Ron Arad
Civil engineer, Arad Bedek Bayit
A home inspection (bedek bayit) engineer's building inspection covers residential roofs as well as roofs on industrial structures. Roofs come in several types: lightweight roofs made of panels on steel structures, tile roofs on wood structures, flat concrete roofs, and more.
Tile roofs are used where the roof needs a slope, mainly in single-family houses.
Flat concrete roofs, usually sealed with bituminous sheets, appear in both apartment buildings and single-family houses.
This article focuses on the lightweight roof typically found on industrial structures, with examples of construction defects found during inspections.
On an industrial structure, the roof is made of panels, sheet-metal boards with compressed cork between them, laid on top of a steel structure.
With this type of roof, it takes high-quality materials and precise installation, especially at the joints between panels and around anything protruding from the roof, such as vents or pipe penetrations.
Otherwise, defects appear.
When the panels are not made of galvanized sheet metal, corrosion sets in and causes many problems. In the picture below, taken during an inspection, you can see how rust, which swells to three times the metal's original volume, pushes the panels apart. The gap that forms lets water into the structure.
The next picture, taken during an inspection of an industrial structure in central Israel, shows an advanced stage of corrosion in which parts of the paneling have disappeared entirely. This roof was only ten years old.
In the following case, you can see a failed waterproofing attempt over an area with rust.
As noted, rust cannot simply be ignored or papered over with waterproofing material, since corrosion keeps progressing and tears through the waterproofing layer.
The next case, photographed during a building inspection by Arad Bedek Bayit, shows corrosion that has spread into the steel structure itself, a real danger to the roof's stability.
Another kind of construction defect is a fault in installation. The panel boards are connected to each other lengthwise by screws, with an overlap between each board and the next. When that overlap is not right, or the screws are not fastened properly, the connection between boards opens up.
Another detail that needs special attention is the connection around protruding elements, made using an additional square board that overlaps the panel boards. The seams between that square board, the panel boards, and the element coming through the roof all need to be sealed well. In the picture below, the overlap was done correctly, but the waterproofing has not held, and gaps have opened up in it.
The engineers of Arad Bedek Bayit, led by building engineer Ron Arad, whom courts appoint as their own expert on construction defects. The company has been inspecting apartments and buildings since 2001. Engineer Ron Arad · More about the company