A/Overview
This document was created to help Property Protect clients understand the most common building defects that can occur during an AS 4349.1 inspection. This is a list of the most common building defects. However, there are many other types of defects. These are the most common.
B/Abstract
This report includes a list of some of the most common residential building problems, as well as the causes. It is based on case studies that were conducted by the author as a licensed builder. Some of the causes have also been included by the writer.
Scope
This report will provide a brief overview of the most common residential building defects and possible remedies.
Method
This case study is based on the personal and professional records of the author during the past 15 years as a licensed builder.
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I believe that a large number of structural building problems listed in this report were caused by stormwater management issues around homes, which led to water movement within the homes. Poor building practices or poor maintenance are responsible for the remainder of these failures.
C/Introduction
These are the most frequent forms of Building Failure that were found during AS 4349.1 home inspections by the Adelaide writer:
Slab Edge wetting
This is caused by horizontal ingress of soil moisture and salts. The concrete’s capillary action (suction) causes the concrete to enter the footing edges. This can be caused by several factors, including Concretors pushing down Fortecon membrane edge forms before pouring a floor slab. Concrete overpours are caused when concrete concretors edge forms don’t go low enough to prevent a horizontal overpour. This can cause water ponding on top of the concrete over pour, creating a pool. Lack of a plastic membrane between the footing and paving is the final reason.
This problem can cause mould and rotting of floor coverings and fretting of concrete due to salt attack on the cement matrix. Salt crystals can expand within the concrete matrix, causing it fret and cracking.
Rising Damp in Walls
This problem is similar to Salt damp, which we will discuss below. Salt damp results in a 90-100% break down of the Damp Course within the wall, while rising dampness causes a partial failure of that Damp Course. This means that the damage to the mortar wall is less severe than Salt damp. It is possible to find rising dampness in pre- 1950 homes. The rising dampness can be limited to the erosion of mortar joints by as much as 1 to 2mm from the original face. Salt damp is an alternative.
Clients should know that rising dampness is rarely treated. The erosion of masonry takes a long time and can take up to 50 years. If the damage isn’t severe, I recommend that clients monitor it.
Salt Damp in Walls
Vertical ingress of salts and moisture into walls can cause wall fretting. Walls may not be able to withstand structural loads and could become unstable. Salt crystals in the masonry expand, causing damage to the bricks and mortar fretting. Sometimes, salt damp can make masonry unstable.
This can be caused by several factors, including the complete breakdown of the dampcourse (pre 1910 homes had pitch and bitumen between bricks and footing, which becomes brittle with age), and paving or render bridging damp course.
Breacher piece failures occur in showers. This happens when the breacher part fails due to metal fatigue through thousands of heat cycles within the wall. (This is where hot and cold water meet in the wall in the bathroom). The water then flows into the walls. A shower will usually have a breacher every 25-30 years. This is very common. Two tiles that are different from the walls of the bathroom can be a sign that a breacher has been replaced.
Property Protect conducts a survey of wet areas walls during inspections. This is done using an electronic moisturemeter to find the defect. A shower that has high moisture levels near its walls is likely to be leaking.
Brick Growth
Brick growth cracks in walls. Brick growth cracks can occur in older homes. They usually appear at the wall’s end in a vertical plane. Clay bricks can expand because they are porous. Bricks that are not connected to the wall can compress one another, leading to cracking.
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