Townhouse.. or not

[TimNY]

Entire lots excavated and a parking garage placed below grade level.

Townhouses proposed to be built per IRC on top of this parking structure. The top of the concrete structure is a concrete slab upon which the units are constructed.

Townhouses, or R-3? Does each unit "extend from foundation to roof"?

Thanks!

Tim

 

[Paul Sweet]

A code modification could be considered if the parking garage meets IBC 509.2 or 509.4. The parking garage structure would have to be designed to carry the gravity and lateral loads from the townhouses.

 

[TimNY]

Thanks, Paul. I am generally in agreement that it is a feasible idea.

Then I started thinking, if the garage is the foundation, the units would extend from the foundation.

All things considered I don't think it is a huge leap to R-3 anyway; the units are sprinklered with direct exits.

Then there is the matter of all utilities, DWV etc being run through the garage to reach the units vs entering from the street-side of each unit.

I thought it was an interesting scenario and appreciate any input!

Tim

 

[mtlogcabin]

An R-3 is limited to a maximum 2 dwelling units

R-3 Residential occupancies where the occupants are primarily permanent in nature and not classified as Group R-1, R-2, R-4 or I, including:

Buildings that do not contain more than two dwelling units .

A Townhouse is 3 or more dwelling units

TOWNHOUSE. A single-family dwelling unit constructed in a group of three or more attached units in which each unit extends from the foundation to roof and with open space on at least two sides.

It would be an R-2 under the IBC. If they are individual garages for each dwelling unit then I might agree it could be an IRC Townhouse

 

[fatboy]

I agree, the top of the parking structure becomes the "foundation". Are the garages separated? I think the utilities for each one still need to be protected from damage from the othere townhouse.

 

[TimNY]

Thanks for pointing that out MTL. The garage is one large, open structure. Tenants could park in any space.

As an example, the septic from each unit would exit into the parking garage and join a common sewer main. Other utilities are the same. COnsequently your sewer is running below other units, not to mention inside a separate building.

At this point I concur with Paul; an argument could be made to allow Townhouse-type construction, but I don't think it is a shoe-in.

 

[rktect 1]

How do they get to their units?

 

[TimNY]

How do they get to their units?

Excellent question! They do have street-front entrances.

The structurals show a solid slab 12" or 14" thick depending on location.

However, site plan with the parking diagrams show stairwells!

 

[bgingras]

Mixed use S-2 Garage with R-2 above.

 

[TimNY]

Yup, I agree.. the stairwells really eliminate any chance of getting a variance to use Townhouse-type construction.

It was an interesting premise prior to the stairwells, though.

I rarely deal with commercial, so I really appreciate all the input.

 

[bgingras]

I have been seeing these pop up around here to save space.

 

[fatboy]

Yup, I agree, S-1/R-2, the common garage plus stairwells.

 

[brudgers]

Definitely not a townhouse, because "from the foundation to roof" is inclusive (otherwise the roof would not be part of the the townhouse and this is something we all accept). Clearly it is R2.

 

[TimNY]

Definitely not a townhouse, because "from the foundation to roof" is inclusive (otherwise the roof would not be part of the the townhouse and this is something we all accept). Clearly it is R2.

Good point, thanks.

 

[Architect1281]

I go with Mt Cabin on that after 2 units its an R2 no matter how its built

 

[peach]

Not IRC buildings; IBC. They may be R-3, but out of the scope of IRC.

DO OVER

 

[brudgers]

Not IRC buildings; IBC. They may be R-3, but out of the scope of IRC. DO OVER

I don't think you can get it to R3 because of the lack of fire separation in the garage.