I have a two story home built in 1979, nw oregon. 2x6 ceiling…

Question

I have a two story home built in 1979, nw oregon. 2x6 ceiling joist, I would
like to take out 8 1/2 feet of wall of what I am almost absolutely sure is a
load bearing wall, top floor. The bottom floor is daylight basement. The walls
from the top floor match with the walls below, blue prints indicate 3 6x6 posts
along the downstairs wall. What size of beam do I need to span the 8 1/2 feet to
support the roof along that stretch.

StructuralEng · Accepted Answer

StructuralEng : Hi
StructuralEng : Hello, how are you doing today. I’ll be happy to help you.
Please give me a few minutes to read your question completely and I’ll let you
know if I need additional information. Before we get started I’d like to point
out that a Professional Engineer’s standard of care typically includes a site
visit to assess field conditions and get an overall understanding of the
structure. This can obviously not be accomplished through the internet. The
information provided here is meant for informational purposes only (general
sizing and budgeting) and is based on the information provided by you. Only
vertical gravity loads will be considered, no lateral loads or analysis is
looked at. The information should be verified by a professional engineer who can
visit the site to ensure that potentially important information has not been
overlooked or omitted
StructuralEng : It will support the roof only?
StructuralEng : what about the attic?
StructuralEng : what is the joist/rafter length on each side of the beam?
Customer:

I have blue prints that may help

StructuralEng : You can upload here with the paper clip icon or upload o
mediafire.com and post the URL here for me to access.
Customer:

What appears to me is they used the 6 x 6 posts every spaced evenly along the
32feet of floor.

StructuralEng : Thats at the lowest level, correct? Not in the wall?
Customer:

correct

Customer:

almost dead center line

StructuralEng : Ok. What is the joist/rafter length on each side?
StructuralEng : is it supporting te roof only or an attic, as well?
Customer:

roof/attic

Customer:

2 x 6 on center, looking for length on each side.

Customer:

collar beems and purling are in place

StructuralEng : It's an interior wall?
Customer:

correct almost dead center

Customer:

it is a door way from the LR to the kitchen, we want to expand it.

Customer:

more open

StructuralEng : What is the joist length on each side? I need that for te
loading
StructuralEng : It's not common for an interior wall to support the roof. Are
you sure that's the case?
Customer:

This is what appears it to be, the blue prints show wall downstairs, 6 x 6 every
6 to 7 feet for a total of 3 interior 6 x 6's. This wall goes the length of the
house approx 32 feet. I have about an 8 foot opening downstairs with a drop
indicating a support there. the upstair walls and downstair walls all line up. I
am not 100 % sure without going into the attic but I think the joist do not go
all the way across, they nail to one another.

Customer:

overlapping of course

Customer:

This is why i think they are load bearing walls

StructuralEng : Yes, I is a load bearing wall, but I don't think it supports the
roof, just the attic.
StructuralEng : i still need the length of the joists on each side of this wall.
StructuralEng : You will need to have the beam below checked out, but that is
not part of this question.
Customer:

why does the beam below need checked, and if you can give me a couple minutes to
crawl in to the attic I can give you that info

StructuralEng : Sure, take your time.
StructuralEng : the beam below will need to be checked, because you'll be
replacing a uniformly distributed load with two point loads. It will likely be
ok, but it does need to be checked.
Customer:

Well different story than what I thought.

Customer:

2 x 4 joists across the width, al the way not spiced, same with roofing and
supports on all joist and rafter. dead center

Customer:

spliced.

StructuralEng : Give me a minute to catch up
StructuralEng : The attic joists are 2x4 and not spliced?
StructuralEng : What is the length, though?
Customer:

length approx. 34 feet max. with a v support to about 9.5 feet from each outside
wall

Customer:

the blueprints and plans are saying differently, but they are on 16 centers

Customer:

not plans, but what is actually there

Customer:

the wall I want to remove is 12 feet from one outside wall measuring inside of
course, and 13 feet from the other outside wall.

StructuralEng : So they are trusses, not rafters and joists?
StructuralEng : Do they have metal plates connecting the truss members?
Customer:

yes, 2 x 4 trusses, nailed.

Customer:

remember this was 1979 so there was not the reinforced screen across the joints

StructuralEng : The wall probably wasn't intended to be a bearing wall, but may,
in fact, be acting as on for the roof
StructuralEng : I'll size a beam to span the 8.5'
Customer:

Thats what I'm now thinking, the trusses need to rest somewhere, especially as a
2 x 4

StructuralEng : You can plan for a triple 2x12 southern pine No. 1
StructuralEng : youll need to have the lower beam checked out and have the posts
and connections designed and detailed by a licensed PE
StructuralEng : if you could rate my answer, I would appreciate ot
Customer:

what about doug fir

Customer:

when I read triple 2 x 12 that would make it approx 6 " wide correct? what about
a 4 " wall?

StructuralEng : A triple would be 4.5" wide. They are 1.5" wide each
StructuralEng : doug-for wont work
StructuralEng : ifworkIf you can't get southern pine, you'll need an lvl
Customer:

what is the difference? and what about just a plain 4 X 12 X 10'

Customer:

why wont doug fir work? What about a glue lam or a plain 4 X 12 X 10"

Customer:

Hello

Customer:

Why not a doug fir? What about a glue lam or a 4 X 12 X 10'

Customer:

ooop sorry

StructuralEng : A 4x12 is only 3.5" wide, so that won't work on paper
StructuralEng : The structural properties for Doug-for are not adequate for that
span and loading
StructuralEng : A glulam of that size will work.
StructuralEng : with a minimum Fb of 2400 psi and a min E of 1800 ksi
Customer:

so a glulam of 4 X 12 X 10 will work

StructuralEng : Doug-fir has Fb of only 850 psi. It's a big difference
StructuralEng : Correct
Customer:

got ya, any idea how to print out this conversation for my records.

StructuralEng : The only way I've found is to highlight the chat box and then
copy and paste into a word document
StructuralEng : If you could rate my answer, I would appreciate it.
Customer:

thank you, XXXXX XXXXX

I have a two story home built in 1979, nw oregon. 2x6 ceiling…

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