Shorter Building Next to Now Taller Building? 1

[JoshH726]

Looking at the attached photo, if client wants to add 2 stories to the stone building on the left, who's responsible for the new drifted snow (pg = 60 psf) for wood facade building on the right if they’re owned by separate business entities?

 

[dik]

In these environs, the new client is... He's the one that is causing the change/problem.

Dik

 

[BAretired]

Looking at the attached photo, if client wants to add 2 stories to the stone building on the left, who's responsible for the now drifted snow (pg = 60 psf) for wood facade building on the right if their own by separate entities?

I assume the red text should read "if they are owned by separate entities".

The answer might depend on the jurisdiction. It is a legal question and we are not lawyers, so please don't quote me in court.

That said, I believe that if the two buildings abut on a property line and if existing zoning regulations permit buildings to be three stories high, the client would be responsible to notify the neighbor that the snow load on the wood facade building would be affected by the proposed addition to the stone building. The owner of the lower building would be responsible for making the necessary modifications to his structure to accommodate the proposed change.

BA

 

[OldBldgGuy]

The ones I've been involved in (and that's quite a few) the new build owner has not been compelled to reinforce the neighbour, although some good developers I've dealt with in Toronto have paid for reinforcing or mitigation measures for their neighbours. Plenty of other places, it's been a case of presenting the neighbour with what they ought to do, & leaving it up to them. I have yet to see a municipality mandate anything from the builder of the new higher building, but I think they should. I have 4 of these under construction right now in Southern Ontario and more in the planning phase.

 

[WARose]

Unquestionably it is the responsibility of whomever is changing the load on the adjacent structure to address it. The IBC has several sections that discuss undermining existing structures by excavation, foundations, and so on. In that vein, I would think you would have no choice.

 

[JoshH726]

Apologies for the atrocious spelling and grammar (thanks 3rd coffee). I also lean toward the responsibility of owner making the changes in height to address any new load demands on adjacent structures. I do favor the idea of presenting the issues to the owners for them to hash out. But I feel in the end it will inevitably be “nuts to you now-shorter building”.

To WarRose’s point, the code does have requirements not to undermine your neighbors foundation, but I don’t see where they speak to requirements like we’re discussing.

Does anyone have any local ordinances or anything from your local AHU speaking to this? If so, please share.

 

[OldBldgGuy]

I agree, but you can bet some lawyers would (and probably have) gotten into this one. If the zoning permits me to build 6 stories high at zero lot line, and you build next door to me first to only 2 stories high, it's hardly my problem. You knew I could come along next year and build my building, so don't accuse me of doing something unforeseen. Go back to your original engineer and accuse him of not designing properly for the conditions on your property.

I'm just playing devil's advocate, and obviously the age of the buildings plays into it (who designed your 150 year old building?) along with a myriad of other things, but you see the can of worms.

Is it now on our heads to look at the possibilities, not just the reality, for neighbouring properties when we're designing? And does an owner have to build for a scenario that may never occur?

 

[JoshH726]

OldBldgGuy, exactly. But in this instance it would be me and my neighbor started at the same height, so assuming “same” design. Now you come back and add two stories. So it falls to me to maybe reinforce my roof (and at my expense?) because you want to build taller?

Who has the liability here?

 

[WARose]

To WarRose’s point, the code does have requirements not to undermine your neighbors foundation, but I don’t see where they speak to requirements like we’re discussing.

It's in the same spirit. The code also doesn't mention driving a truck through your neighbor's house......but you know where the responsibility lies.

You can't predict how this would go as a court case.....so my point is: why take the chance?

 

[WARose]

By the way, wouldn't seismic make this a moot point anyway? (I.e. you would automatically be responsible for changes to the adjacent structure.) With 2 buildings that close together and 2 floors being added to one.....I would think addressing the bashing situation would be unavoidable.

 

[dik]

WarRose: The buildings can be a few feet apart and can cause a 'snow shadow'. This is an item that should clearly be addressed in the building code... no wiggle room.

Dik

 

[hokie66]

I don't think the undermining and snow drifting issues are in the same spirit at all. Snow, wind, and floor loading are the same in this situation...each owner looks after his own building, But if an adjacent owner interferes with vertical or lateral capacity of an existing building, the adjacent owner is liable. Loading and capacity need to be looked at separately.

 

[ajh1]

ASCE 7-16 Section 7.12 states:
Existing roofs shall be evaluated for increased snow loads caused by additions or alterations. Owners or agents for owners of an existing lower roof shall be advised of the potential for increased snow loads where a higher roof is constructed within 20 ft.

So they are mandated to notify, but not necessarily pay for. Civil suit for damages possibly?

 

[JoshH726]

Ajh1, that’s my concern regarding the liability. Curious to see how others approached this? Anyone want to share a case study?

At this point I feel you notify the client/owner (taller building), advising them to inform their neighbor (shorter building) about the increased loads and advise them to consult with a 3rd party engineer, as to minimize any potential conflict.

 

[StrucPEng]

Sounds like based on the ASCE Clause you are only required to notify (assuming there are no overriding clauses in the state or local code). Getting a written and signed acknowledgement of your notification to the owner of the lower roof building would seem to be best practice for liability. If you can work in an indemnification of liability, all the better I would think.

 

[WARose]

[blue](hokie66)[/blue]

I don't think the undermining and snow drifting issues are in the same spirit at all.

And you may be right. But we are not lawyers. And it is hard to predict how this stuff would turn out.

Incidentally, I don't think there is anything in the code saying anything about vibrating equipment/traffic from a adjacent property affecting building occupants. But I've been involved (as a consultant) in lawsuits for such cases. (And they resulted in some pretty good settlements.)

For this drift situation.....maybe there is a structural solution that would confine the problem to the building being built up. Perhaps some sort of overhang (from the taller building) that would cut off/pick up any drift?

 

[MidwestSE]

Check out IEBC section 1101.1 (talks about additions). "Where an addition impacts the existing building or structure, that portion shall comply with this code." Sounds like you're in IEBC territory. Maybe you'll luck out and fall into the "less than 5% increase in gravity loads" exception? Otherwise section 1103.4 says the parts of the existing structure subjected to additional loads from the effects of snow drift as a result of an addition shall comply with the IBC - i.e. beams, connections, columns, and foundations need to be checked.

Separately from code issues, I would think it would be clearly unethical (probably illegal) to knowingly design a new structure that is going to make an existing structure "structurally deficient."

To address the op's question, I think you'd have a hard time finding any lawyer that would argue anyone other than the person adding on to their building is responsible for fixing someone else's building...

 

[Ron]

We don't have to worry about snow drifts, but had a similar situation in Tallahassee, Florida a few years ago. Old buildings sharing a common wall (zero lot line). One old building was torn down to build a multi-story office building. New wall was about 6 stories higher than the existing old building, thus had quite a bit of rainwater runoff (it rains in Florida!) onto the old roof of the existing building. They also created damage to the common wall during demolition so that was an issue as well.

Legal stuff resulted and we were asked to get involved from an engineering perspective. Once the wall damage was repaired, we gave then two options for mitigation. The first was for the new building owners to contribute money toward the re-roofing of the old existing building to handle the additional water. The second was to design an intercepting gutter that sat on top of the old common wall to catch all runoff from the new buildings. Obviously they chose number 2 because it was cheaper; however, they thought it would only require a little gutter and a downspout....nope. Required a big gutter made of relatively expensive material because it was on the common wall but access was only from the old roof, which couldn't handle much maintenance traffic......so little or no maintenance gutter! More expensive than they thought but they paid.

Bottom line....the group that caused the condition had to pay for the mitigation of the condition! To get there, took a couple of real estate lawyers (zero lot line/common walls are sticky) and a couple of construction defect attorneys.

 

[Canuck65]

I have worked on similar projects where a client wants to add a storey or two to an existing building creating a drift snow load on the adjacent roof. In all cases I have advised my client that structural upgrades to the lower roof structure would likely be necessary and likely they should go talk to the adjacent building owner. I have always assumed that the person expanding their building should be responsible for the adjacent owners expenses. In several cases the adjacent owner was not happy and they would not allow work to be completed within their space, even if the other person paid (disturbing tenants, businesses, etc...). In several cases the adjacent owner was happy to work with their neighbor, as long as it did not cost them anything. Never had an adjacent owner pay for upgrades to their own roof to address issues created by others.

 

[JAE]

My experience is exactly as Canuck65 states.

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