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Internal Retrofitting with Hemp-Lime on Brick Masonry : a Study to Prevent Damage Caused by Sodium Sulphate

Balksten, Kristin and Strandberg, Paulien LU orcid (2021) Fifth International Conference on Salt Weathering of Buildings and Stone Sculptures, SWBSS 2021 p.277-286
Abstract
In Sweden there are a great number of neo-gothic churches built in brick masonry
around 1870-1910. They are constructed as massive masonry walls with façade
bricks attached to a core of massive red bricks. In the majority of these churches
there is a presence of sodium sulphate causing salt damages. The source of the salts is known to be the red masonry bricks and the damage occurs both internally and externally on the walls. Damages occurred already after a couple of years after the churches were built and ever since they caused expensive renovations with little or no durability. As the sodium sulphate crystallizes inside the plaster the damages cause spalling of the surface.
Since 2016 a method to prevent or delay salt... (More)
In Sweden there are a great number of neo-gothic churches built in brick masonry
around 1870-1910. They are constructed as massive masonry walls with façade
bricks attached to a core of massive red bricks. In the majority of these churches
there is a presence of sodium sulphate causing salt damages. The source of the salts is known to be the red masonry bricks and the damage occurs both internally and externally on the walls. Damages occurred already after a couple of years after the churches were built and ever since they caused expensive renovations with little or no durability. As the sodium sulphate crystallizes inside the plaster the damages cause spalling of the surface.
Since 2016 a method to prevent or delay salt damages has been studied and evaluated. By adding a layer of insulation on the internal wall the microclimate on and nearby the plaster surface can be changed and the damages caused by crystallization decrease. When adding an insulating layer made by hemp-lime plaster before adding the lime plaster the salts cause less visible damage to the internal plaster.
Full-scale test surfaces have been made both in the laboratory and inside two
churches. After two and three years respectively, there are no visible salts causing
damages inside the churches, where salts previously came back directly after each
renovation. In the wall in the laboratory at Lund University the bricks where contaminated with sodium sulphate and internally rendered with hemp-lime plaster with a lime plaster surface finish. Even though there are lots of salt-related damages externally there are thus far, more than two years after construction, no signs of any damage internally. (Less)
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type
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publication status
published
subject
host publication
Proceedings of SWBSS 2021 : Fifth International Conference on Salt Weathering of Buildings and Stone Sculptures - Fifth International Conference on Salt Weathering of Buildings and Stone Sculptures
pages
277 - 286
conference name
Fifth International Conference on Salt Weathering of Buildings and Stone Sculptures, SWBSS 2021
conference location
Delft, Netherlands
conference dates
2021-09-22 - 2021-09-24
ISBN
978-94-6366-439-4
language
English
LU publication?
yes
id
9f57f8ea-a8e5-4319-b9f8-9cea0d21b7a7
date added to LUP
2022-10-11 11:45:22
date last changed
2023-03-21 15:34:09
@inproceedings{9f57f8ea-a8e5-4319-b9f8-9cea0d21b7a7,
  abstract     = {{In Sweden there are a great number of neo-gothic churches built in brick masonry<br/>around 1870-1910. They are constructed as massive masonry walls with façade<br/>bricks attached to a core of massive red bricks. In the majority of these churches<br/>there is a presence of sodium sulphate causing salt damages. The source of the salts is known to be the red masonry bricks and the damage occurs both internally and externally on the walls. Damages occurred already after a couple of years after the churches were built and ever since they caused expensive renovations with little or no durability. As the sodium sulphate crystallizes inside the plaster the damages cause spalling of the surface.<br/>Since 2016 a method to prevent or delay salt damages has been studied and evaluated. By adding a layer of insulation on the internal wall the microclimate on and nearby the plaster surface can be changed and the damages caused by crystallization decrease. When adding an insulating layer made by hemp-lime plaster before adding the lime plaster the salts cause less visible damage to the internal plaster.<br/>Full-scale test surfaces have been made both in the laboratory and inside two<br/>churches. After two and three years respectively, there are no visible salts causing<br/>damages inside the churches, where salts previously came back directly after each<br/>renovation. In the wall in the laboratory at Lund University the bricks where contaminated with sodium sulphate and internally rendered with hemp-lime plaster with a lime plaster surface finish. Even though there are lots of salt-related damages externally there are thus far, more than two years after construction, no signs of any damage internally.}},
  author       = {{Balksten, Kristin and Strandberg, Paulien}},
  booktitle    = {{Proceedings of SWBSS 2021 : Fifth International Conference on Salt Weathering of Buildings and Stone Sculptures}},
  isbn         = {{978-94-6366-439-4}},
  language     = {{eng}},
  pages        = {{277--286}},
  title        = {{Internal Retrofitting with Hemp-Lime on Brick Masonry : a Study to Prevent Damage Caused by Sodium Sulphate}},
  year         = {{2021}},
}