Brick Veneer Research Articles

Cyclic loading test for brick masonry veneer anchored to reinforced concrete walls

Despite the importance of seismic design for brick masonry veneer anchored to reinforced concrete (RC) backup walls, the effects of several design parameters on the seismic capacity of such nonstructural component remain unexplored. In this study, material tests and cyclic loading tests were performed to investigate the seismic performance of connection for the brick masonry veneer wall anchored to a RC back-up wall under excitation. To this end, tensile tests were first carried out for each element comprising the unit connection to investigate the basic material strengths. A cyclic loading test was then performed on brick-tie-concrete subassembly to investigate the seismic capacity of the unit connection subjected to seismic loads. The major test parameters included the type and embedded depth of veneer anchor, type of mechanical fastener, compressive strength of concrete, and use of insulation. Based on the material strengths and unit specimen strength, the failure mode and seismic capacity of the unit connection for brick veneer anchored to concrete block were evaluated. The test results showed that the presence of the insulation significantly affected the seismic capacity. Based on the test results, design recommendations were proposed to improve the prescriptive design or general design in current practice for brick masonry veneer walls.

New Coal Char-Based Building Products: Manufacturing, Engineering Performance, and Techno-Economic Analysis for the USA Market

Common building products, i.e., thin brick and stone veneer, add the look of brick walls or the enduring charm of natural stones into buildings and houses without imposing a substantial increase in structural load. This study investigates the mechanical strength, durability, and economic feasibility of producing innovative char-based thin bricks and stone veneers. The char-based thin brick vacuum treated with hydrophobic liquid exhibits water absorption rates within the 4–7% range, displays durability against 50 freeze–thaw (F-T) cycles, and maintains a saturation coefficient below 0.6. In contrast, commercial thin bricks have water absorption of 9–12%. Treated char-based stone veneer has water absorption of 5.3% and an average compressive strength of 19.2 MPa, maintains its structural integrity throughout 50 F-T cycles, and exhibits a negligible linear shrinkage of approximately 0.01%. In contrast, commercial stone veneers have water absorption of 10–16%. These engineering properties meet the criteria as per ASTM standards C1088 and C1670 for thin brick and stone veneer, respectively. A techno-economic study was preliminarily conducted to examine the potential cost efficiency and cash flow in manufacturing these char-based building products. The manufacturing cost of USD 25.83 is lower than the average market price of 64.65 USD/sq. m. for thin bricks. The manufacturing cost of USD 32.65 is lower than the average market price of 129.17 USD/sq. m. for stone veneers. These comparisons present a compelling economic advantage for their commercialization. This comprehensive study has demonstrated the advantages of sustainable char-based stone veneers and thin bricks regarding engineering performance and economic benefits.

Hygrothermal performance of corners and floor junctions of timber-framed exterior walls: a simulation study

Corners and basement junctions of different timber-framed walls were studied by computer simulation using Delphin 5.8.3 software. Wooden cladding and brick veneer were compared with each other, as well as different wind barrier solutions. Both internal and external corners were studied, first assuming them airtight and then modelling an air leak. Simulations were performed both in present and future climate conditions. According to the results, the walls with wooden cladding and brick veneer had a big difference in their hygrothermal behaviour. Mould index rose considerably after construction in sole plate of brick clad wall, even if the plate was originally dry. Wet sole plates dried up very slowly. Almost all corner junctions of walls with wooden cladding performed well when there was no air leak. Corners of brick clad walls were more problematic. With an air leak, all studied walls developed considerably high mould indices, underlining the importance of building airtightness.

Impact of different water penetration criteria and cavity ventilation rates on the risk of mold growth in timber frame walls with brick veneer cladding

The present paper investigates the impact of different water penetration criteria on the risk for damage in a common type of building envelope in Nordic countries, timber frame walls with brick masonry veneer. The studied walls are evaluated based on one damage criterion, the risk of mold growth. The study investigates several parameters: water penetration criterion, type of moisture source (uniformly distributed or point source) and its position in the wall assembly, air change rate (ACR) (representing different workmanship scenarios), wind-driven rain (WDR) coefficient, and locations (Gothenburg and Rensjön, with different average annual rainfall and temperature). Two criteria on how to implement water penetration are compared: a) a commonly accepted reference model that assumes one percent of all wind-driven rain deposited on the façade to penetrate the clay brick cladding, and b) a new criterion stating that 3.8% of WDR penetrates when the water content of the brick veneer cladding is above 90% of its saturation capacity. The simulation is done for a thirteen-year period with WUFI Pro and WUFI 2D. The results indicate the greater importance of implementing water penetration compared to ventilation in cavities. Further, the findings suggest that the moisture source’s location significantly impacts the mold growth risk. The results also show that the choice of the WDR coefficient affects the risks, which suggests that this factor needs accurate quantification for hygrothermal analyses. The results in this study suggest that an effective measure for the design/maintenance of such walls should incorporate: a) limiting the amount of water penetrating through the cladding, particularly stopping water from reaching the sensitive elements, i.e., timber studs, b) removing extruded mortar stemming from poor workmanship, if any, which may act as a capillary bridge.

Accuracy of using Moisture Reference Years for assessing the Long-Term Moisture Performance of Wall Assemblies

Hygrothermal simulation is commonly used to understand the effects of climate loads on wall assemblies. This helps determine the risk of deterioration of wall components due to factors such as mould, wood rot, corrosion, and other modes of degradation. Owing to the lengthy computing time and high cost of undertaking simulations over extended periods of time in excess of 30 years, common practice is to select representative years, generally referred to as moisture reference years (MRYs), amongst the climate data series with the assumption that they would provide results similar to that obtained using the entire climate data series. In this study, simulations were performed for a wood-frame wall having brick veneer and fibreboard as cladding and located in 4 Canadian cities using both a 31-year climate data series and MRYs. The mould growth index on the outer layer of the sheathing panel was used as the performance indicator to permit comparing the moisture performance obtained using the long-term climate series to that obtained using MRYs. It was determined that different strategies should be implemented to analyse the MRY simulation results for different types of wall assemblies to obtain a similar conclusion as that of 31-year simulations.

Structural behavior of steel tie connections in masonry veneer walls: Proposal of a simplified approach for practice

Steel ties perform a key structural role in ensuring the stability of buildings façades built with brick masonry veneer walls. These elements are responsible for transferring the loads acting on the veneer wall to the main structure, which typically consists of masonry infill walls used in reinforced concrete frames buildings. Such constructive system is common in Portugal and other Mediterranean countries where the seismic hazard is high. In the event of an earthquake, the ties have to transfer the out-of-plane loads and are subjected to significant tension and compression stress. The characterization of the seismic behavior of these tie connections is an insufficiently explored topic. Despite the codes available for the design of brick masonry veneers and ties, recent earthquakes brought to light the seismic vulnerability of this constructive system. The present paper proposes a simplified spring numerical model validated with experimental results. The simplified model can be applied to perform numerical analyses of greater scale (e.g. to analyze full façades of buildings), which can help to optimize the design. Finally, the paper identifies a common construction problem, which is the probable misalignment of the mortar joints of the masonry walls. A construction solution is proposed by the authors.

Wind-driven rainwater penetration through brick veneer with and without surface treatments

Rainwater penetration through building enclosures is a critical factor affecting building performance and durability. Understanding and assessing rainwater penetration and its prevention through the brick veneer and brick wall is crucial to controlling and avoiding moisture-related problems such as fungal growth and damages in interior structural elements. Addition of a layer of clay bricks as a cladding (veneer) to the exposed surface of a building envelope is a common practice in Canada. Though clay brick veneer provides adequate weather resistance for the building, it does not offer complete resistance to wind-driven rainwater penetration unless other measures such as surface treatment or additional layer of cladding is incorporated. Hence, studying the aspects of resistance to water penetration of commonly used cladding systems is of utmost importance. This paper presents outcomes of an experimental study conducted to determine water penetration of brick veneer specimens with two different initial rate of absorption values, two void amounts, and three different surface treatments. The study found that the surface treatment is a viable method for improving the resistance of water penetration inside the building envelope and the plastering was found to be the most effective method. The study also found that the initial rate of absorption and thickness of the bricks affect the water penetration; however, void amount in the brick does not affect much on water leakage of the masonry walls. • This paper presents various options to minimize and stop water penetration into the building envelope. • Three different surface treatments of brick veneer on rainwater penetration were studied. • Surface treatment with plaster is able to completely prevent water penetration. • Between the two water repellent treatments, water-based water repellent showed a better performance. • The paper also presents effect of IRA and void percentage of clay bricks on rainwater penetration.

Retrofit of Building Façade Using Precast Sandwich Panel: An Integrated Thermal and Environmental Assessment on BIM-Based LCA

The study conducts a comprehensive life cycle assessment (LCA) of precast sandwich panels by integrating operational and embodied phases detailing thermal efficiency and environmental impacts. The analytical regression model is developed for climatic diversity and design variables using the energy rating tool FirstRate5 to compare with a conventional brick veneer construction. LCA is performed on the building information modeling (BIM) platform to connect operational energy and express the relative embodied impacts of insulation constituents, compressive strength, reinforcement, and mix design. Monte Carlo simulation shows significant advantages of concrete sandwich panels in reducing operational H/C loads over building service life. LCA reveals a 100 mm thick external precast concrete wall with 50% fly ash reduces CO2 emission and energy demand by 54.7% and 75.9% consecutively against the benchmark. Moreover, it comprises 84.31% of the total building mass, accountable for only 53.27% of total CO2 emission and 27.25% of energy demand, which is comparatively lower than other materials. In the case of selecting lining insulation, a broader benefit is identified for extruded polystyrene (XPS) and expanded polystyrene (EPS) boards due to their relative weight, thickness, and environmental impacts. Representative equations of energy efficiency and impact assessment will assist in adopting sandwich panels for new construction and refurbishment with relative dimensions.

Resilience of Canadian residential brick veneer wall construction to climate change

Canada employs a prescriptive-based code for residential buildings. The minimum requirements as prescribed in the 2015 National Building Code were developed based on historical climate which was assumed static. It is now evident that the climate is changing and it is anticipated that wind-driven rain events will be more frequent, of longer duration and of increased intensity. These changes may affect the durability of wall assemblies designed following the minimum requirements set in the building code. In this study, the moisture performance of residential wood-framed walls using brick veneer as cladding and meeting the minimum requirements of the National Building Code were evaluated for different climatic regions of Canada. Various types of brick veneer were evaluated using hygrothermal simulations and projected future climate loads. The mold growth index on the sheathing panel was used as performance indicator. Results showed that the future moisture performance of brick veneer walls depends on the brick properties and varies with climatic region. In particular, for brick veneer having relatively high water absorption coefficient and lower vapor permeability, there may be a heightened risk to mold growth in the future if used in locations on the east and west coasts of Canada. As consequence, the minimum requirements for brick veneer walls may need to be reviewed in these locations to ensure their long-term performance.

Trends in Residential Building Materials in the State of Victoria

As the population in Victoria continues to grow, there has been a corresponding increase in building approvals across the State. Houses characterised as low-rise residential buildings often take the largest share of these approvals, with incessant residential building activities being driven by record low interest rates. Low-rise residential buildings comprise various building forms that use a number of specified construction materials to construct the building envelope and other structural and non-structural elements. As materials used for constructing residential building envelopes continue to evolve, these materials must be fit for purpose, and satisfy design criteria and performance requirements, while being aesthetically pleasing. This research analyses the trend in construction materials used in building envelopes of low-rise residential buildings using data from building permits issued between 1996 to 2019. The trend analysis shows that traditional double brick wall systems and suspended timber floors have reduced in popularity for houses built in the 21st century. The analysis also shows that brick veneer wall cladding systems built over slab-on-ground footings is the dominant construction form while the roof cladding material is influenced by geographical location. Insights from the data analysis indicate very little innovation has emerged in materials for residential building envelopes despite its crucial role in providing thermal comfort for inhabitants. Results from this research will serve as a basis to provide quantitative assessment of the trend in materials resource; provide insights about the impact of new building envelope products on existing industries; and perspectives on materials for future building envelopes.

Fire resistance of external light gauge steel framed walls with brick veneer cladding

This paper presents the details of an experimental study to evaluate the fire resistance of external light-gauge steel-framed (LSF) walls with brick veneer cladding. Brick veneer is one of the most opted external cladding in Australian low to mid-rise construction for their aesthetic appeal with load bearing light-gauge steel framing or timber framing as the structural backing. However, no experimental data is available on the fire resistance of brick veneer walls with LSF backing. This experimental study included five small-scale non-load bearing fire tests of LSF walls with brick veneer cladding exposed to the standard fire. Two test walls with brick veneer constructed using normal and high temperature mortars were tested with fire from the external side (brick veneer exposed to fire), and the third wall constructed using normal mortar was tested with fire from the internal side (plasterboard exposed to fire). The first two test walls were also exposed to a second fire exposure. This study also included detailed elevated temperature thermal property tests of brick and the two types of mortar used in the fire tests. Brick veneer cladding provided very good protection to the thin-walled steel studs. No failure was observed in all the five fire tests giving fire resistance level of more than 240 min. Structural failure times of load bearing walls were also estimated to be more than 240 min for fire on the external side under load ratios of up to 0.4 while it was 30 min for fire on the internal side.

Hygrothermal Modelling of the Differences between Single versus Variable Relative Humidity Vapour Diffusion Resistivity Properties of Pliable Membranes

The study investigates through hygrothermal modelling the effect of different boundary conditions and varying measured vapour diffusion resistivity values on the hygrothermal performance of five pliable membranes. Previously, this research quantified the variable water vapour diffusion resistivity properties of five different pliable building membranes. The membranes were assessed under varying humidity conditions using the gravimetric wet and dry cup test method. The varying humidity conditions better represent the boundary conditions experienced by materials in the building envelope. The pliable membranes include two permeable, two impermeable, and one variable products, which are commonly used to provide air and vapour control layers in the construction of framed external wall systems. This article focusses on the transient hygrothermal modelling of each of these membranes as a component of a typical timber-framed, clay brick veneer external wall system. The simulations were completed for three different climate types, namely, hot and humid, temperate, and cool-temperate with snow, and with a northern and western orientation. The results from hygrothermal and bio-hygrothermal simulations highlighted different responses subject to climate type and orientation. These results show that there are significant differences in simulated moisture and mould growth risk between the results of pliable membranes with single vapour resistance factor value and pliable membranes with multipoint vapour resistance factor values.

Numerical Simulation of the Tension–Compression Behavior of Tie Connections in Brick Masonry Walls

Brick masonry veneer walls connected to infill walls inserted in a reinforced concrete (RC) frame are a common constructive system in Portugal. The stability of the veneer wall is ensured by ties that make the connection with the masonry infill walls. These ties enable the transferring of out-of-plane loads to the main structure due to wind, and particularly due to earthquakes. However, the characterization of the seismic behavior of these tie connections is an insufficiently explored topic. The present paper shows a numerical investigation that aims to simulate experimental results of tension and compression tests performed on masonry prisms connected by means of steel ties. The main objective of the present research is to obtain a better understanding of the complex structural behavior of this specific construction system to then develop simplified numerical tools to be used in engineering practice for the seismic design and retrofitting of brick masonry veneer walls. The numerical results match well the experimental ones, and the validated approach can be used in the future to carry out parametric analyses to evaluate the influence of material and geometric properties of the tie and masonry, as well as the type of action and construction details.

Seismic damage and life cycle cost assessment of unanchored brick masonry veneers

This paper develops the seismic damage models of brick masonry veneer attached to the masonry infill without metal ties and assesses the life cycle cost of veneers subjected to earthquake excitation. Even though anchoring veneers to the backup wall has been prescribed in recent building codes, most of the existing brick veneers in seismic prone areas around the world lack the anchoring details. Besides, the damage and consequence models of masonry façades have not been presented in the FEMA-P58 database restricting detailed performance evaluation of buildings with unanchored masonry veneers. This study develops detailed finite element models to simulate various failure modes of the masonry veneer units and joint interface. The modeling procedure is validated by comparing the capacity curve and the crack pattern of simulation with those of an experiment conducted on a masonry brick wall in the literature. Then, a new procedure based on the endurance time dynamic analysis is proposed to generate fragility models for veneers and the backup masonry infill with lower computational demand than conventional methods. It is found that existing of the opening decreases the median collapse capacity of the façade by 25%. To demonstrate application of the developed fragility models, the life cycle costs of three types of veneer, brick façade, and two types of curtain walls, for a ten-story steel building are estimated using the FEMA-P58 procedure. It is concluded that using masonry veneer induces considerable damage and loss at lower levels of earthquake intensity compared to the curtain wall. Despite the lower initial cost of masonry façade, the total loss associated with these façades is almost 70% greater than the total loss of curtain walls.

Development of moisture reference years for assessing long-term mould growth risk of wood-frame building envelopes

A moisture reference year (MRY) is generally used to assess the durability, or long-term performance of building envelopes within a long climatological time period, e.g. a 31 year timeframe. The intent of this paper is to develop a set of moisture reference years that can be used to assess risk to the formation of mould growth in wood-frame buildings over the long-term. The set of moisture reference years have been developed based on 15 realizations of 31-year climate data. Replicated Latin Hypercube Sampling is applied to select 15 sub-realizations with 7 representative years having different levels of moisture index (MI) from each realization. Thereafter, hygrothermal simulations are performed for a brick veneer clad wood-frame wall assembly using the 15 sub-realizations; that sub-realization which produces the highest value of maximum mould growth index over 7-year period is selected as the MRY. The selection process is then implemented for all 15 realizations of the 31-years of data sets, from which 15 sets of 7-year long MRYs are selected to represent the original 15 realizations. It is shown that the 15 sets of 7-year long MRYs can produce the same value of maximum mould growth index as well as the uncertainty as compared to the original 15 realizations having a 31-year climate data set.

Effects of climate change on the moisture performance and durability of brick veneer walls of wood frame construction in Canada

The objective of this study was to assess the potential effects of climate change on the moisture performance and durability of red matt clay brick veneer walls of wood frame construction on the basis of results derived from hygrothermal simulations. One-dimensional simulations were run using DELPHIN 5.9 for selected moisture reference years of the 15 realizations of modelled historical (H: 1986-2016) and future (F: 2062-2092) climate data of 12 Canadian cities. The mold growth index at the outer layer of the OSB sheathing panel was used to compare the moisture performance under H and F periods. Results for the base design that meet the minimum requirements of the National Building Code of Canada showed that cities within the interior of the country, characterized by a low annual rainfall, are less likely to develop significant mold growth under H and F periods, whereas cities in coastal areas, characterized by high annual rainfall, present a heightened risk to mold growth under both H and F periods. For cities located on the west coast, a possible solution could be to use a 38-mm ventilated drainage cavity as this measure would help dissipate moisture from within the cavity. On the east coast, apart from using a 38-mm ventilated drainage cavity, other measures aiming at reducing the wind-driven rain deposition (i.e., increasing overhang ratio or the height of the roof) could be introduced. However, the feasibility of such measures needs to be considered in respect to whether these are to be implemented as part of a new building or retrofit of an existing one.

Enhancement in Free Cooling Potential through Evaporative Cooling Integrated with PCM Based Storage System: Experimental Design and Response Surface Approach

PCM-based thermal energy storage in conjunction with an electric air source is offered as a potential tool to support domestic energy demand reduction while at the same time minimizing supply challenges for the electricity utilities. This study is to advance the use of hybrid ventilation concepts in building design by assessment of PCM storage unit with an operation of the evaporative ventilation system. RSM CCD methods was employed to evaluate and optimize the individual/interactive effect of parameters on the cooling efficiency of the proposed system. Optimization results indicate that maximum efficiency can be achieved when inlet air temperature and velocity of 28 oC and 1.2 m/s when PCM coils number was set to 28, respectively. This research compared the effectiveness of the passive and free cooling application of PCM when applied to a duplex brick veneer building in Melbourne. It was observed that during the studied period, the free cooling application method is more effective than the passive application method in reducing the peak zone temperature.

Energy conservation assessment of traditional and modern houses in Sydney

ABSTRACT This study simulates various residential housing construction scenarios, including improved and standard fibro, brick veneer, double brick and fibro with improved flooring. The total heating and cooling energy requirements for each scenario are simulated with a computer program to determine which one is most energy efficient. In the simulation models, construction types and passive solar and energy efficient design strategies (PSEEDS) were varied while other parameters such as wall and roof thickness, windows sizes and general layout were kept constant. The study shows that a standard fibro house had the highest cooling and heating energy requirements (30,721 kWh/yr). The improved reverse brick veneer house had the lowest energy requirement of 9,628 kWh/yr. Amongst all the construction scenarios, the total energy required for cooling was higher than that required for heating. The results show that improved brick veneer, reverse brick veneer and double brick houses have the lowest net energy requirements for heating and cooling compared to the corresponding standard houses. The results indicate that the thermal mass (measured by R value) and PSEEDS incorporated in the construction have significant impact on the energy consumption. Incorporating these design features in the construction of a house can reduce the heating and cooling energy requirements by as much as 69%.

Alternative Method to the Replication of Wind Effects into the Buildings Thermal Simulation

To design energy-efficient buildings, energy assessment programs need to be developed for determining the inside air temperature, so that thermal comfort of the occupant can be sustained. The internal temperatures could be calculated through computational fluid dynamics (CFD) analysis; however, miniscule time steps (seconds and milliseconds) are used by a long-term simulation (i.e., weeks, months) that require excessive time for computing wind effects results even for high-performance personal computers. This paper examines a new method, wherein the wind effect surrounding the buildings is integrated with the external air temperature to facilitate wind simulation in building analysis over long periods. This was done with the help of an equivalent temperature (known as Tnatural), where the convection heat loss is produced in an equal capacity by this air temperature and by the built-in wind effects. Subsequently, this new external air temperature Tnatural can be used to calculate the internal air temperature. Upon inclusion of wind effects, above 90% of the results were found to be within 0–3 °C of the perceived temperatures compared to the real data (99% for insulated cavity brick (InsCB), 91% for cavity brick (CB), 93% for insulated reverse brick veneer (InsRBV) and 94% for insulated brick veneer (InsBV) modules). However, a decline of 83–88% was observed in the results after ignoring the wind effects. Hence, the presence of wind effects holds greater importance in correct simulation of the thermal performance of the modules. Moreover, the simulation time will expectedly reduce to below 1% of the original simulation time.

The Significance of Sky Temperature in the Assessment of the Thermal Performance of Buildings

Energy-efficient building design needs an accurate way to estimate temperature inside the building which facilitates the calculation of heating and cooling energy requirements in order to achieve appropriate thermal comfort for occupants. Sky temperature is an important factor for any building assessment tool which needs to be precisely determined for accurate estimation of the energy requirement. Many building simulation tools have been used to calculate building thermal performance such as Autodesk Computational Fluid Dynamics (CFD) software, which can be used to calculate building internal air temperature but requires sky temperature as a key input factor for the simulation. Real data obtained from real-sized house modules located at University of Newcastle, Australia (southern hemisphere), were used to find the impact of different sky temperatures on the building’s thermal performance using CFD simulation. Various sky temperatures were considered to determine the accurate response which aligns with a real trend of buildings’ internal air temperature. It was found that the internal air temperature in a building keeps either rising or decreasing if higher or lower sky temperature is chosen. This significantly decreases the accuracy of the simulation. It was found that using the right sky temperature values for each module, Cavity Brick Module (CB) Insulated Cavity Brick Module (InsCB), Insulated Brick Veneer Module (InsBV) and Insulated Reverse Brick Veneer Module (InsRBV), will result in 6.5%, 7.1%, 6.2% and 6.4% error correspondingly compared with the real data. These errors mainly refer to the simulation error. On the other hand using higher sky temperatures by +10 °C will significantly increase the simulation error to 16.5%, 17.5%, 17.1% and 16.8% and lower sky temperature by +10 °C will also increase the error to 19.3%, 22.6%, 21.9% and 19.1% for CB, InsCB, InsBV and InsRBV modules, respectively.