StoTherm combines aesthetics with performance

StoTherm Classic combines aesthetics with performance to blend new development with historic church exterior .

During the early 1990's, St Paul's Church at Worthing, in West Sussex, fell into disuse because of serious structural problems with the roof, which had to be propped internally.

Being a member of a group of four local churches, the congregation were able to continue their worship at the three other churches and, rather inevitably, the decision was taken to find an alternative use for the disused Grade II* listed building.

St Paul's Church was originally consecrated as a chapel in 1812 and has undergone many architectural changes over the years.

It is of brick, partly stuccoed, having a Doric portico with four columns at the east end and with a bell-cupola behind it.

Given its listed status and prominence in Worthing's history, the officials involved were understandably enthusiastic to find a development scheme that was both innovative and sympathetic to the old church.

Overall the site comprised the main Church building and a Church Hall extension built in the 1960's.

The proposal was to demolish the extension and redevelop the site as a four-storey residential building providing 10 flats, along with a single-storey extension.

This incorporates a small meeting room and ancillary service areas to complement the next phase which involves converting the Church into a Community Centre, intended to provide a focal point for local groups and organisations.

An important town centre space Chris Richardson of drp architects takes up the story: "Our design is intended to be simple and takes references from the existing listed building".

"It comprises bold shapes with a circular theme and by linking first and second floor windows emulates the scale and proportion of the Church".

"The masonry section which extends up to three storeys then has a zinc clad timber top floor which floats on the top and repeats the pitch of the roof over the Church".

"The extension is deliberately set back to create an important town centre space with the repositioned war memorial taking a central position".

The new development is a 'warm wall construction' and the right choice of external rendering was critical, not just for its thermal efficiency and weatherproofing qualities, but for aesthetics as well - the finish having to match the exterior of the adjacent St Paul's Church.

The StoTherm Classic facade insulation system from Sto was considered the ideal solution to meet the demanding criteria.

Sto is a major multi-national organisation, dedicated to the development of products and systems that protect, maintain and enhance the value and aesthetics of buildings.

The company was founded in Germany over 150 years ago and StoTherm Classic has been defining technical standards for almost forty of those years.

During that time over 50 million square metres of facade area have been installed around the world and it is acknowledged today as being the most successful system of its type in the world.

Virtually unlimited design freedom StoTherm Classic is a completely organic, highly durable, external wall insulation system (EWIS) with unrivalled performance even in extreme climates - and a shock-proof and impact resistance around ten times higher than inorganic systems.

StoTherm Classic reduces heat loss, protects buildings from heat gain and prevents thermal bridging, resulting in far less temperature-induced stress on the building envelope.

It also guarantees weatherproofing by keeping out driving rain and snow, yet remains permeable to water vapour - again adding to the service life of the facade.

StoTherm Classic permits virtually unlimited design freedom too, with a vast colour choice of renders, or with a brick slip, tiled, or stone style finish.

Up to 15 times the resistance of conventional renders At the heart of the StoTherm Classic facade insulation system is a CFC and HCFC free, rigid expanded polystyrene foam board (EPS), onto which Sto Armat Classic, a cement free, highly flexible, water based fibre reinforced render is applied.

While still wet, a specially developed reinforcing mesh (Sto Glass Fibre) is embedded into the render, the finishing plaster (Stolit K) is then applied creating a stippled, small grain finish.

This is an acrylic, cement-free decorative finishing plaster which over many years has helped establish Sto's competence in the field of facade finishes.

It is highly elastic, resistant to mechanical stress, offers a complete weather protective finish and allows the walls to breathe.

Its balanced formulation and use of high grade materials guarantee low water absorption, optimum adhesion to the substrate and a high elasticity which offers up to 15 times the resistance of conventional modified cementitious renders.

The system can be either adhesively bonded or mechanically fixed and on this occasion it was decided to mechanically fix to the solid blockwork wall substrate at the St Paul's development.

This involves an aluminium starter track being installed at the base of the system and the first row of EPS boards are then inserted, using a 'T' spline between each board.

The row is secured with a horizontal holding track and the process begins again with the next row of boards.

Tony Sheehan of the Joyner Group, who carried out the work on the St Paul's project, comments: "The project has some very pleasing aesthetic features - circular windows, raised bands, sills and a circular tower - but they were a challenge to work with".

"We used Lamella mineral wool insulation to form the tower/turret curves with Sto Therm mineral base and top coats".

"Preformed EPS profiles were fabricated in Joyners Bristol workshop to achieve the architectural requirements of the raised features and circular windows".

"By combining modern techniques with traditional skills, the finished contract is a credit to all concerned, resulting in a visually stunning project".

Being a historic church site there was initial scepticism about the development proposal among some members of the local community, but the new building has been well received and drp architects hope that the St Paul's project might even be an award winner for them.

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