Explaining BouwData - part 5

To realise a building you need money. Whether you are a developer, designer or constructor it is the same amount of money you're talking about. The way you look at this sum is, on the contrary, totally different. This I made clear in one of my previous blogs. Therefore, to gain knowledge I created three codes:

• the development code for developers with emphasis on floor surfaces
• the object code for designer with emphasis on functions
• the material code for constructors with emphasis on materials

Today, I'm going to give you some background on the material code.

To the developers and designers who are thinking: "this doesn't interest me at all !" and whose finger is now moving to the little cross in the right top corner of the screen, I would like to ask to hold on a second. Your attitude is typical 20th century. In the 21th century it is all about transparency and communication (*). And in order to communicate properly, you have to know how the other person thinks and what his needs are. So, please, take a good glas of wine and continue reading. You won't regret it :o)

Having this off my chest, let's go back to the material code. This code is all about how and with what kind of material you are going to realise the building. To know what's available on the market, Google is an excellent tool. But for some products you have standard contracts and certain knowhow is the same in every project. This knowhow is sometimes even exclusive for your own company. So, beside a good search engine on the internet,  you also need a little database of your own to store adresses of favourite suppliers and subcontractors, to keep interesting offers which might be interesting for other assignments in the future and to write down the personal knowledge you gain while working your way through several projects. At least, I felt this need and I see that fellow estimators are struggling with the same issues. A lot of them invent their own structure for this database. I prefer to work according to existing standards. And for this problem there are two possibilities: table 2 and 3 of SfB or the STABU from Holland.

At first I tried to work according to the SfB because this is a worldwide spread classification method for construction. This meant analysing every single thing you purchased by material and by form. For concrete this is simple enough: it will be poured on site so according to table 2 we have code E. And it is made out of sand and stones bind together through a chemical process using water and cement. According to table 3 we have code f2. Together you write it down as Ef2. The code of an Argex block is Ff5. But what with a toilet ? In an estimation this is usually offered by a subcontractor for one single price. No problem: in table 2 I had X for complex shapes and in table 3 I had a if I didn't want to specify anything or if I simple didn't know whether the material was made of organic or anorgonic stuff.

Mission accomplished ?

Since I am quite a perfectionist I spend a lot of time to make sure that the Xa category was kept to a minimum and explaining to people why they should use f2 and not f5. 

Now I had a fairly large Excel file and could start sorting. Problem: in alphabetical order I got a list which hadn't anything to do with the order of materials coming on site. And searching on codes was really hard since there wasn't any connection with the word (nor in Dutch, nor in English) so memorising was a nightmare.

Mission failed, yes ! 

And now I also knew why people in Holland so firmly sticked to their STABU :o)

So, I tried it that way but added something to make it even better: I used the coding of STABU chapters and STABU paragraphs and added a 2 to 4 lettercombination. Poured concrete became 21.50.BET (concrete is beton in Dutch), classical wooden formwork became 21.32.HOUT (wood is hout in Dutch), etc. All items concerning pouring concrete on site were gathered in the 21 chapter, all masonry in chapter 22; just as the order you encounter these items while realising the building.

The 2 to 4 letterword had several advantages: it helped to memorise the codes and it allowed me to make distinctions or add items as much as I wanted to. E.g. next to classical wooden formwork, you also have things like Framax, a system of panels to construct the formwork or additional layers to add texture to the concrete surface. These are all different suppliers but are all to be estimated in the paragraph 21.32 contemporary formwork. In the material code I have now:

• 21.32.HOUT bekistingshout
• 21.32.MAT structuurmatten
• 21.32.SYS systeembekisting

And if a contractor wants another category, well, he simply has to search the according STABU chapter and paragraph and add a two to for lettercode to make the distinction with the other categories in the paragraph.

Another exemple: suppose you have a young trainee estimator in your company who needs to estimate pile foundations inside a building which needs to be renovated - or you as designer or developer start getting an interest in technical solutions ;o)

Instead of starting a search on Google, he or she could start her search in the companies database by using the material code 20.32.REN as a key: 

• in the database with adresses he can find the subcontractors the company already worked with
• in the database with company related experience she knows the additional things to pay attention to
• in the database with ancient offers, he can see the level of cost to expect

So before bumping into your office, the trainee already knows the basics and the time spent together can be used to focus on the SWOT of the project itself. Quite efficient !

But on top of that, the material code in combination with the cost type and the number of the supplier or the number of your library also form the "atoms" of an estimation. 

• 21.50.BET.10.000 - labour pouring concrete
• 21.50.BET.20.25/30EE2/EA1S320 - concrete C25/30-GB-EE2/EA1-S3-20mm (**)
• 21.50.BET.30.32 - concrete pump with a reach of 32m
• 21.50.BET.40.XXX - subcontractor who makes component XXX with his own material and equipment

I am now using this code for six years and never find myself in any trouble. A new material gets his own material code and the possibilities of creating "atoms" for my estimation are endless.

So I, like the people from Holland, am 100% pro STABU :o)

The material code in pdf format can be found on www.bouwdata.net under "downloads".

If you want to receive the material code in Excel format, just send me a mail pbo@pbcalcenconsult.be.

Unfortunately the material code only exists in Dutch. So, if anyone who speaks English from when he or she was a todler and learned "construction" Dutch during his professional carrier, please contact me as well ! Because I would love to make an English version of it.

Kind regards and enjoy the sun !

Peggy

www.bouwdata.net or the Linkedin Group "The Art of Estimating"

(*) look around you and read Alvin Toflers "Third Wave" and after that "The New Normal" by Peter Hinssen and you'll know what I am talking about ;o)

(**) another possibility is to use a simpler number after the cost type. We used to do this because in some estimation software you needed to type the entire code manually.  The disadvantage was that if there comes another type of concrete on the market who is something between two existing types, it ends up at the end of the line with the next number. In modern estimation software you "click" or "drag" the code. So it is better to use a longer code which leaves room for new products to find their place between existing ones.

Explaining BouwData - part 4

When I left my fancy office in 2006, I didn't stop estimating. Quite on the contrary. Where estimating was previously merely a necessity to get the contract signed, it is now the end product of my business. And because of this shift in focus, I realised how sloppy me and fellow estimators sometimes worked.

Let me give you an exemple.

Masons are hard to find. And good masons often start their own specialised company. Therefore, general contractors often depend on them to get the job done. So, when estimating a project, you ask their price. Way too often this price is put into the estimation as a subcontractor. But most of the time these people only bring their own trowel. Bricks and mortar are to be bought by the general contractor; vertical and horizontal transport is to be done for them with the centrally placed tower crane.

Important question: how do you know whether this one tower crane is sufficient to get the job done in the most efficient way ? Well, out of the estimation you derive all the labor hours. Devide them by 8 hours per day and you get the number of "labor days". You  think you will hire the tower crane during e.g. 10 months. In one month you have, on average, 17 to 18 days that people work on the site. Multiply the 10 months by 17 or 18 and you have the "crane days". Divide now the "labor days" by the "crane days". When the result is 8 to 10 this means that, on average, 8 to 10 people are working on site at the same time. In this case you will be doing just fine with this one tower crane. With a higher result the men will have to wait to get their material to work with. With a lower result, the tower crane is not used at its full capacity.

Now, suppose we put the masons we hire as a subcontractor in the estimation. When deriving the labor hours, their hours will not be taken into account. But these people expect that you get the material to the spot where they work in time. If not, they will not be able to work at the estimated efficiency and they will lose money. And people who lose money while working, are usually not the people who deliver the best job. So, in the end the general contractor himself is the victim.

Another issue: all kinds of labor are put in the estimation by the same code because it is usually the same price. Suppose that, at the moment of estimation, it looks like it that there will be enough masons in your own company available for the job. When deriving the labor hours from the estimation, the check of the centrally placed tower crane will be done correctly. But suppose that there is a delay and when the project eventually starts, there are no masons available anymore. Now you have to go through the whole estimation and add up manually how many hours were ment for masonry in order to create a separate budget for these hired masons. In our digital age, a real stupid thing to do.

What can we do about it ?

Apply the set of agreements of BouwData on cost types :o) 

Which cost types do we have ?

• the classic MAMO, used when the design is finished and when the budget is made to do the purchases. But there are costs which can't be considered as a MAMO e.g. costs for assurances, taxes, etc. In BouwData the code 00 is used to summarise all general funds in the estimation
  
  - A of "arbeid" which is Dutch for all kinds of labor: the wages of the workers on site as well as the wage of the projectmanager, as well for own staff as for hired people.
  Further distinction is to be made by the material code (will be threated in part 5 of this blog). In BouwData the code 10 is used to summarise all labor in the estimation
  
  - M of "materiaal" which is Dutch for deliveries, costs for materials used in the building or which can't be used afterwards (e.g. the notice board with all the building partners). In BouwData the code 20 is used to summarise all deliveries in the estimation
  
  - M of "materieel" which is Dutch for equipment, costs for all the things which don't remain on site and can be used in a following project. In BouwData the code 30 is used to summarise all equipment in the estimation
  
  - O of "onderaannemer" which is Dutch for subcontractor: people who come on site with their own materials and/or equipment to realise a component of the building.  In BouwData the code 40 is used to summarise all subcontracts in the estimation
  
  
• As I stated in my previous blogs, there are also other costs to be considered while estimating:
  
  - AK of "Algemene Kosten" which is Dutch for general costs not related to any particular project. Usually this is a percentage added to the cost types mentioned above between 5% and 10%
  
  - W of "Winst" which is Dutch for profit: the estimated selling price minus the estimated costs. Usually this is also a percentage added to the cost types mentioned above.
  
  - R of "Risico" which is Dutch for risk: this is an amount of money for unexspected events.  Usually this is considered together with the profit and can go from 0% up to 10%.
  
  - S of "Stelpost" which is Dutch for a fixed sum. This is used when there are no details available for a component which certainly will needed to be build. E.g. a kitchen in an apartment block.
  
  
• But before purchasing, while designing there is also a need for estimations. In this phase it is too soon to go to the market to ask for prices, though. Usually you search in a database with cost ratio's. There are three levels of cost ratio's, all related to the object code and phasing of projects (will be threated in one of my next blogs as well).
  
  - cost ratio related to the "elementcluster", which is used when defining the programm requirements
  
  - cost ratio related to the "element", which is used when making the structural design
  
  - cost ratio related to the "component", which is used when finetuning the design

All eight sets of agreements are related to each other. Don't expect to understand and see all relationships at the first glance. But believe me, once you get the hang of it, it is a very usefull tool to keep your budget under control. And if you have any questions, just ask !

Kind regards,

Peggy

www.bouwdata.net