Looking for a structural/forensic engineer for brownstone
Hi. We need an engineer to come look at our brownstone. There seems to be more “settling” or movement around the stairwell than I am comfortable ignoring so I am looking for an expert who can come look at the situation and tell me a) is there an issue that needs to be addressed and…
Hi.
We need an engineer to come look at our brownstone. There seems to be more “settling” or movement around the stairwell than I am comfortable ignoring so I am looking for an expert who can come look at the situation and tell me a) is there an issue that needs to be addressed and b) if so, how it should be addressed. We are about to start some renovation work and ideally if I need something done I would do it at the same time.
Would love referrals and recommendations from the collective wisdom of fellow brownstoners.
Over 30 years of historic building restoration, I have found the following.
18′ joists were designed by architects of the time to be the sole structural supports.
What I mean by that is that interior partitions that divide the home into rooms, and seem to the uninformed to be structural, in fact, are not.
Over time, and this is less of a problem in the central Park Slope area, blocks have settled and the entire row(s) now have a tilt. This can be tested by putting a level on a masonry opening, say the masonry outside a window.
If you find your home is not plumb, I suspect that any discrepancy happened quite some time ago. And is un-related to your stairway problem.
There were two primary obstacles facing architects of that time, and sourcing original growth straight timbers from which to fashion joists was not one of those two.
The two problems that they faced concerned heating systems and stairwells.
Heating systems of the time, and your home predated modern, plumbed solutions, required masonry flues. These flues prevented the “joist from masonry pocket to masonry pocket” solution. They couldn’t have joists penetrating flues.
Similarly, the stacked stairwells prevented the joists from going all the way side to side where there were stairs.
The most common solution from medieval times forward were mortise and tenon joints to “jack” beams, that bridged the obstacles.
Later construction utilized steel joist hangers, but date-wise I wouldn’t expect to find these in your home.
Why this long digression into esoteric historical minutia?
Most times, stairwell issues arise because the jack beams “boxing out” the stair well have failed, usually with the jack beam mortise splitting.
If you were to focus on this issue in some other old house that was gut renovated, you probably would find a few split joists centered around the fatter joist used at the end of the box out, or the jack beam mortised into it.
We have found that when the problem is ultimately located, it is something simple.
The repair on bad joists is usually a patch, not a big deal. It just requires that the ceiling below be opened, so we can visually see what let go. Sometimes we use a temporary timber and hydraulic jacks to close the split, then sister or TECO the joist back where it belongs.
If we are talking the parlor floor (up the stoop), then the garden hallway ceiling has to be open.
Bruce
If you type “Engineer” in the search field on the upper right, or just click on “Engineer” under your headline, you’ll find lots of previous posts and recommendations.
Does the settling look new (different from a previous observation)?
I am an engineer, but a different kind, but I have long experience with settling in historic buildings.
Feel free to contact me off-line bruce at jerseydata.net