Factors influencing envelope airtightness of lightweight timber-frame houses built in the Czech Republic in the period of 2006–2019

Böhm, Martin; Beránková, Jitka; Brich, Jiří; Polášek, Marek; Srba, Jaromír; Němcová, Dana; Černý, Robert

doi:10.1016/j.buildenv.2021.107687

Cited by 11 publications

(6 citation statements)

References 29 publications

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“…The improved quality of workmanship has helped to significantly reduce air leakages. In Estonia, prefabrication of timber-based wall structures has been shown to improve airtightness compared to on-site building practice [12] although the Czech study showed the opposite referring to the fact that workmanship quality of on-site building can be regionally very different [15].…”

Section: Discussionmentioning

confidence: 99%

“…Similar results have been achieved for timber-frame low-energy houses in Norway, where measured apartments had airtightness n 50 in the range of 0.5 to 1.3 h -1 [14]. In the Czech Republic, the assessment of 558 newer timber buildings also showed good airtightness with a mean air leakage rate of 1.11 m 3 /(h•m 2 ), a standard deviation below 0.9 m 3 /(h•m 2 ) and a sharp decrease relative to past values [15]. The key factor to low air leakages was the proper installation of a vapour barrier with good workmanship quality and similarly to previous studies of Estonian wooden buildings the compactness of the building envelope and the number of storeys did not have a significant effect on air leakage [12,15].…”

Section: Discussionmentioning

confidence: 99%

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Airtightness of Estonian dwellings – median and base-values for heat loss estimation.

Hallik,

Kalamees,

Pikas

2023

J. Phys.: Conf. Ser.

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The field measurements of airtightness in Estonian detached houses and apartment buildings, conducted between 2003 – 2022, were combined into a large dataset for statistical analysis. The buildings (539 in total) constructed between 1810 and 2022 were classified based on dwelling type, building structure, number of storeys, year of construction, energy classification and compactness factors. The data was statistically analysed to determine the mean and median air leakage rates at 50 Pa and tested (Kruskal-Wallis test with post-hoc Conover test) for significant differences within the grouping factors. Buildings constructed after the enforcement of the compulsory Energy Performance certification have on average across all building structure types significantly lower mean air leakage rate (1.6 m3/(h·m2)) than older buildings (6.9 m3/(h·m2)), although log-wood and brick construction types feature slightly higher average air leakage rate. Previous experience with air leakage measurements help to achieve better airtightness on building site. A systematic and recurring measurement practice within a single construction company leads to significantly lower air leakage also for new concrete buildings. Detailed assessment of older buildings showed that all timber-based construction types had significantly higher air leakage rate along with higher variability compared to precast large concrete panel stone and small block wall and brick buildings. All apartment buildings built before 2010 had significantly lower air leakage rate compared to detached houses while there was no difference in new buildings. Along with the mean and median value a base value of air leakage rate q E50,base was calculated for all construction types and age groups including 50% of measured buildings around the mean within each group with 84 % confidence interval. The calculated mean, median and base values of air leakage rate provide a way for more accurate heat loss estimation at the district-level or building-level modelling of energy saving potential of different retrofitting strategies based on building age, construction type and other building information data.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Airtightness of Estonian dwellings – median and base-values for heat loss estimation.

Hallik,

Kalamees,

Pikas

2023

J. Phys.: Conf. Ser.

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“…According to multiple studies, envelope structures consisting of wood or steel frame have worse airtight results than those built of concrete, bricks, or masonry [11][12][13][14]. Moreover, there is a significant difference between prefabricated walls (higher airtightness) and those built on-site [15].…”

Section: Introductionmentioning

confidence: 99%

Airtightness of a Critical Joint in a Timber-Based Building Affected by the Seasonal Climate Change

2023

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The airtightness of buildings is an essential topic regarding energy preservation. The development of new and more sophisticated materials and technology approaches is inevitable. Uncontrolled infiltration is undesirable in buildings with lower energy demands with regulated ventilation. Envelope structure, building method, quality, and others are the main factors influencing the airtightness of the building. However, the correlation between airtightness and climatic factors is less known and researched. This paper comprises measurements of a critical timber-house corner in climatic chambers. It captures the correlation between airtightness and gradual temperature and relative humidity adjustments, simulated from the exterior side. The initial timber moisture content was 12%, and during the experiment it increased with the exterior conditions to 18%. Afterward, we simulated conditions causing a humidity decrease while measuring airtightness. The drying process caused a decrement in airtightness by 18%. In addition to this experiment, this paper also analyses two methods of an airtight membrane connection—constricting or taping the contact. The discrepancy between those two methods was more than 21% in favor of tape.

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“…Examples of the occurrence are, among others, the connection of a roof and external wall, the placement of facade and roof windows and external doors, the connection of a balcony with a ceiling, rims, and lintels, and the connection of a foundation wall with a floor on the ground and an external wall. To minimize the presence of thermal bridges, the continuity of the insulation should be maintained along the building envelope [4]. A seamless connection of the floor, wall, and roof thermal insulation should be designed.…”

Section: Introductionmentioning

confidence: 99%

Energy Simulations of a Building Insulated with a Hemp-Lime Composite with Different Wall and Node Variants

et al. 2022

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Thermal bridges constitute a significant share in the overall heat losses through building partitions. This is an important issue not only in traditional but also ecological buildings, where the load-bearing structure is often a wooden frame. In partitions insulated with hemp-lime composite, the skeleton is usually hidden in the insulation. However, in some nodes or jambs, wooden elements may be exposed or have a large cross-section, intensifying the heat transfer. This work presents simulations of energy demand in a single-family building insulated with hemp-lime composite, using the BSim dynamic simulation program. The calculations take into account the linear thermal transmittance of structural nodes modeled in the THERM program. The energy demand for heating and the share of thermal bridges in the heat loss of the entire building were calculated for different locations of the structural framework in the walls, as well as the size and number of windows. The share of thermal bridges in heat losses was about 10%, and the differences in energy demand for heating using various frame locations in the wall were negligible.

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Factors influencing envelope airtightness of lightweight timber-frame houses built in the Czech Republic in the period of 2006–2019

Cited by 11 publications

References 29 publications

Airtightness of Estonian dwellings – median and base-values for heat loss estimation.

Airtightness of Estonian dwellings – median and base-values for heat loss estimation.

Airtightness of a Critical Joint in a Timber-Based Building Affected by the Seasonal Climate Change

Energy Simulations of a Building Insulated with a Hemp-Lime Composite with Different Wall and Node Variants

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