Load Bearing and a Truss roof

My house was built in 1983. It has a truss roof. I want to take out the wal between the dining room and kitchen. The wall is 10’ long and is in the middle of the house. The house is 27’ wide

In the attic I have a indoor heating unit that goes with the outdoor heatpump. This unit is just about in the middle of the house also.

My question is this. When I take this wall out, Do I need to put a header beam in its place?

I appreciate the help. I am just worried that if I take the wall out, with the weight of the indoor unit, the truss would not support that weight.

Vince Ringgold

It most likely is a load bearing wall, even without the hvac unit taken in consideration.
Truss roofs are typically designed to use some interior walls as mid span support to save on costs associated with making the truss larger/stronger.

You will need an engineer involved in this since many contractors will tell you anything to get the job. Some people incorrectly think roof loads/bracing must be present on a wall before it is considered load bearing.

With a stick built roof you can easily hide the new beam above the ceiling but you are faced with trusses that need engineered modifications to hide the beam.

You may get lucky and find out that its a non-load bearing wall but that should only be believed when it comes in writing with an engineers stamp on it.

Vince,

To ask a question like that implies you are flirting with disaster.

Do yourself a huge favor, hire a good Structural Engineer to draw up the plans & be sure you get a permit to do the work.

What may cost you a few hundred dollars now could save you thousands later.

The best thing you can do is definitely Hire a local PE. But with a little investigation you can do some checking to get a better understanding of the roof structure.

A 27’ span is not all that long for the truss designer to have designed your Roof system to be clear span, IE no internal bearings!. BUT the HVAC being in the attic complicates matters a bit.

The engineering drawings if you didn’t toss them contains all the relative information to accomplish what you are wanting to do. If you still have them then you’re golden!

HVAC, take a look in the attic and see if these trusses are different in configuration than the rest. If the answer is no then you know that there is a good chance that they are dependent on that loading bearing wall. Check chord sizes and plate sizes on both sides of the HVAC, They may be larger.

Most truss companies will do one of two things, 1- make the HVAC truss with a 2x6 or greater BC or 2- leave the BC the same size and stack another chord in the center panel to strengthen that area for the additional load.

If you trusses are all 2x4 then you have additional problems, they were not designed to carry the HVAC at all!!!:shock:

Get a PE or if you know where the Trusses came from they truss co can take a look at it for you in most cases at no charge!! :smiley:

Jeff Whitley
W&W Truss Bldrs Inc.
www.wwtbi.com

if the wall is parallel to the trusses it is probably not load bearing. If it a perpendicular and some identical trusses dont have that mid support than it is probably not load bearing. I agree with these other guys about having an engineer evaluate if you are not sure but if you are willing to assume the responsibilities about what could happen then have at it.

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You must be a big fan of the good old band Molly Hatchet, because if you are even thinking about doing this major work without an engineer and the proper permits then you are Flirting With Disaster.

Jim

I disagree with everyone. Trusses, unless a special girder truss (which accepts the loads of attached trusses), have no interior load bearing walls. That is the beauty of trusses! Technically, the interior (partition walls) shouldn’t even be touching the truss bottom cord during rough-in, but they usually are. As far as the HVAC system, the trusses that support that load should have been designed to support it…but access to the truss design documents are needed to confirm that. Regardless, the wall beneath it is likely not load bearing.

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Vince,
Identifying if the wall is load bearing is an easy procedure. Bearing walls that are carrying a roof load must transfer that load to a footing. Simply look in the crawl space or basement to identify the presence of a mid point stem wall or piers (crawl space) or bearing wall under the wall above (basement). If the home is slab on grade go into the attic and pull back the insulation to identify if the wall that you want too remove has a single top plate or a double top plate. if it is a load bearing wall it will have two top plates. with all of that said a 27’ span is relatively short for an engineered truss system and i would be surprised if you have a mid span support. As too the air handler the original construction drawing would have to identified the attic location and would be accounted for by the truss designer. Most air handlers only weigh about 200#‘s and are generally supported by 2 truss members the loading is minimal. Typically engineered truss design can clear span using 2x4 top and bottom cord until the span reaches about 40’

If they are 2X6 trusses in a 10 foot span, they should be okay. Now if they are just 2x4 trusses, I would want an engineer to check it out.

If cost is a factor, and it usually is, I would put my money in the header beam, and not in the engineers pocket. You could hire him , and have to put it in anyway. Save the headache of an air handler in the middle of your new kitchen.

Best answer so far

Actually a quick way to determine if the wall is bearing, is to cut hole at the top to see if it has one or two top plates. One top plate and a space between the bottom chord of the truss and the top of the wall…non-load bearing. Chances are this is a non-bearing wall. If there are two plates, refer to an engineer.

A wood truss is designed to free span the width of the home without intermediate support. No bearing walls are necessary during or after the build.
And as Joe mentioned, they should not bear down on the interior partitions.
Identification is simple enough by checking the attic.

Mechanical equipment should be supported by the top chords of the trusses and not bear down directly on the ceiling joist or bottom chord of the truss no matter the design unless specifically designed in the truss itself.
A unistrut is usually installed to the bottom of the top chords of the rafter and threaded rods down to support the equipment. This also provides an avenue to install vibration isolators if the equipment warrants it.

Most codes would request that similar to this;

[size=3]All mechanical equipment must be supported against vertical and horizontal movement in accordance with the engineering provisions of the Building Code.

This is sometimes a problem with attic furnace installations, where the unit is not rigidly attached to the structure.

Lateral bracing must be provided, typically straps running at a 45° angle from each corner of the unit to rigid framing members and tight enough to prevent horizontal movement.

Concerns about vibration must be addressed with isolation devices, not by omitting required supports.

The rafters or trusses must also be designed to handle the additional weight of the equipment.
:):smiley:
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Houses and trusses are not designed soley according to a text book or a code book, they are designed based on many parameters and the individual concerns of an engineer. The cost of the truss will be one of the major concerns. Using an interior wall for additional support to save on the cost of larger trusses is good design. The size of the metal truss plate is another factor that is unknown to many inspectors.

New designs do use interior walls and beams to hold up complex trusses as directed by the plans. I just found some the other day that were missing support at one area during a predrywall. They were able to use cheaper/lighter trusses this way but forgot a short beam.

I had a house built in 1985 that had roof trusses. It had a load bearing wall under some of the trusses. I had it checked out because I had thought about taking a wall out.

A double top plate does not always mean the wall is load bearing. Its easier on the framer to make all walls the same so that alone is no good for determining anything.

The only real answer for the original poster is as some of us have stated, get it checked out by someone that is qualified.

Surely, it can at least be agreed that when the bottom chord of a truss has an air gap to the top plate of a wall, that wall cannot be load bearing.

What about when wall frame has only a single top plate? I agree that two plates doesn’t necessarily mean that a wall is loading bearing. But does a single top plate necessarily mean that a wall isn’t load bearing?

Assume that a wall is load bearing and prove that it isn’t (not the other way around). What proves that a wall isn’t load bearing? I’d say air-gap is obvious.