Why the sq.ft price measurement is useless and missleading

By December 30, 2017construction, prices

A smaller structure costs more than a bigger structure per square foot (sq.ft)

I know it does sound a little confusing but a smaller structure will always cost more per sq.ft than a bigger structure. Thats true with all other things equal so we use for the cost comparison the same materials and basic design only the size is changing.  Please see the below explanation and calculation why it is actually wrong to think that If we can built a 2000 ft villa for $100 per sq.ft you can also build a 400 sq.ft villa for the same $100 per sq.ft. Thats true even with the same building materials, the same labour rate and even the same basic box design. You can only use the sq.ft costs to compare structures which are basically the same size!

As you can see below a 10×10 ft house with 100 sq.ft is about 60% more than a 20×20 ft house with 400 sq.ft.  If you calculate the values for the size increase from a 400 sq.ft cabin to a 2000 sq.ft house the difference would be about 50%. So if the sq.ft price is $100 for the 200ft villa you would have a price for the 400 sq.ft villa of about $150 per sq.ft.  Quite a big difference I would say ….

 

House ModelWidthLenghtWall HeightRoof OverHangArea FloorArea WallsArea RoofPrice per sq.ft MaterialTotal For HousePrice per sq.ft FloorIncreasePrice per sq.ft Roof
feetfeetfeetfeetsq.ftsq.ftsq.ftUSD $USD $$ / Sq.ft%$ / Sq.ft
20x20 feet202084400640784$10$11,184$27.96100$14.27
20x10 feet201084200480504$10$7,304$36.52131$14.49
10x10 feet101084100320324$10$4,524$45.24162$13.96
Calculations:
Area Floor = Width x Length
Area Walls = Circumference x Hight
Area Roof = Width + 2 Roof Overhang x Length + 2 Roof Overhang
Price per sq.ft Material = Fictive Price for Material
Total for House = Sum of Floor Area Price, Wall Area Price, Roof Area Price
Price per sq.ft Floor = Total of House divided by Area Floor
Increase Percentage = Increase of sq.ft price with decreasing size of models
Price per sq.ft Roof = Total of House divided by Area Roof

What is the Square foot price based on?

Another big confusion comes from the fact that everybody uses a different base for their division. Is it the area inside the main walls, the roof area or the whole construction? Some are even coming up with inside 100% and outside areas with 50%. Or how about air conditioned areas only?  As you can see it mostly depends who is using the sq.ft price and for what purpose. Some real estate agents will tell you you can build in Costa Rica for $80, $50 or even $30 and usually at least in Costa Rica they talk about total construction size for the area. Even the college of architects uses that base for their division. In the USA its very common that people divide with the floor area or area between walls.  Thats obviously only makes sense if you compare apartments or structures without roof overhang since those roofs make a big difference.

For example with our very simple example of the 3 house types above you see that we get a sq.ft price of $14 on the 20×20 house if we calculate with the roof area. If we take the floor area we get a sq.ft price of  $30 so roughly double! On the smaller 10×10 cabin its even worse where we have a $14 / sq.ft for the roof area and $45 if we take the floor area so thats 3 times the price per sq.ft. So again depending what we take as a base we get between $14 and $45 per sq.ft for the exact same type of  construction depending on the area we choose for the base and the size of the house.

Whats included in the sq.ft price?

Then of cause everybody includes different things into their calculation for the total cost.

We include in our calculation all labour and the the following materials:

FOUNDATION Included in the core price is a simple pad foundation which is suitable for flat lots with good soils. A soil report from a reputable company is mandatory to confirm specific site requirements!
BASE SHELL The Base Shell consists of the raised sub floor. All SIP walls, the steel transom ventilation system, and a Sip panel roof.
ROOFING Included in the price is a high end stone coated shingle roofing system over a 30 lb felt waterproofing layer. Also included is a Aluminium gutter and downspout system with leave guard.
WINDOWS AND DOORS External Aluminium Windows & Doors. Internal Stained Wood Doors with Schlage Hardware.
ELECTRIC High End Square D electric Panel, Beticino Brand Matix Plugs and Switches.
LIGHTING Built in LED lights and high end low energy fans throughout the house and deck according to standard lighting plan.
PLUMBING Pex Plumbing System with Manablock and PEX built in plumbing boxes for lavatories, toilets, and showers.
PLUMBING FIXTURES High Quality name brand specifications include American Standard Toilets and Krause Showerheads and valves.
BUILT IN CABINETS We build our own Bathroom furniture with water-resistant Egger panels and Quarz Countertops. Kohler Bathroom Sinks and Krause faucets.
STANDARD INTERIOR FINISHES Internal walls and ceilings taped and plastered with a sand finish. Stone floors and tiles according to allowances.
STANDARD EXTERIOR FINISHES External walls and ceiling taped and plastered with a course finish and integral color.
DECKING Teal Color WPC Decking with hidden connectors and stainless steel screws.
OUTDOOR BATHROOMS Usually we place the showers and sometimes even Bathtubs outside or on the deck.

WHAT’S NOT INCLUDED

DRAWINGS AND PERMITS We charge a fee to start the design process and adapt the floor plans to your needs, site and budget.
LANDSCAPING Landscaping is not included in the estimates but we can assist in finding consultants to help with designing and planting surrounding areas.
EXTERIOR IMPROVEMENTS Depending on your budget we can assist with additional external structures, like pools, car ports, enclosed garages, additional deck area, yoga bales, entrance gates and structures and more.
FURNITURE Over the years we have designed a lot of custom made furniture for clients and would be happy to design and include a furniture package.
SEPTIC SYSTEM We will design a Septic system suitable to your soil and site conditions.
APPLIANCES Appliances like Refrigerators, Ranges, Air Conditioners, and Washing Machines are typically not part of our estimates but can certainly be sourced and included in a final bid.
CUSTOMIZATION PROCESS We strive to stay flexible such that they can be combined and adapted to your wishes, as long as our modular building system stays intact.
UPGRADES A lot of upgrades and customizations are possible, from additional deck areas, additional shade and shade systems, interior and exterior floor and wall finishes, etc.

So again you will need a very detailed estimate to determine whats actually included in the sq.ft price since everybody includes different things.

What quality is included in the sq.ft price?

Again it makes no sense to talk about a sq.ft price if the quality of materials is not very clearly determined. We are not really talking here about fancy stuff like high end faucets or similar but pretty basic material choices like should we use a low grade 4 inch PVC drain pipe for the toilet or a higher grade one. For example the lowest grade 4 inch drain tube costs $4 per meter the highest grade $27 per meter so thats 6 times the price. So you can guess which one you probably will get from a low end local contractor. Also very important is to remember that here in Costa Rica there is no building inspector so nobody will actually look at any drawings or will even specify which tube you will get.  In the USA or Europe there is a very low chance that a contractor gets away with stuff like that but here you will get the cheapest material China is able to produce. There is a reason why most toilets fail after a couple years . All the above is true for most basic building materials and there are quality / price differences which are amazing.  In developed countries we also have guarantees and responsibilities from Hardware stores, their suppliers and constructors here in Costa Rica that part is still developing.

Then we could talk about those fancy tiles, faucets and other items which are clearly visible even for the client.  they also do influence the sq.ft price but way less than most people realize.

Conclusion for the sq.ft price mess

Building a house, estimating and budgeting for it is a complicated and lengthy process if done right. Shortcuts like a sq.ft figure is only misleading and will cause problems down the line. Too often we have seen projects in our area which started with a quick promise of say $80/sq.ft from either the architect or the contractor or both. Usually down the line the project was way over budget which was wrong from the beginning.  If you hear from your architect, builder or contractor only a sq.ft price you better walk away quick. The only way to establish a serious budget for a complex project like building a house is to actually calculate ALL materials and all labour and make a detailed estimate. Please see our process for more information on the design process and what that should involve.

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