Category Archives: Precast Blogs

Blog about techniques and tools used in Precast Detaling

Stair Outline Routine – AutoCAD Plugin – Code Attached

An example of the type of stairs we draw. We do a lot of stairs. Both AS 1428 and AS 1657 compliant stairs.
An example of the type of stairs we draw. We do a lot of stairs. Both AS 1428 and AS 1657 compliant stairs.


We continue delving into our discussion of stairs. The boss hates it when I do things like this – releasing code to the public. But it’s too good not to share. Below is a routine you might find useful. We use it to model stairs – it’s super fast, and efficient. It allows us to try different things out and to discard what doesn’t work with ease. I’ve gone to the effort of drawing up an entire flight of stairs and then realised that I’m missing a tread. Then I’d have to redo the whole thing from the beginning. Once you have this outline done, the a good chunk of the work is finished.


One of our many, many versatile routines:


Here is a gif of the project:

A Stair AutoCAD Plugin
A plugin I wrote for AutoCAD. Written using c#.


And here is the code for the benefit of study.


I suppose I should refactor it, but I don’t think I’ll be changing it any time soon. So why worry?

How to avoid trouble in building and construction projects (Part II)

(a) Watch out for situations where people start building from unapproved drawings. You don’t want to get involved in such projects.


Friends, we’ve been in the game for almost a decade. We know the ropes when it comes to building and construction projects. Builders put pressure on fabricators to meet deadlines. Fabricators put pressure on the guys doing the shop drawings. And the guys doing the drawings are forced to come up with solutions……..but there’s a problem. The vast majority of the information required to make good and accurate shop drawings are missing. It’s just not there. You can ask for RFI answers but sometimes they’re just not forthcoming from the builders or the engineers or the architects. So what do you do?


The client is demanding drawings.


“Send me the unapproved drawings,” he says.


When people say things like that: watch out! If the project goes well, then they take all the profits. But if it goes wrong, then you not only do not receive your fees, but you are forced to also wear the fabricator’s loss. It’s a lose-lose situation for you and a win-win situation for the fabricator.


So you’ve got to make a decision: (I) either hold back the release of drawings till you have better information clarity, or (II) you release it making it explicitly clear that any risk is taken up by the fabricator if they build on drawings that weren’t issued for construction. Because at the end of the day, you don’t want to be carrying the can for someone else’s cock up. Ignore this advice at your peril.



(b) Watch out for clients who offer to pay in cash


In this day and age, especially with the sums involved, you gotta be extremely weary of clients who offer to pay in cash. Why would someone do that? Isn’t it much easier to make a bank transfer? Yes, but the reason why people deal in cash is probably to avoid paying tax, or even worse, it’s because the money is black. You don’t want to be involved in any activity like that. So the next time someone offers to pay you $15k in cash, thank him/her for the offer and politely tell him that such an arrangement will not do. If they insist on awarding you the work then quote a high price just to get rid of them. And if they still insist on coming on board – without bargaining – then you really have to watch out: they probably have no intention of paying; so ask them to pay up front. As a general rule, you don’t want to get involved with clients like that. I can’t think of a good reason for somebody walking around with $15k in their pockets.


(c) Quote High


As a general rule, quote high. If the quality of your work is good then you’ll stay in business.


We use genuine licenses. And they cost a fortune. So our rates reflect the need to recoup the license cost. But inevitably, someone will want us to lower our quote so to the level of a dodgy operator out of the Philippines, who doesn’t have a license.


We can’t compete with them. We can’t match their quotes. And we don’t even bother trying. As a general rule, these clients bargain for super low rates, and then find every excuse not to pay. That makes for bad business for you.


No friends, charge high, and deliver good quality work. If your work is good, trust me, you’ll have more work then you can handle. When you’re in that situation, pick and choose the projects that will bolster your reputation, that will book your fast profits, and that will be of enormous benefit to your existing clients.

Apartment Developer Takes over South Brisbane!

Looks like a certain developer is taking over South Brisbane!! Here are some of the projects we’ve been involved with in recent times.

Rarely will you ever see them so closely located together, let alone in the same photo. Personally I thought it was pretty cool. (Please click on the photo below to get a close-up view).


The projects that we’ve been involved with in recent times. Either detailing or tracing.

Why Bubble Deck?

Bubble Deck – What’s so good about it?


A picture of a construction crew on a bubble deck slab.
A picture of a construction crew on a bubble deck slab.
  1. It’s fast, really fast.

If you can build something quicker, than translates into making money quicker. There’s a premium on speed.

  1. Less manpower

Less manpower on site. That means less potential problems to deal with. Which eventually translates into money. Generally speaking, the problems and costs associated with a project are proportional to the number of people involved in it.

  1. Structural Benefits

Bubble deck slabs, because they are filled with air, are significantly lighter. Also you can have wider spans – without as much column support. This is very desirable from an architect’s point of view.

  1. Cost of manufacturing

The BubbleDeckGroup tout it as being cheaper to manufacture. Personally, I’m sceptical of this claim. I think it’s the same, if not more.

  1. Environmentally Friendly?

They also say it’s more environmentally friendly. It probably is relative to other solutions, but I don’t think it’s actually helping the environment. It’s sort of like the marketing on a cigarette packet saying that it’s “healthier” than other cigarettes. It is probably healthier, but cigarettes as a whole, generally speaking are not healthy


What are the costs?

Everything has to be designed correctly and properly early on. This is not necessarily a bad thing. It forces designers to plan and think things out, before the actual construction. But if the design team does a bad job, you can be sure that the entire project is going to be delayed, and is going to be monumentally expensive.

Tek1 Now Drawing Bubble Deck!

Tek1 – Now has Bubble Deck Capabilities

Bubble Deck

After sending our staff overseas for an intensive Bubble Deck training camp, and after the development and preparation of tools to handle Bubble Deck detailing, Tek1 is pleased to announce that in addition to stand panel detailing, Tek1 has started to draw Bubble Deck slabs.

This has been the culmination of months of hard work.


What is bubble Deck?

  • It is basically a concrete slabbed, reinforced, with voids in it. It is perhaps best illustrated with pictures:


Bubble Deck Slabs
Bubble Deck Slabs


Cross section of bubble deck slab
Cross section of bubble deck slab

How to avoid Danger in Building and Construction Projects (Part I)

How to avoid Danger in Building and Construction Projects

 “The prudent see danger and take refuge, but the simple keep going and pay the penalty.” — Proverbs 22:3

The aphorism holds with building and construction.

  • How it works in building and construction

What is the danger in building and construction?

The danger is if you commit yourself to projects which will cost you time and money.

Ideally your goal in building in construction should be this: to (i) produce accurate drawings quickly, or if you are a builder/trade to: (ii) build quality structures and get out as soon as you can.

Why are delayed projects costly?

You do not want a construction site that is delayed by 6 months. Think about it: crane hire: $15,000+ per week. What about site crew? That’s $25 / hour (very, very conservative. More like $100 / hour). How many staff will be working there? What about charge backs? What about the engineers and architects who will put RFI queries to the back of the line in order to focus on jobs that will bring them immediate revenue? Delayed projects straps all interested parties of liquidity, especially the builder, who will try to delay payments to suppliers. And if suppliers/contractors don’t have the liquidity to ride things out they could go belly up, further adding to the monumental costs involved. It’s a vicious cycle. The moment people get wind of a possible insolvency then they’ll pull out of it to focus on jobs that will bring them revenue. In short, delays are damn expensive. And you need to avoid badly managed and designed projects like the plague.

  • How do I know whether a project will be a cock-up?
  • First and foremost: Look at the capital position of a builder

If the builder cannot stand up when times get a little tough, then their strength is small. Builders need to have a strong capital base and liquidity in order to tide them through projects. As a rule of thumb: you can trust the big names: Lend Lease, Watpac, Leighton– because they have the ability to raise capital from markets if things go bad – but even then, you need to have a good look at their financial statements. You cannot trust the big four auditors. Read that again: only a fool would trust in the audited statements of the big four. You don’t need to be a financial analyst, but you do want to see a healthy cash balance, and the ability of these firms to service any impending debts.

  • Second: track record

Make sure the builder has been around for a while. If she’s been around for 10 years she must be doing something right.

  • Third: Price and availability

Good builders know their value and won’t work on the cheap. Consequently, they’re hard to hire because they’re always working. If you see a builder who is cheap and available, you need to very carefully investigate her or her quality.

  • Second: The Designers need to be good

Bad drawings are the bane of this industry, nay bad architects are the bane of building and construction. I see it all too often, and very rarely do I see an architect worth his salt.

If the designs are bad – I mean really bad, then you want to steer clear from that project. Why? Because builders with funds hire the best architects. Builders without funds hire architects who are inexperienced, which means architects which could drag everyone under. This means, as mentioned above: (i) endless changes, (ii) endless RFIs, and (iii) issues getting paid.

 Things to watch out for:

Now you can apply the following general aphorisms when accessing the quality of the drawings you see:

General Aphorism applied

Cockroach theory

  • If you see one, then there will be a hundred hidden behind the scenes somewhere.

Small mistakes, big mistakes

  • If they can’t walk, then they definitely can’t run. This means if you see some elementary mistakes, then you cannot trust them to get the more complicated things right.

What one should specifically watch out for in Construction Drawings:

 Bad design:

    1. I sometimes see the most absurd looking panels. What mind, smoking what substance, would concoct such a creature worthy of standing beside David in Florence? If you see one ridiculous looking panel, this is a sure-fire indicator that the architect knows absolutely nothing about what she’s doing. That means it’s gonna be a long and costly project. Stay clear of these things and let your competitors fall into them, while you focus your energies on projects that will generate a timely and handsome return.
    2. Missing panels.
    3. Misnumbered panels.
    4. Panel details that are not workable.
    5. Too many missing dimensions – another early warning indicator that the architect is careless, or rushed, or lacks resources.
    6. Missing gridlines. These architects ought to be round up and summarily executed.
    7. Dimensions made not to gridlines.
    8. Unnecessary complications in panel design. This is a sure red flag. It just increases the risk that something will cock up.
    9. Architects who make hundreds of revisions. Watch out: this means that people keep finding mistakes, or the architect is making changes continually. And that will bring more errors and more revisions. This means you gotta download 50 new drawings every day from Aconex. And you have to supersede all your old drawings? What if you miss one? This is a dangerous accident just waiting to happen.
    10. Too many misnumbered section views. This means that the architect has made a lot of changes. And when there are changes, it’s not a good sign: it means that there are problems hidden in the drawing, it means that they’re drawings are not easily readable, and will cost you money.

Architects who do not release their CAD files. These architects are costly. And as a rule of thumb you do not want to hire these architects. Because if there is a single missing dimension you have to call them to find out.

  1. Architects that take too long to respond: This means that they’ve taken other projects on, and are focusing on what will pay them money rather than attending to their work. They are too busy to actually be doing work.
  2. Architects that have their own agenda: they are not interested in delivering a quality structure, or a structure that is a commercial success to the client, as much as building a work of art which they can display to their friends/family and put into their portfolio. They are artists and have fabulous visions of grandiose structures without (much) regard for returns. At the end of the day, if you’re a builder, you goal should be to make money. Making cool buildings can be a part of that vision, but it certainly should not come at the expense of the bottom line.


My friends, if you take in just half of what I have written here, then you can surely avoid yourself from entering into strife. But you ignore my advice, then you will fall headlong straight into it!

Technical Note: Lifters minimum 10 tonnes & must use N20 loop bars

What is happening?

Summary: Lifters minimum 10 tonnes & must use N20 loop bars

  • Lifters must have a minimum capacity of 10 tonnes from now on.
  • N20 loop bars must be used on 10 tonne lifters. This is a slightly thicker diameter than the previously used bars.


Suppose you have a 9 tonne panel. Then a 10 tonne lifter will suffice, would it not? Wrong! The panel will sometimes actually be more than 9 tonnes due to dynamic loading. What is dynamic loading? It is the additional load that is felt by the lifter, caused by lifting the panel. If the crane drops the panel very quickly, and then stops abruptly, then the panel lifter will face a strain significantly higher than its static weight. To prevent accidents and injuries – not to mention losing a panel and the antecedent costs, all panels henceforth must have 10 tonne lifters as a minimum.

What to do now?

  • Please make changes to the code to ensure that it is impossible to place a lifter less than 10 tonnes.
  • Please add a check on the audit to ensure that lifter under 10 tonnes are not found.
  • Please add an audit check to ensure staff are following procedures.


For the general public, as an aside:

What is a lifter?

If you don’t know what a lifter is, it is basically a hook that allows a crane to lift up a panel. This “hook” is secured to the panel with what is called a loop bar.

What is a loop bar?

It is simply a bar which secures the lifter to the panel. If you have no bar, then the hook will simply snap off the panel. If the hook snaps off the panel while it is being lifted by a crane, you can be sure that it’s gonna kill some unlucky soul who might be walking under it. So it’s very important that every lifter is secured with the correct loop bar. There is no point putting in a loop bar if you put in the wrong one.

What does N12-200 EF mean?

In this blog post we will explain what N12-200 EF means.

Please see the below diagram:


Well, what does N12-200 EF it mean?

Let’s break it down.

  • N12

This is the diameter of the rod. 12 mm.

  • 200

The 200 portion means that the rod should be spaced 200 mm apart.

  • EF

This means that the rod should be on each face. i.e. on both panel faces. This is best served via a diagram.


I hope you learned something!



Lapping – what is it?

Lapping – what is it?

It’s got nothing to do with being over taken on the F1 track.  Lapping referes to the “overlapping” of reinforcement with another section of reinforcement.

Why do we lap?

  • It gives greater structural integrity to the structure you are fabricating. What does this mean? It means that when you lap, your concrete will be stronger, and will be better able to withstand loads/weights. In other words, a lapped structure will be more sturdy that unlapped structures.
  • AS 2870 requires that we lap.

Lapping Requirements?

Trench Mesh Laps

  • If they are overlapping at T or L intersections, then overlap the full width of the mesh.
  • When end to end, they need to be at least 500 mm.

Please see below:

Showing the extent of the overlap required for trench meshes.
Showing the extent of the overlap required for trench meshes.

Square mesh lap

  • These need to be lapped by 225 mm minimally.

Please see below:

Shows minimum lapping required for square meshes.
Shows minimum lapping required for square meshes.

Reinforcing Bar Laps

  • Lapping needs to be at minimally: 500 mm.

Please see below:

Shows the minimal lapping required for reinforcing bar laps.
Shows the minimal lapping required for reinforcing bar laps.