Telegraphing – Not just the original text messaging system.
Calling it the original text message system is a very apt description in todays world, but long before ‘text messages’ as we know them today appeared, to telegraph had another meaning.
To reveal underlying or hidden conditions that are not directly visible, often through solid materials like these shingles; thats telegraphing the surface below.
In the photo on the left I’ve used red lines to show the information that is being telegraphed through the roof shingling. The photo on the right is the original. Note the screwdriver that has been placed to illustrate the parallel lines that are being telegraphed through this material.
But you have to know your “Morse Code” to read the message. In this case my training as an inspector and knowledge of construction technology, and it’s history, allow me to translate the message.
In this case heat and gravity have moulded the shingle materials to closely follow the sheathing underneath. Here the shingle layer is one layer thick and has been installed directly on the board sheathed roof.
The ‘lines’ that you can ‘see’ are slight ridges that mirror the edges of the boards. They are sharply defined so that tells me that roofing paper, if present is very thin and certainly no ice and water shield membrane in this area.
Here you see the view from the inside.
The boards used for the sheathing are clearly visible and the cement on them reveals that they were first used on the forms of the poured concrete walls. (A common economical practice of the pre-plywood era.)
You can also see the loose fill – blown-in insulation and that it has fully blocked the rafter bays lower than this level (ceiling).
This causes higher heat build up in the shingle areas where we see the telegraphing detail. Higher areas on the roof do not show as much telegraphing as they’ve been cooler and have experienced less heat moulding to the shape of the underlying boards.
So when you are looking at, or investing, in a home or property you want your inspector to be able to correctly ‘read’ the building.
For the Montreal or the surrounding area you know who to call.
Original blog post on ActiveRain: Link to Blog Post