Futureform Benelux by Futureform

GRANT AGREEMENT Nยบ: 315274 MODCONS DEVELOPMENT OF MODULAR CONSTRUCTION SYSTEMS FOR HIGH-RISE RESIDENTIAL BUILDINGS Activity/Area: Research for SMEs Funding scheme: Research for the benefit of specific groups (in particular SMEs)

Project Title Sub Info

Call identifier: FP7-SME-2008-1

Deliverable D 2.2 TITLE: REPORT ON BUILDING TYPOLOGIES FOR MODULAR CONSTRUCTION IN MEDIUM-RISE BUILDINGS Due date of deliverable: 31/03/2013 for D2.2 Actual submission date: 31/10/2013

Start date of the project: 01/01/2013

Duration: 24 months

Lead Partner of this Deliverable: HTA Architects

Project co-funded by the European Commission within the Seventh Framework Programme (2007-2011) Dissemination Level PU Public PP Restricted to other programme participants (including the Commission) X RE Restricted to a group specific by the Consortium (including the Commission) CO Confidential, only for members of the Consortium (including the Commission Services)

GRANT AGREEMENT Nยบ 315274 WP2.2

Page 1

MODCONS Grant Agreement No. 315274 Development of Modular Construction systems for Low-rise Residential Buildings Deliverable D 2.2 Report on Building Typologies for Modular Construction in low-rise buildings

The Design of Low-Rise Modular Buildings WP 2.2 Introduction

WP.2 presents an investigation into the use of modules for residential building design, and demonstrates the use of modular construction for low, medium and high rise construction.

Types of Unit

• • To illustrate this, HTA Design LLP has designed typical • modules for hotel bedrooms, student bedrooms, various • apartment types and sizes and finally, single family houses. • All of these units have been designed to take advantage of the flexibility of modular construction. A number of standardised types of module are chosen to illustrate how to use modules to meet many spatial and regulatory standards in the EU. Typical dimensions are shown based on a 300mm grid, but it should be emphasised that this is for ease of design and modular construction systems are flexible in all dimensions. Types of Building This report illustrates the potential for modular construction by designing examples of the following residential buildings:

• • • •

Apartment Buildings, Student Accommodation, Hotels, Mixed use buildings where the lower floor or floors can be different uses with residential accommodation above.

Hotel Bedrooms, Student Bedrooms, 1 Bedroom Apartments, 2 Bedroom Apartments, Single Family houses

Construction Considerations Generally the larger housing units are made from a group of modules. In all cases the units are designed to be made from modules that fall within a small range of dimensions and variations. This does not mean that these dimensions are fixed. Module dimensions are flexible and can be changed to suit the specific circumstances of a project. These designs are intended to illustrate how to design types of buildings that can be constructed using modules that can be transported from one EU country to another. The transport method has an impact on the size of module that can be used. In this study, module sizes are used that do not need unusual transport or an escort. Rooms generally do not cross modules; this is to avoid complex jointing on site that may be affected by movement over the life of the buildings. Rooms generally are joined wall-to-wall so that any movement is covered by door openings. Sizes The housing unit sizes used are based on common practice in the UK and other countries in the EU. Overall wall dimensions are designed to meet typical UK regulations for thermal performance. Spatial Characteristics For the town houses, the module width is increased to the maximum easily transported width of 4.2 m internally (4.45 m externally), which means that one module per floor may be used efficiently. Stairs may be formed within a module, particularly for housing, or as separate modules. In this case, the modules are manufactured with a partial floor and ceiling which may require additional steel members around the periphery of the module. Where a large opening is formed in the floor or ceiling of a module, a minimum of 300 mm floor or ceiling

Figure 1. Lifting of modular unit on site (Wembley, London)

The Design of Low-Rise Modular Buildings WP 2.2 Introduction

width is recommended to stiffen the junction of the modules. Servicing Considerations Service risers are shown in the corners of modules and are intended to stack vertically. Corridor ceilings can generally be used to run services horizontally on each floor. Generally it is anticipated that individual houses are serviced using individual systems, such as air source heat pumps, gasfired boilers, solar panels, etc. Apartments, student accommodation and hotels are assumed to have communal systems, such as centralised boilers, or are connected to district heating systems. Service Modules In most situations, modules are used to contain all the service elements for a unit, or in some cases a single module may be designed to contain paired services for adjacent units. This approach limits the complex servicing work to a single module and simplifies the work on site to connect services. It also allows modules to be used in a hybrid structure where parts of the unit are constructed using 2D panels instead of 3D modules. Relevant Standards The standards used for construction in this study are UK Building Regulations 2010(1), the London Housing Design Guide(2) and modular construction guidance provided from HTA Design LLP, Futureform Ltd, and the Steel Construction Institute. The design of residential developments for a secure environment is also addressed in an initiative called Secured by Design(3), in which doors and windows have to meet minimum standards of security and the overall development has to make good use of lighting and survelillance.

The following pages describe the particular aspects of each building type and also the unit type. Each bulding and unit type are discussed using the headings: Type, Size, Spatial Characteristics, Servicing Considerations and Relevant Standards. Why use Modular? Modular construction is particularly suited to situations where there is a benefit from the fast construction of the building. These benefits are wide-ranging and include the following: - Improved cash flow into the development project as rental income or sales income can start to flow earlier earlier than if the project is constructed using traditional methods. - A cleaner and quieter construction operation resulting from the majority of the construction work being done in the factory under cover. - Less waste in the construction process due to the factory construction process. - Lower transport emissions and less pollution resulting from the deliveries of the materials to site. - A higher quality of finish resulting from work being done under factory conditions and each construction trade able to carry out their work in an orderly fashion without interruptions. - A quicker operation on site which minimises disturbance particularly in constricted urban locations. - A higher level of construction quality leading to a more reliable delivery of high performance buildings than is possible with traditional methods of construction. - A safer workforce who work mostly in a factory in clean, dry, well-lit conditions.

Unit Type

Indicative UK Volume Housebuilder Size Min (sqm) Max (sqm)

London Housing SPG (Annex 4) Min (sqm)

2 bedroom, 3 person garden flat mid terrace (1storey)

2 bedroom, 3 person flat over garage / walkup (1.5storey)

2 bedroom, 4 person mid terrace house (2storey)

3 bedroom, 5 person mid terrace house (2storey)

3 bedroom, 5 person integral garage house (2.5storey)

107

105

4 bedroom, 6 person end terrace house (2storey)

140

110

4 bedroom, 6 person integral garage house (2.5storey)

116

142

122

Table 1. Typical Unit Sizes in use in the UK

Table 1 shows typical home sizes constructed by UK developers and as regularly specified by London Planning Guidance. (1) Amendments to the Approved Documents, The building Regulations 2010, 2013 (2) London Housing Design Guide, Interim Edition, Mayor of London, London Development Agency, London, 2010 (3) Secured by Design, Police Preferred Specification 4

The Design of Low-Rise Modular Buildings WP 2.2 Cladding types

Cladding systems may be pre-attached to the module, or installed as separate elements on site. In both cases, the connection between the modules may be concealed or emphasised as part of the detailing of the cladding. The thermal performance of cladding systems and the integration of renewable energy technologies are both aspects of interest in modern design.

Lightweight cladding Lightweight cladding takes many forms from insulated render and tiles to metallic sheets and cementitious boards. These cladding systems may be designed to be supported entirely by the modules over any building height. The use of insulated render on a separate sheathing board is a common solution in modular systems. The sheathing board provides weather resistance in the temporary condition and improves the air-tightness of the building is service.

Cladding types in light steel modules Four generic forms of cladding may be considered in the design of modular buildings using light steel framing: 1. Ground supported brickwork, in which the brickwork is constructed conventionally on site from foundation level and is laterally supported by the modules. 2. Insulated render that is applied on site to insulation that is fixed to the external sheathing boards of the modules. This type of lightweight cladding is supported by the modules and conceals the joints between the modules. 3. ‘Rain-screen’ cladding systems in the form of boards, tiles or metallic sheets that are fixed through insulation to the external sheathing boards. For heavier tiled systems, horizontal rails are attached through to the light steel structure of the modules. 4. Brick slips attached to metallic sheets or bonded to sheathing boards that are attached through insulation to the modules. Although the brick joints are mortar filled on site, this type of cladding system is not generally considered to be weather-tight. Also, its weight adds to the loads acting on the modules. Brickwork Brickwork is generally designed to support its own selfweight up to 3 or 4 storeys height (approximately 12 m).

In the case of rain-screen cladding systems, horizontal or vertical rails are screw fixed to the light steel framework of the modules through the external insulation and sheathing boards. When the thickness of closed cell insulation board exceeds about 100mm, the fixings may become too flexible and do not support the tiles or boards effectively. In this case, separate stainless steel or aluminium L-shaped brackets may be required, which can be adjusted to allow for the site tolerances in the placement of the modules. For all rain-screen cladding systems, the modules are designed to be weather-tight and to provide the required level of thermal performance, independent of the type of cladding that is used. For metallic cladding systems, either vertical or horizontal rails may be pre-fixed to the light steel framework of the modules, as illustrated in Figure 4.2. This system acts as a ‘rain screen’ and so an additional sheathing board is required. In this figure, the C sections are shown as perforated, which reduces the effect of thermal bridging through the structural elements. Another form of metallic system is to use horizontally spanning composite panels (also known as sandwich panels), which provide greater rigidity and dispense with the need for an insulation board. Composite panels are weathertight and are designed to add to the thermal insulation of the façade. It is possible to connect tiles to composite panels via horizontal rails that are fixed to the outer steel sheet of the panel.

Lateral support is provided by the modular units by brick ties connected to stainless steel or corrosion-protected vertical runners that are screw fixed at 600mm centres through the external sheathing boards to the light steel framework of the modules. The brick ties are attached normally every 5th brick course, or every 3rd course around windows. It is not normal practice for the light steel modules to provide vertical support to brickwork unless an additional steel support structure is provided. Lintels are required over window openings in the brickwork. However, brickwork cladding is often used for the lower level of a building and light weight cladding is used above.

The Design of Low-Rise Modular Buildings WP 2.2 Roofing

Roofing systems Generally, the roof in modular buildings is constructed in one of four generic forms: 1. The top of the module itself acts as the roof, and it is weather-proofed and laid to falls, often with integral down pipes in the corners of the modules. 2. Purlins that span parallel to the building façade and support a pitched roof. The purlins are attached to triangular or curved wall frames that are positioned over the load bearing side walls of the modules. 3. Roof trusses that span perpendicular to the building façade and are supported by the front and rear façade walls of the modules (or the corner posts of the modules). 4. Modular roof units that are designed to create habitable space. In this case, the modules are generally of mansard shape and are supported directly by the modules below.

Figure 2 shows different types of roof system used in modular construction. A set back module is supported on the walls of the modules below but the ceiling of the module below supports the loads from the roof balcony. Building –in renewable energy technologies in modular construction Renewable energy technologies may be integrated into modular units or may be attached to the roof and walls of modular buildings. The most common renewable energy solutions are photovoltaic panels and solar thermal collectors. Photovoltaics Photovoltaic cells use semi- conductor-based technology to convert light energy into an electric current. The electrical energy that is created can be fed into the national grid (exported) by an inverter which converts the DC current to the AC current at mains voltage. There are two forms of photo-voltaics (PV) – either crystalline or more rigid forms that are used to manufacture self-standing panels, or laminates in the form of amorphous silicone that are bonded to a metallic surface. Large PV panels are generally supported on horizontal rails that are attached to the roof. They are generally located on the south facing slope of roofs, although east and west facing roofs can be used with some loss of efficiency. Dark grey or black tiles incorporating PV layers are attractive as they do not detract from the visual appearance of a more conventional house. The peak power output of crystalline PV panel is around 20 W /m2 panel area in the UK climate. The average yearly output is likely to be around 50 kWh/m2 taking account of seasonal variations and roof orientations. For a typical family house with 40 m2 of south facing roof, the energy created can be up to 2000 kWh, which is equivalent to about half of the energy required for space heating of a well insulated house. Mechanical ventilation systems Highly insulated and air-tight buildings require effective ventilation to avoid build-up of stale air, smells and high humidity levels. Mechanical ventilation and heat recovery (MVHR) systems are often introduced by providing extracts in each major room, and particularly in the kitchens and bathrooms. The extracts pipe the warm room air to a heat exchanger which transfers heat to the incoming cooler outside air. Modular units can be manufactured with in-built pipes and extracts, and also with the MVHR located within the modules next to external walls

Figure 2. Types of roofs

The Design of Low-Rise Modular Buildings WP 2.2 Balconies

Balconies Balconies are an important feature that give greater interest and create usable space in an otherwise bland façade. In dense urban locations they are essential as an amenity space for families, and as a valuable addition to living spaces. Prefabricated or integral balconies are therefore an important component of modular construction. In conventional construction, the floor is continued beyond the building to form the balcony. However, this solution creates a ‘cold bridge’ and does not comply with modern regulations, but this problem can be solved by using thermally broken connections. Also, to minimise the risk of water flowing back into the building, the finished surface of the balcony should be below the internal floor surface. Balconies can be constructed in various ways in modular systems:

separators can be introduced in the balcony connections and the wall insulation is locally applied after the structural connections have been made. A simpler technique is to manufacture the balcony or external space as part of the module, which has been done in various projects. Here the external space must be made water tight and is generally partially enclosed. The sides of the modules project to form the sides of the balcony. An alternative approach is to suspend balconies between the sides of adjacent projecting modules as shown. Fin plates project from the side of the modules to make the on-site attachments of the balcony. For tied balconies, the ties can be relatively unobtrusive, as illustrated in figure 3, but they must be tied back to the corner posts of the module, as they apply horizontal forces to their supports.

• Ground-supported balconies, which are stacked vertically, and where the columns used to support the modules extend to ground level. • An additional external steel structure, which is braced and self-stabilising, and is therefore independent of the modular building • Balconies cantilevering from hot rolled steel posts that are located in the module walls. Fin plates may project from these posts (which are generally Square Hollow Sections) to permit later attachment of the balconies and to minimise ‘cold bridging’. • Integral balconies manufactured as part of the modules. The balconies have side walls or corner posts in this case and are insulated to prevent heat transfer to the modular unit below. • Balconies supported between the sides of the adjacent modules. In this way, the modules provide both the vertical and lateral support to the balconies. • Suspended balconies by ties from each floor to corner posts. In ground-supported balconies, the balcony is partly supported by posts that extend to the ground and the balconies are tied to the modules to resist wind loads. This is a practical solution in modular construction. Alternatively, a separate steel structure may be introduced to provide overall stability and also to support the balconies Cantilevered balconies require substantial steel-to-steel connections to resist the applied moments transferred from the balconies. This generally requires use of hot rolled steel members (normally Square Hollow Sections (SHS)) that are in-built into the modules. The balcony attachments may be made to the SHS posts that are generally located at the corners of the modules. To minimise cold bridging, thermal Figure 3. Example of balconies tied at each floor level 7

The Design of Low-Rise Modular Buildings WP 2.2 Low-Rise Housing

WP.2.2 presents an investigation into the architectural use of modules in residential building in low and medium rise construction General design requirements: Modules are generally 3.6 m wide internally (and nominally on a 3.85 m grid allowing for the wall dimensions and gaps between the modules). These module sizes are suitable for transportation without escort.

Any form of roof may be used, which may be supported either by the load bearing side walls or by the facade walls. The self weight of a fitted out module is typically 10 to 12 tonnes, which is suitable for lifting by a 100 T crane (or 200 T for a long boom). Figure 4 demonstrates that modular construction allows the construction to start on site earlier than other construction methods, and thus to finish construction more quickly. A benefit can be achieved in earlier income from the rented, leased or sale of the building. Borrowing costs are reduced and cashflow is improved.

•

Module lengths are variable, and range from 6 to 16 m dependant mainly on transportation (and particularly turning into local roads).

•

Load bearing side walls of modules align vertically and modules are either supported at foundation level or by a podium (see mixed use building, WP 2.4).

Figure 5 shows delivery of modules in therir protective covering.

•

Internal wall heights are taken as 2.4 m, but can be varied. Externally, the module height is taken as 0.45 m plus the internal height, i.e. 2.85 m, allowing for the combined floor and ceiling depth.

An internal view of housing ( figure 6) shows the use of a pair of modules with partially open sides to create more usable space.

•

Open ends to the modules can be created by inclusion of a rigid steel ‘picture frame’. A nominal 100 mm ‘return’ is allowed on the end walls at doors and window openings.

Figures 7 to 11 show examples of cladding systems need in modular construction, particularlywith low-rise buildings and houses.

•

Service connections are made generally at the corners of the modules and may be accessed from the corridors or other suitable spaces for maintenance. The vertical service routes are made through the module floor and ceiling at these locations.

Construction Time Savings Construction expenditure

Savings in time from use of modular constuction

Time

Figure 4. Modular vs Traditional Construction Timeline 8

Figure 5. Delivery of two modular units on site

The Design of Low-Rise Modular Buildings WP 2.2 Precedents

Figure 6. Internal new of housing development (Harlow)

Figure 7. Housing Development in Harlow (Futureform)

Figure 8. Facade of large steel cassette panels (Tata Steel)

Figure 9. Facade of cementitious panels (Futureform)

Caption

Figure 10. Facade of ceddar cladding Birchway (Futureform)

Figure 11. Facade of composition panel with terracota tiles

The Design of Low-Rise Modular Buildings WP 2.2 Low-Rise Housing

Type 1 maisonette and Type 2 are stacked to form a formstorey block.

3.2

4.2

Figure 12. Ground Floor Plan Type 1 - Maisonette

3.2

Figure 13. Second Floor Plan Type 1 - Maisonette 10

3.2

4.2

Figure 14. First Floor Plan Type 1 - Maisonette

4.2

3.2

Figure 15. Third Floor Plan Type 1 - Maisonette

4.2

The Design of Low-Rise Modular Buildings WP 2.2 Low-Rise Housing

Housing in the EU is generally constructed using traditional forms of construction, using masonry or timber frame techniques. However, as demands for more sustainble development grow, and the availability of development land reduces, it is likely that modular constuction will increase in this sector. Labour and material shortages for use in traditional construction may also drive the sector towards the use of more efficient factory-based production methods. Constructing homes for private rental is likely to make use of modular construction as this will allow the construction of new projects much more quickly than is possible using traditional methods. This has the benefit of bringing in rental income quickly and making such schemes more profitable. The house types we illustrate here in Fig. 19, 20, are designed to be delivered as two or three modules using one module per floor. These are at the limit of modular performance and ease of transport. To construct the dwelling could take as few as three deliveries. The building is designed so that if it needs to be made in two modules per floor each one of 8 m long, this will not have a major impact on the design.

Figures 12 to 15 show the plan form of a low-rise maisonette consisting of 2 modules of 3.2 and 4.2m width. In this format, the maisonettes are duplex layouts and occupy 2 floors, the upper maisonette being accessed from a shared stairs. The illustrated design in Fig 16 is of low rise housing which has a flat roof. This creates amenity space at high level. This type can be constructed in a terrace or as semidetached units. The module walls can also be exended to form a parapet where the flat roof is accessible. Green Roof Flat roofs can be used to form green roofs, either intensive or extensive, depending on the depth of planting medium and the amount of maintenance they need. Extensive green roofs traditionally support 10-25 pounds of vegetation per square foot while intensive roofs support 80-150 pounds of vegetation per square foot These can provide amenity and biodiversity benefits. Figures 17 to 20 show the use of a terraced form house consisting of single modules on each floor. The common service zone is indicated.

Figure 16. Artists Impression of low rise modular housing 11

The Design of Low-Rise Modular Buildings WP 2.2 Low-Rise Housing

Figure 17. Section through 3-storey modular type

Figure 18. Street elevation of three storey modular type showing alernative use of ground floor for garages or as bedrooms

Figure 19. Section through a modular dwelling showing the arrangement of spaces around a central stair and lightwell. 12

The Design of Low-Rise Buildings Low-Rise Housing

Light well

1600

Potential break in module

Service zone

Ground Floor bedroom 1600 Figure 20.â&#x20AC;&#x152;House constructed from single modules on three floors or pairs of modules (lower plan)for each floor

Unit line 13

The Design of Low-Rise Modular Buildings WP 2.2 Low-Rise Housing

Thermal insulation The thermal insulation requirements for housing and residential buildings in the UK are given in Approved Document L1. To comply with the 2010 Building Regulations (England and Wales), the dwelling CO2 emission rate (DER) should not exceed a target CO2 emission rate (TER). The DER is calculated using the energy required for heating, lighting, etc. less any savings due to use of renewable energy systems. The heat transmittance is characterised by the U value of a unit area of the external envelope and its units are W/ m2 per oC temperature difference. The maximum permitted U values were reduced in the 2010 Building Regulations, and will reduce further in 2014. The target U values that are required to achieve the TER are presented in Table 2. These U values should not be confused with the maximum U values given in the Regulations, which are the higher than space target values and are maximum permitted values for any given element of the building envelope. Air-tightness is also an important parameter as studies have shown that unwanted air infiltration can increase heat losses significantly. An air tightness test in the UK is carried out to a relatively high pressure differential of 50 Pa, and a test permeability of 5-7 m3/m2 /hr is considered to be representative of normal building practice. In practice, actual air infiltration through the building fabric in normal conditions will only be about 5% of the test value.

To achieve a U value of 0.2 W/m2oC in both light steel and timber modular construction, it is necessary to introduce 100mm of inter-stud insulation (often in the form of mineral wool) as well as up to 80 mm of closed-cell insulation board placed outside the framework A Report by the Zero Carbon Hub (ZCH) â&#x20AC;&#x2DC;Defining a Fabric Energy Efficiency Standard for New Homesâ&#x20AC;&#x2122;(1) presented a range of solutions to achieve a 25 to 30% reduction in heating energy use in buildings compared to the 2006 Building Regulations. This is the target for the 2013 Building Regulations, and corresponds to a maximum space heating requirement of 39 W/m2 floor area per year for mid-terrace houses and apartments, and 46 W/m2 /year for semi- or detached or end of terrace houses, which reflects their higher exposed surface area. The optimised specification for the building fabric was based on the minimum capital cost less the net present value of the energy savings over 60 years, based on real increase in energy costs of 2.5% per year plus inflation. The target specification for the building fabric that was proposed by the ZCH for new buildings to achieve the space heating requirements are presented in Table 2. Also shown is the equivalent Passive House planning requirements. The thermal bridging parameter, y, takes account of the accumulated heat losses at all thermal bridges and is added to the heat loss in the building fabric (i.e. external walls, roof and ground floor).

The proposed air-permeability of 3 m3/m2 /hr through the Modular units are more air-tight than similar on-site building envelope is much better than in current Regulations construction, which is partly due to the use of sheathing and can be achieved in modular construction. In houses boards and sealed joints between the internal and external of this level of air tightness, mechanical ventilation and boards. If required, membranes can be introduced into the heat recovery (MVHR) systems are installed to maintain manufacture of the modules. Typically modules achieve an air quality and to reduce energy losses. MVHR units are air-tightness of 2 to 3 m3/m2 /hr. normally incorporated in the roof space, but can also be built into the modular units. Table 2.3 Thermal characteristics in the Building Regulations 2013 to achieve 25 to 30% energy reduction relative to the former Regulations (Zero Carbon Hub)

House Types Thermal Parameter

Passive House Standard

All house types except detached

Detached houses

External walls, U value Ground floor, U value Roof, U value Windows, U value Doors, U value

0.18 W/m2K 0.18 W/m2K 0.13 W/m2K 1.4 W/m2K 1.2 W/m2K

0.18 W/m2K 0.14 W/m2K 0.11 W/m2K 1.3 W/m2K 1.2 W/m2K

0.10 to 0.15 W/m2K 0.10 W/m2K 0.10 W/m2K 0.8 W/m2K 0.8 W/m2K

Thermal bridging parameter, y Air-tightness

0.05 W/m2K

0.04 W/m2K

3 m3/m2/hr

0.5 m3/m2/hr

Table 2. Thermal characteristics in the Building Regulations 2013 to achieve 25 to 30% energy reduction relative to the former Regulations (Zero Carbon Hub) (1) DEFINING A FABRIC ENERGY EFFICIENCY STANDARD for Zero Carbon homes, Task Group Recommendations, November 2009

2.4

Impact of fire safety on design

Safety in the event of fire is achieved by measures to allow the occupants to escape safely and to ensure effective fire fighting. This achieved in practice by compartmentation to prevent fire spread, by clear and alternative means of escape,

The Design of Low Rise Buildings WP 2.2 Low-Rise Housing

Fire safety and acoustic insulation Safety in the event of fire is achieved by measures to allow the occupants to escape safely and to ensure effective fire fighting. This achieved in practice by compartmentation to prevent fire spread, by clear and alternative means of escape, by use of incombustible materials, and suitable fire resistance that is dependent on the building height and function. There is no regulatory requirement for use of sprinklers in residential buildings, except in some hotels and ‘mixed use’ buildings. The design of residential buildings is strongly influenced by the layout of apartments and the travel distances to stairs or fire protected lobbies. The Regulations for fire safety are embodied in Approved Document B and BS 999: Fire safety in the design, management and use of buildings Code of Practice, which presents general requirements for all types of buildings. Effective means of escape is achieved by one of the two main approaches in residential buildings with a corridor and fire protected lobby: • By limiting the travel distance from the exit door of an apartment to a smoke-free area. • By provision of alternative means of escape to a smoke free area.

The acoustic performance requirements for buildings for ‘residential purposes’ are given in Approved Document E. In general, the double layer walls and the combined floor and ceiling in modular construction perform well acoustically. However, two layers of plasterboard are required for the ceiling and walls (which also satisfy the 90 minutes fire resistance criterion). Modular buildings are generally designed with two 15 mm thick layers of plasterboard internally to satisfy the acoustic insulation requirements for separating floors and walls. The same build-up of boards generally achieves 90 minutes fire resistance, which is required for buildings up to 10 storeys high. External sheathing boards and fire stops at in the cavity also assist in reducing the passage of smoke in fire. For taller buildings, a further layer of plasterboard is required to achieve 120 minutes fire resistance, and this also improves the acoustic insulation between the modules.

Figure 21.‌Minimum escape distances in residential buildings. The reference are from The Building Regulations 2010, Fire safety, Volume 2: Building other than dwellinghouses, page 26 15

The Design of Low-Rise Modular Buildings WP 2.2 Low-Rise Housing

Module layouts The modules in a residential building may be arranged to either side of corridors of approximately 1.5 m width. The depth of the residential building is approximately 16.5 m, which is suitable for 7.5 m deep apartments. Two modules of ~3.6 m x 7.2 m internal dimensions of approximately 52 m2 floor area, form a one bedroom apartment, and three modules of ~78 m2 floor area form a two bedroom apartment. The balconies are supported on additional Square Hollow Section columns that are connected to the modules at each floor via a thermally broken tie connector. Figure 22 shows a typical plan form consisting of 15 modules averaged either side of a corridor and accessed via a staircase. One module is half-width next to the core and accommodates the kitchen and bathroom.

This corridor type building is typical of many applications, such as: •

Hotels

•

Student residences

•

Residential buildings

The difference between these types of buildings is primarily the size of the rooms, which range in internal width from 2.5 m for student residences to 3.0 to 3.6 m for hotels, and 3.3 to 3.9 m for residential buildings. In all cases, the corridors link the modules and provide for horizontal service distribution. Generally, corridors are manufactured as 2D elements, and modules are manufactured as single rooms with bathrooms, for hotels and student residences, and also with kitchens for residential buildings.

Figure 22.‌Typical plan of modular building showing modules either side of a corridor.

The Design of Low-Rise Buildings WP 2.2 Hotel rooms

Spatial considerations

Plan form

The size of hotel bedrooms varies between 20 and 40 m2. Sizes tend to be set by the specific market that the hotel operator is aiming for and this varies widely. The normal layout is for an average hotel corridor is for 10 30 rooms to share access corridors. Corridors have rooms on both sides to minimise the use of circulation space. This tends to drive hotel buildings to form wings joined by cores. Normal plan forms for hotel buildings are blocks around a courtyard or L shaped.

The typical component of the hotel module of 3.3m x 6.7m Internal dimensions is shown in Fig. 23.

Structural considerations

The rooms are stacked vertically to allow the modular construction to carry the loads to the ground or first floor where there will be a transfer structure above lobbies, restaurants and support areas.

UK Building guidelines.

Regulations

2010,

Individual

operator

22 m2

Figure 23.â&#x20AC;&#x152;Hotel bedrooms - unit: double/twin room 17

The Design of Low-Rise Modular Buildings WP 2.2 Studio apartments (36-40 m2)

Plan form Spatial considerations Studio apartments are used in two scenarios: in student housing and in private sale housing.

The plan form of studio apartments are shown in fig. 24. Two modules are used, one half-width containing the serviced elements. Note that units can be handed to allow two halfwidth serviced elements to be combined in a single module.

Structural considerations Relevant standards The rooms are stacked vertically to allow the modules to carry the loads to the ground or first floor where a transfer structure is often used above lobbies and communal areas.

UK Building guidelines.

Figure 24.â&#x20AC;&#x152;Studio apartment - 0 bedrooms 1 person 18

Regulations

2010,

individual

operator

The Design of Low-Rise Buildings WP 2.2 One bedroom apartments (40-55 m2)

Spatial considerations

Plan form

The size of one bedroom apartments varies between 40 and 55 m2. The size depends on the tenure, whether the unit is designed for affordable housing, private for sale, open market rent or shared ownership.

The plan form of two examples of one bedroom apartments are shown in Figures 25 and 26. The difference in the size of the balconies provided. Servicing considerations

Structural considerations The rooms are stacked vertically to allow the modular construction to carry the loads to the ground or first floor where there may be a transfer structure above lobbies, parking, refuse and cycle storage or other commercial spaces.

Services are delivered through risers that are on the corridor side of each unit where central systems such as cold water, hot water, electrical supplies, are routed to each apartment. Horizontal distribution can be managed by routing services through a dropped ceiling in the corridors. Relevant standards UK Building Regulations 2010, Lifetime Homes 2008, Code for sustainable Homes 2010, London Housing Design Guide, Finnish building Regulations

Figure 25.â&#x20AC;&#x152;One bedroom apartment - Type 1

Figure 26.â&#x20AC;&#x152;One bedroom apartment - Type 2 19

The Design of Low-Rise Modular Buildings WP 2.2 Two bedroom apartment (75-80 m2)

Spatial considerations

Plan form

The size of two bedroom apartments varies between 55 and 80 m2. The size depends on the tenure, whether the unit is designed for affordable housing, private for sale, open market rent or shared ownership.

The plan form of two examples of two bedroom apartments are shown in Figures 27 and 28. The internal dimension of the modules are 3,6 m x 8.5 m. Servicing considerations

Structural considerations The rooms are stacked vertically to allow the modular construction to carry the loads to the ground or first floor where there will be a transfer structure above lobbies, and other spaces.

Figure 27.â&#x20AC;&#x152;Two bedrooms apartment - Type 1

Figure 28.â&#x20AC;&#x152;Two bedrooms apartment - Type 2

The Design of Low-Rise Buildings WP 2.2 Three bedroom apartments (95-105 m2)

Spatial considerations

Plan form

The size of three bedroom apartments depends on the tenure, whether the unit is designed for affordable housing, private for sale, open market rent or shared ownership

The plan form of two examples of three bedroom apartments are shown in Figures 29 and 30.

Servicing considerations Services are delivered through risers that are on the corridor side of each unit where central systems such as cold water, hot water, electrical supplies, are routed to each apartment. Horizontal distribution can be managed by routing services through a dropped ceiling in the corridors. Relevant standards UK Building Regulations 2010, Lifetime Homes 2008, Code for Sustainable Homes 2010, London Housing Design Guide, Finnish building Regulations.

Figure 29.â&#x20AC;&#x152;Three bedrooms apartment - Type 1

Figure 30.â&#x20AC;&#x152;Three bedrooms apartment - Type 2 21

Sample Designs of Modular Dwellings

Detailed drawings The following pages present detailed drawings of terraced houses using modules of various sizes, together with the facade treatments that are possible. The plan forms illustrate the layout of the apartments used in housing and low-rise apartment buildings with one, two, and three bedroom typologies.

Sample Designs of Modular Dwellings Houses

Sample Designs of Modular Dwellings Studio Apartments

Sample Designs of Modular Dwellings One Bedroom Apartment Type 1

Sample Designs of Modular Dwellings One Bedroom Apartment Type 2

Sample Designs of Modular Dwellings Two Bedroom Apartment Type 1

Sample Designs of Modular Dwellings Two Bedroom Apartment Type 2

Sample Designs of Modular Dwellings Two Bedroom Apartment Type 3

Sample Designs of Modular Dwellings Two Bedroom Apartment Type 4

Sample Designs of Modular Dwellings Three Bedroom Apartment type 1

Sample Designs of Modular Dwellings Three Bedroom Apartment Type 2

Sample Designs of Modular Dwellings Three Bedroom Apartment Type 3

Sample Designs of Modular Dwellings Typical Wall Dimensions