BIM Archives - Land & Architectural Survey Blog

Construction technology of Bricks in the UK

As part of the RICS competency on construction technology, we’re going to cover bricks today. A lot of technical and illustration is needed to explain the different bonds and bricks. I hope this is going to be helpful to you.

Bricks in general

The size of bricks and blocks can make a big difference to the construction process because they are important materials. There are many types of bricks and blocks that could be used in construction, but there’s one size that affects how everything else will be built. We’ll talk more about this as we go on, so let’s get started.

Bricks and blocks are ‘man-made’ concrete building materials that you can use to build anything you want. They are made of a variety of materials, such as terra cotta, travertine or clay bricks.

Stone is quarried and shaped, but it also often occurs naturally. Additionally, it was often used as it was found below cliffs or outcrops or on beaches, or from the general stones on or in the ground.

Artificial stone and reconstructed stone are not natural. Artificial stone is made by mixing stone with cement, water, and any other coloring materials. Reconstructed stone uses the same mix but omits the coloring agents because they use only natural stones at the end of the process.

For projects where the original stone is no longer available and the quarry has been depleted, it’s sometimes cheaper to use reclaimed stone.

Most of the structures we will consider are made from bricks and blocks. There is, however, a need for explanation, so we will start by looking at materials, sizes, shapes, etc.

Some materials can be used to create bricks and blocks, such as calcium silicate and concrete.
You can get bricks and blocks in different sizes, shapes, and materials.

Topics on bricks other than the standard rectilinear shape are found in British Standard 4729.

Brick surfaces have names:

The top surface doubles as a bed.
The bottom surface also doubles as a bed.
Ends are headers or header faces
A side is another name for a stretcher or stretcher-faced panel.

Mortar is a type of material used to bind bricks and blocks together. Mortars are not made out of cement, which is generally a dry powder. Cement may or may not be present when making mortar, depending on the type of wall. The topic on mortar will be discussed in more detail later in this blog post.

Bricks are made in different sizes, but in this text we’ll only focus on the standard metric brick. A standard metric brick has measurements of 225 × 112.5 × 75 mm and working measurements of 215 × 102.5 × 65.

Brick manufacture is complicated, because the final size of a brick can be slightly different from what you expect. This is due to things like shrinkage or distortion when drying or firing bricks. That’s why there are two sizes for brick – coordinating and working. Coordinating dimensions are the size of a brick plus the mortar required on one bed, one header face and one stretcher face. Working dimensions are the size to which manufacturers will try to make bricks.

The nominal size of a brick is the difference between the working and coordinating dimensions. The usual nominal size is 10 mm, with a layer of mortar into which the bricks are pressed when laid. Most often this nominal size is the thickness of six bricks or one inch- American units.

Our content is sized according to importance, rather than just by time.

The term nominal sizing refers to the size given by a manufacturer that allows for slight variation. The variations in size – larger or smaller – are generally given in British Standards. Variations on individual bricks may vary, as they’re allowed an extra few millimeters as they are pressed into the mortar, but they will fall between the dimensions width of 225mm and thickness of 75mm.

Durability of bricks

Durability is an important consideration when building in areas with freezing temperatures or high levels of salt. For a classification of durability, see BS 3921.

The durability of brickwork is dependent on two factors: resistance to frost and soluble salt content. Frost resistance falls into three classes: frost resistant (F), moderately frost resistant (M) or not frost resistant (O). Soluble salt content is classed as either low (L) or normal (N). So, one could have a brick that is frost resistant with normal soluble salts content and this would be classified as FN. Likewise, a brick that had no frost resistance and had low soluble salt content would be classified as OL.

Mortar joints

Mortar placed below or on top of bricks is called a bed. Mortar placed vertically in between bricks is called a perpend.

Coordinating sizes

Regularly spaced, matching sizes allow these bricks to be pieced together in a number of different ways. Building brickwork to the specific coordinate size is important for achieving the desired appearance.

Other elements like bits, lints, and window halves are manufactured to fit openings that are calibrated in whole or cut bricks.

When creating a brickwork design, you should make sure that the bricks are all the same size so they will fit properly.

The height of the lintel is 176 mm, or 3 x 65 mm.
The width of the window opening must be a multiple of half a brick, plus the perpends. This means that 8 × 102.5 + 9 × 10 = 880 mm or 4′ 10″.
The length of a lintel has to be the width of the opening plus its pieces that are built into the wall- the rests.
Wall rests are created by using cut bricks. The number of rests needed varies depending on your load, but in this case they are half the length of a brick each, less the mortar required in the perpends between the lintel ends and adjacent brickwork.
The lintel length is 880 + 2 x 102.5 = 1085.

Sometimes brick can be just one long, rectangular piece of material. It might also have a deep indent on both sides, called a frog. Frogs can be either shallow or deep but they won’t exceed 20% of the size in total.

A brick might be:

Cellular – having cavities or depressions exceeding 20% of the volume in total.
Perforations that do not exceed 20% of the brick’s total volume; at least 30% solid brick across the width.

Bricks can be manufactured to fulfill many different functions, such as adding structural support, resisting moisture absorption, or being used as decoration.

The majority of bricks used are from the ‘All other’ category, but don’t have a problem resisting the weight of most buildings. That being said, it’s important to remember that there are limits for bricks when it comes to absorbing water. If bricks will be used for an external wall and you want them to resist weather, it would be foolish to use extremely absorbent bricks or let the absorption level for engineering bricks fall below those required by DPC. At the same time, if a DPC is not in place and you’re using less than average water-absorbing bricks, this might not be necessary and could actually end up causing problems down the road.

The vast majority of bricks used are in the “All other” category, but this compressive strength is perfectly adequate for all but the most severe loadings. However, the water absorption should be limited if you need your external walls to resist weather conditions. It would be foolish to build a wall that has bricks that can absorb lots of water if these bricks were going to become damaged from weather conditions. On the other hand, if the brick is low on water absorption and you’re required to use drying agents, it might be an unnecessary expense.

Testing of bricks

Brick must be tested to comply with British Standards. The tests typically include dimensions, soluble salt content, efflorescence, compressive strength and water absorption.

Bonding of Bricks to form walls (types of bonds)

One of the first building concepts ever developed–bonding bricks together–is still being used today. This quality of a wall is created with layers and various patterns that change from course to course. You can mold your bonding pattern by changing the cut and whole bricks in these layers, or even by using bricks that are shaped differently than standard rectangles.

Cutting a brick in half can be tricky. It’s easy to draw out the lines correctly, but it’s not so easy to cut along the lines with precision. Fortunately, there is a simple solution that will work for any type of brick – even one that has been damaged or deteriorated. By cutting the brick along its half height, you create the perfect surface against which to rest other bricks. You could call this cut a ‘half batt’.

Building walls with straight vertical ends is possible because of the simple cut at the end of the brick.

Another common pattern is called English bond. It is more complex than stretcher bond and it is used only in situations where the wall has a thickness of 215 mm or one brick. If we look at the illustration on this blog, a drawing of two adjacent courses of this type, we can see how another of the standard cuts can be put to good use when bonding bricks together as well as towards supporting vertical end-walls. For walls thicker than one brick, a further development for bonding comes into play. Every bond in this category displays a grouping of bricks which repeats across each course. In some instances the pattern repeats across every course, in others adjacent courses display the mirror of that pattern. In one-brick walls in English bond the pattern is two bricks side by side and turned through 180 degrees (this type is also known as sectional bond). This pattern will be visible in all of the following figures.

What are the thickness of walls

It’s not common for wall thicknesses to be listed in millimeters, but you can get a general idea by adding the “half brick” amount of 102.5 mm and the mortar thickness of 10 mm to understand what that would mean. So a “half brick” thick wall would be 102.5 mm, a “one brick” thick wall would come in at 215 mm, and a “one and a half brick” thick wall would be 327.5 mm.

This is a particularly helpful piece of information when creating plans, creating sections, and drawing out detail. Many contracts have specifications of materials and workmanship that should be included in the document. This terminology can come in handy if you’re using brickwork to describe the details. Whether it’s a standard form contract or not, having the size of bricks mentioned will add more focus to your document.

Types of bonds

We will demonstrate how bond is determined by illustrating three key points in the construction of any wall:

A corner or edge of a wall. Called scuntion or scuncheon.
The point where two straight lines meet, called an intersection.
The right-angled corner of a wall, known as the quoin.

Before we begin, you should know that this is not a complete list of bonds or situations. When reading other texts, you’ll find variations on the bonds discussed here and many other types of intersections and thicknesses.

Stretcher or common bond

The first and most basic form of bond is illustrated here.

Only used for walls of half brick thickness, this is the only practical bond that can be used on a wall of this thickness. Though we’ll build ‘mock’ bonds of other kinds later. A little of that later.
Only show stretchers on the general face, with occasional applications at quoins, scuntions, and intersections.

The thickness of the walls we will consider now vary from 215 millimeters to 327.5 millimeters – 1 to 11/2 bricks thick.

First we will show English bond and continue with Flemish, Scotch, and garden wall bonds. Finally we will show Quetta and Rattrap bonds, both of which are always 327.5mm and 215mm thick respectively. Sectional bonds are shown as hatched lines in all of the following figures.

English bond

Strongest bond
This bond maximizes the strength of the wall
It is used on single-brick walls and upwards
Note how the sectional bond changes as the wall’s thickness increases.

There is a pattern on the face of the wall that slopes in an organized, predictable way. You can tell by looking at it that there must be headers and stretchers mixed together.

Flemish bond

This bond is not so strong as English bond
It is used on walls made of one brick width.
Noting how the width of a secant varies in direct proportion to the wall thickness, one can see that

The decorative pattern on the face of walls shows alternate headers and stretchers in each course, with the headers centered under and over the stretchers in adjacent courses.

Quetta bond

This drawing is the sectional bond. The hatched portion is a void, not the actual sectional bond. This is an attempt to produce a more weather-resistant form of wall than the one brick, solid wall commonly used in housing at the time without using any more bricks or splitting the wall into two layers joined with wall ties. This idea never took off because, although it does provide a way for moisture from outside to travel onto the inside surface of the wall, it adds another step to production and slows down construction.

Bricks are the most common type of masonry wall we see today. They’re all “layed on edge” (or stacked vertically). Due to this, our walls are 1 and a half bricks thick. When building bond with bricks on edge, there are a few things to keep in mind:

Bricks should have plain beds – no raised frogs, cavities or perforations.
If the wall is to be rendered or plastered, choose bricks with shallow frogs or small perforations
If the wall is covered over in some other way, then the size of a frog etc. doesn’t matter.
Coverings could include vertical tiles, slates, or board-like structures that are half an inch thick.
This wall would solve the problem of moisture crossing the wall.

This type of bond uses bricks and concrete. Reinforcing rods are installed in weakened brick bonds to strengthen the walls. For example, for brickwork that is complete and mortar has hardened, concrete is then poured into the gaps between the bricks and rods. This type of construction may not be an economically-feasible solution for keeping out the weather once the cost of overcoating is added, but it is a good option for noninhabitable buildings or garden walls because they don’t require as much upkeep.

Rattrap bond

Like the Quetta bond, the Rattrap bond are laid on edge, which can result in an interesting face pattern. The following information about Quetta bond applies equally to Rattrap bond, with a very low chance of keeping out weather effects. A stronger bond than Quetta, Rattrap is often used for industrial or agricultural buildings. It can be made more weatherproof by over-cladding, and the bond usually involves one stretcher to one header, as seen in the illustration above

Conclusion

I hope this answers the different types of brick bonds, the sizes and common misconceptions about working with bricks. I sure have learnt the two new bonds of Quetta and rattrap bonds from doing this research.

you can get more details about this from this book: Construction Technology: an illustrated introduction by Eric Fleming.

If there are any mistakes or suggestions, please do not hesitate to leave a comment below.

Guide to hiring a measured building surveyor

So you’re planning a house extension or refurbishment of your current property? Then, you need a measured building survey done first, before you hand over the rest of work to an architect.

What is a measured building survey (MBS)?

MBS is vital for any architect before any refurbishment scheme commences and it provides valuable information, including accurate plans of a building. If you’re a landlord, a measured building survey is also produced to provide you with not so detailed plans to compute the Gross Internal Area for letting purposes.

MBS include a vast range of detailed building information to suit your relevant needs. Such information covers many surveyed areas ranging from floor plans, area plans, elevations, roof plans and floor slab surveys, usually using latest technologies or “the tried and tested methods”.

Methods used in MBS

The measured building surveyor can generate accurate building footprint, including internal control points and then sketches and measures the internal layout before he proceeds to the contruction of the CAD (Computer Aided Design) plan. CAD plan is typically based on the measurements the MBS recorded during the site visit.
Another method typical for MBS is via hand-held computers and tablets useful for inputting spatial data whilst on site. Such method is extremely useful for constructing and verifying the survey data as and when on the site.

What to look out for?

Once the need for an MBS has been identified, you can then start looking for a perfect measured building surveyor who will carry out a survey at your property. First thing to remember, like with any project, you need ro prepare a scope sheet with requirements before approaching a relevant surveryor. In this sheet you need to state what needs to be picked, your timescales and what outcome you want to achieve.
Even though an MBS will be equipped in various checklists and tools needed for a survey, you might also have your own checklists prepared, ready for the inspection. You might want to include such areas as ceiling heights, structural elements (i.e. beams and columns), floor levels, steps (including changes in levels), door heights, chimneys, window sill heights and window head heights, rainwater pipes, foul drainage pipes, etc.

You might also need to consider a dedicated engineering surveyor, who will not only carry out the MBS but also a topographical survey and as-built survey. There is a number of elements an engineering survey involves, which ranges from project planning and design through to quality control of construction projects and monitoring the performance and health conditions of completed structures and facilities. Overall, these are the key elements worth considering and keeping in mind prior to a successful MBS.

Following this quick guide to hiring a measured building surveyor will guarantee your preparedness for an on-site survey and will help you look out for key elements involved in creating a survey. Before you hire an MBS or an engineering surveyor, make sure to mention as much information as possible to make the whole process smooth and hassle free.

There are many websites out there, where you can find your local MBS. Have a browse around, see how long particular MBS companies have been established for, see if you can find any testimonials on their websites and whether they have relevant certifications for carrying out surveys. Don’t go with the first website that you like the look of. Reviews and length of service are probably the most important ones to look out for. Also, why not ask around amongst your friends and family and find out if they could suggest a reliable MBS – word-of-mouth is probably the best advertisement.

What is Stage 4 Design of the RIBA Plan of work

A construction project usually consists of four stages. Stage 4 deals with gathering information required to manufacture and construct the building. This requires input from the design team and specialist subcontractors employed by the contractor, regardless of how they got the project. Any changes in this stage may alter the cost in later stages.

All the designing must be done in Stage 4 before the construction phase starts in Stage 5. It is common for the specialist subcontractor’s design work to be completed in Stage 4 . The RIBA Plan of Work intends that Stage 5 exclusively consists of manufacturing, construction, related inspections, reporting, and resolving site queries. On most projects, Stage 4 and Stage 5 run concurrently and there is a contractual ‘firewall’ halfway through Stage 4.
For example, on a two-stage design-build project, the client may be content to sign the Building Contract after major packages are secured; however, in a traditional project with design ahead of construction, the designer’s work should substantially be complete before signing the building contract with the specialist subcontractors’ work completed after appointing a contractor.
By keeping all design work within Stage 4, the lead designer can prepare a Stage4 Design Programme covering all elements of the design team’s and specialist subcontractors’ work.

Between the interface between design team and specialist subcontractors and the procurement route, it is a tough decision to make. However, they are not the same thing. For instance, in a traditional project, you’ll find many prescriptive elements. Design & Build projects will have predominantly descriptive specification as opposed to prescriptive specification. The value brought by our design team delivering Prescriptive Information varies depending on the building type and outcomes you’re seeking to achieve. Many clients will prefer products that are visible upon completion to be specified by our design team, allowing others to be chosen by the contractor. Many specialist subcontractors have design skills well beyond those of traditional designers and can add value to the design process. With this in mind, it’s essential that we set up our Responsibility Matrix at stage one while acknowledging that it can be updated if necessary as our design progresses.

At this stage, you might want to look at getting existing plans of your property (either your land or your building.) These measured building surveys and topographical surveys would be the starting point of the design team to build upon. You could consider it the foundation of the design.

The RIBA has seen a spike in interest in offsite manufacturing methods, as well as other modern construction technologies. But these things need to be contemplated at Stage 2, and embedded into the design from the earliest stage. If you want to be sure that the building is constructed through a specific modern method of construction by the architect, it’s best to mention it in your project brief for Stage 2. If not, it may be wise for the designer to consider what different types of construction might work best based on a consultation with their construction adviser and some research done at Stage 2.

Getting started with Building Information Modelling in the UK – What it is

Introduction to BIM in the industry and this series of blog posts

With the UK Government Construction Strategy releasing plans for BIM and a digitized construction sector back in 2011 (now 2022), there’s been some exciting progress made in constructing a wrap that enables this collaborative approach.

Clients and supply chain organizations are starting to use their data to design, procure assets, and create a more efficient built environment that is more sustainable with better places to live and more intelligent infrastructure.

As the industry moves from BIM mobilisation to implementation, it’s important that there is practical information at hand to help businesses successfully execute digital projects and understand how to instil Level 2 BIM across their business. This series of blogs will offer real-world advice on how you will be able to take advantage of the benefits and innovations that BIM will provide. It offers different ways for you to create your digital transformation.

If your company hasn’t implemented BIM, they’re either moving too slowly or not proactive enough. Do they have a plan?

BIM is currently a hot topic within the construction industry, and for good reason. The UK government has made BIM mandatory on all public-sector projects starting in 2016—no matter how large or small the project.

Building Information Modelling (BIM) has been a growing industry in the UK, and all over the world.

With BIM technologies nonetheless, there is a lack of understanding of the process and how it should be implemented. Makers need to fully understand how to connect disparate applications in order to use them better.

There have been plenty of books and papers that address the theoretical underpinnings of BIM technologies. However, few articles address the more practical aspects of implementing a BIM strategy in construction.

In this series of blog posts, I’ll try to answer important questions on the concept behind BIM rather than just implementing it. Some of the material is country-agnostic, but other topics might seem UK-focused.

Even if this series may at times seem to be UK-centric, it still has relevance in any other country and could easily be adapted to work for you.

The series will be of practical use to engineers, architects, land surveyors, contractors, and client organisations. It will also be useful to college students and adults interested in more advanced courses about buildings.

The central point of the BIM approach is seamless information management for the entire life cycle of an asset rather than just at design and construction stages.

What is BIM?

BIM stands for Building Information Modelling and is an acronym that many people in the construction industry are becoming increasingly interested in.

Building information modelling (BIM) is a collaborative process for managing buildings’ design, construction and operation. It enables teams to work together more effectively throughout the life cycle of a project. BIM uses digital models instead of paper plans, enabling all parties involved in a project to see what they’re working with at any given moment.

Currently, the UK Government’s mandate that all public sector projects use BIM is driving this frenzy. It’s not a new concept, but it is one that many people in the construction industry hang on every word about.

Building information modeling (BIM) is a collaborative process for managing the design, construction and operation of buildings. It enables teams to work together more effectively throughout the life cycle of a project. BIM uses digital models instead of paper plans, enabling all parties involved in a project to see what they’re working with at any given moment.

What is this Blog post covering on BIM?

This guide is intended to help a typical practitioner in the industry. Of late, there has been an explosion of publications, CPD courses, and other ways to learn about BIM in the UK.

This series of blog posts is not trying to replicate what has been said or written many times before on the subject. Instead, it aims to be a “useful” series of blog posts that can provide guidance on delivering BIM-enabled projects. Much of what is discussed here should be considered as a starting point before embarking on a typical BIM-based project. However, some basic introductory information and background of the BIM story will be included in this post.

What is NOT BIM?

There are a few misconceptions about working with BIM:

BIM is a type of software
Employment of BIM software can save my company up to 20%
Our client is asking for BIM software. Let’s purchase some Revit licences.
Since CAD was invented, we have been designing buildings with BIM.
BIM is CAD by another name

So it is just not SOFTWARE and it is

Software developers use the term to describe their products’ functions. And as such, the definition of what exactly constitutes a BIM technology product can vary depending on who you’re speaking with. But to fix this confusion, it’s essential to talk about modelling solutions that don’t use BIM technology. These tools allow for the creation of models in the following kinds:

Models with 3D data but no object attributes. These models can only be used for graphic visualizations, and data integration and design analysis support is limited. An example of this type of model is Google’s SketchUp, an excellent tool for rapid development for building schematics but is limited in its use to only visualization because it has no knowledge of the objects within the design other than their geometry and appearance.

These models are not supported by behaviour. They don’t utilize parametric intelligence, so each change must be tediously adjusted as you work. This makes it possible to create inconsistent and inaccurate views of the model.

Models that are composed of multiple 2D CAD reference files to define the building. It is impossible to ensure that the resulting 3D model will be a feasible, consistent, countable, or display any intelligence with respect to the objects contained in it.

Models that allow changes to dimensions in one view and not automatically reflected in other views. This allows for very difficult-to-detect errors (just like overriding a formula with a manual entry in a spreadsheet).

The UK Construction industry and BIM

Although the construction industry is quite important for the UK economy, it has a few issues that have been present since its inception as a craft-based industry. As a project-based, not product-based, industry, it has some unique characteristics which are often quite complex. For example, the major stakeholders in any construction project are forced to form short-term relationships and collaborate with each other to produce successful projects.

This kind of project management requires a very responsive and agile approach to working with new partners. A lot of work can happen quickly, so you need to be able to develop new working relationships without delay. Maintaining these partnerships over time can be difficult because stakeholders move on to other projects once the initial partnership is complete. You need appropriate infrastructure for effective partnerships in this industry in order to succeed.

One way to ensure effective information is being exchanged is to set up communication strategies. However, in an industry predicated on short-term collaborations with people from different organizations, information exchange is extremely complex.

To address this issue, we must establish standards and protocols for building a smoothly functioning information ecosystem. The key ingredients are the use of standards and protocols for effective information creation, storage, exchange and management.

One of the major issues is that because this isn’t standard in most projects, the outcomes are often dissatisfying and leave clients feeling as though they’ve been given an asset that meets their needs. The other hugely negative impact of this is a poor relationship between the key stakeholders, leading to claims and counter claims.

When there’s no consensus in the industry, companies will make tons of profits by fighting each other and making claims.

Think of all the paperwork that goes into a typical construction project! Typically, a lot of information is shared between the various teams and companies involved in the process.

It’s clear that without the proper protocols, procedures, and technologies in place, it won’t be possible to exchange information effectively. If a system isn’t properly run, the side effects are all too familiar to those who work in this industry: significant time and money lost on claims, as well as projects due to escalation in costs and scope of work.

To be successful, construction projects need to have high-quality information. This includes efficient ways of organizing, storing, sharing and managing information. One of the key elements that ensures this is good interoperability of information between systems used by different stakeholders in a project.

However, it is a matter of common experience and knowledge that interoperability is a major issue in the construction industry, not just in the UK but also worldwide. Most systems used in the industry don’t “talk” to each other. A major study carried out by NIST (National institute of Standards and Technology) in the US found that interoperability was costing over $15 billion/year! 68% of this cost was due to maintenance and operation.

The lesson is that the industry needs to strive to reach a stage where systems can talk to each other as seamlessly as possible, thus saving the industry very large sums of money.

There are lots of different aspects to building information modeling

Building information modeling, or BIM, is a collaborative process that supports all stages of the lifecycle of a building—from design to construction and operation.

BIM can be used as a management tool to plan, coordinate, budget and control the project. It’s also an effective decision support tool for owners and designers to collaborate effectively during design and construction phases. And it can be used as an effective design tool during the creation of 3D models that include details such as fixtures, furniture, equipment and lighting fixtures. In addition to using BIM in these ways during each stage of your project lifecycle, you will use it as a construction management tool after opening day with parametric scheduling software that analyzes how much time something will take based on past performance data (and even weather forecasts). This allows you to optimize workflow while staying within budget constraints; since everything is documented in real time through automated connections between systems like Revit®, Navisworks®, DXF/DWG files etc., no one has any excuse not knowing what’s going on at any given moment!