Picture of refurbished house in Lothrop Road, Queens Park, Westminster
SAP reports are available on request
Creating a thermal envelope keeps a steady ambient temperature in the house except in the most extreme conditions and A mechanical ventilation heat recovery (MVHR) installed to ensure that there is a regular air change and fresh air brought into the house is warmed by the air leaving
The blue line along the floor wall interface shows where the cold is penetrating and cooling the house.
Typically in a Victorian House you will find a void or crawl space when you take up the floor boards, full of builders rubble and anything that has managed to slip down between the floor boards. In these houses the architect wanted to create a platform for the services to reroute the tangle of pipes and wires and then put the floor on top of the foaming concrete. The void also allowed the area beneath the slab to be ventilated.
As much a challenge as finding ways to reduced carbon was the logistics of working in such a constricted space in a busy terraced street
This is the solution that Eco-Slab provided to overcome the problems of the traditional approachand which was then used in the other 6 properties being retrofitted
The Eco-Slab is laid on top of the foaming concrete What is not shown here is a 200mm beam which sits is placed around the edge of the raft and gives equivalent insulation of 200mm to wall edge where most heat is lost.
Eco slab presentation
QueensPark Conservation Area TSBRetrofit For the Future, London 2011
Refurbishment of social housing inQueens Park, Westminster, London 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
Project Architects: EnergyConscious Design (ECD) Lead Architect - Mark Elton Associate Director at Energy Conscious Design On the RIBA ‘sustainable futures’ committeeSpecial 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
Key Improvements to Property 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
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
‘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 ofVictorian 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 whenRetrofitting the Ground floorCHALLENGES OF THE BUILDING SITEWork 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 WhenRetrofitting 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 solution FEATURES OF ECO-SLAB SYSTEM BENEFITS OF ECO-SLAB SYSTEM ‘Just in time engineering’ Minimal materials to store and organise Foaming concrete was delivered by a Lorry No complications or concerns with Council mounted pump, located outside the working Bylaws, area Conditions of working in Confined Foaming concrete used to fill deep void 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
Method Statement for RetrofittingGround Floor with Eco-Slab FEATURES OF ECO-SLAB SYSTEM BENEFITS OF ECO-SLAB SYSTEM ‘Just in time engineering’ Eco-Slab was programmed to be delivered Hand off loaded and no storage required on a light commercial vehicle on day of installation Unloading and installing completed in one operation. Installed by hand by a single semi skilled No machinery required so easily met operative in one day ‘Confined space working Health and Safety Act Eco-Slab was laid directly onto the foam concrete No pressure or penetration of the existing base walls Service and ventilation void was provided by Allowed for simple rerouting of services and 100mm legs Under floor ventilation 75mm thick fibre reinforced wearing slab was Reinforcement was in the concrete so delivery and poured to finished floor level 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 & CarbonReductions 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
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