Masonry walls are generally highly durable. However, when masonry walls in cold climates stay too wet for too long, freeze-thaw damage can occur. This issue has particular relevance for energy efficiency retrofits, because the addition of interior insulation causes the masonry to stay colder and have a lower drying potential.
The following documents present details of BSC’s research and experience regarding the prevention of freeze-thaw damage in retrofit projects. Technical topics such as the critical degree of saturation (Scrit) are discussed, and case studies and recommendations are provided.
An edited version of this Insight first appeared in the ASHRAE Journal. To claim that something that has holes in it can act as a water control layer is a pretty interesting argument. It is both true and untrue.
This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation (2” to 8”) on existing masonry walls and wood framed walls through the use of wood furring strips (fastened through the insulation back to the structure) as a cladding attachment location. Furthermore, water management details necessary to connect the exterior insulated wall assemblies to roofs, balconies, decks, and windows were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.
There is a large existing stock of uninsulated mass masonry buildings: their uninsulated walls result in poor energy performance, which is commonly addressed with the retrofit of interior insulation. Some durability issues associated with interior insulation have been or are being addressed, such as interstitial condensation and freeze-thaw damage issues. However, another durability risk is the hygrothermal behavior of moisture-sensitive wood beams embedded in the load-bearing masonry. Interior insulation reduces the beam end temperatures, reduces available drying potential, and results in higher relative humidity conditions in the beam pocket: all of these factors pose a greater risk to durability.
An edited version of this Insight first appeared in the ASHRAE Journal. The Parthenon was constructed around 450 B.C. as a temple to the Goddess Athena. More recently a temple overlooking Vancouver was constructed by the contractor Gauvin the Younger to honor the God of Building Science Hutcheon. For the past five years the Devout have been sprinkling water on the temple Icons carefully watching the results.
Basements can account for up to one quarter of the typical energy consumption in a house. Therefore, insulating foundations is a critical measure for achieving high performance buildings. This is important in both new construction and retrofits of existing buildings. The fundamental problems and “best practice solutions” for moisture-safe basement insulation have been well established. However, many foundations are damp (either due to bulk water or capillary “wicking” of moisture) or of a type of construction that is not easy or straightforward to insulate (such as rubble foundations). Damp foundation repair methods can be “leveraged” to provide energy efficiency benefits. An example of this “hybrid” approach is spray foam insulation, which can be an effective means of liquid phase water control (leaking basement), vapor phase water control (diffusion and air leakage transported condensation) as well as an effective insulation.
An edited version of this Insight first appeared in the ASHRAE Journal. Engineers are pretty funny people. Engineers say that 1 inch of water exerts a force of – wait for it – 1 inch. Yup, 1 inch of water weighs 1 inch of water. It’s a gift we engineers have. Let me help you all out a little bit here, go suck on a straw and draw 1 inch of water up into the straw.
An edited version of this Insight first appeared in the ASHRAE Journal. It was the ants that finally did it. It wasn’t the shingles that needed to be replaced. It wasn’t the three-dimensional airflow network in the roof assembly. It wasn’t the lack of racking resistance. It wasn’t the lack of thermal resistance. It was the ants. Carpenter ants. There were just too many ants in my renovated barn.
An edited version of this Insight first appeared in the ASHRAE Journal. Imagine a three-dimensional molecular billiard game with billiard balls that are sometimes sticky, and where the rules depend on where you are on the table. Then assume that there are many different types of tables and pockets of different sizes.
An edited version of this Insight first appeared in the ASHRAE Journal. One of the more difficult questions regarding enclosures is can we insulate the interior of a mass wall in a cold climate without causing damage from freeze/thaw cycles? The answer is usually yes, we can insulate. But, and there is almost always a “but,” it depends.
This paper is from the proceedings of the Thermal Performance of the Exterior Envelopes of Whole Buildings XI International Conference, December 5-9, 2010 in Clearwater, Florida. This paper summarizes some of the limitations of the various approaches to assessing the freeze-thaw resistance of brick masonry units and presents a detailed methodology for using frost dilatometry to determine the critical degree of saturation of brick material. Test results are presented for bricks from several historical load-bearing masonry. Recommendations are made for applying this approach together with hygrothermal model in the design of retrofit insulation projects.
A concise history of the improvements to traditional buildings through design and materials.
This report considers a number of promising wall systems that can meet the requirement for better thermal control. Unlike previous studies, this one considers performance in a more realistic matter, including some two- and three-dimensional heat flow and analysis of the relative risk of moisture damage.
An edited version of this Insight first appeared in the ASHRAE Journal. Five fundamental changes to building construction have occurred in the last 50 years – they happened so gradually, so insidiously that we missed their enormous significance.
An edited version of this Insight first appeared in the ASHRAE Journal. Spain gave Florida to the United States in exchange for the United States giving up any claims on Texas. Nobody really wanted to live there except the Seminoles until air-conditioning was invented.
An edited version of this Insight first appeared in the ASHRAE Journal. Stucco was once viewed as a cladding system that solved moisture problems—it is now viewed as one that causes moisture problems. What happened?
An edited version of this Insight first appeared in the ASHRAE Journal. Mold is pretty easy to understand. No water no mold. Any questions? Well, there are a few. For one we have more mold today, but we don’t have more water. What’s with that?
An edited version of this Insight first appeared in the ASHRAE Journal. Sometimes things are so obvious we miss them. The Second Law of Thermodynamics is like that. Most of us get the heat goes from warm to cold thing. It’s the other simple applications of the Second Law that we miss.
An edited version of this Insight first appeared in the ASHRAE Journal. You have got to love salesmen. They figure things out way before physicists, usually before engineers and certainly before greenie weenies. They found, what we should all know, that it is much more cost effective to fix the enclosure so that the actual system that you need is small and therefore does not cost much to install and does not cost much to operate. Oh, by the way, this approach also saves energy. Who knew?
Moisture accumulates when the rate of moisture entry into an assembly exceeds the rate of moisture removal. When moisture accumulation exceeds the ability of the assembly materials to store the moisture without significantly degrading performance or long-term service life, moisture problems result.
This digest will begin with a brief description of the system and materials, review moisture problems in buildings, and summarize how moisture control should be dealt with in strawbale buildings.
