Fire separation distance for existing building on separate lot

[Christine]

Hello,

I know that when a new building will be constructed on the same lot as an existing building, there is an implied property line which can be placed according to construction types, window areas, etc.

What happens if there is an existing house on an adjacent lot, and because it is old, it is actually 6-12" over the property line? There is a new house going up on the adjacent lot, and they placed the building wall 5' from the property line. Doesn't this put the existing house in jeopardy? What would have been the appropriate approach to placing the new house on the adjacent lot? The code does not address this situation. Thank you.

 

[TheCommish]

Why would the building code address the issue of trespass and a civil violatin? Assume the propery line is at the edge of the existing house then build a compliant based on that location.

 

[mtlogcabin]

Zoning would not have given approval for the new house without a boundary line adjustment to bring the existing house into compliance of being all on one lot. I would think the bank would want this corrected also

 

[Christine]

thank you for your replies. I wanted to make sure that this was not addressed anywhere in building code. I think that zoning review was supposed to have flagged the non-conforming adjacent existing house and required that the applicant negotiate an easement and indicate a new setback location for that property line. Does this sound correct?

 

[steveray]

For IRC structures the fire ratings based on separation distance shouldn't be much different on the same lot or different lots.....Really....Start in R302.1

 

[my250r11]

This should be resolved with zoning before permit approval of the new construction. Would not be allowed here with out some sort of property line adjustment through a survey and documents legally file with the assessor's office.

 

[Christine]

For IRC structures the fire ratings based on separation distance shouldn't be much different on the same lot or different lots.....Really....Start in R302.1

Well, you could always argue that the new construction is going to place the burden on the existing house to be in compliance with fire resistance by setting the implied property line all the way up to the existing building wall. That's what I'm trying to avoid. Thanks.

 

[steveray]

Well, you could always argue that the new construction is going to place the burden on the existing house to be in compliance with fire resistance by setting the implied property line all the way up to the existing building wall. That's what I'm trying to avoid. Thanks.

Yep...that's what they get for building over the line...

 

[Jay Smith]

If the new house builds a 1-hour rated exterior wall and limits openings to 25% of that exterior wall, the new house would meet code for a fire separation distance of at least 3 feet. The old house would not, but they’re not applying for a permit.

 

[mark handler]

Residential Code, R302.1 Exterior Walls

Construction, projections, openings and penetrations of exterior walls of dwellings and accessory buildings shall comply with Table R302.1(1); or dwellings and accessory buildings equipped throughout with an automatic sprinkler system installed in accordance with Section R313 shall comply with Table R302.1(2).
Exceptions:
Walls, projections, openings or penetrations in walls perpendicular to the line used to determine the fire separation distance.
Walls of individual dwelling units and their accessory structures located on the same lot.
Detached tool sheds and storage sheds, playhouses and similar structures exempted from permits are not required to provide wall protection based on location on the lot. Projections beyond the exterior wall shall not extend over the lot line.
Detached garages accessory to a dwelling located within 2 feet (610 mm) of a lot line are permitted to have roof eave projections not exceeding 4 inches (102 mm).
Foundation vents installed in compliance with this code are permitted.

 

[Paul Sweet]

The old house might be able to use the Rehab code to avoid having to upgrade their wall.

 

[Christine]

The old house might be able to use the Rehab code to avoid having to upgrade their wall.

I don't see why the burden would be on the existing house to upgrade their wall, while the new construction doesn't have to do so. The existing house was probably built in the late 1800's. They are not applying for a construction permit; my understanding is that the owner of the adjacent lot did not do their due diligence. I welcome any information that supports the existing house being required to upgrade their wall. Thanks.

 

[steveray]

R102.7.1 Additions, alterations or repairs. Additions,
alterations or repairs to any structure shall conform to the
requirements for a new structure without requiring the
existing structure to comply with the requirements of this
code, unless otherwise stated. Additions, alterations,
repairs and relocations shall not cause an existing structure
to become unsafe or adversely affect the performance of
the building.

R113.1 Unlawful acts. It shall be unlawful for any person,
firm or corporation to erect, construct, alter, extend, repair,
move, remove, demolish or occupy any building, structure or
equipment regulated by this code, or cause same to be done,
in conflict with or in violation of any of the provisions of this
code.

Depending on what you do with your Ch 1, I could see lots of reasons to not let someone create a violation....

 

[Christine]

R102.7.1 Additions, alterations or repairs. Additions,
alterations or repairs to any structure shall conform to the
requirements for a new structure without requiring the
existing structure to comply with the requirements of this
code, unless otherwise stated. Additions, alterations,
repairs and relocations shall not cause an existing structure
to become unsafe or adversely affect the performance of
the building.

R113.1 Unlawful acts. It shall be unlawful for any person,
firm or corporation to erect, construct, alter, extend, repair,
move, remove, demolish or occupy any building, structure or
equipment regulated by this code, or cause same to be done,
in conflict with or in violation of any of the provisions of this
code.

Depending on what you do with your Ch 1, I could see lots of reasons to not let someone create a violation....

Thank you. Just to clarify, the existing house is not having any work done. The neighbor is building a new house 5' from the property line, and the existing house is 6" over the property line. This causes the existing house and the new house to be in violation of the fire separation distance requirements, because neither house has rated construction along the property line in question. My reading is that to avoid rated construction, both houses would have to be a minimum of 5' away from the property line. This is why I think that there needed to be a property line adjustment first before the permit was granted.

 

[Left Coasting]

What if the old existing house B is encroaching over the property line, and the new neighbor A has a clear right to have the encroaching wall demolished? Would that make it easier for A to put in a new structure without worrying about fire separation distance from house B?

In general, it seems hard to tease out whether fire separation distances only apply to structures on the same premises, or whether a new structure’s FSD is affected by existing structures on an adjacent, separate, neighbor's property, when they are close to the lot line. The code seems to take this for granted, but where is it granted? Are existing buildings on separate premises exempt by tacit omission?

 

[mtlogcabin]

The existing house does not meet the fire separation requirements in today's code and there are too many unknowns to determine if it ever did or was ever required to have a setback distance either zoning or fire

 

[Left Coasting]

My main question - which seems to be quite difficult to get an answer to - is a general one -
Do FSD requirements apply only to structures on the same premises? Does it matter when you build a new structure what the fire resistance or distance is on neighboring lots?

As for the specific case B mentioned, it looks like a garage that may have been compliant with a zero setback when it was built, but was later converted to living space, probably without a permit. The part that encroaches is a brick wall that would be quite fire resistant.

 

[mtlogcabin]

Do FSD requirements apply only to structures on the same premises?

IMHO Yes

 

[Left Coasting]

Thank you.

 

[steveray]

[RB] FIRE SEPARATION DISTANCE. The distance
measured from the building face to one of the following:
1. To the closest interior lot line.
2. To the centerline of a street, an alley or public way.
3. To an imaginary line between two buildings on the
lot.
The distance shall be measured at a right angle from the
face of the wall.

 

[Left Coasting]

3. To an imaginary line between two buildings on the lot.

Half way between them? Then if B's building encroaches on A's lot, the FSD is measured from the line halfway between the two buildings? Instead of to the lot line. But if B's building is only up to the lot line but not over it, then B's building is not considered in the FSD for lot A. Is that the way it works in principle?
And where is the imaginary line in relation to Bldg A and Bldg B? Thank you!

 

[tmurray]

We have run into this situation in the past. We typically will see the lot line move accordingly. On one occasion they removed the projecting portion of the existing building.

Theoretically, you could use the imaginary line, however, this negatively effects the property owner building a house based on a mistake by the neighbour.

As I always say, you didn't just buy a building, you bought every mistake that happened in the past too!

 

[Left Coasting]

We have run into this situation in the past. We typically will see the lot line move accordingly.

Is the lot line moved merely for purposes of the FSD -- or does the legal lot line change and the ownership of the encroaching slice of land shifts from owner A to owner B? Thanks

 

[steveray]

IF....the 2 buildings are on the same lot, you can draw the line where it is most convenient with wall construction and openings....If they are separate lots, then the property line is the boss and we wouldn't care how close the other building is...Other than to it's own side of the line...