Development Portfolio Report
Ben108- Construction Technology 1
External Fabric. 4
Internal Fabric. 5
Cold water intake. 8
Heating systems. 11
Hot water system.. 11
This report is based upon the proposed construction of five domestic
dwellings within the coastal village of Carnlough in North East Antrim.
Throughout this report the aim is to discuss the main elements that comprise
the construction of domestic dwellings and to select the appropriate method
that should be used in the site at Carnlough.
Carnlough is on the causeway coastal scenic route and is part of the Mid
and East Antrim district. It has a picturesque harbour built to supply and
transport the nearby quarries, it has since been renovated to be used by
fishing and pleasure boats. This creates an appeal for the village in tourism
Domestic dwellings are in demand in this village. “A new build scheme was
on site in Carnlough to provide seven dwellings which will help address rural
housing need in the area.” NIHE (2014)
The proposed site as shown in the appendix is in the north of the town. It is next
to a recently built housing development and is within walking distances to the
nearby shops primary schools as well as a short drive to the nearby secondary
school, Larne is the nearest town 13 miles away.
Health and safety is a priority when it comes to any project regardless of
size. HSENI regulations ensure that risk assessments are carried out on every
building site to reduce the likelihood injury to workers or to members of the
The site is 1.3 hectares and will have 5 plotted dwellings. The site should
be a restricted site for health and safety reasons. Children from the nearby
development could be attracted to the site hence why appropriate fencing and
signage should restrict unauthorised access.
The site will be accessible to deliveries of materials and is ample size to
store materials during the build. Powerlines run across part of the site and
this must be taken into consideration as high sided vehicles may have
restricted movements within the site.
The site is built on a slope and as a result there will be a section of
filled ground within which four plots will be built on. This will be taken into
consideration through the construction of the foundations section. This will be part of remedial work required
by the site.
With regards to the style of the dwellings they could potentially be built
to match the style of the area. The surrounding homes are of single storey
construction with 4 bedrooms, both terraced and detached with brick and whitewash
finish. Homes in the area at the time of writing this report cost £95,000 in
the adjacent development for a similar dwelling. (Daniel Mcalister & Son
Estate Agent, 2017)
A benefit for the site is that due to its proximity to housing there is a
relative solution to services requirements. Fitting plumbing and heating to the
site may come at a reduced cost as a result.
Finally, this site is in a well accessible area, can be made safe and is
located near homes at reasonable prices. The site could be easily fitted with
water and heating however further research is needed. There is also scope for
building detached or semi-detached housing with the addition of a garage which
would add to the potential value.
For this report the analysis will focus on one plot within the proposed
site. The plot in focus is plot two. The plot in question lies atop filled
ground and as a result will require a suitable foundation for the type of fill.
Foundations are the subfloor support of a building. They transfer the loads
of the building, both static and dynamic, to the ground. Foundations should be
designed to support all expected loads and in some parts of the world be
designed to withstand natural disaster such as earthquakes.
When designing foundations there are three principles to consider, the
expected loads, the soil type and bearing capacity and finally the site
For this site the soil typical of the area is boulder clay. This is a
cohesive soil type that can support between 400 and 800 kN/m2 of load and would
be suitable for building domestic homes on with strip foundations.
When fill is factored in the site may have some restrictions. Simpson and
Purdy (1984) State ‘Properly graded and compacted fill can be stable with only
moderate compressibility and good load bearing capacity. Wide or deep strips
can be used with no additional costs… in comparison poor natural compaction
fills which have been badly placed can mean normal strip would be inadvisable…’
For this report research of the site shows that the gradient of the slope
on this site is minimal and the fill may not be much deeper than 2000mm.
Assuming the fill has been properly graded then I would recommend a strip
foundation for this site which wouldn’t need to be at a depth of more than
500mm. This relies on the fill being well compacted and firm. In accordance
with the technical booklet D of building regulations (2012) the trench should
be no less than 400mm wide to support a load not greater than 40kN/m.
For the flooring I would suggest a t-beam and block raised floor. When
insulated and dampproofed this should prevent any water penetration from the
soil and any cold bridging.
The external fabric of a building is designed to resist wind load, prevent
water perforation, reduce the amount of heat loss, allow for daylight and
grants access to the building. Part of the external fabric provides the
dwelling structural support.
For modern dwellings there are 3 main types of wall, porous, rain screen
and cavity wall. For the Carnlough development the most suitable option is the
cavity wall. The area is on the North Antrim coast and there are moderate
amounts of rainfall all year round. A cavity wall’s purpose is to allow any
water that penetrates the masonry of the outer leaf to drain through a gap
between the outer and inner leaf. The water should not penetrate the inner leaf
as a gravity allows water to leave through holes in the outer leaf masonry at
the base of the wall. The outer leaf for the development could be completed
with brick or blocks and to keep with the style of house in the area should
have a whitewashed finish. In keeping with the building regulations, the cavity
walls outer and inner leaf shall both be tied to one another using brick ties.
The reason for this is to allow for structural stability and allows for some
movement in high winds which are also prevalent in the North coast.
Where the outer leaf can be comprised of brickwork or blockwork the inner
leaf can be made from timber frame or SIPs. “SIPs panels consist of an
insulating core bonded between two structural facings. Built off-site, the
panels are very fast to erect on site and achieve good U values and excellent
airtightness.” Snell (2017) SIPs board construction may be slightly more
expensive than timber or blockwork but they can significantly reduce build time
and other associated costs. For this project SIPs could potentially be an
affordable option. The closest merchant for these fitted panels are near Belfast.
This would mean materials could be transported to site within 2 hours based on
the location which is easily accessible via coastal route. The Resistant
company boards may be safer than timber frame based on their ‘non-combustible’
design. The base board 10 design is… weather and mould resistant, breathable
and vapour permeable, robust, and high strength, non-combustible sheathing and
has pre-insulated panels. Resistant (2017)
In terms of internal factors, we include the walls, upper
floors, stairs, and doors. Each are set out in the building regulations
booklets and should have sufficient fire ratings in modern domestic buildings.
Walls- there are 3 types partition, party, and compartment. As
this is a detached house there is no need for a part wall as there are no
neighbouring homes. As for the partition walls there are a few options, timber
stud or metallic stud. The metallic stud walls are generally easier to fit. For
this development however, the timber stud frame would me more appropriate in
keeping the aesthetics pleasing in the dwelling. Resistant also supply
partition wall fittings which can be used much like the external leaf outlined
above. A description is outlined in the appendix as shown. This insulation meets fire
resistance in compliance with British standards and building regulations for
Upper floors- should the house have been built
with internal blockwork rather than the resistant boards selected then T-beam
and blocks would be appropriate. In the case of the development timber joists
can be fitted to the resistant board and timber stud design as laid out by the
resistant company. Shown in Appendix
in compliance with building regulations.
Stairs/doors- there are numerous designs in which
stairs can be constructed. For this development a standard method would be an
acceptable choice. Millar wood crafts provide traditional staircase joinery. Their
location in Randalstown is ideal and within reasonable distance to the site and
would be an advisable choice of joinery specialists to fit the stairs in this
development. Some of their work is shown in the appendix.
Doors for this property should have a hardwood core to
provide a good fire rating. They can come in many different designs and can be
provided by the Millar wood crafts. This could also come cheaper as part of a
The roof has a variety of purposes in domestic building
construction including protection from different elements such as rain snow and
wind, parts of the roof provide protection to the structure’s interior and
Fig 1, example of a
dormer roof, Wessex building products (2017)
Roofs can be of flat or pitched design. For this area a
flat roof would be out of fashion, so a pitched roof design would be advised.
The roof could if desired be made as a habitable area. As a result, the whole
roof would need to be insulated. With a continuous gap of 50mm gap outside the
insulation to prevent moisture and condensation build up as recommended by
British Standards. For this project a dormer roof could be a reasonable option.
Should the loft be used as a habitable room then the dormer comes with a window
extension as shown in fig.1.
As for the garage
the roof can be of lean-to design for aesthetic purposes.
There are two ways to construct a roof, cut or trussed. A
cut roof is designed, cut, and built on site. The advantages of this type of
roof are mainly to do with site restrictions. If the site is in a built-up area
or has poor road access, then the materials can be easily stored on site and
then built to a pre-designed specification.
As for disadvantages this method can be more expensive than trussed
design. Cut roofs are more time consuming and generally have wastage of
materials which adds to costs.
For trussed roofing this can be a more cost and time
effective investment. These roofs are factory built and can be tailored to meet
the needs or specifications provided by clients. The roof then can be assembled
on site without any wastage of materials. The implications for this type of
construction are that the site needs to have good road access and enough space
to safely assemble the roof.
For the Carnlough plot there is scope for using the
trussed method. Just as there is easy access for the SIPs there is a
manufacturer of trussed roofs in Carrickfergus, called Trussed Solutions. As a
result, it would be recommended for time and to keep expenses low that a
trussed roof would be suitable for this. Precautions would also need to be
taken to ensure health and safety around the overhead powerlines.
Cold water intake
Cold water is a necessity in all households. Estimates vary, but each
person uses on average around 150 litres of water per day. Most of this water
is used in showering, followed by washing machine and dishwasher use, and
finally in drinking purposes.
Fig 2 site plan- sewers
and mains based on assumptions (red )
Northern Ireland cold water supplies come in the form of loughs, reservoirs,
and wells. Northern Ireland water provide and own the rights to the pipes up to
the border of the house. Here the service pipe becomes ownership of the
householder. As shown in fig.2 the sewer line and water mains would run along
the road as standard. A connection could be made through NI water.
Within domestic households there are two methods for cold water supply,
direct and indirect.
this method the mains water supplies all the household’s water outlets. This
means that drinking quality water can be obtained from every outlet. A cold-water
storage tank may be needed required based on heating system but isn’t
Using a direct method, the cost of pipework is reduced, safe drinking water
can be obtained throughout the household, and only a small tank may be required
if at all.
Fig 3, example of a
direct method setup, DIY Doctor home improvement hub
this system problems can arise if the mains supply is cut off. As a result, if
there is no tank then the home will be left with no reserve. There is a
potential for back siphonage in this system. Lastly if there is more than one
outlet being used at a time then the pressure can drop thus reducing the speed
at which flows from each outlet. See fig.3 for a basic set up for direct
In this system the water bypasses all outlets in the household except for a
pipe that runs directly to the kitchen sink. The water connects to a storage
tank. From this tank there is a distribution pipe that takes water to the
remaining outlets. The water in this case is not of drinking quality. It is
however less economic than the direct method in terms of pipework as more than
one pipe feed the outlets. As a result of using a storage tank and not all
outlets being connected directly to the mains then the pressure is less likely
to drop in this case. Should the mains be cut off then the benefit in this system
is that there is a cold-water tank that will last for some time before the
mains flow returns. The indirect method has been outlined in fig 4.
Fig 4, example of an
indirect method setup, DIY Doctor home improvement hub
For this plot it may be a
sound investment by selecting a direct system. This along side a small storage
tank would be beneficial, hence providing some water retention in the case of
water outage. To prevent back siphonage each of the outlets should be fitted
with an air gap to allow for an overflow.
Thermal comfort is a necessity in any household. Thermal
comfort is perceived as being comfortable under surrounding environmental
conditions. In Northern Ireland heating is a priority especially throughout winter
months. This plot will require sufficient heating elements to provide suitable
conditions all throughout the year.
Similarly, as with the cold-water system there are two
methods to household heating, direct and indirect.
Direct- This comes in the form of four categories of heating;
solid, liquid, gas and electric.
Solid- fuels include the traditional wood or coal burning fire
and the modernised multifuel stove. Open fires can heat the whole property and
generally adds to the aesthetics however can be highly inefficient, and it creates
excessive air changes, causing draughts
and heat loss. The modern and increasingly popular
multifuel stove can be up to 50% more efficient than a fireplace. It reduces
the amount of dust and reduces the likelihood off heat loss.
Oil/liquid- is similar to the traditional solid
fuel method. Although it can be more efficient it can be a costly venture. It
must constantly be refilled as a storage tank is required on the property. The
tank must be leased in most cases by the householder and fees for oil.
Fig 5, Burley Ambience
Stove – Flueless Gas Stove by Onestop fires. (2017)
Gas- there are a number of systems for gas provision. In place of a fire there
are decorative fuel effect fires and inset live fuel effects. These both
provide an aesthetic appeal to gas as a fuel. Radiant convecters and flueless fires can be built into
walls. Flueless fires produce virtually no carbon monoxide. The gases are also
cleaned by a catalytic converter built into the system making it significantly
safer than solid or liquid fuels. Carbon monoxide poisoning has been a major
problem with gas fuel. By using a flueless fire the liklihood of carbon
monoxide production is reduced.
Electric- the final method for direct method
of heating this comes in the form of direct and indirect radiators or heaters.
This can be a costly heating method however can be easier to fit in households
in comparison to the other fuel types.
This comes simply in the form of a central heating
system. These come in three types as: wet systems, warm air and storage heaters,
as provided by Uswitch (2017). Of the 3 warm air systems are mostly used in
commercial buildings and may not be recommended for the site in Carnlough.
‘With a ‘wet system’ hot water circulates through a
system of pipes that connect to the radiators throughout a house. At the centre
of the system, a boiler burns a fuel – or sometimes there is a ‘heat exchanger’
and this heats the water that feeds the network of pipes to supply the
radiators which heat the rooms via convection.’ Uswitch (2017)
Wet systems that are heated by gas have a water based
medium within a boiler. When the water is heated it can be transported to the
radiators via gravity or being pumped.
There are two designs in terms of piping, one and two
pipe designs. The one pipe system is a cheap method for installation however it
costs more to run as each
successive radiator receives water that has been mixed with cooled water from
alternative to this is a two pipe method. This way the water leaving each
successive radiator doesn’t mix and the radiators will all be at the same
constant boiler temperature. The pressure in this system is maintained at a
high level so more radiators if require can be added.
Storage Heaters- contains bricks capable of storing
large amounts of heat. ‘These are heated overnight using the off-peak
electricity on Economy 7 and, on Economy 10 tariffs, during two shorter periods
during the day.’ This heat is then released the following day slowly. This is a
more efficient use of electricity than in the direct method. The heaters can be
timed to save money especially in warmer months of the year when the heaters
may not be needed much or at all. The one and two pipe systems are sketched out
in the appendix.
Site- for the Carnlough development it would be appropriate to
select the more efficient indirect heating method. Uswitch (2017) In terms of
cons, it is worth noting that electric central heating is often more expensive
as electricity unit prices are up to four times costlier than gas prices. On
top of this, electric central heating storage heaters do not provide instant
control. This means you will have to plan your heating needs ahead as switching
the heating on at night means it will heat up for the next morning. It is for
this reason that gas would be best for the site. In the long term the gas
central heating will be more cost effective. The site should also incorporate a
two-pipe system to ensure the best all round quality, pressure, and warmth
around the property.
Hot water system
Types- we use the hot water
in taps baths and showers as examples. Again, there are two types direct and
indirect. The difference between the two systems is in the direct system water
mixes with water that is used for heating the house, meanwhile in the indirect
system the water is heater through a heat exchanger or coil and never mixes
with the heating water. Within the direct system this can lead to furring of
the in the boiler and pipework, if it is copper.
The indirect system can be described as a
more efficient method although it does require a storage tank. For this reason,
it would be beneficial to select an indirect method for the site. This is due
to the previous recommendation for the indirect cold-water system whereby a
storage tank will also be included. The main problem to this method is a
slightly more expensive running and maintenance cost however the benefits of
decreased furring and increased efficiency outweigh this. In this system an
immersion heater may be a good addition as it provides instantaneous heat when
turned on. This can be effective for when there is a need for hot water
whenever the heater hasn’t been on ie, during summer months. The two systems
are shown in the appendix
water heating- on a final note for water heating there is scope for using
solar panels in this development. This puts a sustainable outlook on the
project. To save on using an immersion heater during the summer months solar
energy could heat up water without using fuel. This comes in the form of flat
plate collectors or evacuated tubing. The flat plate collector is up to 15%
cheaper to produce than evacuated tubing however the latter is more effective
at producing hot water. I would recommend that the development include
evacuated tubing for efficiency especially in a cold climate country.
To conclude this development is in a desirable area.
Carnlough has been subject to a housing deficit and as a result this
development is much needed. Within following the
building regulations this project can be constructed to meet safety
requirements and provide adequate housing in the Carnlough area. The homes in
the area have been considered and the designs of the development have been
selected accordingly to maintain similarity to the surrounding developments. Services such as; electricity, heating, and water
provision can be easily connected and fitted due to the surrounding provisions.
Finally, the research in this project are guides that have been made based on assumptions
about the site in question and further research would be needed such as soil conditions
and water pipe locations.
NIHE, Larne District Housing plan 2014. Online. 19
October 2017. Available from: https://www.nihe.gov.uk/larne_district_housing_plan_2014.pdf
Daniel mcalister & son estate agent. 2017. 19 Croft
Avenue, Carnlough, Ballymena, Antrim, BT44 0EN. Online. 22
October 2017. Available from: https://www.propertynews.com/Property/Ballymena/DMS670370/19-Croft-Avenue/
Snell, D. 2017. Comparing wall system costs. Online. 22
November 2017. Available from: https://www.homebuilding.co.uk/comparing-wall-system-costs/
Resistant. 2017. Base board 10. Online. 23
November 2017. Available from: http://www.resistant.co.uk/base-board-10/
Uswitch. 2017. Central heating systems: what kinds are there available?.
Online. 11 December 2017. Available from: https://www.uswitch.com/boilers/guides/central-heating-systems/
Pawlings. 2017. Internal stud walls. Online. 12 December 2017.
Available from: http://www.pawlings.com/insulation/wall-insulation/internal-stud-walls/
Galloway, T (2004).
Solar House A Guide for the Solar Designer. Oxford: Architectural Press.
Simpson, B.J &
Purdy, M.T (1984). Housing on Sloping Sites a Design Guide. New York:
Chilvers, P, Hill, D & Owen, J (2007). Before you build- A step-by-step guide to
extensions and renovations. London: RIBA.