Building Defects

Introduction Decay and deterioration fanny happen in a mental synthesis for any number of reasons. The first universe piteous rep standard pressure and attention of the construction over its life by users or those creditworthy for its maintenance such as a landlord etc. It can also incriminate that at that authority were original problems with the construction that impair its ability to do as intended, these whitethorn not have been uncovered during the snagging process at the end of the construction stage.These building problems argon referred to as flees, depending on the geek of contact most contracts have a 12 month defect block, this enables the users (and funders) to travel in the building through the different seasons and see if any problems make pass. A latent defect is after the 12 month defect period has lapsed and the new building shows signs of problems that be so significant that they can stop its functionality (a latent defect period can last up to 12 el d on some contracts). Please find below some common reasons for defects * forge IssuesDesign professionals (such as architects or engineers) could perhaps specify material or equipment that cannot coiffure as intended. For example a geological survey that does not cover replete areas on a site could mean that the undersoil is not uniform across the site and therefore could eventually cause subsidence in the building. The architects motivation for the design may be with the building form, function or aesthetics but the completed design could result as a defect as any cost considerations or value engineering science if not well planned, managed and coordinated could result in a defects.The use of humble building materials can cause problems such as windows that leak or fail to perform and function adequately, even when properly installed. Leaking windows are a common defect and prevention requires good workmanship. * set supervision during construction period despicable superv ision during the construction period can result in low-down quality and sub standard workmanship. For example this can often unambiguous in piddle infiltration through some portion of the building structure (cracks in oundations, basis slabs, walls, dry rotting of wood or opposite building materials), electrical and mechanical problems, plumbing leaks and back-ups, lack of enamor sound insulation and fire-resistive construction amongst adjacent housing units, etc. The preceding(prenominal) can prevented with a good Quality Assurance process in place that ensures that all trades are well supervised on site, complete records are kept on workmanship (this can include pictorial evidence) and guidance is given to all staff on the quality expectations that have to be achieved on site.The traditional role of Clerk of Works should also be used to ensure that all measures are met on site level. * Maintenance No building lasts forever. Day to day planned maintenance of a building is required to ensure that it prevents any problems in the future. abject planned maintence can cause defects to occur in buildings that would have performed well had they been cared for properly. For example a master plan for the buildings mechanical and electrical (M&E) equipment to be replaced (such as Boiler replacements, lighting upgrades, ICT kinsperson cabling upgrades etc. also phased window or roof replacement schedule to ensure that all that entire building envelope is protected to protect from the elements. If maintenance of buildings are not kept up to date hence in some contracts latent defects would not be honoured as the users have not maintain the works that were carried out in line with the contract therefore the contractors would not be obligated to rectify any defective works. * Service installationSome equipment requires regular inspection and repair under the terms of its guarantee. For example If a boiler that has been installed with a 10 year warranty is not annually serviced then the manufacture can evoke that the user did not meet their obligations and therefore any replacement in the 10 year period would fall to the user to fund. Common Defects found in Low-Rise Housing Please see below mock defects sheets in relation to the defects strategyd in Common Defects in Low-Rise Housing.These outline the defect, the cause of the defect, the remedy required to rectify the defect and finally any supporting building regulations/guidelines that support this process. STAGEA whole shebang/JOB saddlery NO. 6 LOCATIONSouth Wall DATEtwenty-sixth may 2010 BRE REF NO. Defect Action sheet of paper 116 crack stingy wall ties below check-proof Level CAUSE deplorable design and condition FUNCTIONA wall tie is a small piece of coat generally do of steel that is installed between a cavity wall void or between two adjoining walls. The purpose of this is to keep twain walls together at all times.A wall tie countenances slight movement for expansion but if mightily fitted stops all(prenominal) wall acting respectively of one another so therefore keeps the building strong and stable. DEFECTIVE expanse * Corroded and show signs of de-laminating (this is when the metal starts to peel and splinter) * Corroded due to piss egress ( mouldering of the tie means loss of strength) * Corroded show signs of ferrous oxide (this is when the metal bubbles and expands) this can cause lifting and cracking the brickwork * Cavity walling that is blocked with decayed howitzer that bridged the DPC. Poorly fitted wall ties (this means that it does not function as originally intended) * mistaken wall ties used (there are 4 different types of wall ties for each one tie has its own best area for use) DEFECTIVE fudge factor need * Ties should be placed at 900mm centres horizontally and 450mm vertically * Sufficient lap of Damp proof course is required all round * Wall ties to be of a minimum coat 5/m2 * Ensure that ties are as sp ecify and are of the correct type * Use BS or BBA Certificated ties of length and type suitable for cavity width and purpose * Space ties in accordance with BS 5628 Pt 3 2001.For example the cavity width should be 50 to 300mm, number of ties 2. 5 per m2, 900 mm horizontally 450mm vertically and fork up extra ties adjacent to openings * Check that there is a row of ties at every sixth course of bricks * Ties should be staggered and evenly distributed * Check that the horizontal poses have the correct number of stipulate ties per m2 * Check that ties are at every block course within 225mm of opening RELEVANT British bar * BS5628 Pt 3. 2001 STAGEA WORKS/JOB public opinion poll NO. 1 LOCATIONRear externals DATE26th May 2010 BRE REF NO.Defect Action Sheet 96 DEFECT Mature trees too close CAUSE Poor design and specification FUNCTIONMovement where a building is in close proximity of a mature trees. This is a common problem found generally in the following species Oak, poplar tr ee, Ash, Plane, Willow and elm tree although any very large mature tree close to a building can spell disaster. These trees require a considerable amount of water to grow much of this is taken up by their calm system. For example a mature poplar can take up to 50,000 litres of water from the sub-soil each year.The more mature the tree the greater amount of water it requires. The outcome of the site survey and soil investigation should inform the decision on the type of substructure to be used for the proposed buildings in relation to soil type, saturation levels and lay of land e. g. sloping etc. It is recommended that buildings be built at least a distance equivalent to the trees height away from that tree to protect both the tree and the building although in some cases of Willow, Poplar and Elm the root radius can be twice that of the tree height. DEFECTIVE AREA * The trees potential root radius has not been calculated correctly * Poor choice of substructure for the new building DEFECTIVE CORRECTION REQUIRED * Repair works require the retro installation of a root barrier (see attached diagram). This means detailed surveys are required to identify were the tree roots are. If the tree has a Tree preservation order (TPO) on it then any damage to its roots could mean an appearance in Majesties court and a fine up to ? 20,000 RELEVANT BRITISH STANDARD * BS5837 * Approved Document A & C * Tree Preservation Orders A Guide to the Law and Good Practice 2000STAGEA WORKS/JOB SHEET NO. 22 LOCATIONFlank wall DATE26th May 2010 BRE REF NO. Defect Action Sheet DEFECT Poor Mortars, Bricks, Blocks in sub-structure CAUSE Poor design and specification Poor site supervision FUNCTIONMortar is used a soldering agent to secure brick and block work. These three elements used together ensure that the building is sound, secure and water tight. DEFECTIVE AREA * Poor specification of an inferior brick and blocks that are engineered to support the onusings of the finished buildi ng is poor design planning.A poorly specified mortar could also be the reason that water could ingress the building this could lead to significant problems later for the building. * Poor site supervision of this area could mean that the mortar is poorly laid or not given enough time to set, or could even have been laid in the treat temperatures such as Frosty weather. DEFECTIVE CORRECTION REQUIRED * The building may require additional support. For example underpinning externally could support the substructure sufficiently enough to take the load away from the problem areas. The best method in this case is to pile and beam. This method stabilises the existing substructure by using piles installed either side ofan existing wall. A small excavation is made below the ground level and a reinforced concrete needle beam is used to connect the piles and support the wall. * Reducing the distance between needle beams can accommodate very high loads. RELEVANT BRITISH STANDARD * STAGED WORK S/JOB SHEET NO. 24 LOCATIONInternal/External mixed locations DATE26th May 2010 BRE REF NO.Defect Action Sheet DEFECT Notches and holes for function mis-positioned and oversized CAUSE Poor design Poor site supervision FUNCTIONThe location of holes and notches for services is very important in relation to the functionality and quality of finish to the end building. A misplaced large hole could lead incorrectly fitted lighting, heaters, light switches etc. DEFECTIVE AREA * Poor design drawings that are sent to site with the wrong measurements could mean that the location and shape of the holes for services are installed as per the drawing. It is more lightly that this defect would be down to poor site supervision. This could mean that the opposed person has been tasked to carry out this work such as a labourer that does not have the skill to read drawings but was asked to install holes for services rather than an electrician or electricians mate (i. e. creation supervised by the t rade lead at all times) DEFECTIVE CORRECTION REQUIRED * If caught early enough this should not be a great problem to resolve on site.However, if this was left to practical completion were the building is being handed over to the user/occupier then the works to rectify could be much greater and could include the following * Re-routing electrics and mechanical pipe works to suit correct dimensions * Repositioning of all electrical and mechanical equipment * No direct connection to main sewer therefore re routing all connections to bathrooms, kitchens and any sinks etc RELEVANT BRITISH STANDARD * STAGED WORKS/JOB SHEET NO. 30 LOCATIONDoor No. GF32 DATE26th May 2010 BRE REF NO.Defect Action Sheet DEFECT Lintels in external walls missing, damaged, bedding, insulation CAUSE Poor design and specificationPoor site supervision FUNCTIONA Lintel is a piece of steel or concrete that is used as a support in walls. These are generally used preceding(prenominal) openings (such as windows or doo rs) in the wall to support the load to a higher place. Lintels are usually supplied with load bearing at each end for 100mm openings up to/including 1000mm, 150mm for openings up to/including 3000mm and 200mm for openings over 3000mm. For spans in excess of 1200mm, it is good practice to provide temporary support such as an Acro at every 1200mm point. DEFECTIVE AREA * Poor design could mean that the location window or door opening is in a difficult position to properly fit the correct size lintel * Poor specification could mean that a concrete lintel is specified when the location requires a small and compact steel lintel * Poor site supervision could mean that the area were the lintel is to be installed in not supported antecedent to installation and therefore the floor above is already sagging with the load. Also installation of the wring lintel in time will show on the exterior and interior of the building. DEFECTIVE CORRECTION REQUIRED * Lintels should be carefully bedded on a full mortar go * Wall ties should be positioned in accordance with current building regulations * A damp proof course should be used for all lintels in external walls, and must be fixed in accordance with building regulations * In cavity construction, it is recommended that both internal and external leaves are taken up uniformly * It is good building practice to insert a flexible joint between the lintel and the top of the frame RELEVANT BRITISH STANDARD * BS12 * BS882STAGEE WORKS/JOB SHEET NO. 20 LOCATION DATE26th May 2010 BRE REF NO. Defect Action Sheet 73 & 74 DEFECT Floor joist quality and installation not graded or marked, bowing and twisting, high moisture content and wet rot CAUSE Poor specification Poor site supervision FUNCTIONA floor joist is a beam of wood that stretches from one side of the sub-floor to the other bridging the floor load bearers. They are the essential component to the foundation of each floor level and floor boards are laid onto of them to give a foundation to any floor covering.Wood should be marked Top/Bottom, be graded (for the load) and have a kite mark or brand number referring to BS EN 14250. DEFECTIVE AREA * Poor specification of a floor joist can mean that the wood used is not the correct grading to support the load. This can mean that the floor in time will show effects of overload bowing and twisting are one of the signs. * Poor site supervision of this area could mean that the wood has not been stored correctly on site meaning that it is now warped and twisted and has high water content. If wet rot occurs it is generally at the bearings of timber joists in external walls.For example the sole or head plates rather than in the studs. DEFECTIVE CORRECTION REQUIRED * An assessment on if there is any dead air within the cavity between the joists and the floor board. If so, then air bricks (to BS493) can be installed into the external walls to allow air flow. If wet rot is localised in small area then minor repairs ca n be made * If poor ungraded wood has been installed then the floor will have to be taken up and reinstalled with the correct graded wood to ensure it complies with current building regulations. RELEVANT BRITISH STANDARD * BSEN 14250 * BS493 state H Defect Drains below foundations agreement for Defect * Broken or damaged pipes * Failure to washout subsoil leading to foundation settlement * Lack of clearance to debris or materials * Lack of flexible joints. * Non compliance with Approved Document H * Non compliance with the earth Health Act revised 1985 * Non compliance with Building regulations C scatter 2 * Incorrect type and size of pipe used for subsoil waste pipe * Drainage not laid to correct gradient specification Issue * Possible poor quality drainage pipes specified Design Issue NoSite direction Issue * Compliance with Approved Doc H * Compliance with Public Health Act 1985 * Compliance with Building regulations C part 2 * Correct size and type of pipe use for each t ype of drainage identified e. g. foul, rainwater, soil type. * Ensure movement joints are in place * Ensure drainage meets the required gradient * Ensure pipes are clear from obstructions * Check pipes are not broken or damaged prior to installation. Maintenance NoResponsible area The above defect is due to poor management on site on manual labour hands Image Ref Image taken from NHBC Good Craftsmanship Guide for Drainage commonwealth H Defect Installation of DPC and DPM Reason for Defect * DPC pointed or rendered over * DPCs bridged by mortar droppings * DPM punctured * DPCs and DPMs not lapped * Fill and paving not kept at least 150mm below DPC * DPM should comply with BS CP 102, Section 3, and Building Regulations Approved Document C. Specification Issue No Design Issue NoSite Supervision Issue * Check that progress of DPM projects enough to lap later with the DPC * Sheet should be sealed with adhesive tape and any punctures patched with an overlap of no less than 150mm * Use polythene sheet not less than 500 gauge and should carry a BBA certificate or is to the PIFA standard Maintenance No Responsible area The above defect is due to poor management on site on manual labour workforce Image Ref Image taken from http//www. bricksandbrass. co. uk/images/walls/damp. gif Area H Defect Damp walls Reason for Defect * No DPC installation in walls * Poorly installation of DPC in walls Specification Issue No Design Issue No Site Supervision Issue * A responsible contractor should understand the importance of DPC within the external walls * If just poorly installed retrospective DPC injections can be used to back fill in areas that require additional waterproofing * If no damp proof course is in place then Electro Osmosis method can be used this is when a low voltage steel stake is placed intermediately around the external walls as long as the unit is on it will keep the damp at bay Maintenance NoResponsible area The above defect is due to poor management on site on manual labour workforce Image Ref Image taken from www. petercox. co. uk/prevent Area J Defect No lintel above the window and doors Reason for Defect * No installation of lintel above window and door openings Specification Issues * Possible incorrect lintel specified * Design Issue * For an architect to exclude lintels from the design, it means that they have not complied with building regulations.This is not only a design floor but a dangerous and hazardous way to leave the building Site Supervision Issue No Maintenance No Responsible area The above defect is due to poor design management by the design team up and should have been picked up by various professionals along the process including Building Control Image Ref Image taken from http//www. bancroftcentre. org/images/eco/insulation. bmpArea J Defect Plaster break up on internal walls and ceilings Reason for Defect * Bond failure between plasterwork and plasterboard due to watering down of attaching agent * Plaster itself poor quality or poorly mixed together (plasterer should have a mate to mix for them as plaster can go pip quickly) * quip due to movement * Drying out period hurried and room artificially heated to increase drying time Specification Issue * Poor quality bond or plaster Design Issue No Site Supervision Issue * Remove poor quality plaster, apply a thick oat of Unibond allow to dry and then re-applying a suitably mixed plaster (plasterer should have a mate to mix for them as plaster can go off quickly) * Ventilate and allow to naturally dry out Maintenance * Poor maintenance of internal finishing can make plaster work decay and break up * Poor ventilation or extreme weather (if no heating) then plaster can become brittle and break up Responsible area The above defect is due to poor management on site on manual labour workforce and/or poor maintenance by the occupier/users Image Ref Images taken from Google images plaster workArea J Defect Shrinkage to wooden floor j oists Reason for Defect * Temperature to install to extreme * Stored poorly on site allowing water to penetrate Part C of the Building Regulations Site preparation and resistance to contaminants and moisture * Area needs better ventilation Specification Issue No Design Issue NoSite Supervision Issue * A responsible contractor should have the knowledge and experience to know at what temperatures they can have to install after the installation * Air bricks may need to be installed in the external walls tp improve under floor ventilation * completely materials should be stored off the ground and well covered in accordance with building regulations Maintenance No Responsible area The above defect is due to poor management on site on manual labour workforce Image Ref Image taken from Google images defective timber joistsArea K Defect External wall movement Reason for Defect * Incorrect substructure * Restraints missing from wall to floor Specification Issue No Design Issue * Substruc ture must be designed following an accurate soil survey, bore holes are taken from the proposed site and are inspected in laboratory condition. * The soil samples are tested and categorised in accordance with their load value * Then detailed calculations are erformed by structural engineers to establish the most suitable substructure for the proposed building * Below a tell news report is a measuring device that can check how much a crack is moving over a period of time Site Supervision Issue No Maintenance No Responsible area The above defect is due to poor design management by the design team and should have been picked up by various professionals along the process including Building Control Image Ref Image of a tell-tale taken from Google imagesArea K Defect External wall movement Reason for Defect * No cavity tray installed to discharge water outwards * No weep hole specified in brickwork at lowest tray * No flashing identified, Lead or a suitable substitute should be installe d in accordance with BS 1178 * All roof tiles to Part C of the Building Regulations Site preparation and resistance to contaminants and moisture Specification Issue No Design Issue NoSite Installation & Supervision Issue * A responsible contractor should install cavity tray to ensure water is discharged correctly * Ensure appropriate weep hole is installed in the brickwork at the lowest tray level * Install appropriate flashings where required * Ensure tiles and drainage is compliant with Building Regulations Part C Maintenance No Responsible area The above defect is due to poor management on site on manual labour workforce Image