To effectively adopt Welsh Governments 'Delivering Net Zero Homes', 'Modern Methods of Construction' and 'Design for Manufacturing and Assembly' aspirations do we simply need to 'draw the line' on existing house type layouts?
Twenty years ago, a design guide for Social Housing in Wales featured a plan for a 3-bedroom 5 person house. Variations of this house are still being built today but is it an appropriate solution?
See design guide extract below.
Here are three variations of this house type that Creu Architecture has worked on in the last three years. While adhering to the initial design layout, they:
all have different footprint dimensions.
have all incorporated an air source heat pump cylinder ( which compromises the lounge in two of the layouts ).
have all incorporated a mechanical ventilation heat recovery system including ductwork ( which compromises the useability of the dwelling's storage space allowance ).
Below we analyse one of these layouts to determine its suitability for meeting current requirements.
the lack of alignment between the first-floor partitions and the ground floor complicates the construction process and prevents this house type from being delivered as volumetric modular.
the zone where 200x 100mm ductwork openings can be formed in engineered timber joists without compromising their structural integrity is limited. Loadbearing joists and the provision for a future through the floor lift also prohibits ductwork openings in joists between the lounge and kitchen.
2.6m/sq of useable storage cupboard allowance ( 2.5m/sq required for Welsh Government standards ) but 0.5m/sq of this is compromised by the location of the mechanical ventilation heat recovery unit at high level.
0.75m/sq of dedicated plant storage cupboard housing the air source heat pump cylinder.
no dedicated service riser - risers located in cupboards compromise useable storage space.
a soil stack foul connection is required to the front and rear of the property.
the through the floor lift allowance restricts the space for services within the floor void.
an entrance canopy over the front door restricts the location of the mechanical ventilation heat recovery ductwork inlet and extract grills.
no consistency of wall panel or floor cassette type for ease of manufacturing.
Illustrared further below.
To simplify this we drew a line and developed Creu Cartref's Gamelin housetype.
Creu Cartref's Gamelin Housetype:
has circulation, shower room, storage, plant, c'boards, single bedroom and bathroom to one side of the line and lounge, kitchen and double bedrooms to the other.
at 93m/sq it complies with Welsh Governments standards.
first floor and ground floor partitions are aligned to simplify the construction process and allow it to be delivered as traditional construction ( brick and block ) , panelised frame ( timber/ light gauge steel ) or fully volumetric modular.
the zone where 200x 100mm ductwork openings can be formed in engineered timber joists without compromising their structural integrity can be clearly identified and allows for ductwork runs in the floor joists between the lounge and kitchen.
4.6 m/sq of useable storage space exceeds the 2.5 m/sq required by Welsh Government standards and is completely free from plant and equipment.
in addition to useable storage, there is 1.5 m/sq of dedicated plant and equipment storage.
the layout includes a dedicated service riser that does not compromise any storage space.
a single soil stack at the rear of the property services the shower room, plant and equipment stores and the first-floor bathroom.
the through the floor lift allowance doesn't compromise the space available for services within the floor void.
all inlet and outlet ductwork is at the rear of the property and therefore not compromised by an entrance door canopy.
consistent wall panels and floor cassette types simplify manufacturing.
consistent floor cassettes can have factory-formed openings in engineered timber joists extending to the external wall for ease of rigid ductwork installation.
Illustrated further below
Standardized room modules will simplify design, reduce variation, improve efficiency and provide cost savings for wall panels and floor cassettes. Click below to watch the illustration.
Standard wall panels can be manufactured allowing for minor site adjustments to suit door and window openings. Click below to watch the illustration.
All services are located together with a single soil stack per dwelling. Click below to watch the illustration.
The modular room arrangement could facilitate fully volumetric delivery. Click below to watch the illustration.
The external envelope can vary to suit thermal/ air tight performance and site constraints. Click below to watch the illustration.
Housing projects deliver lounges, kitchens, shower rooms, bedrooms and bathrooms grouped together to create homes. Using only 9 room modules Creu Cartref have developed a 2 bedroom, 3 bedroom, 4 bedroom house and a 2 bedroom and 3 bedroom apartment which all share the benefits outlined for our Gamelin house type.
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