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This section provides benchmark repair strategies for common flood damage scenarios in domestic properties. It covers the basic elements of construction and , where appropriate, suggests a range of measures that can be taken to improve the flood resistance of new and existing buildings that might be vulnerable to repeat flooding. The construction methods and materials used for domestic buildings vary considerably and many older properties need the knowledge of a qualified building surveyor to specify and oversee repair strategies. fig63 Plates show the levels that flooding has reached at this UK city location. Hence, the guidance which follows, will be most applicable to domestic buildings built after 1930. For buildings that predate 1930 and those of non-traditional construction methods the advice of a qualified building surveyor is recommended. The resilient repair options to improve the flood resistance of new and existing buildings follow guidance provided in the document Preparing for floods issued in 2011. = = Standards for repairing flooded buildings = = External walls -- external finish [Flood damaged element; Brickwork, face blockwork and stonework; Unpainted render, smooth, roughcast, pebbledash, tyrolean; Painted finish - on various render backgrounds; Tile hanging, mathematical tiles, cedar shingles, pre-finished panels, PVC-cladding] [Benchmark repair strategy: Pressure cleaning and making good pointing if required Pressure cleaning if required Pressure cleaning -- repainting required Cleaning manually with low pressure hose and brush] [Issues to consider Pre-flooding condition of materials and pointing Pre-flooding condition of render Aesthetics Entrapped moisture c beneath impervious coatings Bonding Substrate Corrosion of fixings Entrapped moisture] [Resilient repair option N/A; N/A Microporous coatings can be considered N/A] External walls -- structural element [Flood damaged element: Solid brickwork or stonework construction of various thicknesses Cavity brick or block work construction of various thicknesses and materials Timber framed construction Chalk-clay, cob or mud walls System built properties of precast reinforced concrete or steel frame] [Benchmark repair strategy: Controlled and monitored drying Stripping out internal finishes and insulation to facilitate controlled and monitored drying Allowing to dry with natural ventilation and seeking immediate advice from surveyor Seeking immediate advice from qualified building surveyor] [Issues to consider: Solid walls may suffer from pre-flood dampness and never achieve 'dry condition' Type of insulation within cavity Silt entry to cavity through a Seeking immediate advice from qualified building surveyor Submersion in floodwater can result in significant loss in strength or collapse Corrosion of metal components and fixings Deterioration of insulation] [Resilient repair option: Considering water resistant coatings externally to 500mm above flood line Ensuring airbricks sleeved and cavity fully sealed where air bricks and services penetrate walls Reconstructing with traditional materials and methods Reconstructing with traditional materials and methods, subject to controls Specialist moisture repelling coatings Self-draining insulation] External walls - insulation: [Flood damaged element: Cavity brick, stone or block with urea formaldehyde foam or blown fiber insulation cavity fill Cavity brick, stone or block with closed cell foam or self-draining mineral wool batts cavity insulation Solid masonry with external insulation of self-draining mineral fiber batts or rigid plastics behind cladding Solid masonry with internal insulation behind plaster boar linings Timber frame walls with mineral wool or other insulation ] [Benchmark repair strategy: Seeking immediate advice from qualified building surveyor Controlled and monitored drying Stripping out plasterboard and removing insulation if of water absorbent type Removing internal linings insulation to facilitate and e controlled and monitored drying of timber frame. Seeking advice from surveyor] [Issues to consider: Entrapped moisture Deterioration of insulation Corrosion of wall ties and insulation fixings Corrosion of insulation fixings Entrapped moisture Contamination of insulation Corrosion of fixings Existence of embedded timber grounds in masonry Deterioration of the external sheathing panels reducing racking resistance Damage to breather membrane] [ Resilient repair option: Closed cell insulation foam Stainless steel ties and fixings Stainless steel fixings Stainless steel fixings Low absorption insulating boards or semi-rigid self draining mineral wool batts] External walls, and internal walls and partitions - internal finishes [Flood damaged element: Gypsum plaster directly applied to masonry a background Lime based plaster on a cement-sand rendered d background over masonry Plasterboard on adhesive dabs applied to masonry or fixed to timber studwork Timber strip, sheet of veneer paneling Ceramic tiles on cement-san rendered background over masonry Paint finish: emulsion, eggshell or gloss; Wallpaper] [Benchmark repair strategy: Removing plaster to 500mm above flood line Controlled and monitored drying following removal of affected decorative finishes Removing affected plasterboard Removing and replacing Washing off and re-grouting if required with a water resistant grout Washing down and removing loose and flaking finish. Repainting Removing and replacing when new plaster thoroughly dry] [Issues to consider: Visible joint between new and old plaster Bonding of old plaster Loss of bonding Visible joint between new and old plasterboard Continuity of vapor barrier a on timber frame where partial removal Salvaging paneling in historic buildings for re-fixing after drying Substrate Insulation Services Integrity Entrapped moisture beneath certain impervious finishes Temporary micro porous paint finish to allow plaster to dry before re-papering] [Resilient repair option: Water resistant render and lime based plaster or hydraulic lime coatings Fixing boards horizontally where re-flooding likely to allow for easier partial replacement. Not suitable for timber frame Waterproof adhesives and grout Microporous paints Avoiding vinyl wall coverings] Internal walls and partitions [Flood damaged element: Timber stud partition with plasterboard Timber stud partition with lath and plaster, or lime and horse hair plaster Masonry walls with gypsum plaster finish Masonry walls with lime based plaster finish on cement and sand render Metal framed partitions with plasterboard sheets or faced gypsum panels] [Benchmark repair strategy: Controlled and monitored drying following removal of w affected decorative finishes Controlled and monitored drying of timber. Replacing lath and plaster with plasterboard Removing plaster to 500mm above flood line Controlled and monitored drying Controlled and monitored drying following removal of affected decorative finishes Replacing plasterboard or gypsum panels] [Issues to consider: Condition of timbers or other works may make replacement more economic Condition of timbers or other works may make replacement more economic Visible joint between new and old plaster Bonding of old plaster Loss of bonding Corrosion of metal frame and fixings] [Resilient repair option: Preservative impregnated timbers; plasterboard sheets horizontally Preservative impregnated timbers and plasterboard sheets horizontally Water resistant render and lime based plaster or hydraulic lime coatings] Floors: [Flood damaged element Vinyl floor tiles or sheet vinyl floor covering submerged Quarry tiles submerged Solid concrete floor submerged Suspended timber floor with chipboard Suspended timber floor with softwood tongued and grooved floorboards Oak blocks set in bitumen on solid concrete floor slab Modern 'thin section' hardwood block or wood strip floors including parquet Suspended concrete floor of beam and hollow block construction] [Benchmark repair strategy Cleaning or replacing Cleaning and monitoring drying Cleaning or replacing chipboard if damaged. Controlled and monitored drying of structural timbers Cleaning or replacing floorboards if damaged. Cleaning, repairing or replacing Repairing or replacing Cleaning and monitoring drying] [Issues to consider Substrate Duration of flooding Type of floodwater Aesthetics Substrate Insulation Services Integrity Entrapped moisture Type of floodwater Access may be required to clean silt from flooded void Access to void beneath] [Resilient repair option Consider relocating services Replacing with solid floor Replacing with marine plywood Replacing blocks with screed and floor finish (e.g., carpet) Replacing with screed if on concrete floor and covering Considering relocation of services] Joinery and fittings: [Flood damaged element Painted softwood or treated hardwood external door Double glazed hardwood patio doors or window units Double glazed PVC-U patio doors or window units PVC-U external door Wooden window frames submerged in floodwater Cellular type internal doors Timber staircase of softwood or hardwood submerged in floodwater Built in wardrobes and cupboards submerged in floodwater Fitted kitchen units submerged in floodwater Skirtings, door linings, architraves and trims of MDF or small section softwood Skirtings, door linings, architraves and trims of large section softwood or hardwood] [Benchmark repair strategy: Cleaning and repainting or replacing if warped. Overhauling or replacing ironmongery Cleaning and allowing to dry out before assessing damage. Replacing glazing units only if seals have failed Cleaning and replacing glazing units only if seals have failed Cleaning and replacing glazing units only if seals have failed Cleaning and allowing to dry out before assessing damage. Replacing double glazed unit only if seals have failed Replacing Cleaning and allowing to dry out before assessing damage. Repairing with strengthening to treads or replacing Replacing Unless of solid hardwood and high quality, removing and replacing Replacing Controlled and monitored drying, removing paint finish, priming and redecorating] [Issues to consider: Considering cost of replacement against salvage where of modest standard Corrosion of fixings, runners and ironmongery Corrosion of fixings, runners and ironmongery Corrosion of fixings, runners and ironmongery Pre-flood condition of windows Shrinkage of glue blocks may cause squeaking when dried out Some stairs may have MDF treads and risers For high quality, purpose-made hardwood joinery, considering specialist restoration N/A Joinery might require removal for other trades but could be salvaged if economic] [Resilient repair option: Replacing with PVC-U unit Selecting units with stainless steel fittings and ironmongery Staircases of solid timber construction below flood level Building off floor using plastic legs PVC-U units Building off floor using plastic legs PVC-U units Hardwood or PVC-U N/A] Electrical services: [Flood damaged element: Electrical installation comprising PVC sheathed cables, sockets, switches and fuse boards submerged in floodwater Fixed electrical appliances submerged in floodwater Electrical metering equipment in contact with floodwater] [Benchmark repair strategy: Immediate advice to be sought from qualified electrician. Presumption for c replacing all components in contact with floodwater Should be replaced Electricity supply authority to be contacted immediately ] [Issues to consider: Remaining installation may R not comply with current c regulations and be condemned Moisture may affect other components] [Resilient repair option: Raising sockets and routing cables above flood line can be considered Repositioning equipment above flood line can be considered] Gas installation: [Flood damaged element: Gas service pipes and apparatus in contact with floodwater Gas fire (wall hung or floor mounted) submerged in floodwater] [Benchmark repair strategy: Electricity supply authority to be contacted immediately and its advice acted upon Should be replaced] [Resilient repair option: Repositioning equipment above flood line can be considered Repositioning boiler above flood line can be considered] Central heating - wet system: [Flood damaged element: Steel panel radiators in contact with floodwater Pipe work and apparatus in contact with floodwater Boiler (floor or wall mounted) submerged in floodwater] [Benchmark repair strategy: Radiators to be cleaned and repainted Equipment to be cleaned and sanitized Any electrical components to motorized valves or controls replaced, and insulation replaced Should be replaced] [Resilient repair option: Repositioning boiler above flood line can be considered] Sanitary ware: [Flood damaged element: Vitreous china sanitary ware submerged in floodwater Bath of pressed steel, cast iron or plastic submerged in floodwater MDF or chipboard base vanity unit ] [Benchmark repair strategy: To be cleaned and sanitized To be cleaned and sanitized Whole of vanity unit to be replaced] [Issues to consider: May need removal to facilitate other works Salvage may be uneconomic Removal to facilitate other works Salvage and storage may be uneconomic Plastic bath may have chipboard frame] Drainage: [Flood damaged element: Underground drains and sewers backed up with floodwater] [Benchmark repair strategy: Debris and silt to be flushed through to remove. Conduct CCTV survey if blockages encountered] [Issues to consider: Pre-flood condition of surface water drainage and sewerage systems] |
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