelter, and the other pipe exhausts stale air. The a b l e, and the design is simple. The contractor may be pi p e s , as a rul e , prot r ude at opposite ends of the shelter. called upon to remodel a basement or to build a The intake pipe is cove red with a hood and a scre e n . du a l -purpose addition. But if he is seriously interested in It is connected at the wall in two places. At one point it building shelters, he will give a great deal of attention to feeds into an ordi n a r y outlet. It is connected to a blower the plans and specifications for undergr ound shelter. An at the other opening. A cap covers the ordi n a r y opening un d e rg r ound facility is what most people have in mind when the blower is being used. Only one opening is used when they speak of a bomb shelter. for the exhaust pipe. In building a fallout shelter, the experienced contrac - The floor can be sloped one fourth inch per foot to al- tor turns instinctively to pre f a b ricated form s. The pre- lo w proper drai n a g e . It is also suggested that a steel pipe fabs simplify planning and eliminate time-c o n s u m i n g be extended into the ground to release moisture fro m details at the construction site. Fo rm manufacture r s the faces of the walls and from the interior of the shelter. ha v e rallied to the needs of both the contractor and the Mo i s t u re tends to accumulate when the hatch is open. civil defense authori t i e s. The manufacturers furn i s h A sump pump with an auxiliary hand crank should be complete kits for the construction of fallout shelters. pr ovided to keep the shelter dry at all times. Some form manufacturers also offer furnishings and ac- Other form manufacturers have developed plans for a ce s s o r ies as a service to the builder. si x -person undergr ound shelter. The drawings show two The manufacture r s’ kits, for the most part, are based types of shelters, one with a hatchway and the other with on specifications of the Office of Civil Defense and Mo- a stairwa y . (The stairway/hatchway option is included in bilization. A kit consists of draw i n g s , a materials list, and OCDM plans. ) Fo rms for the shelter can be purc h a s e d the necessary forming equipment. Along with their kits ou t r ight or ren t e d . fo r m manufacturers give a complete cost brea k d o wn for Wh a t e v er the specifications, no undergr ound shelter a concrete shelter. Most shelters are priced to the con- is worth its salt unless it is free of flooding. In building sumer in the $1,500 to $2,000 ran g e . A shelter of course the shelter the contractor should abide by all the ru l e s can be as elaborate as the buyer wants to make it. Som e that assure watertight construction. It is always a good This shelter form design, shown here in isometric and plan views, has been developed for use with a particular manufacturer’s forming system. The same concern also offers such accessories as steel access doors, ventilating fans and brackets for the mounting of beds, tables and shelves. It is recommended that this shelter be covered with 24 to 36 inches of earth.

idea to cover the ground level with a vapor barrier material. Malleable asphalt hard b o a rd s, polyethylene film, and rigid plastic foam are effective materials to use for this purpose. The floor itself has much to do with holding moisture content to a minimum. A typical shelter floor slab is six inches thick. In placing the floor the contractor should bear in mind that shelter construction demands the best in workmanship and quality control. Be part i c u l a r l y c a reful with the curing. Proper curing goes a long way Prefab forms supplied by one manufacturer are shown above in position for casting an underground survival shelter. The tow a r d reducing cracks and weaknesses in floor slabs. scuttle entrance and baffle wall are partially formed in this Wat e r p r oofing applies to the walls and roof as well as view. Below, the completed form system with heavy steel to the floor. The OCDM suggests that contractors coat reinforcing mat is shown ready for the concrete to be place. the walls of undergr ound shelters with hot asphalt paint. It advises builders to cover the shelter with two layers of roofing felt or other vapor sealing materia l s . Each layer should be cemented in place and then cover ed with hot asphalt paint. The roof of an undergr ound shelter, if it meets OCDM st a n d a rd s , must be at least six inches thick. If the forms p e rmit, the roof can be thicker than six inches. So m e f o rms allow a thickness of up to eighteen inches. The roof should be at least three feet below the ground sur- fa c e . Earth above the roof adds to the shielding. In ord e ring your concre t e, make it clear to the re a d y mix dealer that you need a mix that meets the specifications for an underg round shelter. Avoid at all costs the addition of extra water to your mix. Ex t ra water inva ri- ably reduces strength and causes shrinkage and crac k s . Such defects, in turn, result in a leaky shelter.

The drawing at right illustrates the application of a vapor seal which completely isolates a shelter from soil and moisture. An effective vapor seal assures edible food supplies, mildew-free blankets and clothing, rust-free radios and other equipment. Proper installation of vapor seals gives complete protection against moisture and seepage

Try to get the concrete deliver ed as close to the forms You will find the shelter no more difficult to build than as possible. A long haul from the truck to the forms jolts a foundation or an ord i n a ry basement. One manufac- the mix and causes segregation. Power buggies will tu r er of forming systems rep o r ts that a three -man crew speed up the deliver y if the shelter is located in a spot in- using its kit and forms can set up the equipment and accessible to the ready mix truc k . place the concrete in a single day. The package includes The mix for an undergr ound shelter needs no special ha rd w a r e, bathe wall, steel slab ports and necessary di- ag g r egates to provide adequate shielding. Hig h -de n s i t y mensional lumber. co n c r ete is commonly used for shielding in labora t o ri e s Detailed plans are furnished for setting the forms and and re a c t o r s. Such aggregates as barite and magnetite installing re i n f o rcing steel. In addition this firm makes i n c rease the density of concre t e. But for purposes of a av ailable to contractors a 16-mm sound motion picture fallout shelter ordi n a r y sand and grav el will do the job al- of an actual shelter construction. Ac c e s s o ries such as most as wel l . bunk beds, shelf brac k e t s , ventilating fans, and steel ac- Avoid segregation as you place the mix. Apply the con- cess doors are also ava i l a b l e. Ti e-ends extend into the c rete in even layers that are no more than 12 inches shelter to provide attaching points for bunks and shelf d e e p. Vi b rate each layer enough to settle the concre t e bra c k e t s . against the form s. Proper settlement and distri b u t i o n The contractor would do well to acquaint himself with will eliminate honeyco m b i n g . all the details of furnishing a fallout shelter. His cus- Ob viously the strength of the finished product is of ut- t o m e r s, in all likelihood, will ask questions about food, most importance in a fallout shelter. Cur ing, more than w a t e r, powe r, communications and first-aid supplies. any other factor, determines the ultimate strength of The curious homeowner will probably demand a short c o n c re t e. There f o re give the walls and slabs plenty of course in atomic energy along with the usual curbstone time to cure. In this instance the buyer can afford to be le c t u r e the builder must invar iably deliver to side walk patient. There is eve ry reason to hope that he won’t be su p e rv i s o r s . in a hurry to use the shelter.