StratoDOME

Modular system StratoDOME®     

In the core of the modular system sits the combination of the Modified stratodesic geometry StratoLINE® together with special modules – StratoPANEL®. They are preassembled, with standard sizes and shapes, fitted with almost all the required layers and materials.     

The idea is for the panels to be produced in a factory environment, with strict technological processes, by using special rigs, machines, and instruments. This will introduce effective optimization of the material and labor costs. The approach will also allow for ease of scalability and industrial-scale production with achieving high-quality end product. The panels themselves need to fulfill some very important requirements:

• The maximum level of completion – almost all the different layers and components should be preinstalled, including waterproofing, vapor barrier, thermal insulation, interior finishing, etc.
• The sizes of the panels should provide for easy handling and assembly of the dome without cranes
• The panels should assemble and fit each other reliably and strongly, both vertically and horizontally
• Provision for easy and systematic installation of electrical systems, plumbing, communications, etc.     

After an exhaustive research and development process, many trials, and countless tweaks we have come to the following configuration:    

1. The Main structure of the panel is made out of high-quality Baltic birch plywood for exterior use (with increased moisture resistance). Each of the details is carefully designed and cut on a CNC Router. All the joints and assemblies are made with ‘Torx’ screws and are coupled with water-resistant PVA Glue Class D3. The standard size of the modules is Widht- 1220 mm, Height – 810 mm, Thickness – 350 mm (this is the thickness of the plywood structure only and not the complete panel).    

2. Thermal insulation – by default there are three layers with a total thickness of 30 cm – two 5 cm layers of Stone wool with a density of 30 kg/m3 and a layer of 20 cm thick Glass wool in between. This combination ensures excellent thermal characteristics, fire resistance, moisture resistance, and volumetric stability while keeping the price at bay. For most of the models, there is a possibility of using natural rye straw as insulation. The thermal insulation is protected from the household water vapors with a Vapor barrier.

3. The Sheathing is composed of two layers – for the inner one a 9 mm OSB-3 is used, and the outre is made with fire-resistant Exterior sheathing board Glasrok X (12,5 mm).     

4. Water-proofing – Polymer bitumen membrane with 4 mm thickness consisting of a particular APAO (Amorphous poly alfa olefin) compound combining high-temperature resistance, significant low-temperature flexibility, with stress resistance and dimensional stability. It is expected to have both long life and reliability. The membrane is mounted on each panel with provision for overlapping of the sheet of the upper panel over the one of the lower one. The vertical joints between the ‘columns’ of panels are filled with black silicone sealant (used with glass facades) and are then covered with Butyl adhesive type for perfect and secure waterproofing.     

5. The Facade – for the outer-most finish layer we are using a self-developed Wooden facade from burned boards – StratoBOARD®. The boards themselves are from first-class dried softwood. They are calibrated, burned, and brushed (using the Japanese technology Shou Sugi Ban), then pressure treated in Autoclave for longevity. Finally, they are sealed with natural oils for additional protection and a luxury look. The facade boards are mounted on rafters with oxidized screws. The rafters are made from three layers of pressure-treated softwood which are glued together with water-resistant wood. A special Butyl adhesive tape is installed between the rafters and the bitumen membrane in order to prevent all the possible leakages from the perforation caused by the mounting screws (the screws that are used to attach the rafters to the panel and inevitably are piercing the membrane). The rafters have a total thickness of 40 mm and provide an additional ventilation gap between the facade boards and the dome shell.     

6. The Finish Interior Layer – for the interior there are several options – softwood paneling with different widths, hardwood paneling, birch plywood, magnesium oxide boards, fire-resistant gypsum boards, or some combinations between these. By default is used high-quality softwood paneling with increased width (130 mm) which is treated with natural oils.     

7. Installation openings – they are cut in the panel walls and provide for easy installation of electrical and communication systems, plumbing, etc. The provision is for both horizontal and vertical installations

8. StratoVENT® – a system deserving some special attention. It is designed to constantly ventilate the thermal insulation in the panels. In essence, it is a system of air gaps and channels between the thermal insulation and the sheathing of the panels. It ensures that any moisture or water vapors in the insulation are eliminated and ventilated to the outside, which in itself helps the insulation to do its work. It improves significantly the thermal characteristic of the panel and the dome itself. The idea is that the outside air enters the first panel of each ‘column’ through openings (secured with insect nets) and passes vertically through the whole ‘column’ from one panel to the other all the way to the top of the dome where it is exhausted to the atmosphere with a special vent valve. If there are windows in the way of the air special channels around the windows are provided. If the column is a short one and intersects two longer ones (in other words it doesn’t reach to the top) then the top panel of this column is made with openings in the side walls through which the air passes in the neighboring panels (also perforated on the side) and then continues its journey to the top.     

The combination of the above-described layers, materials, and components is assumed to be the default standard configuration called “OPTIMUM”. It is applied with the bigger domes from the model range (with a diameter of 10.9 m or greater). For the medium domes (with a diameter of 7.8 m and 9.4 m) the thickness of the panel is decreased to 37 cm and the StratoVENT system is removed. For the small domes, the thickness of the panels is further reduced to 30 cm.      The customers are given the option of customizing the panels of their future dome-home by eliminating or changing some of the layers and materials. Two additional configurations (or packs with alterations) are being composed – “ECONOMY” and “PREMIUM”.

A Dome? And why exactly?     

People around the world had used the dome shape since the beginning of time especially for building religious temples. The natural and organic spherical shape induces an instant perception of harmony and calmness. For years we have witnessed the reaction of many people entering a dome for the first time. Invariably they have been astonished and awed and have expressed their delight. Humans simply feel good in a dome. Moreover, the domes have the unique quality of looking small, elegant, and humble from the outside but extremely spacious and modern from the inside.      But if we set aside the subjective feelings and perceptions and try to establish a more objective approach we will discover there are many other advantages and pros to the domes which can be defined and measured more accurately:

• STRENGTH – Have you ever tried to squeeze and break an egg with your bare hand? If so you would have discovered it is extremely strong despite its thin and fragile shell. The strength of the egg is stemming from its spherical shape which distributes the applied forces throughout the whole surface of the shell. Similarly, the domes are strong and stable and can easily withstand with no problem extreme forces induced from earthquakes, heavy snowfalls, and strong winds.
• EFFICIENCY – The sphere has the property of enclosing Maximum volume with a minimum surface area. So if we compare a dome and a standard house with identical volumes the former will have 30% less surface area (floor, outside walls, and roof). Consequently, the dome will be losing 30% less heat during the winter (given the insulation and thickness of the surfaces are identical), so it will be far more energy-efficient. Besides – less surface means fewer materials, time, and labor for construction.
• STABILITY – The shape of the dome induces Natural air circulation throughout the building which helps for uniform temperatures, and a healthy and comfortable microclimate.
• FORM – The shape of the dome generates natural air circulation that promotes even temperature distribution and a healthy and comfortable microclimate in the building.

Our experience

StratoDOME®     

For the past several years we have had hundreds of meetings and conversations with prospective or real clients and it the fact is the vast majority of them wanted TWO basic things – affordability and ‘turnkey’ completion from our side. It sounds simple enough but it turned out we were unable to respond properly to the second wish. The main reason is we are situated in Plovdiv, Bulgaria and most of the customers are from distant cities (or even from abroad) which means deploying a construction team for months at a distant location. This in itself skyrockets the expenses and the overall price of the finished house.      

So basically we stumbled into a problem – HOW TO BUILD A HIGH-QUALITY DOME HOUSE AT A DISTANT LOCATION AT AFFORDABLE PRICE? Our solution – The Modular system for Dome building StratoDOME®. It is a proprietary and unique novelty that came into reality after a long RD process with many experiments, prototypes, changes, and so on. There is no product like this on the world market.      At the beginning of the development we have established a set of some very important goals for the project:

1. A quick and reliable assembly method for building domes of any size
2. Ability to apply the system at any terrain at any location
3. Enhanced Energy Efficiency surpassing the existing norms and requirements
4. Best Quality-Price Ratio and Great Value For Money
5. The predominant use of natural and ecological materials and components in a sustainable manner
6. Standardization snd unification of sizes, geometry, and components of the system
7. Optimization of the production costs and material losses
8. Ease of transportation, loading, handling, and logistics
9. Unmatched look, comfort, and design of the finished product

The geometry of the system

StratoDOME®

Traditionally there are two main geometrical models of domes worldwide – the Geodesic and the Stratodesic (Arched beams dome). The Geodesic model uses straight beams which are interconnected into triangles or polygons (using metal connectors or with connector-less technologies). The polygons are organized into a net which represents the dome structure itself. These domes are particularly robust and stable and are vastly popular around the world. The founder of this model is the American architect, engineer, and inventor Richard Buckminster Fuller. Despite their qualities and popularity the geodesic domes have some quite annoying and tedious drawbacks. By far the most important one is the different triangles (the polygons) of the dome are VERY hard and expensive to cover with roofing and to make them watertight. There are significant losses of materials and time for their cutting and fitting (all of the construction materials are delivered as rectangles). Incorporating standard rectangular windows and doors into the net is also a BIG challenge. And last but not least – the geodesic domes are an acquired taste with their “edgie” shape.      The Arched beams domes (also known as Stratodesic in Eastern Europe) are very widespread in Russia. They consist of several half-arcs (Solid Glulam Beams or Structural Truss Arcs) which are connected at the ‘pole’ of the dome. This geometry is very much similar to a globe with its meridians (the arcs of the dome), parallels, the equator, and the poles. They are easier for finishing works and securing water-tightness, and also standard windows and doors are easily used. On the other hand, some significant material and time losses are still present as the distance between each two neighboring half-arcs is constantly changing. Moreover – the stratodesic domes suffer from some radial instability (they tend to ‘twist’ around the central axis).

Maximum completeness
The maximum level of completion – almost all the different layers and components should be preinstalled, including waterproofing, vapor barrier, thermal insulation, interior finishing, etc.

Compactness
The sizes of the panels should provide for easy handling and assembly of the dome without cranes

Construction
The panels should assemble and fit each other reliably and strongly, both vertically and horizontally

Convenience
Provision for easy and systematic installation of electrical systems, plumbing, communications, etc.

Maximum completeness
Maximum completeness of construction layers, including thermal insulation, waterproofing, vapour barrier and more.

Minimum losses
Comparing a dome and a standard house of the same volume, the dome will have about 30% less enveloping surface (external walls and roof). Which results in 30% less energy to heat in winter or cool in summer.

Comfortable, easy and sturdy
Dimensions allowing easy handling and assembly without the use of cranes and heavy machinery. Reliable and sturdy assembly of elements to each other. Possibility of easy routing of installations, communications, etc.

Modified stratodesic geometry with parallel half-arcs – StratoLINE®

The idea is to use pairs of parallel to each other arcs. This will greatly reduce material and time losses. If we also incorporate the size of 1220 mm between the arcs in a pair we will further enhance the savings since this is the standard size of most of the construction sheets (OSB, Plywood, Magnesium Oxide Boards, etc.)      So – we start with the length of 1220 mm. For the base of each dome, we define a polygon with a certain number of sides (this number can only be even one). The smallest dome with this type of base uses 12 sides (1220 mm each) and has a base diameter of approximately 4.7 m. By increasing the number of sides we can get bigger and bigger domes (the best results are achieved if the number is increased by 4). This means we cannot use any arbitrary size for the diameter of a dome but instead the diameter is the function of the number of sides and their length (which in our case is fixed to 1220 mm). By using this method we have created a set of predetermined bases with a different number of sides and diameter. The arcs come in different lengths. The longest ones reach the top of the dome. The shorter ones intersect the longest at a level below the top, and the shortest ones intersect the others at an even lower level.

STRATODESIC DOMES Stratodesic domes are essentially multiple curved arches that come together at the top of the dome via a metal connector.

MODULAR CONSTRUCTION The StratoDOME® dome construction system is an innovative and worthy response to the needs and wishes of customers and is the result of continuous development and numerous experiments, changes and refinements.

INNOVATION WITHOUT ANALOG The product is entirely our development and has no analogue on the world market.

Benefits

There are many great benefits and plusses of such an approach: – Ability to build domes with spherical shape by using whole rectangular sheets of material (OSB, Plywood, Gypsum Boards, Magnesium Boards, etc.) – Opportunity for the introduction of standard modules and sizes – Simple and straightforward use of regular windows and doors – Ease of handling, loading, and transportation – Increased radial stability of the construction – the short pairs of arcs intersect the longer ones under an angel which enhances the rigidity and stability of the dome – A novel and modern look and design of the construction The Golden ratio      The Golden ratio is a universal expression of structural harmony. It can be found in nature, science, art, and all the domains of human existence. After the discovery of the Golden ratio the humanity had achieved immense insight and wisdom. The Golden ratio (also known as Golden mean, Golden section, or Devine proportion) is an irrational number that is a solution to the quadratic equation X2-X-1=0. In mathematics, two quantities are in the golden ratio if their ratio is the same as the ratio of their sum to the larger of the two quantities. It is designated with the Greek letter φ and is equal to 1,618.

The golden section in dome construction      In our case, we are using the Golden ratio to increase the useable height of a dome. In the general case, the domes are erected as half-spheres, so a dome with a 10 m base diameter uses a sphere with a 10 m diameter for its shape. That sphere is ‘cut’ through the center and half of it is put on the ground. The inconvenience, in this case, is that the useful height of the dome decreases quickly from the center of the dome to the outer radius (reaching “0” at the outer perimeter). The solution – to use a bigger sphere and cut it not through the center but at a certain lower level below the center. The result will be a dome with increased useful height and the same base diameter. So with the help of the Golden ratio, we can calculate the exact diameter of the new (bigger) sphere and the exact level at which to cut it. In our example, we want a dome with a base diameter of 10 m. Using the Golden ratio we define that this diameter of 10 m should be exactly 1.618 times bigger than the height of the dome. With some calculations, we will arrive at the numbers of 10225 mm (diameter of the sphere), 1068 mm ( the level of the cut below the center of the sphere), and 6180 mm – the resulting height of the dome (without this modification the resulting height would have been 5000 mm). The model range StratoDOME®      By using the above described Modified stratodesic geometry StratoLINE® in combination with the Golden ratio we have come to a range of possible domes with different diameters and heights. The multitude of models and sizes allows for optimal solutions and utilization of the domes for any need or purpose – from small greenhouses to multi-family buildings, sports halls, or any kind of public facilities.     

If we analyze the data from the table we can arrive at an interesting conclusion – the bigger the dome, the more efficient and cheaper for any square meter of used area. The direct indicator of this fact is the last column of the table – namely the Coefficient of usage, which represents the ratio between the Possible area of a dome to its surface area. For example, the model “Ralitza” has a Coefficient of usage of 0,48 which means that for every 1 m2 of the useful area we should build 2,066 m2 of dome surface area. On the other hand, the model “Cosmos” has a Coefficient of usage of 1,51 – for each 1 m2 of useful area, we will need only 0,66 m2 of dome surface area (which is over 3 times less compared to “Ralitza’).

The smallest domes of the range are built with modules with a standard thickness of 30 cm. They are perfect for greenhouses, garden sheds, glamping units, kid’s playhouses, gazebos, etc. The medium size domes are suitable for seasonal or vacation houses, country houses, villas, small homes, etc. They will come with a standard thickness of the panels of 37 cm. The bigger domes from the model range are intended for full-size family homes. Their external walls will be thick 47 cm by default. An option is added for a panel with increased thickness and usage of natural rye straw as thermal insulation. The biggest domes of the model range allow for the building of public facilities, trade complexes, sports halls, multi-family dwellings, etc.

[mesmerize_gallery id=”mesmerize-gallery-2″ columns=”3″ ids=”190,185,186,187,188,189″ lb=”1″ masonry=”1″ size=”large” link=”file”]

The assembly of a dome with the modules StratoPANEL®     

The modules fit one another vertically by using special mounting ‘ears’ and slots (the protruding ‘ears’ of the lower panel are inserted into matching slots in the upper one). The ‘ears’ are secured into the slots with ‘torx’ screws and PVA glue Class D3. Additionally, the sheathing of the upper panel is fixed to the main plywood construction of the lower one with screws. By stacking the panels vertically some arched “columns” are being formed with different lengths. The longest ones reach the top of the dome (the pole of the globe) while the shorter ones intersect the longest at a lower level at an angle. The shortest ones (if there are such in the model) reach to even lower level.      

The panels of one “column” diverge in height with the panels from the neighboring ones with a resulting checkerboard pattern. Horizontally a panel is fixed to a neighboring one with screws through its “ears”. In the side-walls of each panel are carved channels that are filled with self-expanding mounting polyurethane foam which enhances the rigidity and the overall strength of the dome shell.      

There is an exact sequence for the assembly process and each panel has a particular place and time in it. Our goal is the job to be independent of cranes or heavy lifting machines. A team of four well-trained workers should be able to fully assemble a big dome in a matter of 4-5 work-days.

Foundation and interior architecture construction     

Generally, the domes of the system StratoDOME® should be regarded as a separate and independent structure from the interior construction. If we go even further we can consider them simply as the roof (and a beautiful facade) of the house. What sits beneath this roof is entirely up to the owner. There are three main approaches for building the foundation and interior construction:

• Monolithic construction (‘Wet’ technology)– concrete strip foundation, concrete columns and slabs, brick masonry walls
• ‘Dry technology’ – individual footing foundation with steel ground-screws and post and beam construction with dry-walls
• A combination of the two – concrete strip foundation with post and beam construction and dry-walls     

Although the StratoDOME® structures are extremely strong and stable, they in fact are very light and can be combined with a ground-screw foundation.      The ground-screws are huge steel screws that are galvanized. A typical size is a Diameter – 90 mm, Lenght – 1500 mm, Thickness of the walls – 4 mm. The particular size, shape, quantity, and arrangement of the ground-screws for a given dome house are being specified by an engineer taking into account the size and mass of the dome, the geology, and topology of the plot, etc. The screws are driven into the terrain with the help of a specialized hydraulic machine. Each of the screws has a flange on the upper-end which is used for mounting the wooden beams of the foundation frame (or metal). The frame is elevated over the ground at a certain distance. Water-proofing, thermal insulation, and a vapor barrier are installed. Finally, two layers of OSB, plywood or gypsum-cement boards are laid down. This system can boast excellent thermal characteristics, very good protection from water and moisture (due to the distance between the terrain and the construction), quick and very clean processes ( no digging and concrete jobs, no back-fills, etc.). It has no alternatives when building in protected areas, parks and reserves, wet and marshy areas, landslides, or plots with huge denivelation.

* Source – Internet Not a property of Stratobuild Ltd.

* Source – Internet Not a property of Stratobuild Ltd.     

The interior architecture is then also accomplished using ‘dry’ methods – either prefabricated SIP panels or post and beams skeleton with dry walls (mineral wool for sound-proofing and gypsum boards or plywood, OSB, magnesium, wood paneling). The ‘dry’ system is a fast, clean, and environment-friendly method. Also in case of demolition or dismantling of the building, it is an easy and straightforward process. Shortcomings of the system are the possible vibrations and increased walking noise between the floors, the lack of thermal mass, the limited experience of the builders and the engineers with the ground-screws.      By utilizing the ‘wet’ approach with concrete and clay bricks many of the above-mentioned drawbacks are avoided. It is a well-known and traditional technique, with many experienced builders. The whole construction plays a vital role as a thermal mass and the concrete slabs are far more rigid and noise-free. An important note – in some countries, this is the only way for building a mortgage-eligible house (in Bulgaria for example one cannot take a loan from a bank and use the house as a guarantee if it is a ‘dry’-built).

The cons of the method are – slower and dirtier process, excavation works are needed, the production of the concrete is energy and carbon-intensive, any demolition and removal works are hard and expensive.

Thermal characteristics of the system StratoDOME® One word – EXCELLENT!     

By default, any dome is rather efficient in that domain given the fact it has 30% less surface area when compared to a standard rectangular house with identical volume. If we combine this intrinsic feature of the domes with some proper insulation the result will be spectacular and a very good choice.     

If the dome is built with StratoPANEL® modules in configuration “OPTIMUM” with 35 cm width of the panel sidewall then the U-value is U=0,13 W/m2К (overall heat transfer coefficient).      For the model LEADER for example (a big two-floors dome with a total area of 200m2) these numbers mean that if the dome also has a well-insulated foundation and some standard (but good enough) windows with triple glazing then the heat losses per hour will be only 1900÷2000 watts (given the outside temperature is 0°C and the interior one is 21°C). If these losses are recovered by a heat pump with COP=3 (coefficient of performance) then it will consume only 0.650 KW electrical energy per hour.     

All the calculations are made without taking into consideration neither integral ventilation system StratoVENT® (which basically is an additional insulating layer of air with a thickness of 5 cm), nor the sheathing plus the facade ] StratoBOARD®. Should these layers are also included in the equation then the result will be spectacular.     

If the prospective owner wishes so there is an option of installing in the panels Stone wool only (instead of a combination of Stone and Glass wools). This will further reduce the U-value to 0,10 W/m2K. That is enough for achieving the Passive House standards, with the provision of some additional measures and systems. When building a passive house one should also install an Interior ventilation system with heat recuperation plus some special “passive house-certified” windows and doors. The whole house should be made airtight to a certain level, particular attention is paid to the elimination of all the possible thermal ‘bridges’, and also there should be minimization of windows on the northern side of the house to enhance the solar gains (this applies for the northern hemisphere only), plus some other measures. As complicated as it may sound it is not and it is feasible, so should someone wishes to have a Passive Dome Home – no problem, we can do it!     

Ok, but where can I see a real dome from this system?     

Although we are still a young and small company, we have accumulated over 30 completed orders for dome structures of all sorts and sizes (geodesic, stratodesic, modified stratodesic ones with diameters from 4 to 15.5 m). The system StratoDOME® is our latest product and at this stage, there is no completed dome with this technology, only prototypes of several different panels. The truth is, after we finish the first real dome-home with these types of panels and share some pictures and videos of it there will be no real need for articles like this one. We tend to believe such illustrative materials will be good enough to keep our phones and e-mails busy all the time. At the moment, however, we are still waiting for the first real investor. We are in the process of negotiation with several prospective ones and our belief (and hope) is the first deal is a matter of days or weeks.

Let’s talk about prices!

In conclusion

■ Modular system for building of dome structures StratoDOME®
■ Modified stratodesic geometry with paralel arcs StratoLINE®
■ Smart building module with all the layers preinstalled StratoPANEL®
■ Integral wall ventilating system StratoVENT®
■ Luxury pressure treated burnt-wood facade StratoBOARD®
■ Modular system for building of standard (rectangular) structures StratoCUBE® – in development

Features and benefits

■ An innovative modular system without analogs on the market, organized around the size of 1220×2440 mm (standard for most of the building sheet materials)
■ Utilization of intelligent specific geometry – a set of pairs, formed by parallel arcs
■ Modular panels, completed with all the necessary load-bearing, water-proofing, thermal insulation, and decorative layers
■ The individual panels have precise shape and sizes and fit each other easily and reliably
■ Carefully designed integral wall ventilation system inside the panels
■ Excellent thermal characteristics
■ Sustainable and ecological combination of materials
■ Precision and high-quality production with minimization of material waste
■ The rapid and easy assembly process
■ A wide set of customization options
■ Independence of the ‘building’ from the weather conditions and the seasonal time
■ Feasibility for organizing a mass-scale production with a 24/7 cycle
■ Ease of handling, loading/unloading, and transportation (the size of the predominant modules is 1200x800mm which the size of the standard euro-palet)
■ Extremely suitable for the building of low-energy or passive houses
■ An option for using natural rye straw as a thermal insulation
■ A very good price-quality ratio
■ Suitable for ‘turnkey’ projects irrespective of the location worldwide