Category: Budget

Deep Thoughts

No, not a Jack Handey reference, although I did find those amusing at one time.

I’m here to talk about my basement.  Why on (or more accurately, under) earth would I put thousands of extra dollars into a basement which doesn’t even provide living space?  It turns out that there are a host of reasons, many of which are quantifiable in dollar terms.

  1. Rainwater storage: $5,000 saved without direct burial.
    There are conventional water storage tanks which are designed to rest on a floor, and there are direct-burial “cisterns”. Even though both can be found in the price range of $0.70 to $1.20 per gallon, the cisterns tend to be on the higher end of the price range.  For 1500 gallons of water storage, a difference of $0.50/gallon is $750.  However, this is the least of the concerns.  A direct-burial cistern needs tank heaters if the frost line is below the level of the tank (and of course, it is here1).  These would obviously consume precious energy.  Then, there’s the excavation cost (assume a tank height of 48″, buried at maximum depth of 36″, in a 15’x10′ hole, excavated 8′ deep and then partially backfilled with compacted sand) which could add another $3,000.  Plus the materials for backfilling, perhaps another $1,200.
  2. Doing plumbing labor myself: $4,000 saved with basement.
    When one is doing plumbing work in a slab, one is literally setting into concrete the pipes and drains.  Any mistake (due to inexperience, or a design change) becomes extremely difficult to rectify after the fact.  I think it is fair to assume that being able to do the plumbing entirely myself will save $4,000.  (Typical plumbing costs for the reference homes were $8,500 to $9,200.)2
  3. Reduced heating costs relative to slab-on-grade: $150 per year
    By using the super-insulated SIP flooring over a relatively constant basement temperature, we’re able to save significant energy costs for heating and also require a smaller heating system. 3
  4. Solar storage battery lifetime extension: $600 per 10 years.
    Lead-acid batteries have a significantly extended lifetime and better retention of stored energy (albeit at a somewhat reduced capacity) if they are kept at lower temperatures.  Assuming a $2,000 battery array with a basic lifetime of 10 years, the loss in capacity might require a 10% increase in size, but the lifetime might be extended to 16 years.  Obviously the larger the battery array, the greater the impact, and this is an ongoing reduction in maintenance costs rather than a significant difference in initial cost.  The lifetime of electronics such as inverters and chargers is generally better at lower temperatures as well.
  5. Space for drain water heat recovery: $100 per year
    With a ground floor bathroom, it would be difficult to install a drain water heat recovery system.  This system can provide significant savings in the energy required to supply the home with hot water.
  6. Space for solar batteries and inverters.
    Although this doesn’t have a calculable direct cost impact, the fact that these large items don’t take up space in the home means that the living space doesn’t need to be increased to compensate.
  7. Space for greywater recycling.
    Again, this has no easily measurable cost impact.  However, because the toilet by itself uses over a quarter of the water in a typical US household, reuse of greywater from other sources for toilet flushing can dramatically extend the capacity of rainwater storage, allowing for a smaller system or better performance of the same-sized system (fewer “dry spells” that must be sourced from groundwater supplies).
  8. Space for rainwater first-flush system.
    Probably the greatest source of contaminants in rainwater comes from dust that collects on the roof between rain storms.  A “first-flush” system which discards the first 0.1″ of rain during each storm allows these contaminants to be washed away, providing much better water purity at the input.  Meanwhile, the flushed water can be routed directly to the greywater storage.  Such a system could be installed outdoors, but then it would be susceptible to freezing and potentially need to be disconnected during the winter time.  By implementing it inside the basement, it can be easily interconnected, easily maintained, and protected from freezing all at once.

So on the assumption that I have the house for 10 years, the basement is saving me on the order of $12,000.  Although I don’t have a direct way of comparing, this is comparable to the cost of the basement, and it also provides a number of non-monetary benefits listed above.

So, we go deep.

  1. “Frost depth for a normal winter in the northeast is usually no more than 4 feet, so traditionally pipes are buried at 4 or 4 1/2 feet (5 ft for the main).  With only one day in February above freezing so far, the frost line has gone well below normal.” ↩
  2. Electrical work might be similar, except that in general very little of it needs to be done in the slab. ↩
  3. Detailed calculation: Slab-on-grade, 102′ perimeter, 0.5 BTU/(hr-ft-°F), 24 hours/day,  6803 degree-days, adjusted to 8628 70°F-degree-days, gives about 10.6e6 BTU/yr.  SIP floor, 648 sqft, (70-50)=20°F temperature difference for comparability, R-41 SIPs, gives 361 BTU/hr or 2.8e6 BTU/yr.  Assuming a heat pump at $0.14/kWh, this difference is about $156/year. ↩

Budgeting for Construction

Below is the budget that I have developed for the construction of the Little Rental House.  The lot was already paid for a long time ago (to help the community get the funds it needed for legal and infrastructure work) so that aspect is already known with accuracy.

When formulating the budget for the Little Rental House (#3, 992sqft, 2br 1ba), I used a combination of numbers from three homes previously built here at White Hawk: my own home (#6, 1536sqft, 3br 1.5ba), the home next door (#5, 1408sqft, 3br 1.5ba), and my parents’ home (#2, 1800sqft, 4br 2ba).  Because #2 was built in 2014-2015, while #5 and #6 were built in 2007-2008, the former gives prices much closer to “current day” while the latter need to be significantly adjusted for inflation.  However, #2 is a 4-bedroom home built with double-stud walls, so many of the architectural elements are very different.  #6 is the only reference with a basement, but was built with a lot of extras such as oak trim and flooring, so those costs aren’t representative of what I’m building.  And #5 is a good reflection of the trim level, but is larger and built a decade ago.

In all cases, I have the budgets (actual cost for #5 and #6, builder-estimated for #2) broken down into great detail, rather than just a lump sum total cost.  Thus, I was able to pick and choose, taking for example basement costs from #6, flooring costs from #5, and roofing costs from #2, with appropriate adjustments for number of rooms, square footage, etc.  Contractors often estimate construction costs on the basis of cost per square foot, and on that basis we find a range of $105/sqft for #5 to $124/sqft for #2 to $142/sqft for #6.

My basic budget (without the “extras”) has the Little Rental House just below the high end of the range at $136/sqft, even with almost no labor costs.  With the extras, it pops up to $147/sqft, higher than all of the reference houses.  There are several reasons for this.  First, the actual living square footage of the house is the smallest, so even though it is the lowest total construction cost, this increases the cost per area.1 Second, the basement is adding a substantial cost (about 6%) to the total.  Third, the additional cost of more heavily insulated walls adds another 6%.  However, it’s also unclear whether it’s fair to compare 2008 prices to 2019 prices; perhaps the homes built back then would be substantially higher today. 2

The budget below 3 represents the baseline that I’m working toward, will provide the structure for reporting the actual costs as we go along, and also provides the initial basis for estimated return on capital.

Budget ItemEst CostBasis for Estimate
Lot lease fee$40,000Contractual
Site preparation and excavation$8,000Assume same as home constructed on adjacent lot
Utilities-Oversight - was not budgeted
Foundation$10,330Assume: $4,000 for slab, $4,000 for ICF, 24.3cu yd concrete at $100/yd
I-beams$2,084Estimated based on weight of steel at $1/lb
Structural Insulated Panels (SIPs)$14,118$7.25/sq ft budgetary estimate, 1830 sq ft, $850 delivery
Framing material$3,000Detailed estimate from spreadsheet, rounded up
Framing labor$0Building it myself
Roof material$2,178Rafter framed, plus sheathing and steel roofing
Roof labor$1,600Assume same as home constructed on adjacent lot
Siding$1,800$1.5/sq ft
Siding labor$0Install myself
Windows and exterior doors$5,077Detailed estimate from spreadsheet
Electrical$2,250$25x40 outlets, $50x25 light fixtures
Plumbing$2,000Assuming I hire someone for septic but not for DW/DHW
Plumbing fixtures$1,700Use numbers from adjacent home but refactor for single bathroom
Heating$1,400Daikin RXS12LVJU
Wall finishes$7,000Use 60% of number from adjacent house based on smaller area
Interior doors$1,3004 interior doors
2 closet doors
Floors$5,952$6/sq ft
Kitchen$1,850Detailed estimate from spreadsheet for cabinetry, plus kitchen sink cost
Appliances$5,300Unique UGP-24CT1
Unique UGP-470L1
Combo washer-dryer
Microwave
Insulation$2,5004" R-6.5 foam over 7.25" R-3.6 cellulose in cathedral ceiling
Deck/porch$0Not including in initial build budget
Contingency$15,88820% of sum of above (except lease fee)
Extras - solar$6,718Battery backup
LED lighting
Extras - water$4,000In-basement rainwater collection and treatment
Total$146,045(including extras)

 

  1.  Some items, including the lot, have a fixed cost, so the smaller the home, the higher their impact.  Others, including site prep, plumbing, electrical, and roofing, have a significant base cost even if they do scale with home size.  Another important consideration is the fact that the home is mostly on a single story.  While this helps with accessibility, it means that there is, for example, more roof per square foot of house than there would be for a two-story home. ↩
  2. One source suggests that this could have increased by as much as 50%, so that even the cheapest $105/sqft would really be $157/sqft, but I think that exceeds the construction cost people are seeing for other homes here, ones for which I don’t have detailed budgets. ↩
  3. I apologize for the somewhat awkward formatting – I was torn between using TablePress (which gives you content in a searchable text form but doesn’t let me control the layout at all); or alternately inserting an image (which would let me make the format more legible, but wouldn’t contain text that you could access). ↩

A New Start

This blog has languished for some time while a number of shifts have happened in my life.  While I’ve learned many things in this time, I haven’t been producing much intellectual output aside from my work.  I wanted to change that, and as this timing coincides with receiving a building permit for a new home that I’m about to build, it seemed a great chance to combine the two threads.

So, while this post is a new start for the blog, it also represents a new start in the sense that economists would call “building starts” – a permit has been issued for #3 White Hawk Ln. (affectionately known as the Little Rental House), and I’m hoping to begin construction soon.  I expect to be blogging about the design, the process, and various other aspects.

The new house will be essentially one story, with two bedrooms and one full bath.  There is some additional loft space above that can be used for storage, office, etc., but other than the house is intended to be ADA accessible by design.  Beyond that, it will also have the highest insulation levels of any home yet built at White Hawk, in an attempt to reach “passive house” levels of efficiency.  (I won’t write that out in German because I think it’s a trademark if I do.)  I have a wide range of other “neat features” planned but I won’t spoil all the fun by writing about them in this first post.  I plan to be doing a lot of the construction myself to keep costs in check.

Obviously, I don’t have any interesting pictures to share, but I’m including a rendering of the house as seen from the west (looking in the windows into the kitchen, at the left, and the living room, at the right).  I have also uploaded the full plan set (large, 2.3M PDF) for people who might be interested in those details.

The current status is thus: I have the building permit in hand.  I am waiting for the surveyors to come out and mark for both the lot position and the house position.  I’ve started seeking quotes from contractors for excavation and foundation work, which I don’t feel qualified to do myself.  I’ve been learning about the differences between pre-fabricated Bilco basement entry steps and building the staircase myself; and I’m looking into how this impacts the choice of equipment that I can potentially put into service in the basement.

And I’ve already (based on the first quote) gone something like $13,000 over budget.  So… I’ve got to work on getting that down.  My estimate was based on the fact that the total cost for site prep and excavation for my current home was $5,300 (in 2007).  I expected this to go up, and resources like this suggest that maybe 50% increase was reasonable, so my budget was $8,000.   You can imagine my surprise when I got a quote for $21,000.  Of course, the quote isn’t quite comparable, because it includes work that on my current home was recorded under “utilities,” and which I hadn’t properly estimated in my initial budget.

I’ll keep you posted on how things look as I move along.