Professional Structural Engineering Advice for Architects, Business, Property Managers and House owners. Calculations for building regulations, structural design calculations. Based in Ashford and working in Ashford, Maidstone, Canterbury, Deal, Dover, Folkestone, Hythe, Thanet, Kent.
Design of steel-fibre-reinforced concrete is not covered by design standards such as BS 8110 (now withdrawn) or Eurocode 2, which assume the use of bar reinforcement.
Various design approaches are currently adopted.
The first may be described as Design on the basis of material properties. In this approach, material properties such as residual tensile strength are determined from standard small beam or statically determinate slab tests. These properties are then inserted into equations determined mathematically or empirically that define the performance of the concrete element to determine the load capacity. In general, the design equations will be linked to properties determined from a specific test.
This approach is discussed in detail in Concrete Society Technical Report 63, Guidance for the design of steel-fibre-reinforced concrete.
Other approaches are commonly used, such as Design assisted by testing. This approach has been used widely for the design of pile-supported slabs and more recently has been used for fully suspended slabs. The basic premise is that the performance of the concrete in small beam tests, while satisfactory for linear elements, is not representative of the performance of elements such as slabs. Thus, the process consists of testing round indeterminate slabs to determine the design flexural resistance. The slab can then be designed by yield line theory. This design procedure is justified by the results of load tests on large-scale sub-assemblies of suspended slabs.
A partial application of this approach is the design of composite slabs on steel decking where tests to determine the local performance of fibre-reinforced concrete, e.g. around stud shear connectors, have been used to demonstrate that the performance is adequate. Slabs with fibre-reinforced concrete can thus be designed in accordance with the Standards for composite slabs with fabric reinforcement. The approach is approved by SCI (Steel Construction Institute) for specified combinations of steel fibres and decking.
Design by performance testing, or proof testing, is applicable to precast units where a large number of items are required for a particular purpose. The element’s dimensions, fibre content, etc. will be determined on the basis of judgement or experience. Representative completed units will be tested to demonstrate their ability to carry specified loads.
fib Model Code for concrete structures (2010) contains some clauses for design.
The 4th edition of the Concrete Society report TR34 Concrete industrial ground floors (2013) provideds a design approach for warehouse floors.
Swedish Standard SS 812310 Design of fibre concrete strcutures (in English), which is complementary to Eurocode 2, is due for publication in 2014
Ever wondered about the difference between planning permission and building regulations approval?
Very often home owners, business owners and property developers are confused by the need to obtain approval from the council for their building work. Does this sound like you?
The fact is that Planning applications and Building Regulations (Building Control) applications are considered under different laws.
So what is the difference between planning application and building control application?
Do you need to make both applications for your project?
Here’s the answer: Planning permission covers the principles of development assessing whether the development will accord with local and national policies and whether it would cause unacceptable harm, for example, to neighbours’ amenities, whereas the building regulations cover the structural aspects of development and progress throughout the construction.
So… When you make a planning application you are seeking permission to enable you to carry out development. On the other hand, when you make a building regulations application you are seeking to have the details of your development checked and approved for compliance with the standards of construction. That is the main difference between planning permission and building regulations.
Planning permission and building regulations approval (building control) are different and they are two separate pieces of legislation. Sometimes you may need both; sometimes you may only require one; or none at all. Because the planning legislation is distinctly different from building control legislation, it should not to be assumed that one grants consent for another.
What is Planning Permission?
Planning permission controls the way our towns, cities and countryside develop. This includes the use of land and buildings, the appearance of buildings, landscaping considerations, highway access and the impact that the development will have on the general environment.
The government gives Local Planning Authorities the power to manage where people build and what they do with land. The Development Management team of Local Planning Authorities handle planning permission applications.
When making a planning application, it is important to make sure that a fully completed set of forms is submitted. Accurate scale drawings should accompany all applications. These should include Full set of Planning Drawings, Design & Access Statement Report and Duly Completed Application Form.
The drawings should indicate all architectural features including walls, windows, doors, rooms, building and ceiling heights and materials. A Design and Access Statement report is also required with planning applications for most types of new developments or change of uses to justify how design standards and planning policies are met.
But here’s the funny thing: In addition to the Government’s national requirements, most of the councils have different local requirements for applications of a particular type, scale or location. You must include all the necessary information with your planning application. If you do not, your application cannot be validated.
What is Building Regulations (Building Control) approval?
Building regulations (building control) are standards that apply to all buildings to make sure they are safe for people who are in or around them. The Regulations are a series of Approved Documents covering the technical aspects of construction work.
Most building work whether new, alterations or extensions or change of use require building regulations approval. Examples of when building control approval is required include but not limited to building extensions and loft conversions, converting garages into a habitable room, carrying out certain structural alterations, installing cavity insulation, changing the use of a property, underpinning and carrying out drainage works.
How to make a Building Regulations (Building Control) application?
Each local council in England has a building control section. The local council has a general duty to see that building work complies with the building regulations.
As an alternative to gaining approval from Local Authorities, the Government has introduced legislation to allow private Approved Inspectors to check work requiring building Regulations approval. You are free to choose which type of building Control Body you use on your project.
Let’s dive in…
There are two ways you can make a building regulations application, either by making a Full Plans application or by submitting a Building Notice notification. A Full Plans application will consist of detailed plans and full specifications of the construction details together with the appropriate fee.
Or you would use a Building Notice if you are doing simple work to a domestic building. A Building Notice application doesn’t generally require the submission of detailed plans or full specifications of the construction details. However, you will not receive the protection and reassurance that an Approved Plan would give you, and the whole process of making sure your work complies with the building regulations is carried out at the site inspection stage.
Now: Whether you are renovating your home from scratch, converting your property, or simply adding an extension, you will need a structural engineer proficient in preparing your structural drawings, calculations and specifications for your building regulations application.
What is the difference between Building Regs and Planning Permission?
If you want to renovate a new home, there is a good chance you will need some form of permission before starting any building work.
Building Regulations set the minimum standard for the design and construction of buildings to ensure that any work has been done correctly. They cover safety standards for the construction of everything from staircases and chimneys to the heating efficiency of boilers and providing access facilities for the disabled. You may need building regulation approval to cover work on your home both internally and externally.
Planning Permissions are more about the external appearance of the building and making sure any landscaping considerations are in keeping with the local environment. Ultimately, Planning Permissions are there to avoid architectural ‘eyesores’ and oversized extensions being built that would be ‘out-of-keeping’ in an area.
Both are legally required and must be submitted to your local council before beginning any work. Failure to comply could lead to a fine.
What are Building Regulations?
Before you carry out any building work, you or your builder/architect/surveyor must submit full plans for approval to your local council’s building control team or through the buildings notice procedure. Some examples of what building regulations cover, include:
Structural stability of a building.
Correct Fire Safety measures including fire escapes.
Ensuring a building is water and weather tight.
The use of toxic substances in cavity fill insulation systems.
Levels of sound insulation between buildings and rooms.
Technical design standards for sanitary pipework and drainage.
Underpinning the foundations of a building.
The design, installation, inspection and testing of electrical installations.
What is Planning Permission?
If you are planning to build a new home or alter the appearance or scope of your home, getting planning permission is one of the first hurdles you will have to face. They are many different types of permission and your architect or builder will be able to help you determine which ones apply to your property project.
The main types of Planning Permission include:
Householder Planning Consent – Required for extensions, conservatories, loft conversions, dormer windows, garages and out buildings.
Full Planning Consent – Required if you are planning on changing the number of dwellings on the site, or changing the use of a property. You do not need planning permission for many internal renovations.
Outline Planning Consent – Find out if the scale and scope of your plans are likely to be approved in principal before you commit to any substantial costs.
Planning Permission in a Conservation Area – If you live in a conservation area, you will need planning permission before any relevant demolition of property.
Listed Building Consent – If your property is a building, object or structure judged to be of national architectural or historical interest, then you will be subject to extra conditions before any work can begin.
Lawful Development Certificate – For peace of mind that an existing or proposed work is lawful, or that you do not need planning permission, you can apply for a Lawful Development Certificate or LDC.
Retrospective Planning Permission – If you have made changes to your property without getting planning permission, you can make a retrospective planning application for work you have already carried out.
“Ground Investigation Reports” (GIR) and “Geotechnical Design Reports” (GDR)
One of the things I’d like the most about my job is the fact that I still learn new things, even on topic were I wrongly believe there is not much more new to see.
This week during a telco with my accomplice in crime Eduardo I’ve discovered a new trick that I suspect has been invented by someone in the US (or possibly in the UK) – the split between “factual” and “interpretative” geotechnical report.
In the countries were I’ve worked until today, the geotechnical survey is usually a huge package of documents full of formulas, picture, diagrams and numbers. I’ve been never touched by the idea that part of the content was somehow different.
However, I’ve discovered that somebody (I bet a lawyer) introduced this categorization.
The Geotechnical Data Report (AKA the “Factual stuff”) would be the part including things like:
Trial pits logs
Field test (SPT, cone penetration, etc.)
Laboratory data (water test, CBR, etc.)
This is the type of things that could safely land in a contract and that should be shared and used by the subcontractor.
However, a civil engineer would like to see other information to do his work. He would expect the type of information that should appear in the Geotechnical Interpretative Report (AKA the “don’t rely on me stuff”), with things like:
Ground behaviour of geotechnical units
Geotechnical cross sections
Construction methods and proposed technical solutions
Basically, nothing connected with design and construction.
Know you know that, wherever possible, you should ask to the geotechnical survey company for the full package (factual + interpretative) but keep them separate – at least if you face a big project with a high geotechnical risk.
Said that, I also want to reiterate my opinion that a good geotechnical survey can make the difference between a successful project (at least for roads and foundations) and a nightmare project with claims and over cost.
It might be difficult to find the budget for this kind of investigation in the early phases of the project but believe me, it’s worth every euro that you will spend on it.
Making a construction plan before beginning the construction is imperative. It provides a detailed overview of the building. Keeping that in mind, a different types of drawings is used today for this purpose. Apart from providing the technical details in a readable format, these drawings are also essential to get the project approval.
They set a benchmark for the construction process and assure compliance to the building standards.
It can be said that these construction drawings provide an outlet to the architectures to convey their ideas and concepts regarding any building.
Types of Drawings Used in Building Design
Listed below are the majority of the construction drawings. All the types of construction drawings can be segregated into the following sets of drawings:
Electrical & Plumbing Drawings
Architectural drawings are the technical representation of a building that is made prior to the beginning of the construction process. They are made with lines, projections and are based on a scale. Different types of architectural drawings include:
A Site Plan is an aerial view of the construction site that includes the primary building and its adjoining constructions. Among its wide applications, we can include construction drawings for building improvement, understanding the scope of construction activities. Along with it, it helps identify the topography of the building including roads, pavements, etc.
These are an in-depth version of the room layout. Floor plans are made irrespective of the fact that they are to be utilized during the construction of a home, shop, or a commercial project. Applications include an understanding of the dimensions and different kinds of installments. This helps get an idea about the usage of the limited room space.
Cross sections allow the architect to look at the different components of a building vertically. This 2-dimensional imagery is useful to provide an overview of both the visible and hidden components in a building. Another type of cross-section is Wall cross-section that is useful to get a view of both sides of the wall.
Elevations help an architect understand the facing of the building. It is useful to know about the direction of the sun and the wind corresponding to the building. They also indicate the height of the building, the external and internal marking which includes the doors and sizes of the windows too.
The landscape plan is the aerial of the whole area in which the building is built. It includes the areas designated for trees, street lights, parks, pools, and everything else. Landscape plans are more often used to depict the external aesthetics of the building. You can also include in them the paths, roads, pavements, parking areas, and whatnot.
The Finishing drawing has a close relationship with the elevation drawings as they also talk about the smaller details of a building. Among the various types of finishing drawings, you can include the patterns of the floor, type, and shape of false ceiling, paint colors, plaster, textures, and whatnot. They are important to maintain the aesthetic value of the structure.
The designers create working plans or construction plans for the contractors to help them understand the scope of the project. The benefits of such a plan include the convenience to fabricate the construction material according to the overall design. Working drawings also include a legend that provides information about the different components.
As the name suggests, the section drawings show the structure in a sliced form. This kind of construction drawing helps identify the primary structures in relation to other surrounding structures of the building. Further, section drawings also provide information for the types of materials to be used in the construction.
The general note does not have any drawings. It contains detailed information about the buildings. This includes the by-laws, codes, length, mapping forms, construction type, legends, abbreviations, and everything else that is essential.
Excavation drawings are needed to know the length, depth, and the width of the building excavation. It talks about the extent of excavation, removal of soil, and the process of excavation. The different processes used for excavation comprises of trenching, wall shafts, tunneling, and others.
The As-built drawings provide a comparison between what has been built and the original plan. It may happen due to circumstantial conditions the contractors may have to change the construction pattern and design. The As-built drawings are made either during the construction process or after the construction is complete.
These are the single line depictions of the structure of a room. The lines are drawn exactly as the different configurations of the room will be. It has the sizes of the rooms, the position of the doors with proper labeling. A line plan provides an overview of how the whole room will be planned out.
Shop drawings are also a sort of construction guide that personifies how an object has to be installed, fitted, or manufactured. Most of the time, the shop drawings are prepared by contractors and subcontractors. Also, suppliers, manufacturers, and fabricators can prepare these drawings. Shop drawings ensure compliance with the original design and specifications of the object.
There are plenty of installations that can be added to a building. Some are essential, like the ventilation, heating, and cooling system. So, in that matter, a plan to help with all kinds of installation can be useful to the contractors and the development team. From the most complex structure like data centers to control rooms, these kinds of drawings are also essential from the management point of view.
Location drawings are also referred to as general arrangement drawings. They are made to showcase the composition of the entire project. And if that project has several parts and buildings to be constructed, a location drawing will include details for all of them. Under it, you may consider adding elevations, projections, different plans, and sections.
The location plan further covers a wide area. This kind of construction drawings requires the architect to check out the whole area where the building is to be constructed. Also called General Arrangement Drawings, they represent the objects and more importantly, they show the relationship between the different stages of building development.
“Life is the Art of Drawing Without an Eraser” — John W. Gardner
Structural Drawings are also called engineering drawings and they focus on the structural aspect of the building. These drawings are included in the proposal documents and act as a guide for the workforce.
Column layout reinforces the design and pattern of the columns of the whole structure. This plan is divided floor wise and demarcates the exact size and distance between every column of the building. Column layout drawings further make it easier for the contractors to make sense of the whole building layout.
Plinth Beam Layout
Plinth beams are yet another form of beam structures that reinforce the support system of a building. The plinth beam layout drawings showcase the position, length, and sectional design of the plinth beams. Here too, the plinth beams drawings are also made floor wise.
Lintel Beam Layout
Lintel beams are yet another form of support structures that are made above the doors and windows. These are reinforced structures that are made to provide strength to the part of the building that is made above the windows and doors. In these kinds of drawings, you will find the correct positions, dimensions, and the number of lintel beams on every floor.
Roof Beam and Shuttering Layout
A roof beam is made to strengthen the building’s overall structure. A roof beam is a triangular structure that is usually made on the top of the building and supports the roof. Roof beams are usually made out of wood, but it can also be made from steel or concrete.
Roof Slab Layout
Roof slab layout is more prominently made in the AutoCAD architectural software. The main purpose of the roof slabs is to provide a detailed account of the floors, roof faces, and other such surfaces that require precise edge information.
A Block plan is the representation of a wider area that is in proximity to the main building under construction. A block plan may include the adjoining buildings, the roads, boundaries, and other such components. More importantly, a block plan is represented in scales, which also means that they cover a wide area.
Framing plans are similar to the beam layouts. They offer information about the framework, sizes and positions of the beams. Framing plans are helpful to the builders as they can easily understand and lay out the plans for the roof, floor, and other such structures that are an essential part of a building.
The component drawings are majorly referred to as the drawings supplied by the manufacturer of a product. These kinds of plans are replete with the drawings of the component thus providing a detailed insight into its markings and different sub-parts.
Concept drawings are more like the first draft of a construction project that is made in the first instance. They are not very detailed or distinguished. The concept drawings are like rough sketches of the building and the nearby areas. They are more prominently used to describe an overview of the building to potential clients or stakeholders.
Any building may require the installation of some engineered objects or components. So, an engineering drawing is targeted towards the convenient construction or placement of these kinds of structures. They are more of a guide to help the contractor and the engineer, they work in sync with each other and get the desired results.
In the construction industry, these types of drawings are made to depict the connection between two components of a structure. It shows how the different parts of this structure fit together. It has all kinds of designs and patterns including 3D, sectional, and elevation views.
The design drawings are somewhat similar to concept drawings. This means that they are also useful in case of fetching new conversions for a particular project. They are also useful in proposing the designs to the stakeholders and then providing a rough idea to the designing teams for their reference. Design drawings can also become a benchmark or can be used as a comparison.
Through the use of DAWSON-WAM’s relatively silent and vibration-free pile installation we can offer a virtually zero tolerance installation when working adjacent to existing buildings and structures. This can be extremely beneficial to clients in maximising space when working within built up environments such as city centre sites.
The Cased CFA systems operates an offset system where the most outer part of the system is the casing which mean piles can be installed extremely close to existing structures. Typically piles can be installed within 100mm of existing structures where Conventional CFA systems are restricted by the drive motor geometry and require at least 600mm clearance.
For a Client’s peace of mind DAWSON-WAM can carry out all pile testing, vibration & noise monitoring, pile deflection analysis and sensitivity analysis of adjacent structures when completing close proximity works.
We have been working with Toorc Consulting Ltd and Soiltech on producing a new piling rig. As you know building basements with CFA piles is normally the most cost effective solution, however being close to boundaries and tree protection orders causes significant problems with clearances such that you have to either reduce the basement size or opt for the sheet piling zero rig which is very expensive (about twice standard sheet piling rates). Normally you need to leave a minimum 750mm from face of obstruction to centreline of pile thus nearest internal basement wall face to an obstruction is 1200mm or so.
We have developed a piling rig that can now install 450mm and 600mm diameter CFA piles to within 15mm of any obstruction such as boundary walls, TPO’s etc, to a depth of 14.5m. Therefore face of basement wall will be circa 650mm from boundary, adding an extra ½ metre to the basement. At this depth of pile most residential basements and basement pools can be accommodated. The rig will be owned and operated by Burras. The motor will not overhang the boundary therefore does not affect party wall awards which is the most common difficulty we face on tight urban sites recently. This is a way of reducing basement costs and maximising footprint on these tight sites.
The main difference between Joist and Rafter is that the Joist is a horizontal structural element transferring load from flooring to beams, typically running perpendicular to beams and Rafter is a structural members in architecture.
A joist is a horizontal structural member used in framing to span an open space, often between beams that subsequently transfer loads to vertical members. When incorporated into a floor framing system, joists serve to provide stiffness to the subfloor sheathing, allowing it to function as a horizontal diaphragm. Joists are often doubled or tripled, placed side by side, where conditions warrant, such as where wall partitions require support.
Joists are either made of wood, engineered wood, or steel, each of which have unique characteristics. Typically, wood joists have the cross section of a plank with the longer faces positioned vertically. However, engineered wood joists may have a cross section resembling the Roman capital letter “I”; these joists are referred to as I-joists. Steel joists can take on various shapes, resembling the Roman capital letters “C”, “I”, “L” and “S”.
Wood joists were also used in old-style timber framing. The invention of the circular saw for use in modern sawmills has made it possible to fabricate wood joists as dimensional lumber.
A rafter is one of a series of sloped structural members that extend from the ridge or hip to the wall plate, downslope perimeter or eave, and that are designed to support the roof deck and its associated loads. A pair of rafters is called a couple. In home construction, rafters are normally made of wood. Exposed rafters are a feature of some traditional roof styles.
Lateral Torsional Buckling in Beams = Lateral Deflection + Torsion
Lateral torsional buckling occurs when an applied load causes both lateral displacement and twisting of a member. This failure is usually seen when a load is applied to an unconstrained, steel I-beam, with the two flanges acting differently, one under compression and the other tension. ‘Unconstrained’ in this case simply means the flange under compression is free to move laterally and also twist. The buckling will be seen in the compression flange of a simply supported beam.
WHAT IS Lateral Torsional Buckling?
Lateral torsional buckling may occur in an unrestrained beam. A beam is considered to be unrestrained when its compression flange is free to displace laterally and rotate. When an applied load causes both lateral displacement and twisting of a member lateral torsional buckling will occur. Figure shows the lateral displacement and twisting experienced by a beam when lateral torsional buckling occurs.
What causes the lateral deflection?
The applied vertical load results in compression and tension in the flanges of the section. The compression flange tries to deflect laterally away from its original position, whereas the tension flange tries to keep the member straight. The lateral movement of the flanges is shown in Figure. The lateral bending of the section creates restoring forces that oppose the movement because the section wants to remain straight. These restoring forces are not large enough to stop the section from deflecting laterally, but together with the lateral component of the tensile forces, they determine the buckling resistance of the beam.
In addition to the lateral movement of the section the forces within the flanges cause the section to twist about its longitudinal axis as shown in Figure. The twisting is resisted by the torsional stiffness of the section. The torsional stiffness of a section is dominated by the flange thickness. That is why a section with thicker flanges has a larger bending strength (pb) than the same depth of section with thinner flanges
How to prevent Lateral torsional buckling
The best way to prevent this type of buckling from occurring is to restrain the flange under compression, which prevents it from rotating along its axis. Some beams have restraints such as walls or braced elements periodically along their lengths, as well as on the ends. This failure can also occur in a cantilever beam, in which case the bottom flange needs to be more restrained than the top flange.
The location of the applied load is a major concern. If the load is applied above the shear center of a section it is considered a destabilizing load, and the beam will be more susceptible to lateral torsional buckling. Therefore loads applied at or below the shear center is a stabilizing load, with little risk of the buckling occurring.
Below is a guide to typical construction costs of various buildings per m2 of gross internal floor area (internal area measured over internal walls and partitions, stairwell openings etc). The costs are typical guide costs for a building of the size stated, constructed to a typical or mid-range specification. Building size and shape, number of storeys, ground conditions, design and material specification can all have a significant impact on costs. It is quite possible for costs to vary from the guide costs given here, perhaps by +20% or more and even this higher figure is not absolute but a guide only.
Costs are set at current index 188 – 1Q2020 (Year 2000 = 100), at UK national average (index 100). See the Construction Indices, the Regional Variations and the Project Value Adjustments pages for more details. The costs are for the building only, inclusive of preliminaries and contractor’s overheads and profit. The costs are exclusive of furnishings, external works, allowances for risk (contingencies), fees and VAT.
If you don’t know any better, we would typically add a further 20% of the costs below to cover the possible costs of external works (hard pavings, landscaping, external fences and walls, etc., foul and surface water drainage, and external services) and to the new sub-total figure a further 15% to cover risk (contingencies). This is only very much a rough guide and depends very much on the size of the site associated with the building and the level of specification and complexity of the external works. Professional fees can be anything from 5% to 10% depending on the size of the project – generally the larger the project the smaller fee percentage.
Building prices can be influenced significantly by local conditions, local market conditions, size and specification. The prices given here are intended only as an indicative guide and should be used with caution as prices outside these ranges can be encountered in meeting local conditions and specific client requirements.
An example of how a construction works budget may be put together is given at the end of this page.
Factory, light industrial, including office accommodation (4.5m high)
Warehouse including office accommodation (7.3m high)
High bay warehouse including office accommodation (excludes racking), (21.0m high)
Distribution centre including office accommodation (15.0m high)
Office, low rise, air conditioned, basic specification
Office, low rise, air conditioned, higher specification
Office, high rise, non-air conditioned, basic specification
Office, high rise, non-air conditioned, higher specification
Office, high rise, air conditioned, basic specification
Office, high rise, air conditioned, higher specification
Shop unit (block of three small units)
Shop unit with flats above
Shop unit with offices above
Health and welfare buildings
Home for the elderly
Home for the mentally ill
Refreshment, entertainment and recreation buildings
Leisure centre with swimming pool
Sports hall with swimming pool
Sports changing pavilion
Educational, cultural and scientific buildings
College, non-air conditioned
College, air conditioned
Hall of residence
Hotel, air conditioned
If you wish to what see costs below comprise why not download our app and create a cost model yourself. It’s simple, easy to do, quick and completely free of charge! Go to our download section now and use our wizard to create your cost model from scratch.
Example of putting a budget together
The following is an example of how an early cost advice budget may be put together when all that is know about the project is building size (gross floor area), location and an indicative start of construction date.
This example is for a proposed new office block in York, 2000m2 gross floor area, with a proposed construction start date of January 2021.
It is a requirement of Building Regulation Part H that adequate provision is made for rainwater to be carried from the roof of the building.
It is generally considered good practice for flat roofs to be designed to clear surface water as rapidly as possible. According to BS6229 & BS8217, flat roofs should be designed with minimum falls of 1:40 to ensure a finished fall of 1:80 can be achieved, allowing for any inaccuracies in the construction.
Water ponding on membrane roofs should be avoided because:
It encourages the deposition of dirt and leaves which can be unsightly, may obstruct outlets and /or become a slip hazard.
In the event of damage, the interior may suffer greater water ingress.
It increases the dead load and may cause progressive deflection of the deck.
Ice may be a slip or wind hazard during the winter months.
Roofs with extensive ponding require increased maintenance input.
Falls in the structure can be achieved by adjusting the height of the supporting beams or purlins, by using tapered supports, or by the addition of firring pieces before the deck is laid. In the case of a cast in-situ concrete slab, falls are normally provided by use of a screed.
Tapered insulation systems are a lightweight, convenient and cost effective alternative method of providing falls to the roof and can be used with our reinforced bitumen membrane (RBM) and synthetic single ply roof systems.
Drainage needs to be provided via internal rainwater outlets and downpipes or via external guttering systems or hoppers. Even if a roof is very small, it is recommended there are at least two drainage points in case one becomes blocked. Internal gutters linking internal outlet positions should be at least 500mm wide.
BS EN 12056-3 and the Building Regulations Approved Document Part H contain relevant design information to enable rainfall calculations to be undertaken and give design principles for gutters and downpipes. Alternatively, most drainage component manufacturers will make recommendations regarding the type, size and location of their products for any given roof project.
The method for naming a file is detailed within BS 1192:2007+A2:2016 Collaborative production of architectural, engineering and construction information – Code of practice.
Before we get into the detail of how the naming works, a couple of key points:
To comply with Level 1 BIM (and subsequently Level 2 BIM) standard naming applies to all project documents (and not just drawings and models)
Project codes (ideally) should be defined by the client within the Employer’s Information Requirements (EIR) or alternatively are defined within the BIM Execution Plan (BEP)
The fields required for file naming (and only those required) are clearly defined within the code of practice. All fields are required in the defined order (within the exception of the optional and metadata fields which may be omitted)
So, to deliver BIM level 2 all project document files should be named in accordance with BS 1192, no alternative methods are accepted. However, in practice not all the file naming requirements will work for every project any deviation should be clearly referenced within project documents (EIR and BEP).
The arrangement for file naming, with each field separated by a hyphen (generally the table below and further information applies to the BS 1192 standard coding):
Volume or System
Levels and Locations
Required or optional
To match the selected classification library
4 integer numeric digits
3 – with additional decimals for WIP
As applicable application
This is an individual code for the project that will be used consistently throughout the project. Ideally the project code should be confirmed at the early stages of the project, ideally by the client and confirmed in the EIR. For a project where a client does not initialise a project wide code, but the design team require a consistent reference, this should be developed by the project team and confirmed within the BEP.
Some large projects, for example a large development, may consist of multiple projects with some of the projects being sub-projects. The project code can be setup to have a main project number with sub-projects identified with an additional reference.
Main project code 101
A unique code for each organisation, so that the originator for the file can identified from the file name.
Volume or System Code
This provides a code for identifying an individual or system. The code should be one to two characters long.
A volume can consist of groupings such as existing building with another code for the proposed new building. Projects can also be split into systems, allowing for items such as primary electrical containment or steelwork to have a unique system code. The codes can be viewed as similar to CAD layers, they allow related parts of a model to be provided as a single volume.
Volume and system codes can also be used to organise large estates with separate volumes being provided for each facility and then sub-volumes for departments. Depending upon the size of the estate this may require additional codes beyond those available with the allowable 2 digits. The use of additional digits would not be in accordance with the requirements of BS 1192, but the standard provides guidance, the use of codes should work for your requirements.
Levels and Locations
Standard codes for levels
Where the file applies to multiple levels, for example a cross sectional drawing
For files that are not relevant to the levels, for example specifications or meeting minutes
For linear assets (for example roads) or where GF isn’t applicable
The first level primary level above ground level
Mezzanine level above level one
Mezzanine level above level two
The first level below ground level
The second level below ground level
A code to identify the type of file, the full list of type codes from BS 1192
Drawings & Models
Animation File (of a model)
Combined model (federated mutlidiscipline model)
Specific for the clash process
2D model file
3D model file
Model rendition file (for example thermal analysis)
Visualisation of a model
Bill of quantities
Health & Safety
Information exchange file
Minutes / action notes
Room data sheet
Request for information
Schedule of accommodation
A code to identify the originator of the file, the full list of codes from BS 1192
Drainage, Highways Engineer
Geographical and Land Surveyor
Heating and Ventilation Designer
Public Health Engineer
Town and Country Planner
For standard codes, BS 1192 references codes compliant to BS ISO 12006 and the Uniclass publication. The Uniclass 2015 tables that may be utilised for classification include the Products and Systems tables.
Some points to note
Standards have been defined as “an agreed, repeatable way of doing something”, they are not compulsory and should be a live and evolving document. Therefore, deviations from the standards shouldn’t be discounted subject to any deviations providing a meaningful benefit to a project and are clearly defined and agreed
Number, PAS 1192-2 identifies 5 digit numerical characters (an additional digit to BS 1192)
Number, it’s possible to add in the CI/SfB code into the number character. For example the first two digits relate to the CI/SfB code (for example 43 floor finishes and 90 external works) and the next three digits providing the drawing number within the series.
Role, the single letter character can be insufficient for complicated projects with multiple stakeholders and consultants (such as acoustic or catering)
Suitability, PAS 1192-2 lists a similar (not the same) suitability codes table and headed as status codes. Status = Suitability Code + Revision Code. Some of differences include:
Within clause 15 Status, BS 1192 section 15.3 has the following for Standard coding:
Standard status codes for ‘status’: Standard codes should be used for the ‘status’ fields wherever possible.
Standard codes for ‘suitability’: The ‘suitability’ code should be one or two characters. The ‘suitability’ codes given in Table 5 should be used.
The above extract shows that the table is for ‘Standard codes for suitability…’ but the heading of the column above the codes (S0, S1 etc) says ‘Status’.
PAS 1192-2 provides a similar table (although it contains less detail)
The above table makes no reference to suitability (except within Note 2 as listed above) with the codes being clearly referenced as status codes.