Foundation removal for HVAC

Now before the debate begins, I am well aware of what the “Correct answer” should be. I also know that many of you don’t get the pleasure of being able to inspect anything over 50 years old except on a rare occassion, and you don’t get to see the great and creative ways some of the older homes were build in the land of the inbreeder.

I have looked at tons of houses with this same type of installation. It is an acceptable practice around here, (on older homes) and I have yet to see one with the first sign of a problem.

What is your opinion on removing the block to make room for hvac ductwork without first installing a lintel or support of any kind.

it looks like a mess from here


Like you said, we all know the answer. The foundation wall should not be altered without having some type of support to span the opening. I know I have and many others have seen it done without the support. I note what I see and how it should be, but what’s done after that is most likely nothing. Most people leave it as it is, I rarely see any additional support added.

Glad to know the epidemic is nationwide.

Probably just enough support between the sill plate and rim joist or header (assuming there isn’t a splice right there), combined with the sheathing to just span the opening. Doesn’t mean it isn’t hanging on by a thread and one unusual wind/seismic even will cause a failure. Should get flagged every time.

JMO & 2-Nickels … :wink:

i liked the electrical wire with bare ends wrapped around the metal strap

makes you wonder whats the difference between this and the crawl space door? A lot of doors are built with out a lintel support. Plus most crawl spaces in my area are pier and curtain walls so most of the support is being done by the pilasters and not the curtain wall

Other than a HVAC duct work mess, improper wire support, improper pipe support, and other things we don’t see, I see no need to get alarmed with a box sill spaning 2’ +/- over an opening like this. Been done like this for hundreds of years.
Although it don’t meet today’s standards in framing an opening under a residential floor, it will not collapse because of this opening.
I would be more concerned about everything else around it.

You might get concerned though when you see something like this;

Make head room for a garage door on a commercial building.

Make room for headroom by cutting out the barjoist, hell, the wall will carry it.

Well the floor was not strong enough to support the storage above because the floor joist span was to great for the condition, so lets reiforce it with a beam.

Now this is when a concern steps in. And guess what, that was an automotive parts storeroom above and been like that for I don’t know how many years.
I told the client, I am sorry, but this needs an evaluation by a structural engineer, which I don’t do very often, but like I told her, even though it has been like that for many years, dosen’t mean it will not fail the minute I walk out the door. She said, I understand your position. :slight_smile:

You win the defect of the year award!!!
I will send you your prize as soon as you correct the problems Marcel. LOL

I see brick veneer walls penetrated every week for a package system. I always call it out, recommending a lintel.

What is the exterior envelope made of first of all?:neutral:

That bean is carring all the metal truss ends?

No header/lintel is also a common issue in my area where an addition with a crawl space is added to a 2-story house with a basement and the crawl space access is an opening in the old foundation wall. Should get flagged every time.

Robert, you tell us that a hollow block traverse to a beam is adequate for support, but here you say that a lintel is necessary for a block opening with no masonry above it.
You confuse me, cause now you are saying that a 2"x6" sill plate with a 2"x10" box header can’t span a small opening of 16" to 30"?
They are all over the place and never seen one collapse yet. :slight_smile:

Absolutely, if it has the required pier cap and meets other limitations like height … no doubt at all

I meant for an average 2-story house … fixed. A span of just 16" would likely be okay (no sill/header splices). That opening wouldnt accommodate typical ductwork or the minimum 24" wide crawl space opening. I typically see those openings 32" to 36" wide. Commonly a 2x8 rim joist, or 2x10 for wider houses, would not span that … see the IRC Header tables for a 2-story house.

Visual appearance or something not collapsing has absolutely nothing to do with structural capacity (unless it’s really bad) … or having appropriate safety for things like unusual events and common material defects like checks in wood (called factor of safety).

So would this work?

Header over foundation opening

Looks like it would for average loads … the header per that diagram is a double box/rim I-Joist … :slight_smile:

For a 2-story house I would flag it if it didn’t have a doubled joist as a header for openings around 32" to 36" … a little less for I-joists because they are more likely to be at greater spans than conventional framing (e.g. 32" max per that detail) … :wink:

I know it looks bad, but unless there’s a point load above the opening, I don’t think it’s going to fail. I see them too and hardly ever have seen one even sag, except one time when they broke the bottom plate right in the middle of a 4’ opening and then put a joist on the break. Number of ways to correct it.

Would you not conceder the exterior envelopes cladding and opening size?
Yes a lintel is perfered.
A masonry clad home would have a lintel introduced.
A tin or vinyl sided home may not need to have a lintel if the open is short. Up to24".
The ledger plate girder should support a short opening. Like in the photo provided.
PS: Moisture intrusion. Top right joist. Marked In red.

Suspect: Torn, riped, damaged insulation or loose connection to the boot.

Duct sweating presents potential risks to the structure of the home and to the health and safety of people in the home because of mold and mildew damage caused by water dripping from the duct and from the air vents in each room. Taking steps to prevent ductwork sweating also can save you money on utility bills

Read more: What Causes Air-Conditioning Ductwork to Sweat? |
Recommend: new Insulation or repair of the existing ducting.
The angle of the branch vent line off the main trunk in the photo looks constricted. It is bent 180 degrees and should have been install straight up off the main trunk line.
Reduced air flow.They appear to be half there normal diameter. Marked in blue

Link for conventional wood fame construction.

Great job keeping it real around here, Marcel!