Assumptions of the 3-story apartment

[ken]

by Hanlin » Mon Aug 07, 2006 11:22 pm

All of the assumptions:

1. 3-floors apartment
28 units studio: wide is 14', length is 23'
Parking spot: wide is 10', length is 16'
Stair’s structure: wide is 11.5', length is 18'
one Laundry room & Warehouse: wide is 14', length is 23'
Wall－wood word is 2×6 for each, total is
Concrete topping is 1.5×1.5 for each
Anti-Fire Requirement: R2 or R3 (the cheapest one)
One window for each unit: wide is 6’, length is 2.4’
No balcony
No handicap allow
2. Fundamental Structure:
Soil-sandy base, using spread footing system
3. Construction:
Time schedule-6 months
4. Structure Material: Wood Frame, wood floor and wall, with 1 1/2 inches
concrete topping.
5. Out wall decorate: stucco

[ken]

by ken » Tue Aug 08, 2006 10:28 am

**8/8/06
Comments to Org. Assumptions:

All of the assumptions:

1. 3-floors apartment (ok)
28 units studio: wide is 14', length is 23' (kind of small, but ok)
Parking spot: wide is 10', length is 16' (ok, can be smaller - no handicapped space)
Stair’s structure: wide is 11.5', length is 18' (ok)
one Laundry room & Warehouse: wide is 14', length is 23' (ok)
Wall-wood word is 2×6 for each, total is (ok)
Concrete topping is 1.5×1.5 for each (see notes below)
Anti-Fire Requirement: R2 or R3 (the cheapest one) (choose R-2)
One window for each unit: wide is 6’, length is 2.4’ (need more windows, revise)
No balcony (ok)
No handicap allow (ok)
2. Fundamental Structure:
Soil-sandy base, using spread footing system (see notes below)
3. Construction:
Time schedule-6 months (6-9 months average including site work)
4. Structure Material: Wood Frame, wood floor and wall, with 1 1/2 inches (see notes below)
concrete topping.
5. Out wall decorate: stucco (ok)

================================================
**8/8/06
New Functional Assumptions:

A. Building Code Requirements & Design Parameters
-Building Code: IRC 2003
-Use and Occupancy Classification: R-2
-Type of Construction V-A (Combustible 1-hour fire rating)
Sprinkle system or 2-hour fire seperation at common corridor and stair (steel-pan system)
-Wind: 105 mph (3-second gust) Exposure C
-Seimic Design Category: B
-Overall Building Height: 30 ft. max. height
-Parking space: 8'-6" min. x 17'-0" min.
-Stair Exits (2 min.) 8'-0" min. wide x 12'-0 long with landings
(Steel stringers and 2" concrete topping over steel corrugated deck pan)

B. Sitework Design Criteria:
-Civil work: Land survey, site plan, etc.
-Utility Line Hookup: etc.
-Site preparation: etc.
-Excavation: (per soil condition)
-Soil report: Soil boring drilling (use this to determine the foundation system)
-Drainage: (per design)
-Shoring: (assumed no shoring is required at the existing building or soil condtion)
-Misc.

C. Architectural Design Criteria:
-Roof: Composite Shinge Roofing Systems
-Exterior Siding: Stucco (or equivalent)
-Window: Galzing window (opening area should meet building code requirements)
-Automatic Sprinke System: At corridor only (2-hour fire rated wall is optional)
-Mechanical room, storage room, etc. (per design)
-Stari Exits: Steel-pan pre-engineered stari system
-Lighting: Fixtures, etc. (per design)
-Story Height: 10'-0 max. total height
-Wall systems: 2x6 at 16" o.c. exterior and at cooridor walls; 2x4 at 16" interior wall
(2) 2x4 at 16" 0.c. at demised common seperation walls between units
Common wall is about 10" thick - used as bearing wall
Lower story wall: all stud spacing is at 12" o.c., upper 2-story is at 16" o.c.
-Floor framing: 1-1/2" gypcrete topping or light-weight concrete topping over wood floor framing
-Fire Rated Wall: 1-hour (two layers of 5/8" Gypsum-X Sheetrock walls and 2x studs)
-Insulation: R-12 to R-20 (per design)
-Mechanical: Duct work, AC units, etc. (per design)
-ELectrical: (per design)
-Plumbing: (per design)
-Misc. (per design)

D. Structural Design Criteria:
-Design loads: Roof Snow load: 30 psf (ground snow load: 30 psf)
Roof Dead Load: 25 psf
Floor live load: 40 psf Floor dead load: 10 psf
Public area live load: 100 psf
-Foundation: Spread footing (36" wide by 12" deep with 3-#5 rebar bot. continuous)
Stem wall (10" wide x 2'-0" min. stem height over footing) at front/back/corridor walls
Interior column footing 6'-0 sq. x 12" deep (7-#5 bot. each way)
-Roof framing: Pre-engineered trusses @ 24" oc. spanning between front/back wall to corridor walls)
-Floor framing: 11 7/8" TJI-pro 210 floor joist at 16" o.c. spanning side-to-side to common walls between units
3/4: T&G subfloor above floor joists
-Wall framing: 3rd/2nd floor framing: 2x6 at 16" o.c. exterior; 2x4 at 16" interior; (2)2x4 at 16" common walls
1st floor framing: 2x6 at 12" o.c. exterior; 2x4 at 16" interior; (2)2x4 at 12" common walls
-Columns: (6) 2x4 at common walls at 14'-0" o.c.
-Headers: (2) 9-1/2" TJ Microm Lam at each door and window openings (Span= 6'-0" max. add one for greater span)
-Connectors: at the roof or other framing (add 5% of structural framing system cost)

E: Facility Management:
-Architectural interior, laundry room, garage collection, etc. (per design)
F: Maintenance:
- AC units, light, etc. (per design)
G: Misc. (per design)

[ken]

by Hanlin » Wed Aug 09, 2006 11:31 pm

Dear Ken:

We are very appreiciated your help! After reading the new infromation above, I try to organize the main changes from my original design:
1.our width of interior wall has changed from 6" to 10"
2.exterior and corridor wall is 2×6 16”; Interior wall is 2x4 16”
3.Our entrance will a little bigger, from 6' to 8'
4.Parking spot: wide is 8.5', length is 17'-- So we can have more parking
lots.
5.Use and Occupancy Classification: R-2
6.Type of Construction V-A (Combustible 1-hour fire rating)
-Wind: 105 mph (3-second gust) Exposure C
-Seimic Design Category: B
--other assumptions are the same with your reply.

It seems that I don't have to change my orginal design too much.
And if we use this assumption, can you help us to estimate the rough price of the whole building construction?

Thank you very much again!!

Your sincerely,

Hanlin

[ken]

by ken » Thu Aug 10, 2006 12:13 am

You should use RS Means estimating tables to do the overall cost.
This shoud be a good exercise for your team. (I do not have the current version of cost data.)

- From roof top down to wall and to floor and foundation system
- Ex. Roof area x $$$/sf = roof cost
Wall area x $$$/(ht. x length) = wall cost
Floor area x $$$(joist lengthx Qty) = joist cost
Concrete yard x $$$/unit cost = foundation cost - concrete portionon
Steel reinforcing x $$$/unit cost = reinforcing portion
etc.....
-Use excel spreadsheet to itemize all compents/systems

This should give you an overall cost data for your project and you need
this data to present your report.
-Compare your cost/sf against my average cost data and let me know the difference.

[ken]

by Hanlin » Fri Aug 11, 2006 10:45 pm

It's sad, I can't find out the cost data..there are too much information I don't understand...

But according to this website:http://www.building-cost.net
It calculates a rough cost list below.

That is the rough assumptions which the website adopt:
===============================================
1.the total living area is 14655 SF
2.Foundation: Concrete slab.
3.Exterior Walls:Simple wood frame floor and roof plan.
4.Exterior Finish:Composition siding or minimum quality stucco.
5.Windows and Doors:Aluminum sliding windows. Minimum quality doors
and hardware.
6.Roofing, Soffit, Fascia:Minimum quality composition shingle. Simple
open cornice.
7.Interior Finish:Minimum quality wallboard. Minimum built-in lighting.
8.Flooring:Class 4 Composition flooring or low cost carpet throughout.
9.Bathrooms:Two bathrooms back-to-back, minimum quality resilient
floor, minimum-quality plastic counter tops in each bathroom. Minimum
quality tub and shower enclosures. Minimum quality vanity and
medicine cabinet in each bathroom.
10.8 to 12 linear feet of low cost cabinets with laminated plastic counter
top. Minimum-quality appliances.
11.Plumbing:8 low cost fixtures, plastic supply and waste lines.
12.no attic, balcony, basement, garage, porch not under the main roof
13.9770 SF living area above the second floor?
14.This home is in a housing tract
15.This home is built outside the metropolitan area
16.This house use forced air central ducted heating only.
17.There is no fireplaces in the building
18.The building is in CO, Zip:802-804 Denver
===============================================

Item Name Material Labor Equipment Total
Excavation -- 6,406 2,135 8,541
Foundation, 17,901 21,708 4,344 43,953
Piers, Flatwork
Rough Hardware 1,748 2,123 427 4,298
Rough Carpentry 57,886 65,880 -- 123,766
Insulation 10,840 5,713 -- 16,553
Exterior Finish 33,314 14,973 2,246 50,533
Exterior Trim 2,087 2,533 509 5,129
Doors 5,291 3,422 -- 8,713
Windows 9,112 4,776 -- 13,888
Finish Hardware 881 571 -- 1,452
Roofing, 24,203 15,652 -- 39,855
Flashing,Fascia
Finish Carpentry 3,212 12,474 -- 15,686
Interior Wall Finish15,419 18,358 -- 33,777
Painting 9,212 16,583 -- 25,795
Wiring 9,354 13,615 -- 22,969
Lighting Fixtures 7,013 1,701 -- 8,714
Flooring 6,890 7,537 -- 14,427
Carpeting 13,709 3,770 -- 17,479
Bath Accessories 3,396 1,612 -- 5,008
Shower & 2,168 1,402 -- 3,570
Tub Enclosure
Countertops 6,557 4,237 -- 10,794
Cabinets 21,558 5,227 -- 26,785
Built In Appliances 10,489 1,129 -- 11,618
Plumbing Rough-in 9,843 18,430 1,406 29,679
and Connection
Plumbing Fixtures 19,996 4,884 -- 24,880
Heating Systems 23,917 35,875 -- 59,792

--------------------------------------------------------------------------------

Subtotal Direct Job Costs
$325,996 $290,591 $11,067 $627,654

Final Cleanup -- 3,156 -- 3,156
Insurance 22,091 -- -- 22,091
Permits & Utilities 13,412 -- -- 13,412
Plans & Specs 3,156 -- -- 3,156

--------------------------------------------------------------------------------

Subtotal Indirect Job Costs
$38,659 $3,156 -- $41,815

Contractor Markup
98,620 -- -- 98,620

--------------------------------------------------------------------------------

Total Cost $463,275 $293,747 $11,067 $768,089

[ken]

by Hanlin » Fri Aug 11, 2006 11:26 pm

If above data are hard to read, please visit my blog
http://www.wretch.cc/blog/Hanlin

[ken]

by ken » Sun Aug 13, 2006 9:56 am

Using you data, you will have an average construction cost:
Avg. Cost= $768089 / 14655 sf = $52.4/sf (using living area will give you a conservative cost indicator)

This falls in my average cost summary table:
Type 2B (based on NBC90 old building code) the fourth one in series
Avg. Cost Range: $52.4 to $72.2/sf

So, you are in the right direction.
Use RS Means to compute each "component" price per squre footage,
then you can get an average "component" price according to Means book
and refine your total construction cost. (Should be a little more than $52.4/sf).

You may want to validate and include some of the fire-seperation and exit/stair construction cost. (ex. sprinkling system in the walkway or fire-rated wall requirements-1 hour min., steel-pan stairs, etc.)

It is difficult to estimate the minmum total cost because you have to imagine and consider all the construction processes.

If you have any question regarding a particular component, please let me know. Thanks for the updated info.