Your building on firm foundations

Transcription

1 Your building on firm foundations

2 The Company We carry out piling and underpinning projects, as well as designing and implementing foundations systems. Our clients include construction professionals, developers, national and regional building contractors, local builders and private householders throughout the south east and southern England. For more than 35 years we have been active in foundation engineering, from restricted access domestic sites to major commercial contracts. The range of our piling capability includes continuous flight auger (CFA), auger bored, rotary, driven, tripod and Grundomat. We have wide experience on new-build projects, such as single or multiple house plots, extensions and refurbishment, and on large brownfield sites as well as tidal and riverside locations. We work on private houses, flats, industrial buildings, commercial properties, underpinning, domestic extensions and basements. We keep a wide range of equipment and materials at our base in Farnborough, Hampshire, so piling, foundation and underpinning projects can be started at short notice. We have associated consultants and engineers, enabling us to offer a complete foundations design and drawings service as part of the contract package if required. We have a number of speciality rigs that can operate in confined spaces, including those with restricted headroom, and which can pass through standard doorways.

3 Contractors and Developers With our wide range of piling rigs we can offer an economical solution to meet the demands of most sites and strata. Our clients include construction professionals, developers, national and regional building contractors and local builders. If necessary we can design the foundations to suit your project and provide the calculations and drawings you will need for Local Authority approval. If you are a developer and not yet working with a building contractor we can even, by prior arrangement, provide site facilities such as a mobile toilet, piling mats, setting out and temporary protection for nearby properties.

4 Private Householders Most domestic home owners don t think about their foundations until there is a problem. Perhaps you are constructing an extension or conservatory and the local authority has advised you that you will need engineered or reinforced foundations. Or perhaps your property is affected by subsidence. Whatever the problem, our 35 years experience means we can solve it quickly, efficiently and cost-effectively, whether you live in Hampshire, Berkshire, Surrey, Sussex, Kent, Buckinghamshire, Middlesex or London. If necessary we can design the foundations to suit your project and provide the calculations and drawings you will need for Local Authority approval. Don t worry if access to your property is restricted or if work will have to be carried out inside the house. We specialise in these types of project and have small rigs to suit.

5 Planning Permission and Building Regulations Most new building work, including extensions and conservatories, requires planning permission and compliance with building regulations. If you have any doubts you should contact your local council before starting work. Party Wall Act 1996 If the work is adjacent to a party wall or boundary, the Party Wall Act says you must inform the owner of any adjoining properties at least two months before starting work. If your neighbour(s) rents the adjoining property you will need to inform the landlord(s) as well. Insurance-Backed Guarantee As members of the Association of Specialist Underpinning Contractors (ASUCplus), we are able to offer an independent, 12 year insurance backed guarantee against certain works we carry out, free of charge. The advantages of piling Driven, auger or CFA piles reach suitable loadbearing substrata, as a quicker, cheaper and more reliable alternative to conventional deep trench foundations.

6 Pile Types Continuous Flight Auger (CFA) Piles 250mm 600mm to 24m Deep This is a cost-effective way of piling through made ground, sands, gravels or any unstable water bearing strata, eliminating the need for temporary casing and Tremmie techniques. Essentially the auger is drilled to achieve the required depth. When this is achieved, concrete is pumped through the auger as the auger is being withdrawn. The reinforcement cage is then placed through the wet concrete. Our Soilmec, Klemm and Kitten rigs are used for this type of pile. The choice of rig depends on access, size of project and number of piles required. Driven Cased Piles There are many advantages to driven cased piles. They are simple and economical to drive with an internal drop hammer, there is less noise and thin casings can be used. They provide flexibility as piles can easily be cut or lengthened and casings can be supplied in any length and in a wide range of diameters and thickness. Casings are light but rigid enough to be transported and handled without the precautions needed with precast concrete piles. Cased piles can be installed in difficult site conditions Used on open sites where soft soils overlay more competent strata, permanant steel cased piles are driven with an internal drop hammer to achieve a solid set at depth. Suitable reinforcement is then added and the casing filled with concrete. This is a displacement pile and creates no arisings. It is particularly useful when piling in contaminated ground as the expensive disposal exercise is avoided. It is also of use on restricted access sites when the removal of spoil is particularly awkward.

7 Rotary/Auger Bored Piles 150mm 600mm Diameter to 25.5m Deep This piling method is ideal for use in cohesive soils. The rotating auger screws into the strata reaming out the soil. Once the required depth has been achieved the steel cage and concrete is placed. These highly mobile rigs are economic to use on large open sites or small restricted locations with cohesive ground, and on some chalk or sand. Smaller models are suitable for internal use. As a rotary auger causes minimal vibration it is ideal for use next to buildings or underground services. Tremmie techniques can be used if water is present. load, size of site and the number of piles to be installed. If piles need to be formed through loose or wet strata a temporary cased, continuous flight auger or driven piled solution may be preferable. Grundomat Mini Piles The Grundomat or mini driven rig uses 150mm and 219mm casing and is suitable for use in and around buildings. This air-driven system vibrates steel casings down to strata that give suitable resistance. Casings are welded in small sections on site to attain the required depth and subsequently filled with concrete and steel reinforcement. This rig can operate in very restricted headroom and limited access situations. This method of piling creates no spoil to remove from site. A number of our rigs can install this type of pile and the choice is dependent on pile

8 Other Services Piled Underpinning In this instance slab/beams/needles are supported on piles and toothed into the wall of a building, divorcing it from its previous foundations. Loss adjusters frequently choose this option to overcome subsidence or settlement problems. Combining piles and traditional underpinning makes it possible to provide deep foundations where none existed before. External ground level Dry Pack Blinding Clayboard Existing underpinned wall Insulation Piles are installed on either side of the structure, or externally, in a cantilever situation and then beams are cast between them, providing a bridge for the structure to sit on. This technique is used when traditional underpinning becomes uneconomic. Traditional Underpinning Underpinning can be used to rectify subsidence, to provide additional bearing capacity when building above an existing structure or to provide a new bearing position if deep excavations, such as those required for basements, are to be formed adjacent to an existing property. Excavations are made beneath the existing foundations to the required depth and concrete placed leaving a space of 50mm 75mm for a dry pack material to be placed to ensure a tight joint between the new underpin and the old foundations. Existing footing to be isolated by removing 100mm of masonry TYPICAL SECTION THROUGH UNDERPINNING NIB

9 Piled Retaining Walls Contiguous bored and secant walls, designed as either free cantilever or propped, provide a vertical face construction in dry or waterbearing soil conditions. This method of piling creates a retaining wall to restrain the strata while excavations are carried out to form basements or to maximise the useable space on a site. Piles may form part of the permanent structure or be used solely for the temporary excavation stage. If required, for instance in water bearing or granular strata, piles can be interlinked in secant construction to exclude the water or prevent the granular material becoming dislodged during the excavation stage. Adjacent Building Foundation of Adjacent Building Soil Pressure Pile Wall Excavation New Basement Floor Pile Caps, Ring Beams and Slabs Following completion of the piling works we can carry out installation of reinforced concrete beams, pads and slabs to link the piles together and provide a platform for further superstructure construction. On most projects we use proprietary formwork and shuttering, such as Pecafil, to ensure the correct alignment for the works and maintain adequate concrete cover to the reinforcement. If ground conditions require it we can place a voidformer beneath to allow the underlying strata to heave without destabilising the foundations. Voidformers used include Claymaster, Cellcore or Clayboard. Retro Fit Basements The high cost of property, particularly in built up locations such as London, is prompting more clients to consider extending their existing property by excavating the land below it to form a basement. Our basement service includes design, excavation, underpinning and construction to floor slab stage, for fit-out by other contractors. Either piles or traditional underpinning can be used and in many instances occupancy can be maintained in the property above while the basement works are carried out.

10 Site investigation and testing It is important to establish the strata that foundations are to bear into prior to the commencement of the project to ensure the correct foundation method is utilised. For the price of a small geotechnical study or survey you can reduce the risk of the final cost on the project increasing. Generally the information provided by this study will enable the piling contractor or subcontractor to create a more accurate design, reducing the costs incurred by unnecessary piling length. On domestic projects we can offer a service in which we carry out a trial bore using one of our piling rigs to establish the most suitable type of pile for a project. In many cases the fee for this service will be refunded if we are subsequently awarded the piling project. Other forms of testing that we offer include: Pile integrity testing, to ensure that the piles have no cracks or voids in them. Pile load testing, to ensure that the piles are capable of carrying the design load. This may be either by dynamic load testing or static load testing. We can implement preliminary or working pile tests and investigate sites to establish the best, most cost-effective method of constructing foundations. Concrete cube testing, to ensure that the concrete used on our projects has achieved its designated strength. Design We can offer a design and construction service for all piling foundation schemes from drawings provided by your architect for submission to the Local Authority. All design works carried out by us are backed by a 5m professional indemnity insurance. In instances where we carry out the design of the foundations we are able to plan the scheme to suit our capabilities, ensuring we can offer a cost effective solution for your foundation needs. Piling mat preparation It is important in all situations to provide a suitable surface from which to carry out our piling operations. The requirement varies depending on the piling rig to be used. We can offer the design and installation of the piling mat if required.

11 Our services Site visits and advice on most suitable foundation types Site investigations Rapid quotations Design calculations and drawings for Local Authority approval, for complete foundations to damp proof course Setting out Full range of pile types and techniques Ground beams, slabs and drainage Piling where access is difficult or the working area restricted, including low headroom Electrically-powered rigs for environmentally sensitive areas Pile retaining walls (contiguous and secant) Underpinning, both traditional and pile. Piling mats

12 Our commitment to service and satisfaction With over 35 years tradition of delivering service and satisfaction, we aim for the highest standards of site safety, tidiness, efficiency and environmental management. This is achieved through continuous staff training and development, which has won us accreditation as an Investor in People. All employees are registered under the Construction Skills Certification Scheme and have been independently assessed as having the necessary skills and training to work safely and effectively on a construction site. We are insured for Employer s, Public and Products Liability up to 10 million and covered for Professional Indemnity up to 5 million. All design work supplied by us carries Professional Indemnity insurance. Neil Foundations Systems is also a member of ASUCplus (Association of Specialist Underpinning Contractors), the independent trade association for the underpinning industry. This means that we have passed the Association s stringent technical and financial audits and are committed to its prescribed safety procedures. In certain circumstances we can therefore offer an ASUCplus insurance-backed guarantee lasting 12 years. We carry out regular Health and Safety site inspections by an Independent Advisor and are members of the Chas and Constructionline pre-qualification schemes. Neil Foundations Systems Ltd Stake Works Invincible Road Farnborough Hampshire GU14 7QT Tel: Fax: piling@neilfoundations.co.uk