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One story with basement or two story- ‘bang for the buck’

Muddytyres | Posted in General Questions on

Good morning and thank you in advance. I am have a house built (zone 5-6) starting next year. I have known it was going to be significantly more expensive to build than the house will originally appraise. It does seem that it may be worse than I thought. We are still in design phase and the current design is proposed as 1700sqft with unfinished partial daylight basement (the daylight part will be south facing) and a 2 car garage with/without an additional potential living space for over the garage or in the basement for family/potential income. 

What’s the best ‘bang for the buck’? Two stories (or one and a half) no basement, garage/no garage? 

My contractor/designer really wants to stick to the present ‘plan’ and guarantees that the basement will be dry (almost no basement in the area is dry). I have been leaning more recently to doing the ‘unfinished or minimally finished space as the second floor so that it will appraise better and because if I have to do steps, I really don’t care which way I have to walk on them. 
Or should I bag the garage? (I haven’t had one in 12 years) 
We need toy storage (bikes, skis, kayaks, and all of our all weather gear) and space to work on the toys. 
Thanks again

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Replies

  1. Expert Member
    Dana Dorsett | | #1

    >"almost no basement in the area is dry"

    Just because most basements in the area are damp doesn't mean much. If the architects & contractors know what they're doing it's possible to build a truly dry basement that feels/smells like other fully conditioned space. In a zone or 6 location continuous wall & slab insulation can be a big part of it. It's more than mere water proofig & vapor barriers. Code calls out R15 continuous insulation for basement walls, but nothing for the slab. A continuous 1.5-2' of EPS under the slab makes a real difference in the mold potential, even though it does very little for the energy use aspects.

    Whether a finished walk out basement has a comparable bang/buck in resale value as a second floor, or the amount of value a garage with "bonus room" adds is dependent upon the local market.

  2. Aedi | | #2

    General disclaimer: Don't add features to your house just because they will "appraise better". Then you're just paying more property tax for the privilege of having built features into your house that you don't particularly like or intend to use, and might not still be popular when it comes time to sell the house. You are *way* better off including (and renting out) an apartment space, which will provide immediate, stable, real income.

    One cheap way to maximize usable space is have a finished basement. Overall, I'm not a big fan of basements as living spaces. People like natural light, so finished basements often come across as drab and dreary. A partial daylight basement helps in some ways, but it is only a "partial" solution. But there is a way to retain the value of a basement without all the drawbacks, by going with a shallow basement. That will allow for at least some window space on all sides. Split levels are one common way to accomplish this, and can work great on sloped lots. It also segments the living space in a way that makes it easy to include a separate in-law/apartment space. Alternately, you can just finish the portion of your partial daylight basement that has the most light, and use the rest for storage.

    Attached garages are bad for indoor air quality. Living spaces over garages are even worse -- they are rarely insulated properly, and even more rarely air sealed right (or at all). But again, an attached garage is the cheapest kind of garage, and finishing the space above one is a very economical way add more space. If money is tight, one solution might be to go garage-less for now, and leave room on the lot for a detached garage to be constructed at a later point.

    Finished attic spaces are weird, but again it is a cheap way to add space. They are usually low-light, or involve a lot of dormers (which are expensive and often leak), but you can address those problems early in the design process by using long shed dormers. They are more expensive to insulate than an attic, but that doesn't matter much if you were planning on including ducts in the attic anyway. Whether it makes economical sense depends on the area, and if you'll actually use it.

  3. Expert Member
    AKOS TOTH | | #3

    Sara,

    Generally building a box topped with a simple roof is the cheapest. It is also the most energy efficient.

    Depending on your roof shape, it can be fairly simple to design the roof to be either finished or easily finished down the road.

    Things like insulate the roof not the attic floor, for gabled roof go with a structural ridge and rafters (simple to build, leaves the space completely open), service chase from the basement to attic, bump up ceiling joist size so they can also be used for floor, plumbing vent tie to the stack above the flood line of a 2nd floor bath. These are low cost to do up front.

    Empty attics are a waste of space in my book, a post build finished 1/2 story might not show up on the property taxes, but will definitely add to the value of the house. Skylights, bad for energy use but great for light, is simple way to add extra light if needed and much simpler/cheaper than a dormer.

    The garage or no garage really comes down to the neighborhood. If all houses around you have 2+ car garage, than you really need to include one. With a walkout, it might be possible to use part of the basement as a garage or the bottom of a large main floor deck as a carport.

    Aedi is right on the mark with the rental suite. They add real income and value to the house. Using 5/8 drywall + RC for the basement ceiling, a bath in the basement and hookups for a kitchen are easy to do up front and will make adding in a basement apartment easy down the road.

  4. Muddytyres | | #4

    Thank you! The basement is probably the way we're going to go. I'll definitely ask about the EPS under the slab for the mold reduction. Also, I do not intend to build something that we're not going to use as far as the 'bang for the buck', only maximize the value of the build.
    Thanks again

    1. Expert Member
      Dana Dorsett | | #5

      Take a look at the "whole assembly R" values in Table 2, p.10 of this document:

      https://buildingscience.com/sites/default/files/migrate/pdf/BA-1005_High%20R-Value_Walls_Case_Study.pdf

      Those values include the thermal performance hit from any thermally bridging elements (like stud framing) and the thermal performance gains from elements other than the insulation, such as wallboard, sheathing siding, air films, etc. For zone 5 they're suggesting R7.5, which would include the R value of the slab itself and any finish flooring. At 1.5" and 1.5lbs per cubic foot density "Type II" EPS would be about R6.3 for the foam layer, but a wood subfloor plus finish flooring would bring it up to about R7.5. In zone 6 they're suggesting R10. At 2" Type-II EPS delivers about R8.4, which is about right for the rest to bring it to R10.

      The additional cost of that "extra" half inch of EPS to bring it from 1.5" to 2" is only about 20 cents per square foot. So for a 1000 square foot basement it would be at $200 cost-adder above 1.5"- the labor cost will be the same independent of foam thickness. That last half inch may or may not ever "pay back" over the lifecycle of the building depending on your local energy costs, but it's kind of "in the noise" on the overall cost of the project.

      The sub slab EPS goes above the compacted clean gravel, and the ground vapor barrier goes between the EPS and concrete. Putting the vapor barrier in that location avoids "iceberging" the foam board during the pour, since the flowing concrete can't get under the foam board and lift it up. If the vapor barrier were between the foam & gravel there is a potential to get puddles of liquid in voids on top of the vapor barrier that would take forever to dry through the foam. The foam itself can take the high humidity of being next to the gravel layer without damage or loss of function.

    2. Expert Member
      BILL WICHERS | | #7

      If you’re seriously thinking about renting out a basement suite, I recommend hanging the drywall for the ceiling in that suite using resilient channel and use a double layer of 5/8” type X drywall with green glue in between. That’s about the best you can do for noise protection, and if you also include mineral wool in the joist cavities you’ll have a relatively soundproof floor/ceiling assembly. This will help keep you from hearing any future tenants, and keep them from hearing you.

      Bill

  5. walta100 | | #6

    I found the construction loan / appraise very frustrating in that the things I see as adding value the appraisers do not. (Above code insulation, high efficiency HVAC equipment and good windows) I do not see a way to build a high performance custom home without about 50% cash or land equity.

    If you want to understand what the appraiser is looking for visit the model home at a subdivision builders. It will be the perfect balance cost vs. appraised value.

    Doing anything unusual in your local market is unlikely to appraise for more than it cost to build.

    I like my basement but we have elevation so draining to daylight is no problem but if you are somewhere you hit bedrock just a few feet down or the water table a basement is a no go.

    Nothing gives you more square feet per dollar than a one and a half story house but they are almost impossible to air seal and insulate so no free lunch.

    It may be possible in a very few years the idea of a human driver is as ridiculous as a horse and buggy on a state highway and the goofy owning a private car and a building to store it just so you can have it around and use it 2% of the time. But I built a 3 car garage and wish it was a 4.

    If you are going to build a custom house with the plan to sell in a few short years I say make a new plan. Way to much work for how much money you will likely lose. If this is going to be your last house and you can find the money build what you want and forget about resale value.

    Walta

  6. Andrew_C | | #8

    Does your neighborhood have an association of some sort, and do they allow rentals? Accessory Dwelling Units? Something to check on.

    This isn't perhaps the cheapest, but if you are sure you're going to rent and/or have relatives coming home to roost, and if your lot allows, I'd consider a separate garage with an apartment overhead. This will provide a lot more privacy for both parties.

  7. Expert Member
    Peter Yost | | #9

    Hi Sara -

    You mention that you have a "contractor/designer." I think that the role of a designer is to take your priorities and translate that into a design that delivers them. For example: attics and basements can provide spaces for high performance mechanical systems but it is also possible to design in space for mechanicals without using attics or basements. Make sure that your design--with or without a basement--takes into consideration your priorities for useful spaces for both occupants AND high performance mechanicals, including distribution.

    My buddy Steve Baczek is a high performance architect for both custom and production homes. And he always says: high performance is just an additional design constraint and quite often it means designing in dedicated connected spaces for MEP, with or without using attic or basement spaces.

    Peter

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