Robust Solutions for Internal Retrofitting Solid Masonry Walls in Historic Buildings with Regards to Hygrothermal Performance PDF Download

Author: Nickolaj Feldt Jensen
Publisher:
ISBN: 9788778775627
Category :
Languages : en
Pages : 0

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Author: Ekaterina Tzekova
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Historic buildings are less energy efficient than modern structures due to the nature of their construction. Although envelope improvements can reduce operating energy, such retrofits can potentially accelerate the deterioration of the historic facade. Consequently, the challenge is to improve the energy performance while maintaining a durable facade. This research proposes a retrofit approach for historic buildings that addresses both energy consumption and durability of the masonry facade. To improve energy performance, an 1879 historic solid masonry home was retrofitted using an innovative Nested Thermal Envelope Design (NTED). An envelope controlling heat, moisture and air movement was constructed around Core and Perimeter zones that were independently operated. Conditioning the entire house provided 36% space heating energy savings below the Ontario Building Code 2012, while turning off the heat to the Perimeter areas increased savings to 68%. To address durability concerns arising from insulating the masonry walls, the use of a vented airspace installed between the masonry and the thermal insulation was explored. The vented airspace at the first field trial increased the drying potential of the historic masonry during the winter when the brick was most vulnerable to freeze-thaw damage. An estimated 1.1 kg/m2/a was removed at South and East walls. The second field trial showed drying between 4.3 kg/m2/a and 5.7 kg/m2/a at the South and 0.08 kg/m2/a wetting at the North. In situ moisture content levels of the brick varied between 10% - 15% while laboratory testing of similar brick revealed a saturated moisture content of 29%. Both field trials showed that the vented airspace drying potential was influenced by facade orientation and solar radiation levels. An alternative way of constructing the airspace was then tested in the laboratory to explore the use of air permeable insulation in lieu of a clear airspace. Walls constructed with rock wool insulation and vent holes, but with no clear airspace, removed between 52% - 90% of moisture, depending on the insulation density and vent hole area. Walls featuring a clear airspace removed between 59% - 95% of moisture. These laboratory tests showed that enough air was able to move through the air permeable insulation thereby improving the drying potential of the walls.

Author: Nastassja Pearson
Publisher:
ISBN:
Category :
Languages : en
Pages : 0

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Insulating historic masonry buildings will improve thermal performance. However, heritage requirements often limit the addition of insulation to the interior surface. This can lead to colder and wetter walls. Freezing temperatures coupled with high moisture levels in the brick leave the walls susceptible to frost damage. Current retrofit designs attempt to control condensation of interior moisture. However, these designs do not consider exterior moisture sources, nor do they allow for interstitial moisture to be easily removed. This thesis presents an innovative, ventilated masonry retrofit that utilizes drainage and drying to address moisture accumulation issues. Computer simulations are used to assess and compare the hygrothermal performance of typical and ventilated masonry retrofits. The results show masonry moisture contents are reduced when ventilation drying is provided. Further, these simulations show it may be possible to increase thermal insulation levels in historic masonry buildings without damaging the very façade to be preserved.

Author: John Straube
Publisher:
ISBN:
Category : Concrete walls
Languages : en
Pages : 45

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In 1997, CMHC was involved in the renovation of a building with solid masonry walls. Part of the renovation involved the addition of insulation to the interior of the solid masonry walls. This retrofit technique is contentious within the construction industry as it is thought to cause wall durability problems due to freeze thaw cycles, interstitial condensation and thermally induced stresses. Monitoring of the project shows that the wall systems are thus far performing well. CMHC engaged a consultant to use a hygrothermal modelling tool to assess the degree to which the tool can track the wall performance monitoring conducted to date and to assess the long-term performance of the retrofitted wall system. The project found that modelling tools can be set up to provide comparable output results of the conditions actually monitored in the wall assemblies. However, the success of such an effort is highly dependent upon the knowledge of the modeller, the availability of information on material properties and knowledge of the working boundary conditions. The research concluded that once the modelling is reconciled with the monitoring data, the model can then be used to evaluate the impact of variables such as the use of different systems, climate, geographical location, etc. on the performance of the retrofitted wall assembly. The project also made several recommendations with respect to monitoring and modelling procedures that should be used to improve the overall quality of the evaluation.

Author: Canada Mortgage and Housing Corporation. External Research Program
Publisher: CMHC
ISBN:
Category : Dwellings
Languages : en
Pages : 75

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Author: Straube, John
Publisher: CMHC
ISBN:
Category : Concrete walls
Languages : en
Pages : 45

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Book Description
In 1997, CMHC was involved in the renovation of a building with solid masonry walls. Part of the renovation involved the addition of insulation to the interior of the solid masonry walls. This retrofit technique is contentious within the construction industry as it is thought to cause wall durability problems due to freeze thaw cycles, interstitial condensation and thermally induced stresses. Monitoring of the project shows that the wall systems are thus far performing well. CMHC engaged a consultant to use a hygrothermal modelling tool to assess the degree to which the tool can track the wall performance monitoring conducted to date and to assess the long-term performance of the retrofitted wall system. The project found that modelling tools can be set up to provide comparable output results of the conditions actually monitored in the wall assemblies. However, the success of such an effort is highly dependent upon the knowledge of the modeller, the availability of information on material properties and knowledge of the working boundary conditions. The research concluded that once the modelling is reconciled with the monitoring data, the model can then be used to evaluate the impact of variables such as the use of different systems, climate, geographical location, etc. on the performance of the retrofitted wall assembly. The project also made several recommendations with respect to monitoring and modelling procedures that should be used to improve the overall quality of the evaluation.

Author: Baird M. Smith
Publisher:
ISBN:
Category : Dampness in buildings
Languages : en
Pages : 52

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Author:
Publisher:
ISBN:
Category :
Languages : en
Pages :

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?There are many existing buildings with load-bearing mass masonry walls, whose energy performance could be improved with the retrofit of insulation. However, adding insulation to the interior side of walls of such masonry buildings in cold (and wet) climates may cause performance and durability problems. Some concerns, such as condensation and freeze-thaw have known solutions. But wood members embedded in the masonry structure will be colder (and potentially wetter) after an interior insulation retrofit. Moisture content and relative humidity were monitored at joist ends in historic mass brick masonry walls retrofitted with interior insulation in a cold climate (Zone 5A); data were collected from 2012-2015. Eleven joist ends were monitored in all four orientations. One limitation of these results is that the renovation is still ongoing, with limited wintertime construction heating and no permanent occupancy to date. Measurements show that many joists ends remain at high moisture contents, especially at north- and east-facing orientations, with constant 100 percent RH conditions at the worst cases. These high moisture levels are not conducive for wood durability, but no evidence for actual structural damage has been observed. Insulated vs. non-insulated joist pockets do not show large differences. South facing joists have safe (10-15 percent) moisture contents. Given the uncertainty pointed out by research, definitive guidance on the vulnerability of embedded wood members is difficult to formulate. In high-risk situations, or when a very conservative approach is warranted, the embedded wood member condition can be eliminated entirely, supporting the joist ends outside of the masonry pocket.

Author: David Pickles
Publisher:
ISBN: 9781848024427
Category : Historic buildings
Languages : en
Pages : 26

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Book Description
This guidance note provides advice on the principles, risks, materials and methods for insulating solid masonry walls. Traditional solid wall construction is often the most difficult and in many cases the least cost effective part of a building to insulate. However, adding insulation to solid walls can lead to a significant reduction in heat loss but thought and care is needed to make sure the works are appropriate, effective and do not cause long-term problems. Whether applied externally or internally, this type of work can have a significant impact on the appearance of the building. Wall insulation will also alter the technical performance of the solid wall and can either exacerbate existing moisture-related problems or create new ones. In some cases the technical risks of adding insulation to solid walls will be too great and alternative ways of providing a more cost effective long-term solution to improving energy efficiency may be more appropriate. External insulation can be particularly difficult to incorporate into some older buildings as costly ancillary adaptations such as changes to the eaves and verges of roofs, drainage pipework, and window and door reveals are often required. As a consequence such works needs a high degree of quality control. For listed buildings any form of wall insulation is likely to require consent. For many buildings, including those in conservation areas and national parks, external wall insulation will usually require planning permission. This guidance forms one of a series of thirteen guidance notes covering the thermal upgrading of building elements such as roofs, walls and floors.

Author: Alexandra (EURAC research) Troi
Publisher: Birkhäuser
ISBN: 303821650X
Category : Architecture
Languages : en
Pages : 336

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Book Description
This handbook holistically summarises the principles for the energy retrofitting of historic buildings, from the first diagnosis to the adequately designed intervention: preservation of the historic structure, user comfort, and energy efficiency. The content was developed by an interdisciplinary team of researchers. The wide range of different expertise, design examples, calculations, and measuring results from eight case studies makes this manual an indispensable tool for all architects, engineers, and energy consultants.