Problem Solving Forum
December 14 - December 18, 2020
What’s the best way to protect a masonry wall from freeze/thaw cycling?
Zenith Czora of Durotech Industries, Inc. on
December 16, 2020:
Freeze- thaw damage in masonry walls is caused by ...read more Freeze- thaw damage in masonry walls is caused by water ( in a form of rain, snow, dew and humidity) that comes in contact with and penetrates within the masonry walls. During the freeze-thaw process, the water that penetrates in expands by 9% when it freezes and causes deterioration, cracking, expansion and scaling due to the build up pressures within the masonry substrate. The cracking begins from the inside of the masonry substrate. Depending the desired aesthetic look of the masonry walls, the freeze-thaw damage can be prevented by application of either the following: 1. Impregnating/penetrating water repellent - does not change the surface appearance of the masonry walls 2. Film-forming sealer - provides stain resistance and cosmetic change ( darkening, gloss, and colour) 3. Hydrophobic elastomeric wall coatings - withstands wind-driven rain and prevent bulk liquid to penetrate in but still allow the wall to breathe.
Elango Van of Berger paints india ltd on
December 15, 2020:
In one case, there may be improper surface prepara ...read more In one case, there may be improper surface preparation, variable coat thickness. In another case, may be total mismatch between surface & the paint or failure of inner coat adhesion. Cracks, crevices, alligatoring & scaling may also develop frequently leading to peeling of entire films if the house is built during damp season & if the paint material is applied too soon after completion of the masonry works. It is advisable that new walls should be allowed to dry out at least six months before the application of non-porous system. Peeling occur when paint film applied to damp surface or to surface which later become damp, have high cohesive strength & are pushed away from the surface by water pressure from behind. If the paint is applied too thick leading formation of numerous tiny blisters & the temperature increase favors the failure.
Cristiano Godoy of KCC Safety on
December 14, 2020:
Briefly speaking about the freeze-thaw cycle is a ...read more Briefly speaking about the freeze-thaw cycle is a major cause of damage to construction materials such as concrete and similar assemblies. Freeze-thaw on my understand is, when water fills the voids, porous material and then freezes and expands. I believe the volume of frozen water is 9% greater than liquid water, so when water freezes pressure is exerted on the surrounding material, and when the pressure exceeds the tensile strength of the material, cracks will result. During this process, the voids are enlarged, enable the accumulation of additional water during the next thaw; this results in additional cracking during the next freeze. The two types of damage are surface spalling and internal cracking. How to protect: Both surface spalling and internal racking are progressive, also are numerous strategies for preventing damage: Control rain, ice, and snow penetration, control groundwater, Use water resistant brick and use the designated concrete.