I would agree with Harold S. about the suitability of two walls in this
instance. The only time I use a single wall is with wood construction
where the tied weak link firewall can be used. I am sure that some of the
other types of tied fire walls have their uses but not in strange
situations such as the one you describe. Only in the very symmetrical
situations do the others seem to work. I have only used the cantilever
walls in relatively short one story buildings.
A question for those who use double firewalls.......
If you are using two 8" block walls and they are bearing walls...what do
you do at the doorways through the walls. According to the rules the wall
should maintain its integrity for 2 hours. If one side collapses before
this then the doorway can't be attached to it. What if the other side falls
down? I have come up with my own solution but it can't be the only answer.
I built a separate structure around the doorway with concrete columns and
beams and did not rigidly attach the floor to it. It cantilevered from the
foundations two storeys. This way either wall could fall down and not
affect the doorway.
Any other thoughts on ways to achieve this.
David Handy, P.Eng.
The Thompson Rosemount Group, Cornwall, Ont. Canada
Opinions expressed are personal only.