Installing Short Lintels in an Existing Wall 1

[Archie264]

I don't sanction it but for installing short lintels (i.e. 2'-6" to 3'-0") in existing masonry some masons just take out the old and reinstall the new, with no needling, pinch beams, shoring, etc.

How would you folks respond to such a practice where you know or suspect it takes place? Just curious.

 

[SWEG]

If you meet the parameters for arching action to occur over a CMU opening (adequate CMU height above opening, CMU wall length beyond jamb, etc...) then technically the floor/roof load will flow around the opening to the jambs. The only thing you would need to support/shore up is the CMU remaining below the arch which may fall down during cutting of the new opening.

One would typically find this most often with small openings, as you mentioned, but depending on floor to floor height it could apply to larger openings as well.

Hope this helps.

Virginia PE, SE

 

[Archie264]

Actually I meant to refer to the fact that masons do this as a matter of course knowing they will "get away with it". Somehow that just doesn't sit well with me...even if they are routinely "getting away with it".

 

[SWEG]

If it doesn't need to be shored then it is "means and methods".

If I designed the wall to be shored prior to cutting the new opening and installing the new lintel, then of course I would call them out on it. It not only deviates from the contract documents but also may be causing other irreversible damage to the permanent structure. I think you also have leverage to influence the Owner to stop the work.

If you didn't call for it to be shored and it doesn't need to be shored then the contractor is simply using their own means and methods for installing the new lintel.

Virginia PE, SE

 

[XR250]

They do it all the time like that around here. Never heard of an issue.

 

[Archie264]

I guess I just don't understand how, if a lintel is needed to support the brick above it over the long term, why it's then safe for the mason's mother's son to be working underneath it with the same brick unsupported. I suppose there are long-term vs. short-term effects to consider but I wonder how the mortar knows how long it's supposed to hold on... <==(emoicom represents mason after being hit on the head by a brick)

 

[XR250]

I imagine the mason does not actually stand under the brick - that would be foolish.
I have seen many masons have a shoring in post in the middle of a long lintel on new construction. They feel the lintel is just formwork and the brick holds it self up. Probably alot of truth to that.

 

[KootK]

I've been turning a blind eye. I had a 16' opening cut out of an 80 yr old, two wythe brick wall one time. It was a bearing wall and there was about 4' left above the opening. The contractor ignored my needle beam spec. Not a single brick fell out. Not. One. This stuff clearly works reliably. I just don't know how to deal with it from a liability perspective.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.