Queens Park Conservation Area TSB Retrofit For the Future, London 2011

2-bedroom, 2-storey Victorian terraced properties built around1865

In a Conservation Area of approximately 400 other similar properties

Client - City West Homes Contractor - United House Project Manager – Anna Debenham

Refurbishment of social housing in Queens Park, Westminster, London

Lead Architect - Mark Elton Associate Director at Energy Conscious Design On the RIBA ‘sustainable futures’ committee

Special Interest in: The potential for reducing carbon emissions through

retrofit of the existing stock Refurbishment schemes that combine super-insulated

fabric improvements with integrated renewables

Project Architects: Energy Conscious Design (ECD)

Internal wall insulated to the exterior solid walls Roof insulated Doors and windows improved and replaced Acoustic insulation fitted to the party walls of bedrooms Ground floor suspended timber floors removed and

replaced with an Eco-Slab floor system Mechanical ventilation heat recovery (MVHR) installed

Key Improvements to Property

Thermal image showing heat loss

Project funding

Retrofit for the Future project is funded by the Technology Strategy Board (TSB) to find ‘innovative and replicable measures to make deep cuts in carbon dioxide emissions from existing properties in the social housing sector’

Driving Innovation in Retrofit

UK Technology Strategy Board (TSB) funding was specifically designed to stimulate the implementation of innovative cost effective solutions within the demonstrator houses that can then be applied across the UK.

Evaluation

SAP tests before and after retrofit Used by BRE as a Pilot for their

‘BREEAM Domestic Refurbishment standard

Evaluated alongside BRE EcoHomes XB target criteria and discussed with the local conservation officer

Typical Heat Loss Pattern

Generally agreed that 15% of heat is lost through the ground floor but it can be higher in older properties

Heat is lost through draughts in the floor boards as well as through the fabric

Draughts in a typical Victorian House

‘THERMAL ENVELOPE’

Insulate the property to keep heat inside in winter and outside in summer and maintain a constant internal temperature

Create an airtight seal to eliminate heat loss from draughts

Thermal Image of Interior of Victorian Terraced House

Retrofitting the Ground FloorSchedule of Works

Disconnect Services Remove joists and floor timbers Fill void Reroute and reinstall services Lay new floor

Challenges of the Site when Retrofitting the Ground floor

CHALLENGES OF THE BUILDING SITE

Work had to be carried out in a confined space which meant: Confined space working Health and Safety Act had to be observed so no petrol

driven machinery Materials and installation had to be handled manually Labour intensive options not possible No room for storing materials in building Delivery of materials had to be tailored to the demands of restricted site access

The original Victorian features had to be protected The integrity of the Substructure had to be maintained Services had to be re routed Void had to be filled and ventilated The material effects of retrofit on adjoining properties had to be considered Party Wall Act applied Security had to be maintained at all times

Challenges of the Street When Retrofitting the Ground floor

New Road and Street Works Act:

Health and Safety conditions Relate to the control of deliveries

Needed road signs and barriers

Traffic control

Timed deliveries

Make good any damage to road or footpath

Local Council By Laws:

The by laws change depending on the Borough

Not able to start work before 9am

Road had to be cleared and swept by 5pm

No weekend working

Noise and dust restrictions

The traditional approach

15 tons of aggregates were delivered, stored on the road and shoveled and barrowed in to the house to fill the void at a rate of a ton a day

Diesel driven whacker plate was used to create a flat surface putting pressure on substructure and creating toxic fumes in confined space violating Health and Safety laws

The Eco-Slab solutionFEATURES OF ECO-SLAB

SYSTEM

‘Just in time engineering’

Foaming concrete was delivered by a Lorry

mounted pump, located outside the working

area

Foaming concrete used to fill deep void

BENEFITS OF ECO-SLAB SYSTEM

Minimal materials to store and

organise

No complications or concerns with Council

Bylaws,

Conditions of working in Confined

Spaces Health and Safety Act and New

Road and Street Works Act were satisfied

Replaced 15 tons of granular material

Pump set up, filled the void cleaned up

and left within one in an hour with no

manual handling

Minimal Impact on the Street:

Site Activity, Traffic movement, Noise and

Dust all substantially reduced

Minimal supervision to organise delivery

Eco-Slab Module

Method Statement for Retrofitting Ground Floor with Eco-Slab

FEATURES OF ECO-SLAB SYSTEM

‘Just in time engineering’

Eco-Slab was programmed to be delivered

on a light commercial vehicle on day of

installation

Installed by hand by a single semi skilled

operative in one day

Eco-Slab was laid directly onto the foam concrete

base

Service and ventilation void was provided by

100mm legs

75mm thick fibre reinforced wearing slab was

poured to finished floor level

BENEFITS OF ECO-SLAB SYSTEM

Hand off loaded and no storage required

Unloading and installing completed in one

operation.

No machinery required so easily met

‘Confined space working Health and

Safety Act

No pressure or penetration of the existing

walls

Allowed for simple rerouting of services and

Under floor ventilation

Reinforcement was in the concrete so delivery and

fixing of reinforcement was not needed

All Local Council By Laws and New Road and

Street Works Act easily met as

noise, dust, site activity etc. reduced

Insulation Values & Carbon Reductions

Eco-Slab is made from Carbon Enriched Jablite EPS which has an

A+ rating in the BRE Green Guide

The unique lap & ledge system ensured a continuous 100mm of

insulation throughout the ground floor

200mm Edge beam system gave a U value of zero at the wall/ floor

interface

The Eco-Slab floor provided the base for the thermal envelope

In conjunction with other technologies the energy use for the building was

reduced from 16000 kilo watts per year to 2000 kilo watts without

renewables

ECD Architects – Eco-Slab system ground floor section

Conclusions Traditional methods of construction cannot meet the demands and complexities of professional

retrofitting on the scale required

We need to employ new ways of working and new materials

Modern methods of construction and in particular ‘just in time engineering can assist in meeting the challenges

The Eco-Slab system offers a fast and cost effective solution for retrofitting the ground floor when working in a confined urban environment

It is particularly cost effective when retrofitting several houses in one area and the costs of hiring the pump can be shared among several properties

The Eco-Slab retrofit system using foaming concrete and the Eco-Slab base significantly reduced the operational and embodied carbon compared to traditional retrofit methods and combined successfully with other technologies to create a thermal envelope

www.eco-slab.com