New Homes Construction
Overview
To Code 4
Long Meadow, Diss
Mark Hart
Divisional Construction Director
New Homes overview to Code 4 - LONG MEADOW - DISS
How to get to Code 4
• Carefully considered design to suit the location and
existing facilities
• 100mm CFC interlocking insulation to ground suspended
slab
• Bespoke timber frame system
• Hemcrete insulated walls and Hemp fibre roof insulation
• Air source heat pump heating and hot water
• Mechanical Ventilation and Heat recovery
• Airtightness to 3
• Life time secured by design
• Fully recyclable materials
New Homes overview to Code 4 - LONG MEADOW - DISS
Site
• Longmeadow, Denmark
Lane, Diss, Norfolk
• 1st phase of 29 new
homes of a 3 phase
development of 114
– 2, 3 & 4 bedroom homes
• Traditional sub-structure
with bespoke timber
frames for Hemcrete
product
• Element of affordable
housing supported by
grant funding
New Homes overview to Code 4 - LONG MEADOW - DISS
Hemp Material
• Grown locally to development
and processed at Halesworth
• Grows fast from seed to 4
metres within fourteen weeks
• Consumes C02 during growth
• Strong and very good
insulator once processed
New Homes overview to Code 4 - LONG MEADOW - DISS
Pre planning
• To integrate various
works
• Scaffold
• Services
• Cranage
• Timber frame
• Airtightness
• Life time products
New Homes overview to Code 4 - LONG MEADOW - DISS
Sub-Structure
• Typical sub-structure as used on
most housing sites
• Trench fill concrete foundation
with brick and block to over site
level
• Overall size to suit timber frame
and Hemcrete = 300mm
• Standard drainage and services
• Concrete Beam and interlocking
polystyrene blocks create fully
insulated floor structure
• DPC & DPM covers complete
oversite
New Homes overview to Code 4 - LONG MEADOW - DISS
Scaffold
• Bespoke scaffold for timber frame and
Hemcrete
New Homes overview to Code 4 - LONG MEADOW - DISS
Roof structure
• Erect roof trusses in
position on the sole
plates at ground level
• Remove to adjacent
level storage
New Homes overview to Code 4 - LONG MEADOW - DISS
Timber Frame
• Erect ground floor timber
frame,
– which is pre-constructed to suit
the Hemcrete product,
• Internal multipro board as
internal shutter
• Floor cassettes,
• Followed by 1st floor timber
frame
• Lift finished truss structure
into position
New Homes overview to Code 4 - LONG MEADOW - DISS
External Services
• Fix all external services, ducts
and boxes, any timber back
ground must be fixed ready for
all future external structural
elements, such as balconies or
porch roof structures, with all
penetrations carefully sealed
for air tightness
New Homes overview to Code 4 - LONG MEADOW - DISS
Formwork
• Erect two sections light weight
plastic form work to external
substructure brickwork
– ensuring precise dimensions
– level and plumb
• Fixed into position with
spacers and bespoke fixing
screws
• Timber battens are fixed to the
timber frame at each level to
create stability between
Hemcrete and timber frame
New Homes overview to Code 4 - LONG MEADOW - DISS
Hemcrete Installation
• Hemcrete is batched and
mixed on site
• Hand poured into the shutter at
approx. 600 layers,
• Shutters are removed from
lower level and used to
continue as works proceed
• Seamlessly installed around
the complete envelope of the
building
• Contributing to an airtight
insulated shell
New Homes overview to Code 4 - LONG MEADOW - DISS
Curing Process
• Once cured after 1-2
days shutters are
removed to expose a firm
tactile structure
• which will need to fully
cure over the following 4
weeks or so
– according to weather
conditions,
• Once cured a robust shell
is created
New Homes overview to Code 4 - LONG MEADOW - DISS
Internal Services
• During the Hemcrete
stage internal services
and fit out are carried
out
• Followed by window
and door fixing
• Fully seal all
penetrations
New Homes overview to Code 4 - LONG MEADOW - DISS
Roofing
• Roofing and roof lines are completed once
formwork is removed
• Loading of the roof tiling needs to be
delayed to allow shrinkage of timber frame
and Hemcrete
• Hemp insulation quilt is laid to the roof
void areas
New Homes overview to Code 4 - LONG MEADOW - DISS
Rendering or Cladding
• Once full drying of the
Hemcrete has been
achieved and all
apertures solutions
are fixed, rendering or
cladding can be
finalised
New Homes overview to Code 4 - LONG MEADOW - DISS
Airtightness
• Airtightness requires careful management
• All construction stages from DPM to pre-plastering
need to be carefully completed
• Airtightness barriers installed as design
• All service penetrations need to be fully sealed
• Airtight sealants applied to window and door
apertures prior to plastering
• Sealing around window boards and within service
voids are important
New Homes overview to Code 4 - LONG MEADOW - DISS
MVHR
• Fresh outdoor air is taken into the Mechanical
Ventilation & Heat Recovery System which then
passes through the filtration system to reduce the
incidence of pollen and dust.
• Air removed from the house is passed through the
HRV System to 'transfer' the heat to the Air taken in
from outdoors, before being passed to the outside
• The heat exchanged warm air taken from outdoors is
then carried to specific rooms
• Condensation from poorly ventilation rooms and
smells are taken from rooms (i.e. Kitchen, Bathroom,
Toilet) to be dispensed outside.
New Homes overview to Code 4 - LONG MEADOW - DISS
Electric Air Source Heat Pump
• Mitsubishi Ecodan domestic models installed
• Provides space heating and hot water for all the
household needs
• Captures ambient heat from outside air and
upgrades it to useful temperatures for heating hot
water and radiators
• Best performance in well-insulated homes connected
to underfloor heating
• As the insulation and air-tightness of the property are
at a very high level, the house design is ideally suited
for the heat pump
New Homes overview to Code 4 - LONG MEADOW - DISS
Conclusion
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Design elements need to be selected to suit the location
Hemcrete has excellent insulation properties, with limited additional on site requirements
Timber frame is similar in design as traditional, but bespoke to suit the construction
Careful pre-planning is required to ensure seamless installation on site
Scaffolding requires careful adjustments to give safe working platforms as works proceed
The drying process of the Hemcrete and the lime render is subject to weather conditions
Airtightness is an important element
Triple glazed windows and doors, secured by design and lifetime certified
MVHR units ensure additional energy savings and comfortable air circulation
Electric air source heat pumps provide single source energy effective heat solution
Once completed the structure provides a practical, environmentally friendly alternative to
traditional masonry built structures, creating a peaceful, comfortable and economic living
environment
Recycling ethos is embedded within the whole concept
Bring on Code 5 & 6
New Homes overview to Code 4 - LONG MEADOW - DISS
I am happy to answer any of your questions.
I will also be available to answer your questions after the presentation.