Research Trends and Results

Determination of Degradation Conditions based on
Actual Survey for Demolished Buildings
TAKAHASHI Satoru, Research Coordinator for Housing Warranty
Housing Department
NUNODA Ken, HeadNAKAGAWA Takafumi, Senior Researcher
Housing Production Division, Housing Department
NISHIDA Kazuo, Senior Researcher
Housing Stock Division, Housing Department(Key words)

Timber housing, Demolition survey, Ant harm, Decay

1.
Introduction
Thisresearch
determines
thesituation
ofdegradation/damage and defects or the like of existing
detached timber housing according to actual surveys
targeting demolition cases, attributes of building (date ofconstruction, location environment, formulation of eachpart or the like) and arranges relationships between
emergence trends and locations of degradation, damage
or the like, and on that basis, aims to develop a simple
inspection method for their current state contributing torational comprehension of the current state of existing
housing.
This paper introduces knowledge, analyses and so on
obtained through surveys for demolition/reform objectsof detached timber housing implemented up until now.
2. Content of research(1) Improvement of actual example data in respect todegradation and damage of existing detached timberhousing
According to a survey for demolished buildings or thelike, with the emergence of sites of degradation
phenomenon in detached timber housing, we consolidate
actual example data with reference to conditions ofdecay/damage or the like to members inside the structure.
By conducting actual condition surveys for existing
detached timber housing and so forth built in each district
throughout the nation, we will take into account not only
effects on degradation by difference in climate
conditions , but also the location of housing and methodsof use, to consolidate data with respect to degradation anddamage occurring to detached timber housing.
(2) Guideline of current condition inspection method forexisting detached timber housing
Based on the actual example data obtained in (1), byfocusing attention on degradation phenomenon affecting
housing performance, we shall establish a current
condition inspection method to efficiently and rationallygrasp the conditions of gradation/damage. Specifically, aguideline for the actual state inspection method fromvariations of appearance to be confirmed by visualinspection, occurrence of degradation/damage or the likein parts difficult to visually look into such as the interiorof walling bodies shall be configured based on actual
example data to give estimates with a certain level ofaccuracy. In addition, in regard to parts with highoccurrence risks, a guideline of the actual state inspection
method capable of being induced so as to confirm theoccurrence of degradation/damage or the like byconcentrated current state inspections and detailed
inspections and so on shall be configured.
3. Survey results
Prior to initiation of demolition work, by carrying out
current state visual inspection for variations such as
cracks and rain infiltration, discoloring or the like, and onthat basis, carrying out investigation on the degradation ofinterior members such as decay, damage, harm caused bytermites or the like after the demolition of the finishedmaterials. In accordance with this, we tried tocomprehend variations in parts capable of visualinspection and the actual state of interiordegradation/damage and their relationship. As a result,
we were able to detect degradation phenomena notpreviously assessable in the current state surveys such as
in in water areas like the bathroom, toilet and so forth.
Through these results, the current state survey
incorporates a method to determine the general current
state in assumption/consideration and through a trial ofsurvey methods combined with degradation surveys,
which
carry
out
actualdetermination
ofdegradation/damage or the like. Through this, we haveconsolidated the guideline of the current state inspection
method, and deliberated on this so that the surveys in thefuture can be smoothly carried out and the survey results
efficiently collected.

Photo 1: Implemented situation ofcurrent state survey

Photo 2: Implemented situation ofdegradation survey

Table: Type of relationship between changes and degradation
Current statesurveyDegradation
surveyAssumed case1

Withchanges

Withdegradation

・A case of emerging deformation (inclination, etc.) due to structural materials withconsiderable degradation
・A case where degradation was assumed to emerge affected by degradation factors(moisture, termites, etc.), due to occurrence of cracks or the like.

2

Withoutchanges

Withdegradation

・A case where detection cannot be made by inspection due to an unchanged
appearance, even though degradation of structural materials has advanced

3Withchanges

Without
degradation

・A case where structural materials have not been degraded, even though changes
are detected in the appearance.