Traditional low-rise Domestic Building

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Task 1: CARE OF EXISTING BUILDINGS
Task 1 a. Traditional low-rise domestic building
Low-rise domestic buildings are made up of the smallest buildings that are
constructed in large quantities (Walshaw 2017). A good example is detached houses
for single families which normally consist of two to three stories and enclosed space
of 90-180 square meters. These buildings have low unit costs due to the limited
purchasing power of the owners. Demand in such type of housing exhibits a wider
geographical distribution hence most of them are usually contracted to small local
contractors.
Foundation
All the foundation in the low-rise domestic building should transit the building loads
to a stable stratum of the earth (Kopp et al. 2012). The following are two criteria for
stability in such buildings; First, the soil below foundation should be able to
accommodate the the load imposed upon it without more than an inch of the
settlement as shown in the attached diagram below. The bottom of the foundation
winter should not be above the maximum level of frost at winter since wet soil would
otherwise expand while freezing repeatedly which may move the building up and
down hence damage (Roberts 2008).
The maximum depth for a frost varies with climatic conditions and the topography.
The depth can be four feet in the cold continental climates while in tropical and
subtropical areas the depth should be zero (Roberts 2008). In case a typical concrete
footing is used, it provides support to foundation walls that serve either as retaining

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wall or frost wall with the earth on all sides(Walshaw 2017).
 Adapted from;http://www.steelconstruction.info/Construction
Structural system
Masonry walls
A structural masonry wall is used in traditional low-rising building to enhance greater
load-bearing capacity and to resist fire. The common materials are brick and concrete
blocks. However, bricks are preferred for its appealing exterior surface and durability
(Kop et al. 2012). Two vertical masonry layers should be build on either side for rigid
insulation. In colder regions, cavity walls whose heat flow is 50% of the solid wall

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are preferred and are joined together by steel reinforcement (Bryan 2011). In some
cases, there is the use of precast pre-stressed how concrete panels. The panels should
be fire prof with a span of up to 30 feet.
Enclosure systems
There is a varied enclosure system for low-rise domestic buildings. For the roofs,
traditional wood-shingles or felt asphalts singles and semi-cylindrical clay tiles are
used. The rain-waters from such roofs are normally caught in metal gutters, channeled
to exterior downspouts that disposes onto splash blocks or underground channels
linked to sewers in the storm (Bryan 2011).
The wall surface of any low-rise domestic building is clad with a variety of materials.
Traditional elements of wood like horizontal shiplap or clapboard siding are used on
light timer frames. A brick of a stone veneer is applied over timber and anchored with
a metal fastener (Bryan 2011). Cement plaster and stucco is a preferred traditional
material while enclosing both the timber and masonry structures in low-rise buildings
for its plasticity. Alternatively, a thinner synthetic stucco may be applied directly to
the plastic surface for foam insulation. The two commonly used types of insulation
are rigid and non-rigid. Rigid insulation is primarily plastic with varied thickness, one
to two inches while non-rigid has fixed thickness(Walshaw 2017).
Interior finishes
The most commonly used method of finishing a wall is a prefabricated form of non-
modern wet plaster known as gypsum board (Bryan 2011). The wet gypsum plaster is

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placed between a paper facing, forming larger panels which are then nailed to metal
frameworks or light timber depending on the material used(Yuen 2010). Doors in
traditional low-rise buildings are hollow-core and the door frames assume machined
timber shapes. Cast iron pipes with threaded joints are used in designing a drainage
system to get rid of wastewater(Yuen 2010).
Task 1 b. Reasons for deterioration in low-rise building
There are various reasons for the deterioration in low rise buildings with a good
number having to do with exposure to elements. Unless there is regular maintenance,
exposure to weather leads to deterioration depending on what material is used in the
building (Bryan 2011). Builders have the obli8gation to consider the environments for
the planned building before settling the materials for building.
Concrete corrosion
The main reason for the deterioration of concretes is corrosion. Two classes of
concrete corrosion exists namely; general corrosion which results from the
carbonation and pitting corrosion which results from the chloride ions (Bryan 2011).
Carbonation exposure to reinforcement structures after a given period leads to
widespread cracking of the concretes. On pitting corrosion, exposure to chloride ions
from water, leaking into the concretes leads to their deterioration (Yuen 2010).
Salt crystallization
Most of the buildings that are made of stones suffer from crystallization of salt. A
porous stone has higher chances of getting affected with crystallization compared to a
less porous stone. Usually salt enters stones in gaseous state into the pores where it is

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typically crystallized hence causing deterioration of the stones converting them to a
fine powder (Walshaw 2017). Typically, slat results from mixing the air pollutants
and stones. Salt may also result from the groundwater chemical cleaners, salt used for
de-icing as well as sea spray.
Frost damage
Frost is another element associated with the deterioration of buildings. Buildings that
consist of stone more so in regions where buildings risks high freezing temperatures
and precipitation are highly affected by this type of deterioration. Frost causes more
damages to stones with small pores compared to stones with larger pores (Walshaw
2017). That is, stones with smaller pores are more frost-susceptible.
Microbiological growth
In some cases, it is not whether that has an influence in deterioration of a building but
life may also contribute on the same. Life may contribute to the deterioration of a
building depending on the area in which it is built and the nature of the material used
during the construction of the building (Bryan 2011). Microbiological factors that are
known to be contributing to the deterioration of buildings include plant roots, birds
and other microorganisms. These factors contribute to the decay in some of the
building materials used. For instance, microorganisms would easily facilitate decay in
wooden materials compared to stones (Yuen 2010). Microorganisms such as fungi,
algae, bacteria are the most associated with damages in buildings since they attack
silicate and carbonate minerals for acid and other chemicals (Bryan 2011). Most of
such acids that these micro-organisms depend on are common in a variety of stones.
Task 1 C. Planned vs reactive maintenance