Storm Shelter Construction

Jan - 15

Storm Shelter Construction

The photos below show the various steps involved in building a Monolithic Dome, from bare land to the final paint. This dome has a diameter of 22′ at the raised floor level and 20′ at ground level and a height of 16′.

Locating the dome

A storm shelter can fit into most back yards due to their small size. This is a fairly small yard with numerous trees, yet a 22′ dome will set nicely here. The location is in the center rear area of the photo, indicated by the yellow area (graphically added).

The Foundation

A Monolithic Dome begins with the ring beam (footer) and concrete slab, both use a substantial amount of steel reinforcing. For smaller domes these items are poured together while larger domes have the concrete slab poured after dome shell completion.

Slab Completion

The completed concrete slab has addition rebar (steel reinforcing rods) extend vertically from the slab to be connected later with the dome shell.

Airform Preparation

Construction materials needed inside the dome are placed on the slab then covered with the airform. The airform is securely attached to the ring beam and a duct connects the dome to the blower fan used to inflate the airform. This image indicates the airform has begun to inflate.

Airform Inflation

In a few minutes the airform is completely inflated, revealing the final size and shape of the dome. At this point the dome moderately rigid, able to handle brisk daily winds without budging and is very firm to hand pressure.

The Fan

The blower fan will continue until the wall structure inside is capable of supporting itself.

Construction Entrance

An airlock allows personnel and material to enter the dome while maintaining air pressure inside the dome. The lower square in the door is an opening to vent excess air and provide for materials such as rebar to pass into the dome. Now the real work can begin.


Building Layers

This image shows several items have been completed. Polyurethane foam covers the inside of the airform with a thickness of three inches. Rebar is attached to the foam via special anchors, in preparation for the shotcrete. Notice, two small square boxes on the wall are part of the rough electrical preparation that is also covered with shotcrete.

Strong Everywhere

This ceiling image shows how the rebar is in every part of the dome’s structure. The weight of the steel rebar is supported partly by itself, being tied together, and substantially by the Polyurethane foam layer. Even at this midway point, the dome has considerable strength.

Shotcrete Application

Shotcrete, a special concrete mixture, is sprayed on in layers until a thickness of three inches is reached. For larger or utility purpose domes, much thicker layers are used. The slight obscurity in this image is due to difficulty in keeping the camera lens clean.

Dome Shell Finished

After the shotcrete has set, normally 24 hours, the blower fan is turned off and the airlock removed. In this case, the coverings for the lower for air flow openings can also be removed. The Monolithic Dome shell is now full strength, complete and interior finish construction may begin.

Advanced Planning Items

Here we show several electrical conduits protruding from the dome shell, indicated by the arrows. Early planning for such items is essential. This storm shelter dome will not have internal walls and, therefore, overhead lighting wires must be routed through the dome’s shell.

Beginning Interior Completion

Our storm shelter will have a raised floor, located where the supporting band board (center of image) is secured to the shell. While the shell will support most items attached to it, addition rebar is used at the finished floor level. The rebar also serves to strengthen the entire dome shell.

Adding The Floor

For this dome TJI sections were chosen for the floor joists. After attachment to the band board, cross supports will be added (not shown) and plywood is glued and screwed to the TJIs. The result is a solid, squeak free floor.

Adding A Deck

The exterior deck, shown partially complete, extends nearly half way around the dome. Anchoring the deck is accomplished by bolting through the dome shell and posts standing on concrete footers. The result is a rock solid, vibration free deck surface.

The deck, with its almost completed railing shown here, is constructed at the same height as the interior floor. This elevation is above expected flood level generated by most hurricanes.

Entry and View

This entryway is framed with aluminum to avoid rot and rust. The glass is shatter resistant storm glass. The entire entryway is very strong, capable of repelling wind borne debris and obstacles during a storm. All windows in the dome are built to the same standard.

Interior Rear

Ready for final paint. Built-in lighting and ceiling fan with light make the room soft yet well lit. The short partition conveniently holds the electric panel on the back side.

The Finished Dome

After paint, we’re finished. Just add imagination and furniture to taste. This dome uses a free standing, portable air conditioner (not shown). The ceiling fan and the dome’s insulation features make the space comfortable while using only a trickle of energy for cooling.

This one room dome is suitable for an office, spare bedroom, muiti-purpose room, hobbies or whatever you can imagine. Yet, in time of natural disaster it is a life saver only a few feet from your home.


Thank you for viewing our project. We hope you found some value from our presentation.


To inquire about having a Monolithic Dome storm shelter built for you please use our Contact Page

Leave a Reply

Your email address will not be published. Required fields are marked *