BACKGROUND:
This was a large two-part project in 3rd YR of Architectural Technology; it involved the refurbishment and reuse of an existing protected structure (the former Courthouse in Bagenalstown Co. Carlow) as well as introducing a new extension to the front of the building and detailed instruction on how we intended to connect the old with the new.
We had to survey the existing buildings and identify where there were existing problems, what the problem was and how it could be rectified. This included defects/ailments to the fabric and the structure, as well as outdated inaccessible construction elements; in particular, access for people who may have a range of various disabilities (in relation to Part: M of the Building Regs).
As with previous Architectural Technology projects, the suggestions made here are probably out of date (as it was a couple of years ago we undertook the project) but at the time everything would have been on par with or exceeded the current regulations.
In hindsight I was very happy with my construction design and process, it was simple light and affordable and would not impact on the fabric of the existing building at all (The construction type was timber-frame structural insulated panel – SIP)
Also at the time the connection detail seemed to be the most fitting (to connect the new SIP structure with the existing via curtain-walling) but again now with architectural years of experience under my belt, it feels like that option was a bit of a cop-out (an easy solution as opposed to an architectural one).
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EXISTING - ELEVATIONS | PLAN | SECTION
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EXISTING SITE LAYOUT
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PROPOSED GROUND-FLOOR PLAN
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PROPOSED FIRST-FLOOR PLAN
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PROPOSED ELEVATIONS
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- ON THE REFURBISHMENT OF THE EXISTING FABRIC -
EXTERNAL WALLS:
The cement-based external render on the east and west side of the walls (and part of the south gable) is contributing to the problems of the moisture retention with the masonry fabric of the building. The optimum solution I felt would be to hack off all of the external render and replace it with a new lime render finis. Particular care should be paid to the south gable wall (that used to be connected to the old south-annexe), it will be necessary to replace the plaster carefully here to achieve the appropriate flashing detail.
WINDOWS:
Allowance should be made for repainting all external joinery, including the frames of the casement windows (if they are not to be replaces). In this case it may be necessary to put localised spliced repairs to some of the window frames. Each window should be checked to ensure that it can be easily opened and localised adjustments as required.
FLOOR:
Moisture Resistant Flooring Grade Chipboard
Use 2 layers of 18mm, T&G glued and taped.
Layer 1 floats on Layer 2 with a glue only fixing to the acoustic membrane for superior acoustic dampening.
We fit a strip layer fitted around the perimeter cassettes to attenuate transmission to the wall panels.
The chipboard uses 100% or near 100% recycled wood.
GROUND:
I feel the most appropriate way to deal with the water0ingress coming up from ground level is to install A French Drain, which should be excavated along the east and west side of the external walls of the former courthouse. This will involve the excavation of a trench along the base of the wall, to be line with a terrim membrane; a perforated land drain will be laid at the bottom of the trench, to discharge into an existing surface water drain or soak pit; the drain will then be backfilled with clean rounded gravel and finished with pea shingle. This is a priority detail; to reduce the existing levels of rising damp through the external walls.
INTERNAL WALLS:
The existing Gypsum plaster finish is inappropriate for a historic building of this type. The plaster finish has failed over a large area of the east and west external walls as a result of excessive moisture content within the fabric of the walls. It would be recommended that all gypsum plaster be hacked off the walls. The walls should be replastered using a traditional lime-plaster (with no cement content). Also all timber wainscots dating from the 1990s (or probably later considering the little damage that was present) should be removed and discarded.
FLOORS:
Localised opening should be carried out in timber floor to access the condition of the floor joists. Provisions should be made for the introduction of a number of ventilation grilles on the east and west side of the former courthouse to facilitate under- floor ventilation.
ROOF:
A detailed inspection of the roof space over the former courthouse should be carried out as a priority. The existing attic hatch in the centre of the ceiling is inaccessible. It would be preferable to perform a new opening in one of the coffers of the ceiling over the north gallery; this would facilitate periodic inspections of the attic in the long-term.
VENTILATION:
Arrangements should be made to facilitate the regular problem of natural ventilation to the interior of the former courthouse. This will involve the opening of a number of the windows on each side of the former courthouse on a regular basis to allow cross-ventilation. This will be a management/employee issue and will note require and capitol expenditure.
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SIP WALL CONSTRUCTION DETAILS
WALL BUILD UP:
SIP BUILD PANEL BUILD-UP: CORE:
100% recycled material of superior performance.
Composition: 80% gypsum (recycled) and 20% cellulose fibres derived from recycled papers, mixed with water. The entire production process is also fully recycling, which means that all by-products are fed back into the production cycle.
Moisture Resistance - ideal wall board for kitchens and bathrooms, it can withstand humidity levels of up to 80% Rh & can be installed before building envelope is complete.
Acoustic Performance - a 100 mm wide stud wall with Fermacell board gives better acoustic reduction stud gives nearly twice this performance.
Load Carrying and Structural Properties - meeting BS 5234: part 2 Severe Duty Rating, so is much stronger than plaster board; high load bearing and can carry up to 30kg from a single screw and up to 50kg from a wall plug fitting which eliminates the need for noggins.
Can eliminate plastering - easy to use and is ready for decoration without the need for plaster. For a "glass" finish use FST (Fine Surface treatment) to apply a skim coat finish using DIY skills and is dry within 45 minutes.
VAPOUR BARRIER:
Thermo reflective low emissivity vapour control membrane
Used is a robust highly reflective low emissivity vapour control layer which provides significant thermal, strength and performance enhancements over conventional vapour control layer materials with the added benefit of a service cavity. It is a triple-ply construction including a tough polywoven core layer with a bright high purity aluminium foil which is pressure bonded with a further polypropylene interlayer. AHS installs facing into an unventilated airspace, effectively blocking infra red radiation and enhancing the thermal performance of the airspace, and hence the overall U-value of the construction.
CORE INSULATION:
Mineral Wool - probably the best trade off between cost friendly mineral wool insulation with embodied energy reduced by up to 70% compared to traditional oil based binders. Made using sand and recycled glass bottles, the insulation does not contain artificial colours or added formaldehyde, resulting in environmental credentials of A+ in the BRE's Green Guide. The insulation's acoustic, thermal and fire protection - class
A1 - properties are the same as the traditional mineral wool.
PLASTERBOARD:
Knauf Fireboard 30mm 2hr Fire Protection; Knauf Fireboard is a glass fibre reinforced gypsum board specially developed for high performance lining and encasement, providing up to two hours of fire protection. Knauf Fireboard is non-combustible to BS 476: Part 4: 1970 (1984) and Class 1 Surface Spread of Flame to BS 476: Part 7: 1997. Knauf Fireboard complies with the Class 'O' requirements of the Building Regulations when tested to BS 476: Part 6: 1989 and Part 7: 1997 and with the limited combustibility described in the Building Regulations. The smoke production is negligible.
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SIP WALL CONSTRUCTION DETAILS
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CONNECTING THE NEW BUILDING WITH THE EXISTING FABRIC
CURTAIN WALLING:
Curtain Walling Fixed Glazing by APA Systems;
Type: TB50.
Support grid and with no need for capping to retain a flush finish to the exterior face of the facade.
The glass is secured in place using toggles, which are placed into channels; these form part of the central seal of the double glazed units. All joints are weathered using a silicone seal producing a flush non-interrupted surface of glass -to- glass butt joints.
Fritting of the edges of the double glazed units is not required when a black spacer bar along with a special
Dow Corning edge seal edge is used. The double glazed units are manufactured in Ireland ensuring short lead times.
STAIRS:
Stairs are Precast Concrete; manufactured by
Concast Ltd.
Rise: 150mm
Going 300mm
18 Risers in total
Stairs fully comply with part B, K and M of the
Building Regulations - Encased/Fire Protected
Ambulant Disabled Stairs.
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INTENDED SITE SITE LAYOUT INC. LANDSCAPING
LANDSCAPING
The landscaping was to be quite similar to the original but less snake like (less winding paths up the steep slope). The circular areas are designed as resting spots. These are to remain flat and not follow the steep contours of the site, this is to allow the disabled or ambulant disabled to rest after making their way up the steep sloped paths.
The route to the north entrance of the courthouse (the Portico side) is to be simplified, less turns and with wider – 1500mm – paths; A triangular paving area is to be added to the front of the entrance; directing people to the three optional routes (the left and right paths – that leads to the South entrance and the central option that leads to the bottom of the north entrance portico steps – this area to also be levelled and not follow the natural contours of the site).
