1900's Brick Rowhouse Endwall Bulging outward (not basement wall bulging)

[Ben29]

Can anyone point me to a good reference for structural brick exterior wall bulging repair? Specifically I am wondering how much bulge is too much for a repair to work? Assume the repair is a "star" bearing plate and tension rod tieing back to the floor joist. This is not basement wall bulge. This is a bulge near the second floor.

A homeowner is asking me about a repair for the floor joists of their house which have pulled away from the exterior brick wall (end wall of multiple rowhouse units). My first thought is to bolt a ledger plate to the inside face of the brick wall for the existing joist to hang from via face-mount hangers, and then provide tie rods + star bearing plate to tie the brick wall to the floor joist at every 48 inches o/c.

I guess the big issue is that the brick itself is deteriorated beyond repair, so much so that it would be a bad idea to bolt a ledger plate to it.

 

[LittleInch]

Be careful until you know more about the structure.

https://www.eng-tips.com/viewthread.cfm?qid=507372

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[RPGs]

Are you describing a bearing wall, where the joists pocket into the brick masonry, pulling away from the joists? Obviously that's very concerning.

I would likely not ledger into the brick wall if it's not in good condition and, if I was concerned about the support for the floor platform(s), would recommend immediately installing 2x bearing walls or other shoring structure under the joists coming out of pocket. It is important to provide additional in-line support to carry the shoring down to an appropriate foundation.

Unless the masonry is in poor condition or the bulge is severe, it is possible to stabilize the bulging wall with tension tie backs into floor platforms and/or helical ties to new interior 2x walls, but you need to diligently follow the load path.

It may be best to safely demolish the wall and replace as a veneer with appropriate backing.

 

[LittleInch]

I think the biggest issue is imminent collapse of the wall and floor.

what sort of bulge and distance are we talking about here? 1mm, 10mm, 50mm?

Some pictures and a diagram might help.

and evacuation of the building and immediate supporting structures for the floor if it's a visible bulge wouldn't be going too far. IMHO.

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[phamENG]

Ben - if the joists have lost bearing, it's gone too far. Some people will try to sister them and get the new segments back in the pockets, but I find that dubious at best. Of course, it's probably better than letting the building collapse into the street, but it should be avoided if possible. Now if the joist ends are rotten, you don't have a choice but to sister them.

If you want to see 'how far is too far' you can do some calculations. You have axial loads on your wall (acting at some eccentricity), you have a deflection in your wall (which will increase the eccentricity and produce a secondary moment in the wall) and you have lateral/wind loads on the wall. Run through your load combinations and figure out your worst case combined bending/axial condition. Take a look at TMS 402 for unreinforced masonry. You'll be limited by the flexural tension in the bed joints and the shear flow in the collar joints. You can use that to determine the deflection at which the wall no longer meets the code requirements. Be careful, though - the chart for allowable flexural tension only goes down to Type N mortar. You're likely to encounter weaker mortars in a building like this (Type O or even Type "L" as some call it) so some judgement will be required.

 

[LittleInch]

Specifically I am wondering how much bulge is too much for a repair to work?

One you can see with the naked eye?

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Also: If you get a response it's polite to respond to it.

 

[phamENG]

and evacuation of the building and immediate supporting structures for the floor if it's a visible bulge wouldn't be going too far. IMHO.

While I understand the reaction to Davenport (that collapse has helped me to adjust some of my risk considerations when evaluating old buildings), we do need to make sure we're not going too far. By this criteria, half the buildings in one local city's downtown would have to be evacuated. These row houses are typically multiwythe brick walls with wood joists spanning from party wall to party wall, and the roof often bears on the front and rear with beams on the party walls. Spans are short, loads are less. They're usually not that weird riveted steel/masonry hybrid they used in Davenport. I've seen these things hold up walls with plaster alone (that was an evacuation condition, of course). They need to be repaired, but a bulge - even of an inch or two, is rarely an immediate danger to anyone. Of course, the engineer on site needs to make a careful inspection to be sure - the difference between a 1 inch bulge 20 years ago and a 1.25 inch bulge now could have significant additional damage that is harder to spot.

 

[LittleInch]

I get that it's very difficult to say this house will collapse tomorrow/ next week, when it's been sitting there like that for possibly months or years.

But.

We have no data here and not sure Ben has so don't know if its 10mm or 100mm bulge.
Has it got worse recently?
Have the beams actually pulled out and are being supported by the floor boards?

Houses especially small ones will withstand a lot of damage without falling down, but as someone on that collapse thread said brick buildings generally give you a LOT of warning that something bad is happening and you ignore it at your peril.

This is the end wall.

Is a "row house" another name for a terrace?

Rather dramatic, but this building had stood for 600 years until they tried to make it habitable again..

https://www.dailymotion.com/video/x6e9ore

go to minute 18.

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Also: If you get a response it's polite to respond to it.

 

[GeorgeTheCivilEngineer]

Rather dramatic, but this building had stood for 600 years until they tried to make it habitable again..

https://www.dailymotion.com/video/x6e9ore

go to minute 18.

Complete lack of competence for temporary works didn't help much either.

 

[LittleInch]

No it was a bit dodgy from the start. Once they scraped the rubble away from the bottom it all got undermined too much and a couple of acrows and a thin bit of wood wasn't going to hold up all that.



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[Ben29]

I started this thread to try to gain knowledge before I actually take on this job. I asked the realtor to send me photos of the condition. I have not been to the site yet. I am still trying to figure out if I should take this on. Here are some of the photos that the realtor sent to me.

 

[LittleInch]

My guess is that the only thing holding those floors up is the chimney breast so they had better not start knocking that down...

That looks like >100mm of displacement??

Difficult to see if the joists are actually free flowing, but I would get some props in there today and advise a closure of that alley way.

Any photos of the beams close up? - without putting a ladder against that wall.

That really looks absolutely horrible. It may even be a call to the local authorities / building inspector to make their decision.

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Also: If you get a response it's polite to respond to it.

 

[phamENG]

Yikes. That one is pretty bad. Temporary shoring needs to go up quickly. I also agree with LittleInch regarding the chimney. That's what has saved that wall so far. It's likely going to be a rebuild.

Whether or not you take it is up to you and whether or not you feel comfortable. Trust your gut. If you have doubts, pass.

If you do take it, I would suggest this:

1) Shoring to stabilize the wall. With these it can be difficult to tell what is actually holding things up. Like I mentioned above, some times it's the plaster. Shore the floor/roof above as well with enough room to get at the wall.

2) Demo finishes so you can see the joists going into the wall and the interior condition of the wall itself.

3) Assess the joists, their connection to the brick (likely non-existent), and the brick itself.

Lack of maintenance of the mortar, particularly if there is a leak, can cause the wall to shift. There really isn't a way to shift it back - the mortar that once held the wall in position is either gone or not capable of rebounding into its original position. If it can't remain as is with some good repointing, it has to be rebuilt.

 

[bones206]

My personal feeling is that shoring/stabilization projects should be left to engineers and contractors who specialize in that work. Especially older/historic buildings. I feel like there is too much risk and nuance for general practitioners.

Or at least specialists should be brought in to consult at some level.

 

[LittleInch]

I think it's one of those that is soooo bad there really isn't any argument about knocking it down and re building it before it falls down and kills one or many. Might be next week, might be whilst they are trying to "fix" it or 5 years time when someone has a party on the second floor, but that is not a "repair job". IMHO.

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Also: If you get a response it's polite to respond to it.

 

[Ben29]

Thank you all for the input. I think I will let this one pass. I will tell the realtor that:
1)it appears the wall needs to be rebuilt
2)it appears that the chimney is supporting the brick wall and preventing it from collapsing
3)they should hire a shoring / stabilization specialist to stabilize the floor framing prior to reconstructing the brick wall.

 

[phamENG]

Not preventing it from collapsing - either currently supporting the wall or delaying a potential collapse. Nothing is preventing it from collapsing. Saying otherwise, even in an offhand or 'unofficial' way could come back to bite you.

 

[Ben29]

pham, Thank you!
(I wrote pharm but went back and deleted it. Force of habit.)

 

[LittleInch]

I would reverse the order of those points.... delete the last six words of the current third bullet and add "immeadiately".

We've had posts here before about the ethics and professional responsibilities of informing authorities of dangerous situations and I think you're close to that here.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[bones206]

I agree.