These stages are just a general guide and include what some warranty providers may want checking on site. It is not conclusive but is here as a general guide so always ensure the correct stages are being surveyed as part of your warranty and do not rely solely on the information here.
Stages may not be reached on site in the sequence they are presented below
This is not design information. All work should be designed by a competent architect / designer and, where applicable, engineers and built on site by competent contractors and all to current building regulations and other legislation.
Foundation stage
Some elements the survey is looking at
· The site and surrounding area. Features such as rivers, cliffs, pylons, buildings not in keeping with general area, e.g. a supermarket or school adjacent to residential. Should include all trees, shrubs, and vegetation within 20m of any part of the unit, including on neighbouring property. Should include an indication of species and height.
· All trenches excavated, no loose or water. Any changes in soil colour, material, and description of texture, e.g. hard, soft, sand, clay. Steps, day joints, roots, heave precautions, features, e.g. wells and compensating measures, changes to design, unusual design, e.g. gabions, etc.
· Any steelwork, showing cover, laps, links, chairs.
· Piling – layout, caps, cages, inc links and chairs, cover, formwork.
· Any uncovered drainage, inside or outside the unit.
· Depth and width of excavations
Common defects found during the survey
· Incorrect steel mesh.
· Waterlogged trench.
· Soft ground.
· Inadequate cover.
· Nearby trees, hedges, or shrubs which the design does not allow for.
· Foundation design not adhered to.
· Inadequate lap of steel mesh.
· Site investigation report recommendations not followed.
· Undermining of other buildings.
· Excessive steps.
· Inadequate width or depth.
· Unsuitable bearing pressure / soft ground
DPM stage
Some elements the survey is looking at
· Membrane laid over the whole floor area before being covered by concrete or insulation.
· All service penetrations complete, sealed, and ready for pouring concrete.
· All laps, taped, including with the damp-proof membrane (DPC). A double-sided butyl tape and additional single side tape over should be used.
· Any uncovered drainage, inside or outside the unit.
· Is a gas barrier being installed and is it as per BRE 211 guidance.
Common defects found during the survey
· Inadequate cavity drop, less than 225mm.
· Gas barrier across the cavity with no tray above.
· Cavity wall insulation not low enough in the cavity.
· Inappropriate cavity wall insulation installed below DPC.
· DPC not lapped and taped to the DPM, or no provision for lapping later.
· DPM not adequately taped with double sided butyl tape and single tape over, or as per the manufacturers installation instructions. This includes all laps and connections.
· Walls not positioned correctly on the foundation.
· Top hats or other suitable product used over service penetrations.
· DPM covered by the insulation.
· Damaged or torn membrane.
· Normal DPM used instead of a gas barrier (where applicable).
· Insufficient ventilation.
DPC stage
Some elements the survey is looking at
· Have details from Approved Document C been followed such as a minimum 225mm drop below the DPC in the cavity (150mm if a tray is being used)
· Is there provision to connect the DPC and DPM.
· If standard details are not being used, how will damp be prevented.
· Any uncovered drainage, inside or outside the unit.
· Is a gas barrier being installed and is it as per BRE 211 guidance.
· The DPM may also be in place at this time.
Common defects found during the survey
· Inadequate cavity drop, less than 225mm.
· Gas barrier across the cavity with no tray above.
· Cavity wall insulation not low enough in the cavity.
· Inappropriate cavity wall insulation installed below DPC.
· DPC not lapped and taped to the DPM, or no provision for lapping later.
· DPM not adequately taped with double sided butyl tape and single tape over, or as per the manufacturers installation instructions.
· Walls not positioned correctly on the foundation.
cavities / structural elements, roof level not water tight
Some elements the survey is looking at
· General elevations.
· Where partial fill cavity insulation is used: clean cavities, wall-ties and drips at appropriate centres and distances from reveals, clipped insulation,
· Lintels, including insulation, beams, steels, joists, bearings to all of these and noggins, bracing, struts. Insulation thickness and brand. Reveals and if possible, show ties. Trays and stop-ends, weep holes and vertical DPC’s and movement joints.
· Rafters including trusses, bracing, restraint straps, flat roof joists and decking, hips, valleys, and ridges.
· Any uncovered drainage, inside or outside the unit.
· Roof structure for bracing, fixings, suitable bearing, and restraint.
Common defects found during the survey
· Debris in cavities
· Wall ties inadequately bedded.
· Wall ties sloping towards the inner leaf.
· Cavity wall insulation not installed as per manufacturers recommendations.
o Tongue and groove boards orientated incorrectly.
o Vertical DPC’s omitted, where applicable.
o Not taped, where applicable.
o Not suitable for below DPC.
o Missing in places leaving cold bridges.
o Not positioned low enough to meet SAP thermal bridge requirements.
· Restraint straps and noggins not installed.
· No provision to connect DPC and DPM.
· No provision for movement joints, as applicable.
· Cavity trays sagged or not turned up at edges.
· Weep vents omitted from cavity trays.
· Roof trusses not braced as per the manufacturers design.
· Restraint straps omitted or without noggins.
· Roof structure not as per design.
· No provision for shrinkage of a timber frame.
· No provision for ventilation and draining of a cavity (timber frame) or cladding.
Water tight / first fix
Some elements the survey is looking at
· General elevations.
· If cavities are accessible - Where partial fill cavity insulation is used: clean cavities, wall-ties and drips at appropriate centres and distances from reveals, clipped insulation,
· Lintels, including insulation, beams, steels, joists, bearings to all of these and noggins, bracing, struts. Insulation thickness and brand. Reveals and if possible, show ties. Trays and stop-ends, weep holes and vertical DPC’s and movement joints.
· Rafters including trusses, bracing, restraint straps, flat roof joists and decking, hips, valleys, and ridges.
· Roof coverings.
· Any uncovered drainage, inside or outside the unit.
· Roof covering. Slate may require certification.
· Valleys and ridges correctly formed.
· Flat roofs – warm deck or cold, ventilation requirements, flashing upstand.
· If the stage includes watertight – door and window installations may be checked, primarily Part B, K, L, Q will be considered.
Common defects found during the survey
· Debris in cavities
· Wall ties inadequately bedded.
· Wall ties sloping towards the inner leaf.
· Cavity wallinsulation not installed as per manufacturers recommendations.
o Tongue and groove boards orientated incorrectly.
o Vertical DPC’s omitted, where applicable.
o Not taped, where applicable.
o Not suitable for below DPC.
o Missing in places leaving cold bridges.
o Not positioned low enough to meet SAP thermal bridge requirements.
· Restraint straps and noggins not installed.
· No provision to connect DPC and DPM.
· No provision for movement joints, as applicable.
· Cavity trays sagged or not turned up at edges.
· Weep vents omitted from cavity trays.
· Roof trusses not braced as per the manufacturers design.
· Restraint straps omitted or without noggins.
· Roof structure not as per design.
· Ridges not mechanically fixed.
· Tiles not adequately secured.
· Roof covering not suitable for the pitch.
· No provision for shrinkage of a timber frame.
· No provision for ventilation and draining of a cavity (timber frame) or cladding.
completion
Some elements the survey is looking at
· General – all roofs, elevations and openings, all walls where they meet the ground, loft spaces showing insulation and roof structure and strapping and all openings (windows and doors) from the inside. Stairs and all sanitary appliances and extract fans including kitchens.
· Roof-coverings including mechanical fixings of ridges and verges and cross-ventilation. All flat roofs and balconies, above ground terraces etc, upstands, fall. Flashings, valleys, gutters, and downpipes. Chimneys and flues as far as possible, terminal locations and protection. Roof structure if accessible including insulation and ventilation.
· Drainage system. Inspection chamber lids should be removed before by the client or their contractor to allow for checking for debris and back falls, benching, channels etc. The system should be run and checked it clears, photos required of chambers before test, during test and after test. Any wastewater (foul or storm) treatment plant or holding tanks, including outfall. Gutters and downpipes.
· Services penetrating external walls. All openings in external walls including entrances/ exits / DPC level / finished ground level, ramps, steps, and any other structures potentially compromising DPC.
· Boilers, stoves, flue terminals, heat pumps, solar panel and photo-voltaic arrays, mechanical ventilation and heat recovery systems and wet rooms
· In some cases, stairs, guarding and handrails, fire detection, means of escape.
· In most cases, even where not specifically included items such as fire safety may be added for advisory purposes only.
Common defects found during the survey
· Drains not accessible, blocked or holding water.
· Windows, doors, movement joints and service penetrations not weather sealed.
· Ground levels completed within 150mm of DPC.
· No drainage channel at level threshold.
· Incomplete elements.
· No provision for ventilation and draining of a cavity (timber frame) or cladding.