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Thread: Construction costs per square footage compared to nominal square footage increase

  1. #1
    Unfrozen Caveman Planner mendelman's avatar
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    Construction costs per square footage compared to nominal square footage increase

    I have a question that I know the answer to fundamentally, but don't really know a good defensible way to write it.

    I am working to change our minimum exterior side yard (side adjacent to a street) setback calculation methods (here), but the change would have a 'benefit' for some property owners. Many cconforming lots in the muni were built when the exterior side and front yard were considered the same and a 25 foot setback was required. Well, with my code change is appears that corner lots with existing 25 foot setback would now have a minimum required setback of 22.5 feet, effectively giving them 2.5 feet of buildable area they didn't have before.

    Now, the concern could be raised that this change is giving these property owners a valuable benefit, but I really think that giving a property an additional 2.5 feet of buidable area is actually quite nominal.

    So, my reasoning is that the costs of construction to maximize the additional buildable area would not be justified by the realtively small increase in house square footage. Now, just saying the above may not be sufficient, so I am wondering if y'all can help me with a better way to phrase my argument so that it is more convincing and logical.

    Thanks
    Last edited by mendelman; 14 Feb 2006 at 3:23 PM.
    I'm sorry. Is my bias showing?

    Let's not be didactic in this profession, because that is a path to disillusion and irrelevancy.

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    Member CosmicMojo's avatar
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    not cost-effective

    That's Just what I would say: the construction cost per square foot would be too high. Widening an existing room or home by 2 feet is not cost-effective. Widening an exisiting room is not marketable (who wants a with two noticible parts, one old and one new?) and building a 2'x14' room is not usable.

    Is that what you want?

  3. #3
    Cyburbian donk's avatar
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    Check with your building department for teh RS means book, it will explain costs.

    Then write a sentence something like

    Having reviewed the expected construction cost for a typical addtion this change in standards would permit, it is staff's opinion that no real gain is being provided to existing land owners.In addition to the cost of any permitted addtion, there are other items that would make an additon with a width of 2.5 feet unrealistic.
    Too lazy to beat myself up for being to lazy to beat myself up for being too lazy to... well you get the point....

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    Cyburbian mallen's avatar
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    This isn't exactly what you are asking for, but to a complainer I would just say: "So what! It doesn't matter if someone is getting 2.5 feet of additional value. Good for them. Worry about your own situation." Now if you don't like the proposed change because of code, aesthetic, or other planning reasons, then we can debate the merits of 25' vs. 22.5'. But to simply say someone is gaining value is not even worthy of your time to debate.

    Acquiescing to this argument is a slippery slope to ALL changes in regulations (ala Oregon's Measure 37). I write zoning text amendments that change small zoning elements all of the time - sometimes people gain value, sometimes they lose. But the totality of financial impact because of regulation is really impossible to quantify.

  5. #5
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by mallen
    ...I write zoning text amendments that change small zoning elements all of the time - sometimes people gain value, sometimes they lose. But the totality of financial impact because of regulation is really impossible to quantify.
    I hear what you're saying, but in the political realm of planning even seemingly minor changes like this can be misconstrued by someone, so I am just trying to be ready (plan) for a potential rebuttal.

    Though, making changes such as this is at some level arbitrary.

    donk, thanks for the direction....I should have realized that the Building inspectors would be a perfect resource for such a question.
    Last edited by mendelman; 14 Feb 2006 at 3:24 PM.
    I'm sorry. Is my bias showing?

    Let's not be didactic in this profession, because that is a path to disillusion and irrelevancy.

    Six seasons and a movie!

  6. #6
    Cyburbian Wannaplan?'s avatar
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    What about coming at it with the "maximum lot coverage" angle? [If your regs have this measure.] Run two scenarios, one at the 25-foot setback and another at 22.5-feet. You may find that under each scenario the same footprint area can be built, providing you a good defense that there is no difference between the setback restrictions.

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    Member CosmicMojo's avatar
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    I don't know if Means if going to help you; Means will give you an average cost per square foot for a certain type of construction, but that doesn't address the question if the actual additional building space is usable, and thus of value.

  8. #8
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by CosmicMojo
    I don't know if Means if going to help you; Means will give you an average cost per square foot for a certain type of construction, but that doesn't address the question if the actual additional building space is usable, and thus of value.
    I understand waht you're saying, but I think I can argue away any concern about this change "benefiting" some property owners by successfully arguing that any addition to maximize the newly acquired buildable area would be considered irrational by the average property owner due to cost vs "value".

    Quote Originally posted by Wanigas?
    What about coming at it with the "maximum lot coverage" angle?
    good point. We do have maximum building lot coverage and the potential increase in buildable area due to the code change wouldn't be affected by the average existing building.
    I'm sorry. Is my bias showing?

    Let's not be didactic in this profession, because that is a path to disillusion and irrelevancy.

    Six seasons and a movie!

  9. #9
    Cyburbian Wannaplan?'s avatar
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    Quote Originally posted by mendelman
    good point. We do have maximum building lot coverage and the potential increase in buildable area due to the code change wouldn't be affected by the average existing building.
    And then compare each of the respective max bldg lot coverage figures with the building envelope for each scenario. If the building envelope for each can support the max bldg lot coverage, then you have easily shown there is no benefit for the setback change.

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    Member CosmicMojo's avatar
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    I assumed you were talking about primarily residential lots with existing homes.
    But now I see you're talking about undeveloped lots.

  11. #11
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by CosmicMojo
    I assumed you were talking about primarily residential lots with existing homes.
    But now I see you're talking about undeveloped lots.
    No, I'm talking about both, but, yes, primarily already developed single family lots (because our muni. is practically built out, although we are having many teardowns).
    I'm sorry. Is my bias showing?

    Let's not be didactic in this profession, because that is a path to disillusion and irrelevancy.

    Six seasons and a movie!

  12. #12
    Member CosmicMojo's avatar
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    Quote Originally posted by mendelman
    No, I'm talking about both, but, yes, primarily already developed single family lots (because our muni. is practically built out, although we are having many teardowns).
    So the arguement against is that the tear-downs will have an advantage because they'll be able to build larger homes?

  13. #13
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by CosmicMojo
    So the arguement against is that the tear-downs will have an advantage because they'll be able to build larger homes?
    Well, that could be another item raised. Thanks.

    I was mainly concerned with existing buildings, but teardowns is a contentious issue right with some in the community, and some could precieve this potential for buildable area expansion as a benefit for those doing teardowns. Though I think I could counter that by saying that though teardowns are a relatively common occurance here, it is still a small porportion of the house construction work in total. Most of the permits are for house additions and getting a relatively small increase to the buildable not really benefit those doing additions to existing houses.

    So, I spoke with one of our Building Dept. guys yesterday, and he explained that such minor increases to buildable area would not be much or a benefit because average cost of construction around here (central Chicagoland) is $130/sqft and ideal construction is done is 1.6 foot increments. So, any oddly sized construction (such as 2.5 feet in depth) wouldn't be cost effective for such small increases to house square footage.
    I'm sorry. Is my bias showing?

    Let's not be didactic in this profession, because that is a path to disillusion and irrelevancy.

    Six seasons and a movie!

  14. #14
    Cyburbian donk's avatar
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    Quote Originally posted by mendelman
    So, I spoke with one of our Building Dept. guys yesterday, and he explained that such minor increases to buildable area would not be much or a benefit because average cost of construction around here (central Chicagoland) is $130/sqft and ideal construction is done is 1.6 foot increments. So, any oddly sized construction (such as 2.5 feet in depth) wouldn't be cost effective for such small increases to house square footage.

    I would have thought that for a small additon the price per square foot would be higher.

    Think of the cost of underpinning the foundation (attaching it to the existing foundation) as a percentage of the total costs. it costs the same regardless of the area of the addtion and is not cheap, it typically requires engineered drawings and an engineer on site whle it occurs to make decions as they arise.
    Too lazy to beat myself up for being to lazy to beat myself up for being too lazy to... well you get the point....

  15. #15
    Unfrozen Caveman Planner mendelman's avatar
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    Quote Originally posted by donk
    I would have thought that for a small additon the price per square foot would be higher.
    yes, it would be higher. The $130/sqft is an average number for more typical construction projects.
    I'm sorry. Is my bias showing?

    Let's not be didactic in this profession, because that is a path to disillusion and irrelevancy.

    Six seasons and a movie!

  16. #16
    Cyburbian mallen's avatar
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    Another way to look at it is to examine land values in the area.

    Say the lot in question is 100 feet long along this property line and you are giving it an additional 2.5 feet of newfound "usability." That is only 250 square feet (and I have not even deducted for rear yard setbacks which would further reduce the development potential of the property). Nevertheless, now say a residential land in your area is generally valued at $50,000.00 per acre. Then the per square foot value would be only $1.14 ($50K/43,560). The resulting value of this "newfound" land would be just $286. That really is a marginal "value increase."

    Also, this makes some generous assumptions. It assumes that only developable areas have value. If you consider that non-developable areas (within setbacks) have value the number is even less.

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