Building Cost Planning assignment 2

Building Cost Planning

Mikkel Jorgensen

1


Assignment 2

‘Sketch Design and Life Cycle Costing’

Trimester 3, December 10 2014

Student No. 214305185

Mikkel Jorgensen

Pages

Words

(Excludes front-page and reference list)


Mikkel Jorgensen

2

Table of content

Introduction 3

1. Part I: Sketch Design Costing 4

Bpi adjustment 5

1.1 Sketch Design Alternative One 6

1.2 Sketch Design Alternative two 7

1.3 Elemental cost alternative one 8

1.4 Elemental cost alternative two 9

Comparing 10

Recommendations 10

2. Part II: Life Cycle Costing 11

2.1 Option A 11

2.2 Option B 11

2.4 Option B 12

Recommendation 3% 13

Recommendation 6% 13

References 17


Mikkel Jorgensen

3

Introduction

After the design team and the client have reviewed the schemes and the estimated prices first

presented. I have been required to give more information regards to scheme A. It is my

responsibility to collect the envelope cost of scheme A and create 2 different alternatives on how to

build the envelope.

Part 1, my aim with this Sketch Design costing and life cycle report is to determine how much the

envelope will cost, doing different circumstances. I will present two options and come up with the

best solution to get the most value for money by creating awareness of the cost consequences of

different solutions.

Part 2, Later I will look into the information provided regarding the life cycle cost of a curtain wall

doing different circumstances,

The information provided will make reason for my calculation of the lifecycle cost of the different

options and then I will come up with the best recommendation of the different alternatives


Mikkel Jorgensen

4

1. Part I: Sketch Design Costing

This cost report deals with the development of a 7-story office building at a site in Geelong CBD.

The floor to floor height is initially determined at 4.00 meters. Throughout preliminary elevations in

the scheme shows the following:

Floor to ceiling height windows

The level one will contain the offices / showrooms and will have 75 % of the wall glazed

Level 2 to 7 show that 75 % of the total wall area is solid

Below I have prepared an elemental cost for two different design solutions of the envelope. The

envelope consist of the following three elements in both options:

External wall

Windows

Roof

I will come up with two different alternatives on how to construct the envelope with different

materials. Later in the report will I do my recommendation about which alternative would be the

best option


Mikkel Jorgensen

5

Bpi adjustment

In order to establish the builders price index (BPI) for the expected tender date of the project

(December 2015) this table has been created. The historical bpi data has been sourced from

Rawlinson’s 34th edition 2014. Using the data’s I have calculated the change in the BPI from year to

year, this made it possible to forecast the price on the projects tender date in December 2015

As shown in the table. The difference from Rawlinson’s 34th edition 2014 the latest known BPI was

December 31, 2013 this gave me an indicator on the expected tendering date of the project. So from

the data collected I can determine an increased price on approximately 1.99% a year this means that

from the latest known BPI until the tendering date of the project we have an increased price on

3.98%. Witch also is shown on the graph below.

194.24

198.12

202.06

206.07

185

190

195

200

205

210

2012 2013 2014 2015

BP

I

Year

BPI forecast

BPI forecast


Mikkel Jorgensen

6

1.1 Sketch Design Alternative One

Exterior wall

Alternative one is a 125mm thick tilt-up concrete wall panels in 30 MPa concrete, fixed in position,

with a white cement and aggregate finish. Seen from an aesthetic point of view this creates a

simple, calm skin of the building.

The concrete elements comes in panels of approximately 25.0 square meter. All connections joints

and sealants fire rated due to safety reasons.

Insulated on the inside with glass wool batts vertically fixed R 2.5 with the ability to adjust down to

rating R 2.0 the insulation is fixed between wooden studs that forms the inside of the wall. And is

finished with 2 x 13 mm plasterboard rendered and painted with two coats of white semi-gloss

acrylic paint

Windows

At level one there will be windows of clear anodised aluminium shop fronts standard selection

curtain wall glazed with 6mm toughened safety glass.

Between level 2 and 7 the windows will be an aluminium curtain wall, single glazed fixed light

Roof

The roof construction will be a steel framed roof construction consisting of steel work in roof.

Containing trusses/beams up to 15m clear span, steel purlins and insulation in glass wool battens on

mesh, the roof is finished with aluminium ripped decking. The ceiling consist of a suspended

ceiling with acoustic plaster tiles in pre-finished two-way exposed steel suspension system 600x600


Mikkel Jorgensen

7

1.2 Sketch Design Alternative two

Exterior wall

The exterior wall is built up with a standard clay brick wall laid in stretcher bond with 270mm

cavity between the two 110 mm skins of brick. The cavity is insulated with 100 mm glass wool

battens R 2.5 witch is the maximum of the recommended by different construction sources, this

allows the client to use R 2.0 if the price needs further adjustment. The insulation is vertically fixed

with insulation plugs of aluminium.

The inside of the wall is rendered with Acratex 1 mm / 2 mm white wash finish witch create a nice

and atheistic beautiful interior surface to give the office a bit of character

Windows

At level one I selected clear anodised aluminium shop front standard selection curtain wall. Glazed

with 6 mm toughened safety glass to prevent theft. At level two to level 7 there will be clear

anodised aluminium framing curtain wall with clear float windows in double glazing. This is due to

the hot summer days where temperatures easily reach 40 degrees +

Roof

The roof on this alterative is a built up roof construction consisting of

Suspended slabs N.E. 150mm thick MPa 25

2 x 50 mm thick Class VH expanded polystyrene prefabricating forgoing to falls against the drain.

Bitumen waterproof membrane, Single layer polyester reinforced app modified bitumen lining 4

mm thick, with add on with bitumen SBS modified waterproof membrane 150mm high skirting

including aluminium trimming.

The ceiling will consist of a normal suspended ceiling with Acoustic plaster tiles in pre-finished

two-way exposed steel suspension system 600 x 600


Mikkel Jorgensen

8

1.3 Elemental cost alternative one

Source:

All prices has been collected from Rawlinson’s 34th edition 2014. The location index is collected

from VIC Commercial OCT/NOV/DEC 2014


Mikkel Jorgensen

9

1.4 Elemental cost alternative two

Source:

All prices has been collected from Rawlinson’s 34th edition 2014. The location index is collected

from VIC Commercial OCT/NOV/DEC 2014


Mikkel Jorgensen

10

Comparing chart

Recommendations

Alternative one witch consist of the tilt up concrete panels and the roof construction of steel is the

more durable of the two options, it is also the most price efficient and time efficient due to its better

and easier build ability.

However there are down sides to alternative 1, from an aesthetic point of view would alternative 2

be more valuable due to the traditional masonry walls and the roof construction and windows. The

walls of alternative 2 is wider and has a better u-value due to the thick brick walls. The same can be

said about the windows, the double glazing will make the building more sustainable and

environmental friendly since there would be a decrease in the use of electricity to heat up, or cool

down the building. The roof solution in alternative 2 is also the better of the two. When dealing

with steel in roof construction as in alternative 1 you have a risk on condensation, this must be

avoided at all cost. My recommendation would therefore end up being alternative 2


Mikkel Jorgensen

11

2. Part II: Life Cycle Costing

My client has proposing to build a new office block and asked for my advice on the curtain wall of

the office they should choose. Assuming the interest rate is 3% per annum compound and product

life of a curtain wall is 12 years: I will compare the life cycle cost on option A and B

2.1 Option A

2.2 Option B


Mikkel Jorgensen

12

In this case we assume the rate of interest is 6% per annum compound and product life of curtain

wall is still 12 years: I will compare the life cycle cost on option A and B

2.3 Option A

2.4 Option B


Mikkel Jorgensen

13

Recommendation 3%

Due to the higher refurbishment and maintenance cost of option B the lifecycle cost exceeds the

cost of option A. the interest of 3% is very low and it is therefore highly recommended to pay more

in the capital cost and get the cheapest outcome in the long run. Therefore I recommend option A as

the cheapest option.

Recommendation 6%

In this case where we deal with an interest rate of 6 % the numbers turn out different even though

we have a higher refurbishment and maintenance cost in option b than in option a, it would still be

the better solution to choose option b this is due to the discount rate that will “discount” the costs of

refurbishment and maintenance so much over time that it would be cheaper to go with alternative B.

I therefore recommend option B as the cheapest outcome in this scenario


Mikkel Jorgensen

14

Calculations

Finding the area of the floor plates

12m

80m

GFA = 12 * 80 = 960 m2

The floor to floor height is initially determined at 4.00 meters. Throughout preliminary elevations in

the scheme shows the following:

Floor to ceiling height windows

The level one will contain the offices / showrooms and will have 75 % of the wall glazed

Level 2 to 7 show that 75 % of the total wall area is solid

How much is 75% of level one?

Level one envelope measure = 80 + 80 + 12 + 12 = 184 * 4 = 736 m2

75 % of level one glazed = 736 * 75 / 100 = 552 m2

Remaining 25 % solid = 736 – 552 = 184 m2

How much is 75% of level 2 to 7?

Level 2 to 7 shows 75 % of the total wall area is solid

Envelope measure = 184 * 4 = 736 * 6 = 4416 m2

75 % = 4416 * 75 / 100 = 3312 m2

25 % = 4416 * 25 / 100 = 1104 m2

Total wall = 184 + 3312 = 3496 m2

Total glass = 1104 + 552 = 1656 m2


Mikkel Jorgensen

15

Bpi adjustment

How to calculate the bpi adjustment

198.12 – 194.24 = 3.88 * 100 / 194.24 = 1.99752%

198.12 * 1.99 / 100 = 3.9425

Bpi 2014 = 198.12 + 3.94 = 202.06

202.06 – 198.12 = 3.94*100/198.12=1.98869%

202.06*1.99/100= 4.02099

Bpi 2015 = 202.06 + 4.02099 = 206.07

Location index

Since we are building in Geelong CBD the price would be different from the once we got in

Rawlinson’s witch is from Melbourne. So to find the correct price I have found the location index

of Geelong in VIC commercial from 2014. Price index Geelong = 1.005

Melbourne price 1.822.775, 76 *1.005 = Geelong price = 1.831.889, 639


Mikkel Jorgensen

16

Discounting

1.0 _

(1+R)n = X

3%

1.0 _

(1+0.03)1 = 0.97087

To get the following years you substitute the power with the year number you are trying to find the

answer for

6 %

1.0 _

(1+0.06)1 = 0.94339

Again here to get the following years you again substitute the power with the year number you are

trying to find the answer for


Mikkel Jorgensen

17

Appendix


Mikkel Jorgensen

18


Mikkel Jorgensen

19


Mikkel Jorgensen

20

References

Rawlinson’s 2014, ‘Australian Construction Handbook’, 32nd edition, Rawlinson’s Publishing,

Perth, Western Australia.

Smith, J & Jagger, D 2011, ‘Building Cost Planning for the Design Team’, 2nd edition,

VIC Commercial OCT/NOV/DEC 2014

Documents

Building Cost Planning assignment 2