GENERAL INFORMATION

Haugerudtunet Oslo

Intervention year: 2017

Scope: Research

Area of intervention: Retrofit

Technology maturity level: Project

Climate zone: Dfb - Warm-summer humid continental climate

Haugerudtunet 17-19, Oslo, Norway

Architect

Filter Arkitekter
Owner

Boligbygg Oslo KF, Oslo Kommune

Intervention year: 2017

Scope: Research

Area of intervention: Retrofit

Technology maturity level: Project

Architect

Filter Arkitekter
Owner

Boligbygg Oslo KF, Oslo Kommune

The retrofit project involves a small multi-family building (2 storeys) and 8 apartments, built in 1975. The envelope, façade and roof, has been entirely retrofitted.

The building’s façade has been renovated using prefabricated modules with integrated high-performance technologies. The approach minimized disruption for residents by enabling work to be completed within a very tight timeframe. The renovation was carried out as part of the European project H2020 4RinEU.

Building sector

Residential

Building use

Multi-family building

Heated floor area

320 m²

Facade area

350 m²

Building height

Low rise (1-3 storeys)

Interstorey height

2.4

Existing building structure

Wooden construction, Siporex on ground floor within the envelope structure

Existing wall stratigraphy

Wooden construction with poor fiberglass insulation (10 cm wall, 15 cm roof), according to building codes of 1969. When the building was opened for initial inspection, Siporex construction (expanded concrete), was detected in ground floor wall construction.

Total renovated facade surface (industrialised and not industrialised)

100%

Percentage of renovated facade with industrialised approach

100 %

Window to wall ratio

10 %

U-value existing windows

1.8

U-value existing façade

0.36

U-value after renovation

0.13

envelope facade timber wood retrofit building

Energy concept

The 4RinEU energy performance target is to reduce the primary energy use at least of the 60%, compared to pre-renovation levels.

Façade renovation is a key to reach that target. Retrofitting the envelope improves thermal comfort and ventilation as well.

For the deep renovation, the primary target is the passive house standard in compliance with Norwegian Standard NS 3700.

BEFORE RENOVATION

Technology solution sets	Type of system	Generation	Distribution
Heating system	Decentralized	Electricity	Radiator
Mechanical ventilation	Decentralized	Extraction only mechanical ventilation at building/apartment/room level	Natural ventilation without opening automation
Domestic hot water	Decentralized	Not integrated with the heating system (Electric boiler)

AFTER RENOVATION

Technology solution sets	Type of system	Generation	Distribution
Heating system	Decentralized	Electricity	Radiator
Mechanical ventilation	Centralized	Balanced mechanical ventilation with heat recovery at building/apartment/room level Air ducts
Domestic hot water	Decentralized	Not integrated with the heating system (Gas boiler)

industrialised deep renovation building oslo

Integrated technologies

The prefabricated façade elements integrates multiple technologies:

energy-efficient triple-glazed windows embedded in façade panels;
rockwool insulation in walls and in roof elements
supply air ventilation ducts pre-installed in north façade connecting bedrooms to technical rooms;
building-integrated photovoltaic (BIPV) panels mounted above windows on south façade as external cladding;
prefabricated technical rooms housing air handling units with heat recovery.

All components were factory-installed off-site, minimizing on-site work and tenant disturbance during the 8-week installation.

Replacement of windows is considered a cost-effective measure to improve energy efficiency. Windows in bedrooms and living room are energy efficient standard produced windows integrated in new façade elements, while the windows in new entrance area are built in a façade system.

Mechanical ventilation

Ventilation supply ducts from the technical room to the bedrooms have been installed off-site in the façade elements, then placed on the north side of the building.

The supply air for the living room and the exhaust ducts from the bathroom and kitchen have been installed in the stairways using a traditional approach.

The technical rooms with air handling units (AHU) have been constructed as a prefabricated module on north façade. Two AHUs and shaft ductwork are installed on site in each room. Each AHU is serving two apartments on the same floor. Access to the technical rooms is from the outside to minimize tenant disturbance and ensure good maintenance.

Both the air intake and exhaust are placed in the exterior wall of the prefabricated shaft on the north façade.

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detail timber facade retrofit industrialised

BIPV

PV panels are integrated above the windows in the prefabricated elements on the south façade as part of the off-site production of elements.

There are in total 16 panels, each 1.7x1.0 m2, and total 27.2 m2.

The installed power is 4.56 kWp, and the panels are said to have a nominal efficiency of 19.5%.

Integration in wall elements require safety glass in the PV panels to prevent accident in public places.

BIST

Smart windows

Envelope technology

Prefabricated envelope technology

Multifunctional Timber Prefabricated Façade

The façade elements are made of a solid wood exterior cladding based on slow-grown thermo-treated pine (heat treatment to improve timber stability). In the elements, both the OSB board on the inner surface and the outside wind barrier provide airtight layers within the building envelope.
New energy efficient windows are integrated in the façade.

External finishing

Ventilated cavity

Main structure

Insulation

Compensation layer

Anchoring element

Joints

Tolerances

Circularity

Ease of disassembly (system level)
Ease of reuse
Ease of recycling (component level)

Materials origin
Material use efficiency / Waste produced during production of the technol
Circularity certification

General Data

Max panel width

Max panel height

Panel Weight

kN/m²

Panel thickness

Performance

U-value

Acoustic resistance

Fire resistance

Seismic

Water/Air tightness

Certifications and tests

Simulation campaign

Tests

CE mark / type of certificate

Prefabricated roof technology

10 roof elements were produced off-site. The added insulation is 450 mm, a factor of four increase from the insulation thickness of 150 mm.

It is expected that the average U-value is reduced from 0.30 W/m2K before renovation to 0.11 W/m2K after renovation.

Design and Installation

Construction process

The "from outside" deep renovation approach uses prefabricated elements with integrated PV panels and ventilation.

In order to do that, new foundations have been constructed around existing building.

The renovation was split in 2 phases (half building at a time), resulting in 7 weeks on-site construction time vs 12-16 weeks traditional approach.

This amounts on average to 94 m²/day (10 working days, including removal of old windows for 936 m² of façade).

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Auxiliary elements (i.e. scaffolding)

Works on balconies

Demolition and reconstruction, Loggias

Works on roof

Retrofit

Interaction with the existing structure

Limited interaction - external addition system without major structural intervention. New concrete foundation built around existing Siporex/aerated concrete structure due to low load-bearing capacity. Existing timber-frame upper structure and expanded concrete ground floor preserved.

Interaction with existing facilities

n/a

Level of disturbance

Minimal tenant disturbance - residents remained in apartments throughout renovation. Short visits only for window adjustments and air inlet diffusers. Nine-month scaffolding period caused some inconvenience. Temporary walls constructed to separate work areas from living spaces.

Installation time

94 m²/day

Methodology used for the audit and survey

Building condition assessment was conducted in August 2017.
Façade opening for structural analysis. Laser scanning of building combined with manual control for digital modeling.
Load-bearing capacity analysis. Hazardous materials mapping.
Blower door testing for airtightness evaluation.

Digitalization of the pre-design phase

Building Information Modeling (BIM) decided early - Norway frontrunner in this field.
Laser scans converted to 3D line model.
Point cloud transformed to digital architect model accurate enough for further design.
No original paper drawings available, requiring complete digital reconstruction.

Digitalization of the design phase of the façade

Complete BIM workflow from architect model to production BIM.
3D graphical model (Project Information Model) established.
Digital workshops between architect, structural engineer and manufacturer.
Design BIM transferred to Lindal for production optimization and element subdivision.

Digital compatibility of data between design and manufacturing phase

Seamless BIM-to-production integration.
Design BIM objects used directly in Lindal's production line.
CNC machines automated parts production using BIM data (pre-cut, laser layout).
Digital continuity from design through manufacturing enabled automated production processes.

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digital model building deep retrofit oslo

Prefabrication at component level

Advanced prefabricated elements with integrated building services.
PV panels, windows, insulation, ventilation ducts integrated in factory.
CNC pre-cutting of studs and beams.
Laser-guided assembly system.
Standard ductwork integration.
Elements designed for crane handles during production.

Prefabrication at whole-facade level

Complete façade system prefabrication.
South façade elements with integrated PV panels and windows.
North façade elements with integrated ventilation supply ducts.
Elements sized 2.5m x 10m for standard truck transport.
Eight weeks production period March-April 2018 at Akland factory.

Transport typology to building site (any additional equipment needed)

Standard pallet trucks (2.5m x 10m x 2.5m height).
Just-in-time delivery to narrow construction site with challenging curves.
Special precautions for PV panels.
Crane handles pre-installed during production.
Mobile crane equipment needed for installation.

Distance from the production site to the building site

230 km (from Lindal's production facility at Åkland to the construction site in Oslo), 3h transport time.

Performance and energy savings

Use stage

Before renovation, the thermal comfort was not optimal: issues with draft from air inlet openings, especially in winter, were observed. After the deep retrofit, there has been an increase of comfort, around 33%, with greater uniformity of indoor temperature.

	Before renovation	After renovation
Primary energy demand (total building consumption)	236.8	143.8
Energy demand for HEATING	212	119
Energy demand for COOLING	0	0
Energy consumption for HEATING	212	143.8
Energy consumption for COOLING	n/a	n/a
Energy consumption for domestic hot water	54.2	54.2
Thermal comfort		33% improvment

Pre-renovation monitored data availability

Yes

Renewable energy production after renovation

2,959 kWh/yr from PV panels

Primary energy savings

39 %

LCC

Product / technology cost

1,850 €/m²

Construction / installation costs

1,290 €/m²

Maintenance

Operation

Replacement

End of life

Payback period

LCA

Technology impact

Product and construction stage (A1-A5)

Use stage (B1-B5)

Operational energy (B6)

End of life (C1-C4)

Benefits and loads beyond the system boundary (D)

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Haugerudtunet Oslo

Energy concept

BEFORE RENOVATION

AFTER RENOVATION

Integrated technologies

Mechanical ventilation

BIPV

BIST

Smart windows

Prefabricated envelope technology

Multifunctional Timber Prefabricated Façade

Circularity

General Data

Performance

Certifications and tests

Prefabricated roof technology

Construction process

Use stage

LCC

LCA

Cultural and climatic aspects

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Explore prefabricated integrated technologies