is unprotected opening allowed for a limiting distance of 0.39m?

[sunyaer]

This is the back of two houses of two stories. One house is doing basement and ground floor addition. in the first picture, red lines are newly added concrete foundation walls, blue lines are newly added basement walkout stairs. Pink dimensions are side setbacks.

In the second picture, green lines are newly added ground floor exterior walls. The newly added stairs has roof cover too.

The yellow line in the second picture is open to neighbor, is this unprotected opening allowed for a limiting distance of 0.39m? In order to answer this question, I guess we have to answer if the walkout stairs is considered an occupancy?

 

[sunyaer]

Clear pictures attached.

 

[sunyaer]

This is the real picture:

 

[tmurray]

It depends...

If the stairs form part of an access to an exit, it must meet greater protection requirements.

If the stairs are above grade (over 1m) then it could trigger a requirement.

Otherwise, there really isn't much that would apply.

 

[Inspector Gadget]

Are they houses, or townhouses? Reason I ask is that houses are 9.10.15, while townhouses are 9.10.14, or part 3.

To calculate (I use part 3 for everything) you would need to provide exposed building face.
One could argue that stairs are exempt, but the roof and supporting materials - not so much. By the looks of it, there are violations of NBC 9.10.15.5(5) - which do not allow combustible projections within 1.2m.

 

[sunyaer]

Are they houses, or townhouses? Reason I ask is that houses are 9.10.15, while townhouses are 9.10.14, or part 3.

…

They are houses.

 

[sunyaer]

Are they houses, or townhouses? Reason I ask is that houses are 9.10.15, while townhouses are 9.10.14, or part 3.

To calculate (I use part 3 for everything) you would need to provide exposed building face.
One could argue that stairs are exempt, but the roof and supporting materials - not so much. By the looks of it, there are violations of NBC 9.10.15.5(5) - which do not allow combustible projections within 1.2m.9.10.15.5. Construction of Exposing Building Face of Houses

9.10.15.5. Construction of Exposing Building Face of Houses
...
(5) Except for houses, combustible projections on the exterior of a wall that are more than 1 000 mm above groundlevel, such as balconies, platforms, canopies, eave projections and stairs, and that could expose an adjacent building tofire spread, shall not be permitted within,
(a) 1.2 m of a property line or the centre line of a public way, or

...

It looks like houses can get away with 9.10.15.5.(5), doesn't it?

 

[tmurray]

9.10.15.5. Construction of Exposing Building Face of Houses
...
(5) Except for houses, combustible projections on the exterior of a wall that are more than 1 000 mm above groundlevel, such as balconies, platforms, canopies, eave projections and stairs, and that could expose an adjacent building tofire spread, shall not be permitted within,
(a) 1.2 m of a property line or the centre line of a public way, or

...

It looks like houses can get away with 9.10.15.5.(5), doesn't it?

Yes.

"Houses" is a defined term in the OBC and includes detached, semi-detached and row houses containing not more than two dwelling units. The definition actually doesn't really make sense as it gives a maximum of two dwelling units, which would create a semi-detached building, but also explicitly includes row housing. I think the intent was to address secondary suites to allow them, but to keep them limited to a single secondary dwelling unit in each dwelling.


In the national code it would apply similarly based on the application statement in 9.10.15.1.

The thing that triggers a building to the more general 9.10.14 would typically be when you have a dwelling unit above or below another. like an apartment building or condo.

 

[Inspector Gadget]

9.10.15.5. Construction of Exposing Building Face of Houses
...
(5) Except for houses,

Alas, once more, the difference between OBC and NBC rears its head.

Another key clause in NBC, to see if it meshes with OBC

11) Where roof soffits project to less than 1.2 m from the property line, the centre
line of a lane or public thoroughfare, or an imaginary line between two buildings or fire
compartments on the same property, they shall
a) have no openings, and
b) be protected by
i) not less than 0.38 mm thick sheet steel,
ii) unvented aluminum conforming to CAN/CGSB-93.2-M,
“Prefinished Aluminum Siding, Soffits, and Fascia, for
Residential Use,”
iii) not less than 12.7 mm thick gypsum soffit board or gypsum
ceiling board installed according to CSA A82.31-M,
“Gypsum Board Application,”
iv) not less than 11 mm thick plywood,
v) not less than 12.5 mm thick OSB or waferboard, or
vi) not less than 11 mm thick lumber.
(See Note A-3.2.3.6.(2).)