Six types of enclosing structures for low-storey houses. Economic comparison

The article represents comparative economic analysis of 6 types of enclosing structures for low-storey houses. They are: masonry, foam concrete blocks laying, glued laminated lumber, timber frame construction, light-weight steel thin-walled framing, glued veneer panel. The last one distinguishes of a high factory readiness level, allow using nonconforming veneer in its compound, may contain underlining depending of the exact region. Analysis was carried out using five-grade scale in several groups of parameters, such as: physical characteristics, building conditions, extra works if needed and maintainability, economical characteristics, probability rate. The results obtained maid it possible to recommend glued veneer panel for universal application.


Introduction
As a rule, materials and structures for detached house are chosen based on such parameters as durability, practicability and price. But a potential buyer hardly ever meets a manufacturer who will pay attention to his products defects or gaps.
Based on Saint-Petersburg State Polytechnical University a comparative analysis of structures for low-storey construction has been already carried out in 2013 [1]. In Federal state budget educational institution of higher education "Moscow state university of civil engineering (national research university)" data obtained during that survey were updated with regard to the 2018 year prices. In addition to this, the economical parameters of new structure (glued veneer panel) [2,3] comparison was carried out.
Glued veneer panel [2,3] is a new structure type with industrial producing and a high factory readiness level. It combines bearing and enclosing functions. This panel consists of two veneer plates, girt and internal dimensioned frame [3], and in whole used for composing a house.
Glued veneer panel classification, which includes wall structures (solid; filled-in panels: doors or window) as well as flooring or covering [2], has a high factory readiness level. That is why it allows to cut down the construction process duration dramatically.

Methods
In order to estimate objectively, general parameters and requirements were chosen: 1. The external side of the wall must satisfy so called "brick finish"; 2. The internal side of wall must satisfy "fine finish"; 3. Thermotechnical characteristics for central federal district value: 3,087 m 2 о С/W; All structures were estimated by five-grade scale: from point five (5)the best result among represented structures, to point one (1)the worst result among represented structures. The comparative analysis was carried out using five groups of parameters [5]. The data obtained were put on into a table.
 The first group of parametersare physical characteristics: 1. Actual thermal transmission resistance (For central federal district -3,087 m 2 о С/W); 2. Fire-resistance (III grade); 3. Ecological compatibility (in accordance with the standards); 4. Noise insulation (in accordance with the standards); 5. Combustible materials presence; Eventually the best result in this group of parameters showed light-weight steel thin-walled framing application. This fact is represented in Table 1. Glued veneer panel as well as timber frame construction lost two because of combustible materials presence in it. 11. Transport expenses (considering massm and volumev); 12. Delivering to remote places; The results for the second group of parameters are represented in Table 2.
 The third group of parametersextra work required/ maintainability: 13. Extra work before internal "fine finish"; 14. Facade finishing changes; 15. Utility systems laying; 16. Special requirements to bearing structure of the building, extra works; 17. Reconstruction capability [6,7]; The results for the third group of parameters are represented in Table 3. Glued veneer panel showed one of the best value by collecting the highest amount of points in all of the criterias.   18. Active area of internal rooms for a house dimensions 8х10m (m 2 ); 19. The building cost with the "fine finish" (rub.); 20. The one m 2 structure costsolid part of the wall (rub.); Estimated cost of all structure was calculated with the use of price-list from March, 2018. The results are represented in Table 4. The best value has glued veneer panel, because of its high factory readiness level and automated process of panels setting-up. Light-weight steel thinwalled framing 22. Arror probability as a result of a "human factor" (meaning the experience level in raising such structures); The analysis of regarding enclosing structures by probability parameters is represented in Table 5.
Special diagrams were composed based on data, obtained during the tables 1-5 analysis (Fig. 1. and Fig. 2.). These diagrams represent total amount of points, which was assigned to each of the enclosing structures for low-storey building and also the average point for each of the structural systems.

Results and Discussion
Based on the investigation worked out we may confirm, that glued veneer panel structure characteristics are comparable to the ones of light-weight steel thin-walled and timber frame houses, which are made with the use of framework technology. The main problem of the light-weight steel thin-walled structures is the necessity to prevent the corrosion attack.
As for timber framesthe main problem is its low level of maintenance [8].

Conclusions
In return glued veneer panel structures has great advantages, such as:  Low structure mass (doesn't require heavy foundation and cranage equipment);  High factory readiness level;  Simple installation process, connection between each other;  Opportunity to use filling grid (nonconforming veneer) in structural elements;  Economical positive effect  High level of maintenance [8]. Conclusion: glued veneer panel may be recommended for the universal appliance in lowstorey houses building.