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Barriers for Deconstruction and Recycling of the Currently Built Single Detached Houses

S. Nakajima Building Research InstituteJ. Koga Building Research Institute

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1995 2000 2005

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LandfilledBurned/DryedRecycled

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1995 2000 2005

Year

LandfilledBurned/DryedRecycled

Recycle ratio of concrete and wood

Concrete Wood

The recycle ratio is increasing for these ten years in Japan.

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1995 2000 2005

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LandfilledBurned/DryedRecycled

Recycle ratio of concrete and wood

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1995 2000 2005

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LandfilledBurned/DryedRecycled

Most of the concrete wastes are used for road beddings.

Concrete Wood

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1995 2000 2005

Year

LandfilledBurned/DryedRecycled

Recycle ratio of concrete and wood

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10%

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30%

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100%

1995 2000 2005

Year

LandfilledBurned/DryedRecycled

Concrete Wood

Most of the wooden wastes are used in the production of energy.

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- Gypsum boards: - Glass:- Plastics:

The recycle ratio of the deconstruction waste are still very low.

Other Materials

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- Currently built single detached houses are significantly difficult to deconstruct and the waste generated during the dismantling process have low potential to be recycled as raw materials to reproduce building materials or other products.

- To make effective feedback loops of the building materials it is quite necessary to design houses that can be easily deconstructed.

- To do this it is quite necessary to precisely know what is ongoing on the deconstruction or dismantle sites to get the ideas for better design.

Introduction

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- The dismantling or deconstruction process of 16 single detached houses were carefully recorded to get information that can be fed backed to the design of the houses.

Introduction Continued

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Record Keeping on Site- The record of the whole dismantling or

deconstruction process of the 16 houses was kept on site.

- The types of the dismantling or deconstruction works and amount of the workers being involved in each work were recorded every 30 minutes.

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Hand Works

Items of the Dismantling Works

Machine Works

Waste Transportation

Others Works and Activities

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･･････ Total 17 sub items

Hand Works

Sub Items of the “Hand Works”Curing

Removing furniture

Removing facilities

Removing doors and windows

Removing flooring materials

Removing fixed furniture

Removing interior finish

Removing interior fittings

Removing gypsum boards

Etc.

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Machine Works

Sub Items of the “Machine Works”

Preparation works

Dismantling Building

Dismantling Foundation

Dismantling building

Separating waste by machine

Moving waste by machine

Loading waste by machine

Water sprinkling by hand

Separating waste assisted by hand

Loading waste assisted by hand

････････ Total 5 sub itemsEtc.

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Sub Items of the “Transportation”

Transportation

Preparation works

Arranging the bed of the truck /Taking photos

Write the declarer sheets

Transportation

Loading and unloading the container

Truck washing

Waste Transportation

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Sub Items of the “Other Works”

Cleaning

Consultation

Break

Waiting

Preparation works

Instruction

Others Works and Activities

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Database and Tool- The records kept on the dismantling and

deconstruction site were formed into a database.

- A tool was prepared to demonstrate and analyze the data.

Date and time

Items of works Numbers of

workers in charged

Detail information

Machine operation

DATABASE

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Data Demonstrating Window

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Data Demonstrating WindowThe types of works being conducted

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Data Demonstration Window

Number of workers being

involved

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Data Demonstration Window

Usage of dismantling machine

YES / NO

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Data View Window

Detail Information of the of the dismantling or

deconstruction works

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Data View Window

Date and time

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Data Analyzing Window

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Data Analyzing Window

By choosing the item and the sub- item the total works for those items can be calculated.

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Data Analyzing Window

By choosing “Machine Operation (Y/N)” the total works consumed in machine dismantling process can be calculated

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Data Analyzing WindowAll dismantling works were categorized into 6 types of dismantling processes. The processes are:

(1) Dismantling / Deconstruction(2) Separation and selection(3) Loading(4) Preparation works(5) Transportation works(6) Other works and activities

Works spent in each process can be calculated.

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Data Analyzing Window

Results

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Results – Works Spent

ConstructionType

Name

Post and Beam House A 2.18House B 2.26House C 2.27House D 1.99

Two by four House E 2.71House F 1.75House G 2.30

Wood Panel House H 1.76 1.76Steel Framed House I 4.40

House J 3.69House K 2.14House L 1.52House M 2.87House N 2.20

Post and Beam House O 3.64 3.64Steel Framed House P 2.27 2.27

Unit Dismantling Work

(Man x Time / m2)

2.18

2.25

2.80

Dismantled

Deconstructed

Works spent to dismantle or deconstruct a unit floor area.

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Results in Detail - House A

Dismantling Worksby Hand

DismantingWorks by Machine

TransportationWorks

Other Works

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70%

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90%

100%

Rat

io (

%)

Other WorksLabor Consumed

(Man x Hour)Cleaning 16.8Consulation 5.5Break 90.5Waiting 8.0Preparation 8.5Instruction 0.0

Transportation WorksLabor Consumed

(Man x Hour)Transportation 66.0Preparation 0.0

Types of Machine Dismantling WorksLabor Consumed

(Man x Hour)Preparation 7.5Dismantling Building 113.0Dismantling Foundation 27.8Leveling of Ground 3.5Removing Plantings 0.8

Types of Hand Dismantling WorksLabor Consumed

(Man x Hour)Curing 22.0Removing Furniture 33.0Removing Facilities 24.5Removing Doors and Windows 7.3Removing Flooring Materials 0.0Removing Fixed Furniture 9.5Removing Interior Finish 0.0Removing Interior Fittings 2.3Removing Gypsum Boards 56.0Removing Interior Framings 0.5Removing Insulation 7.3Removing Exterior Finish 3.5Removing Roofing Materials 30.5Removing Exterior Fittings 0.0

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Ratio of Each Work

Dismantling Worksby Hands

Dismantling Worksby Machine

Transportation Works

Other Works

0%

20%

40%

60%

80%

100%

Hou

se A

Hou

se B

Hou

se C

Hou

se D

Hou

se E

Hou

se F

Hou

se G

Hou

se H

Hou

se I

Hou

se J

Hou

se K

Hou

se L

Hou

se M

Hou

se N

Hou

se O

Hou

se P

Rat

io(%

)

DeconstructedDismantled

P&B 2x4Wood Panel

Steel Framed

P&B

Steel Framed

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Ratio of Each Works

Dismantling Worksby Hands

Dismantling Worksby Machine

Transportation Works

Other Works

0%

20%

40%

60%

80%

100%

Hou

se A

Hou

se B

Hou

se C

Hou

se D

Hou

se E

Hou

se F

Hou

se G

Hou

se H

Hou

se I

Hou

se J

Hou

se K

Hou

se L

Hou

se M

Hou

se N

Hou

se O

Hou

se P

Rat

io(%

)

In average 65% of the dismantling work was spent in the dismantling works.

P&B 2x4Wood Panel

Steel Framed

P&B

Steel Framed

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Ratio of Each Work

Dismantling Worksby Hands

Dismantling Worksby Machine

Transportation Works

Other Works

0%

20%

40%

60%

80%

100%

Hou

se A

Hou

se B

Hou

se C

Hou

se D

Hou

se E

Hou

se F

Hou

se G

Hou

se H

Hou

se I

Hou

se J

Hou

se K

Hou

se L

Hou

se M

Hou

se N

Hou

se O

Hou

se P

Rat

io(%

)

In average 40% of the work was spent in dismantling the house by hand.

P&B 2x4Wood Panel

Steel Framed

P&B

Steel Framed

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Ratio of Each Work

Dismantling Worksby Hands

Dismantling Worksby Machine

Transportation Works

Other Works

0%

20%

40%

60%

80%

100%

Hou

se A

Hou

se B

Hou

se C

Hou

se D

Hou

se E

Hou

se F

Hou

se G

Hou

se H

Hou

se I

Hou

se J

Hou

se K

Hou

se L

Hou

se M

Hou

se N

Hou

se O

Hou

se P

Rat

io(%

)

In average 25% of the work was spent in dismantling the house by machine.

P&B 2x4Wood Panel

Steel Framed

P&B

Steel Framed

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Ratio of Each Work

Dismantling Worksby Hands

Dismantling Worksby Machine

Transportation Works

Other Works

0%

20%

40%

60%

80%

100%

Hou

se A

Hou

se B

Hou

se C

Hou

se D

Hou

se E

Hou

se F

Hou

se G

Hou

se H

Hou

se I

Hou

se J

Hou

se K

Hou

se L

Hou

se M

Hou

se N

Hou

se O

Hou

se P

Rat

io(%

)

In average 10% of the work was spent in transporting the waste.

P&B 2x4Wood Panel

Steel Framed

P&B

Steel Framed

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Hand v.s. Machine Dismantling Work

y = 0.6859x - 0.7499R2 = 0.8894

0.0

0.5

1.0

1.5

2.0

2.5

0.0 1.0 2.0 3.0 4.0 5.0

Total works spent in dismantling

(Man x Hour / m2)

Am

ount

wor

ks d

one

by h

and

(M

an x

Hou

r / m

2)

y = 0.016x + 0.6005

R2 = 0.0096

0.0

0.5

1.0

1.5

2.0

2.5

0.0 1.0 2.0 3.0 4.0 5.0

Total works spent in dismantling

(Man x hour / m2)A

mou

nt o

f wor

ks d

one

by m

achi

ne

(M

an x

Hou

r / m

2)

The total work required to dismantle the house depended on the work consumed in the hand dismantling process.

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Works Spent in Each Process

Dismantling/Deconstruction

Separation/Selection

Loading

Preparation Works

Transportation

Others

0%

20%

40%

60%

80%

100%

Hou

se A

Hou

se B

Hou

se C

Hou

se D

Hou

se E

Hou

se F

Hou

se G

Hou

se H

Hou

se I

Hou

se J

Hou

se K

Hou

se L

Hou

se M

Hou

se N

Hou

se O

Hou

se P

Rat

io(%

)

In average almost 25% of the work was spent in the dismantling process and 15% was spent in the separating and selecting process.

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Types and Amount of Waste

0.0

0.2

0.4

0.6

0.8

1.0

1.2

P&

B (

C)

2x4

(E)

Woo

d P

anel

(H)

Ste

elF

ram

ed (

M)

P&

B (

O)

Ste

el U

nit

(P)

Am

ount

of

Was

te (

ton/

m2 )

Mixed WastePaperFiberWoodPlasticsSteelTiles and ConcreteGlass/CeramicsGypsum BoardConcrete

Deconstructed and rebuilt

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Fiber type insulationmaterials (Not formed).Difficult to handle.

Pulp type insulationmaterials (Not formed).Difficult to handle.

(2X4) (Steel Framed)

Undesirable Designs For D

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(Post and Beam)(Steel Framed)

Interior finishingmaterials glued toplywood.Difficult to separate.

Gypsum boards gluedto the wood framings.Difficult to separate.

Undesirable Designs For D

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(Steel Framed) (Steel Framed)

Gypsum boards gluedto the wood framings.Difficult to separate.

Vapor barrier glued tothe wood framings.Difficult to separate.

Undesirable Designs For D

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Wood framings gluedto the exterior sidings.Difficult to separate.

Wood framings gluedto the steel framings.Difficult to separate.

(Steel Framed) (Steel Framed)

Undesirable Designs For D

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Floor composed of 4layers of differentmaterials.Difficult to separate.

Flooring glued to theconcrete slab.Difficult to remove.

(Post and Beam) (Steel Framed)

Undesirable Designs For D

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(Steel Framed) (Post and Beam)

Flooring glued to theconcrete slab.Difficult to remove.

Plastic mats glued tothe floor.Difficult to remove.

Undesirable Designs For D

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Concrete panelsjointed with sealant tothe steel framings.Difficult to separate.

Composite exteriormaterial.The composingmaterials are difficult toseparate.

(Steel Framed) (2X4)

Undesirable Designs For D

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Insulation glued toconcrete slab.Difficult to separate.

Composite exteriormaterial. Thecomposing materialsare difficult toseparate.

(Steel Framed) (Post and Beam)

Undesirable Designs For D

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Floor composed withsteel, plywood andinsulation.Difficult to separate.

(Steel Framed)

Undesirable Designs For D

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Undesirable Designs For D- Using difficult to handle materials.

For example non-packaged fiber or pulp insulation materials. These materials can easily brew away all over the floor and become difficult to handle.

- Using materials composed with different types of materials.

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Undesirable Designs For D- Gluing finishing materials or sub materials to the

wood framings or steel framings.

- Gluing different types of materials to compose slabs or walls.

- Sealing the gap between the steel framings and the concrete panels.

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Conclusion- The database for the dismantling process of the

single detached houses was formed.

- The database gives useful information for the future designing of the buildings.

- Particularly the finishing materials are usually replaced say every 15 years during the service life of buildings.

- At least for these materials we should think about the alternative design that enables the resource circulation.

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Conclusion Continued- To design demountable houses it is important to

minimize the use composite materials.

- To design demountable houses it is important not to make composite members in the process of constructing buildings.

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Thank you for your kind attention.