I am working on completing drawings for a home in the east end of
Toronto. I am showing the existing roof being taken off to facilitate
adding a second floor. The existing wood stud walls must be extended
to satisfy an owner request for additional headroom.
Does anyone have a suggestion, or can refer me to a previous post
where wall studs are extended up, or a short stud wall is added and
securely attached to the lower stud wall without having to replace the
existing wall studs?
Thankyou in advance.
In most cases, framing one wall directly on top of the other would create a
pivot point. It would act sort of like a large hinge. Strong winds or
seismic forces could easily cause the wall to bend (and possibly fail) at
the point where the two walls meet.
If this wall extends unsupported from the first floor to the second, you
should tear it out and reframe with continuous studs. Then add fireblocking
every 8' or so in the studbays.
If you can't remove the existing wall for some reason, you could probably
sister full height studs next to the existing shorter studs. But, that's
probably more work than just reframing the wall.
I think you've answered my question. I believe it's best to sister a
new 2"X6" wd stud wall to the existing 2"X4". I"ll widen the base
plate to accept. We need the extra depth to obtain the min required
insulation anyways. I should clarify that there is no second floor
yet, just a roof. It's an existing bungalow whose roof we're
You were very helpful in this, thankyou once again.
hmmm. more or less a kind of strapping on the face of the joist. I
think that the nice thing about sistering new 2x6's to the existing
2x4 is that I have more room to achieve the r value im going to need.
Good suggestion though. Thanks
Code won't allow extending studs this way for seismic and wind
reasons. The failure is known as "hinging", where the original top
plate rocks off the studs. However, you can support the extension
with angled supports between the new floor joists and original top
plate. This would create a strong triangle that would prevent
hinging, and so the planning department would likely accept this to
stabilize the stem wall without additional engineers ink. The other
approach would be to have a truss company design floor trusses (they
have their own engineers) that would sit on the original top plate,
but which are designed to have added ceiling clearance below.
Otherwise as said, you'll need an engineer, and many engineers aren't
too good at this sort of design work it seems to me. They are more
used to figuring out the basics of load on conventional foundation and
beam situations. But, if you are building up, you may need an
engineer to ensure the existing foundation can take the load.
I forgot to add that the angle support idea would result in an unusual
interior ceiling around the perimeter, so that the 2x4 wood brackets
would need to be placed 16" on center for the wall board to attach
to. The space would be a good place to route HVAC ducts, water pipes,
or electrical wire. But then again if the ceiling/floor joists extend
out over the exterior for a sizeable overhang, these angle brackets
could be on the exterior and perhaps hidden in an architectural facade
of some sort.
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