The main feature of Stratodesic dome covering is it’s shape. It can be implemented as close as possible to a half of the sphere (ball), and such domed building in the respective sizes enraptures and impress – the feelings are similar to those that the pyramids, the Sphinx, the Statue of Liberty arouse.
From an engineering point of view, stratodesic dome covering is a structure without any outer walls which is both the foundation and the roof. These particular circumstances make architects pay more scrupulous attention to the choice of the stratodesic dome covering.
Traditionally while selecting the covering for structure’s roof the following basic factors are taken into consideration:
– Climatic conditions in the construction area
– The roof shape;
– The customer’s financial capacity;
– Architectural and designer’s solutions;
– The bearing capacity of the building (strength characteristics of the supporting carcass);
– Ecological preferences;
– Local building traditions and peculiar properties;
– Local building codes and regulations.
As a rule virtually all types of coatings offered in the market are designed for the roofs that consist of one or several flat sections interconnected at different angles.
If you consider the properties of geometric figure the sphere you can notice that this is a double curvature surface and it can not be deployed to a plane surface without deformation. This circumstance imposes strict limitations on the applied roofing materials and their installation technology.
On the basis of the complex of initial data mentioned above, you can consider several different variations of the stratodesic dome covering.
Thus, it can be:
– Ceramic tiles;
– Natural tile (slate stone);
– Transparent cover (safety glass, acrylic, polycarbonate);
– Bitumen shingles;
– Wooden shingles;
– Awning covering;
– Herbaceous materials (reed roof, straw roof);
– Seamed metal roofs (copper, titanium-zinc, galvanized iron, stainless steal).
Each of them has its own advantages and disadvantages. Let’s try to form an understanding of them in detail.
Stratodesic dome covering: Ceramic tile
A prevalent type of covering in many regions of our planet.
– Service life 30-40 years;
– Resistance to temperature changes;
– Fireproof material;
– No corrosion;
– Excellent waterproofing;
– A high level of soundproofing (noise absorbtion);
– Does not accumulate static electricity;
– Makes a favorable microclimate under the roof: preserves the cool in summer, the warm in the winter;
– Allows the entire multi-layer roof structure to “breathe” and to get rid of the natural moisture condensation;
– The opportunity to implement a designer’s stretch of imagination;
– Simplicity and rapidity of installation;
– Environmentally friendly.
– The necessity of using special types of ceramic tiles:
Grooved ceramic tiles (semi-circular):
– the cost highly depends on the type, the style, the color and the area of the construction;
– fragile material;
– comparatively high weight;
– the need to change the type of the roof if the elevation angle of the roof is less than 20 degrees (for example the stratodestic dome covering with a copper.
Stratodesic dome covering: Natural tile (slate stone)
Slate roof’s advantages:
- this is an ecologically-friendly and natural material;
- durability – the service life of around two hundred years;
- it has high strength;
- it does not fade or change color for the lifetime;
- is resistant to corrosion and ultraviolet light influence;
- it does not react to temperature changes;
- it has a low water absorption;
- it has a high frost resistance;
- it has a high density;
- it does not get deformed when subjected to heat;
- It has an excellent soundproofing.
Another sagnificant advantage of the roofing slate is the ability to be installed on roofs with varying complexity and geometry of the slope. You can make the roof more beautiful and give it an individuality by using tiles of different sizes, shapes and colors. The unique qualities of slate and diversity of installation technology allow to equip the roofs of different levels of difficulty.
Along with all of these slate’s advantages there are some features which make the roof hard to afford for many people:
- The high cost, which is conditional on the difficulty of extraction of raw materials (deep location of rocks) and processing by using high-skilled manual labor in the production (roofing slate costs from 50 to 150 euros per square meter, the price depends on the slate quality, shape and size of the tiles and on the method of installation).
- The proper high-quality slate roof installation requires upscale roofers with a great experience.
- The roofing cost is quite high due to the time consuming and rather complicated process of slate tiles installation.
- The natural slate can be only gray, brown, burgundy and dark green.
- High weight. One square meter of slate can weigh up to 50 kg, and it requires setting up a rafter system of an increased strength
Stratodesic dome covering: Bitumen shingles
The advantages of the bitumen shingles:
- The popularity and availability. Nowdays bitumen shingles take 80% of dwelling house’s sloped roofs market in the US;
- Flexible material – can solve any architectural challenges associated with the roof;
- Easy and fast installation of the roof;
- Excellent waterproofing;
- Resistance to temperature changes,
- fireproof material;
- no corrosion;
- the high level of noise absorbance (soundproofing);
- high resistance to mechanical action;
- extensive choice of textures and colors;
- long service life;
- extensive choice of textures and colors;
- extremely low volume of waste during the process of covering the roof, about 2%.
The disadvantages of the bitumen shingles:
- in case of damage of one of the tiles you will have to change not just one or two tiles but a certain part of the roof (due to the natural conglutination of tiles). However the cost compensates it;
- The installation of bitumen shingles is impossible at temperatures below zero (due to the inefficiency of clutch of the adhesive layer of the bitumen shingle roof);
- The reliability and durability of the bitumen shingles is 25 years;
- The bitumen shingles have to be placed on a solid sub-base made of waterproof plywood which, in turn, is layed on lattice (boards crosswise) that in a combination with a big number of additional elements, increases the cost of the roof *.
* – The thing is that the wooden boards of the lattice may warp during the drying process. So that a layer of plywood should be used to stop the bitumen shingles from repeating the shape of the warped lattice. The material OSB (oriented shavings-wood board – chipboard) can be used for the same purpose). The lining carpet installed on the perimeter of the roof and on the gable has to be the most important part of the bitumen shingle roof.
Stratodesic dome covering: Wooden shingles
- The availability and low cost of raw materials
- The ability to cover the roofs of complicated geometric shapes.
- Environmentally friendly
- Long service life (20-25 years with a protective coating up to 40 years). There are some 300 years old churches covered with wooden shingles in the Ukrainian Carpathian Mountains.
- comparatively lightweight roof (the specific gravity of 15-18 kg / square meter)
- The laboriousness of manufacturing the wooden shingles and mounting roofs
- High flammability
- The wooden shingle roof requires a periodic renovation of protective coatings
Stratodesic dome covering: Bent safety
Skylight — is a transparent structure on the roof emphasizing the originality and the style of any building and attracting an additional influx of natural light. The transparency of forms helps to emphasize the lightness of constructions and gives the building a unique look, and the natural lighting allows to save the significant amount of energy. Skylight has another name – clerestory.
Obviously, a transparent roof – is first of all the beauty, aesthetics, natural lighting, energy saving. But besides the special aesthetic qualities and a special attraction, the glass roof has certain features of exploitation which is also its disadvantage in some degree. On a sunny summer day the structure might transform into a greenhouse as the sun rays freely penetrate into the room and heat it to high temperatures. In this case you will have to use special protective measures for the sunlight isolation.
Besides that the glass has a property to lose its transparency due to the precipitation and dust. Furthermore it’s a problem to make a steep gradient like slate roof and tile roof have.
All these disadvantages are offset by modern materials, technologies and designer’s solutions. The roof is designed the way well adapted for regular cleaning. Robust unbreakable tempered glass does not leave any doubts as for its reliability to all who are beneath it.
The disadvantages should also include the complexity of design and installation.
It has nothing to do with amateurs as this work requires careful and laborious calculations because the glass roof can have almost any form due to its design features. And the more complicated the roof, the more complicated the calculations. Otherwise it makes no sense to talk about the transparent roof service life, not to mention the security of its residents.
Replacing the glass by polymer coatings (acrylic, polycarbonate) also causes a number of problems. It also has negative sides along with all the advantages (cheapness, lightness, etc.)
Firstly, the service life. For acrylic (well known as Plexiglas) it is an average of ten years (under warranty), and for polycarbonate – fifteen years.
Secondly, acrylic would let ultraviolet rays through too well, and if it is not provided with a special covering (which will make it more expensive), then the interior, furniture, walls, floor, etc will fade more intensively in the room which has a glass roof built above.
Third, polymers undergo expansion at high temperatures easier, that is why working with them requires a careful thermal processing, not to mention the high-precision design of polymer transparent roofs. All mentioned above makes the transparent glass roof more expensive than the conventional options.
Stratodesic dome covering: Awning covering
The advantages of awning fabrics are also their lightness, durability, long service life, resistance to the process of decaying, a wide operating temperature range, high grade of light fastness – awning fabric of a high quality almost does not fade in the sun, there is a large selection of colors. PVC fabric is ideal for the digital printing application and it is a good base for self-adhesive pellicles. Tent PVC fabrics are very technological, they are easy to sew together, to paste together, to weld with hot air, hot wedge and high-frequency electricity. The awning fabric provides good operational characteristics at low cost.
The disadvantages of the awning covering applied to the stratodesic dome covering can include a high degree of flexibility which requires a cautious approach to the formation of the contour of the sphere as the slightest shape flaw will cut the eye. It is also necessary to implement constructively complicated, in terms of waterproofing, units of adjunction the edges of the tent to the base, knots of tension and setting the apertures.
Stratodesic dome covering: Concrete
Certainly, the application of this type of covering is a pretty controversial issue, since it requires a lot of calculations and taking many specific factors of these materials’ behavior (both independently and in combination) into consideration. However, it would be wrong not to mention the concrete as an alternative possible covering for the stratodesic dome covering.
In this case, the stratodesic dome covering (lattice) will act as the formwork for pouring the base covering – concrete. If we choose this option then we will get all the advantages of a concrete structure, and we will see a wooden frame with its unique shape and texture in the interior.
A serious disadvantage of this method is its cost as the matter of fact we get two houses instead of one.
The other disadvantage is that in case of using the concrete it is necessary to make the cross-section of wooden supporting structures higher, which also affects the cost of construction.
Stratodesic dome covering: Herbaceous materials
(reed roof, straw roof)
The reed roof is practical and convenient because it is lightweight, environmentally friendly and spectacular as no other. Water reed Phragmites australis is being specially cultivated for harvesting the material for reed roofs. The stems of this breed of reeds are especially strong, moisture-resistant, flexible and durable. Actually, wild reeds growing in different countries also have good characteristics. In fact they have been used in the past, and they are now used for the reed roofs in many settlements on the planet.
The reeds gain the required properties after impregnating with special composition which protects the material from pests and mildew. Reeds have to be processed by fire retardant components – only such reeds can be used as a covering for the roofs and comply with fire safety requirements. Reeds impregnated with fire preventing materials have fire resistance which is not inferior to other roofing materials. It is better to assign the professionals to cover roofs with the reeds because this requires special skills and tools.
Reed roof does not require additional heat, hydro, and vapor barriers.
Reed roof does not need the under-roof ventilation. Pedicellate structure of such roof provides the necessary airflow thereby forming the phenomenon of “breathing roof”.
Properly installed reed roof lasts about 50 years.
The disadvantages can include:
- the high price of the raw material (!)
- the high cost of skilled labor for laying the reeds
- high risk of making a home for unwanted neighbors (mouse, insects, birds, reptiles willingly inhabit in the reeds)
Straw roof emphasizes the “naturalness” in terms of closeness to the nature, imparts unrepeatable specificity and unique colouring to wooden or stone house (cottage) . The straw is of current interest as a roofing material in architectural projects of houses and hotel-type cottages, where it is important to emphasize the original style of construction (where the roof style plays an important role).
Thanks to its original advantages and high technical specifications, the popularity of the straw roofs has been continuously growing for the last several years . The use of natural straw allows to have the coolness in the summer and to maintain the heat in the winter. The straw roof, like the reed one, “breathes” without conducting any specialized roof ventilation diverter. The transcalency of the straw roof corresponds to the transcalency of ten centimeters layer of modern types of insulation, but the advent of various anti fire impregnation (flame retardants) significantly decreases the risk of the straw roof ignition. The straw roof has good water-repellent, thermal and sound insulating properties, which makes it a very popular type of roofing material in the segment.
It’s useful to remember that the slope of the roof must be at least 30 °, unless it is equipped with dormers, or not less than 45 °, if there are such. The slope angle is recommended to be increased up to 50 ° in areas with higher level of snow.
One of the disadvantages is the complexity of the gutter system installation due to the considerable thickness of the covering. This problem is resolved individually for each particular roof.
The other disadvantage is a high cost. Covering the house roof with reeds or straw will cost considerably more than covering with any other material . On the other hand, there is no need to spend money on additional hydraulic and vapor barrier, which means that the final total cost of work will not be much more expensive than installing of any other covering.
Stratodesic dome covering: Seamed metal roofs
(copper, titanium-zinc, galvanized iron, stainless steal)
«Pros» and «cons» of seamed metal roofs:
In addition to reliability, impermeability, strength, modernized system of fastening and high-quality, the seamed metal covering has many other advantages even besides listed above:
- Lightweight material. This is very important because this property allows to use the construction of almost any kind, including the simplest, which might save the funds allotted on construction;
- Materials on their chemical properties are not flammable. And this is a huge addition to the security for you and your property;
- The smooth surface of the roof. The surface’s smoothness allows water to drain quickly and directly, without stopping;
- High flexibility and ductility of the metal compared to other roofing materials. Makes covering the roof of absolutely any shape possible;
- The comparative ease of renovation;
- Quite a long service life – from 20 to 150 years;
- A wide range of colors for the covering
- Anti-corrosive coating
- This type of roofing is good for both ventilated and unventilated coverings and for absolutely any type of base.
- The width and length of the panels in a huge range;
- Direct production of materials takes place either at the factory or at the point of conducting the roofing out of profiled rolled metal through the use of ultra-modern portable equipment;
- The availability of the ventilation system, snow retention, gutter;
- A quick and quite easy mounting of this type of roof.
And, of course, as any type of construction works, seamed metal roofs installation has its drawbacks, though not so many. Here are some of them:
- Quite a high transcalency resulting in the formation of icicles on the roof in the winter;
- The snow and frazil may roll down like an avalanche because of the smoothness of the roof’s surface.
- Poor sound insulation;
- The necessity of installing a lightning rod;
- If you come close you can see unevenness on the metal surface at very detailed consideration, but this does not in any way affect the quality of the welds.
The main disadvantage is a high cost. This is, let’s say, the exclusive, the prestigious roofing material, used primarily in the restoration of medieval castles, buildings that have a historical value. But, nevertheless the exclusive and prestigious items, furnishings and finishes are in demand. There is a segment of consumers who will find these materials the best design solution for the roof covering. Exclusive roofing materials include copper, titanium-zinc and some other roofing metals. All of these materials have a different structure and physical properties, but their main hallmark and feature is their appearance: they impart the building a special aristocratic or bourgeois look. These materials are mainly used in restoration work, as well as for emphasizing the exclusivity of the building and the clanship. Thus, titanium-zinc was used in the restoration of historic buildings in Europe.
Stratodesic dome covering: Titanum-zinc roofing covering
The titanium-zinc is treated as an elite finishing material mostly thanks to it’s performance characteristics. Exploitation of the titanium-zinc roof with no repair is possible for a very long term – 70-100 years. For the same reasons, manufacture of drainage systems out of titanium-zinc is expedient. The titanium-zinc roof does not require painting, thanks to its appearance it fits perfectly into the architectural ensembles of both historical monuments and modern buildings. Apparently, listed above reasons explain the wide use of titanium-zinc in Europe both in the restoration of historical monuments and for modern buildings. The alloy roofing materials, consisting of refined zinc and alloying elements (titanium, copper, aluminum), were used in the restoration of historic buildings in Europe. The last two elements give the material the plasticity, titanium gives a particular strength. Noble patina that appears in time, gives the surface an elegant “vintage” look as its shade varies from whitish to dark gray. In recent years, this material – titanium zinc became popular in the elite facades finishing.
Stratodesic dome covering: Copper roof covering
Copper roofs are historically as traditional as ceramic ones but much more aristocratic. Roof made out of copper is good in all respects – practical, malleable and very light, it is suitable for roofs of any complexity by all characteristics. It is generally recognized that copper is the most lasting and durable material for a gently sloping roof with a slope of 10 degrees. “Normative period” – one and a half century without any significant operating costs. Copper oxides formed on the surface in time protect the roof from any aggressive natural exposure.
This protective patina gradually gains a unique and picturesque texture – malachite tracery that looks like a miracle of the primordial world, still untouched by the human. None of the metal coverings has such interesting and rich palette of natural shades as copper. The copper roof never requires any additional costs for the painting. The copper roof has another important feature that should be considered while installing it. The temperature changes might significantly affect the linear dimensions of the copper. That is why special fasteners and some specific techniques should be employed for covering roof with the copper to compensate for the shifts of the roof . Another important advantage of copper is its environmental friendliness. Not many of roofing materials can be compared with copper in terms of safety for human health.