The philosophy of over engineering

[i_am_fubar]

While over engineering a solution from specification (regulations or otherwise) will always cost more and take longer (and is thus usually a good reason to not do it). Does anyone prescribe to the idea of purposful over engineering?

From expeirience, I've learned that customers rarely know exactly what they want, and more often than not, half way thought a project they ask for new features or capabilities that wouldn't be supported by the existing work unless a level of over engineering or future proofing has been put in.

The same can be viewed in building projects. If I could afford it, and if it were for my house, I would over rate joists, over rate cables, over rate foundations, add more sockets or network points than needed... etc.

Because it's only after you finish (or are well into) a project you think 'I wish I could use this roof as a deck' or 'I wish I had more sockets' or 'I'd like to make this 2 stories rather than one'.

As me ol' ma' used to say "Just good enough, isn't"

Thoughts welcome.

Fubar.

 

[tony1851]

Over-engineering something incase a customer changes his mind is a waste of resources.
If you are building, say, a single-storey extension, you could incorporate a slightly wider strip footing and deeper flat-roof joists to take a possible 2nd storey, probably at marginal extra cost.
But to over-engineer everything to allow for unknown future changes can be expensive chrystal-ball gazing.
Putting extra sockets in during a re-wire may not necessarily be over-engineering; it may be that the normally accepted standards are out of date.

 

[i_am_fubar]

Oh, as I said, it will always be more costly, and from a buisness sense is a huge, and usually pointless, risk.

Though for DIY, you are allowed to take those leaps from a comfort stand point. For instance, the maths may show that a x by y joist will be suitable and acceptable to BC, but you may want to go larger just so that there is a little less spring in them. Likewise for a ply floor, 18mm may be ok, but 22 will give you a much more solid feel.

I guess in those instances though, you're simply paying for cosmetics, albiet from a structural point of view. There has to a be a limit to how far you go, but it's amazing how many people aren't prepared to increase their budget by 0.1% (usually just because they don't even think about it) to make any future developments much cheaper and easier.

An example would be that whenever I design a product PCB, I will always take spare micro controller pins to connectors. It adds a couple of quid. But when sales asks for an extra sensor, or output, or bit of functionality, it can be done in a day with almost no cost.

Fubar.

 

[^woody^]

If you have not got a clue, then you tend to think you are "over engineering" when in fact you are just wasting time and money

All structural design calculations already have factors of safety built in (eg the timber span tables), so there is no need to over design. The foundations for a single storey, will do for a three storey, so again, if you think in terms of wider, deeper, then its a waste of time and money not over design

And if you are thinking of "what ifs" then you will be there all day with these alternative scenarios which never actually occur

 

[jeds]

Far better to make sure clients are informed of and consider all options well in advance of the points of no return. You'll always get people that mess you about but they just get what they deserve if they don't listen to advice.

 

[i_am_fubar]

Jeds, I did mean this thread more from the DIY side of things rather than commercial, in which case competitive pricing will generally be the over ruling aspect. And I agree, beating the final spec out of a customer before commencing work, or going past the point of no return is essential, but sometimes, just doesn't happen.

And Woody, I completely disagree that to 'over engineer' something is to 'not have a clue'. In fact, that is the opinion (in my opinion) of someone who is given a book of rules to work to and follows them religiously, and hasn't the slightest clue where those rules came from.

Sure, there are safety margins. And while the regs include these and may appear to say 'this is the best sizing/method/mixture' what they are actually saying is 'this is the best sizing/method/mixture KNOWN AT THIS TIME, WITHIN FINANCIAL REASON'. If it were a book of absolute best practice rules, then the regs would never change, but they do.

I will admit, having never done foundations before, I was unaware of that, so bad example. I will even concede that many, if not all of the building regs are over engineered already (through having the safety margins). But to add an additional saftey margin onto that does not imply you don't have a clue, it simply means your prepared to invest in an even higher saftey margin.

Fubar.

 

[i_am_fubar]

I should also just say that I don't think you are a person who has no idea where the rules come from. I'm pretty damn confident you know your s*it and I appreciate the assistance you give people on this forum.

It was just that, as an engineer (a real one, not a bigged up job title that has engineer in it to sweeten it) that really bugged me.

Fubar.

 

[Norcon]

Isambard Kingdom Brunel knew how to over engineer.
Did he not? And didn't do any harm.

 

[tony1851]

Fubar; just a few points re. your comments on Building Regulations.

Many years ago, the regs. tended to be prescriptive, setting certain definite non-negotiable sizes/dimensions etc. Now the regs are generally cast as performance standards and designers are free to use any method/material/design they wish, as long as it meets the required standard.

But my view of the standard may be different from the Inspector's view.

As an example: if I wanted to put a timber-joist flat roof on my 10ft span attached garage, the tables in the previous edition of the relevant document said I should use 6x2 joists. But I could use 4x2 if I wanted. They would bend considerably, but there would be nothing the inspector could do, because the roof would not be a 'health and safety' issue.[/b]

 

[tony1851]

Isambard Kingdom Brunel knew how to over engineer.
Did he not? And didn't do any harm.

Brunel was probably fortunate in that he had clients who were wealthy and prepared to spend.
If the money was there, he could build a brick retaining wall 6ft thick without staying awake all night worrying about whether it would fail or not.

But if money was tight, he would have had to work out carefully if a 4ft-thick wall would suffice instead, and that might have kept hime awake at night worrying if he'd got it right.

Whilst not in anyway denigrating IKB's achievements, engineering is often about achieving the end result at minimall cost.

 

[i_am_fubar]

Thanks Tony, pretty enlightening. So, building regs essentially boil down to 'is a building safe' when build. Whether it has has utilised the recommended solutions, novel ones or a combination. providing all aspects meet a few (well, a lot) of core criteria, it is deemed as compliant.

However, this would be down to a BCO's personal opinion. And if he is unsure, he will need to see proof that that the structure is safe in design and construction. How in depth would that proof need to be? (A clear sketch, archatectural drawings, the load calcs... etc).

Cost is always an issue in engineering and while a good engineer will always come in on budget, a great engineer can see ways to make something better for disproportionally small cost increases and, where possible, present these ideas to the customer or marketing.

I don't believe that over engineering is always needed, there are times and places to save as many costs as possible; to reduce the cost of consumer goods perhaps. But many people are prepared to pay more for something that doesn't just do a job, but does it really well (Dyson, Apple... etc).

Interesting article here on 'Frugal engineering' I just found.
http://www.strategy-business.com/article/10201?gko=24674&tid=27782251&pg=all

fubar.

 

[^woody^]

Over the years, after doing jobs for people from an engineering or manufacturing background involving precision, I have noticed that they find it difficult to grasp the imprecision that is building work. They seem to think that everything needs to be to mm accuracy, and components need to be doubled, be stronger or have extra this and that. Basically they seem to want to over engineer as standard.

Building is about building efficiently. Anything more is waste and adds no value and no purpose

 

[^woody^]

Isambard Kingdom Brunel knew how to over engineer.
Did he not? And didn't do any harm.

He was an engineer not a builder. You could just as well said that Charles Dickens knew how to over engineer his pieces of literature

Can you provide an example relative to construction?

 

[i_am_fubar]

It goes without saying that building work is hardly done to the accuracies of precision machining. The nature of the raw materials alone stipulate that there is a maximum achievable level of accuracy.

This, I feel is where DIY diverges from comercial building. While a builder is against the clock and may know he can get away with a +/- 10mm length of timber, a DIYer, who also knows it CAN be out by that much without effecting the structure of the project, may take the extra time to make it +/- 2mm (easily achievable on most cut lengths with almost no extra effort).

Having had a few profesionals in, it amazes me how inaccuratly they are prepared to work to. Sure, it works, and unless other details like cosmetics are stipulated in the contract, they have fulfilled their job. Pipes run at odd angles next to the pipes I've laid neatley, consumer units stuffed with wires with no thought to how neat it looks, plaster that isn't true to door frames... etc

I could have run my CH and water pipes with the same thought of 'well, it'll be boarded over so whats the point in making them look good' and I say it comes down to a level of pride in your work. Sure it may not add any value (until it comes to repairing it) but the purpose is to know that you did it to the best of your ability, that you've committed to ongoing self improvement and practiced at being precise so you are better at it when it does matter.

As a cross discipline rule, I cringe at the idea of 'hey, I only have to be so accurate, so that is what I'll aim for'. There is a time and a place for relaxing your tollerances, but to a DIYer, working on their own home, I don't feel there is an excuse.

I think you've hit the nail on the head with engineer vs. builder there. And yes, Dickens is a good analogy, as is DaVinchi, Dyson and Testla.

A builder works to reach a completion point while an engineer will always push to achieve better. This does mean that engineers will generally make inefficient (but I won't say bad) builders, but they make good DIYers.

 

[i_am_fubar]

With regards to IKB...

The Cliffton suspension bridge. Still standing, still in use and with only a few minor upgrades, coping with the the massive increase in traffic since it's design. Over engineered for sure, but to a massive long term reward.

The Themes tunnel. Admitadly, massivly over budget and due to alternative themes crossigns since, no longer in use. It is a marvel of engineering and still standing today.

That isn't to say he couldn't not massivly over engineer a solution. The Renkioi hospital was an example of something he designed to a spec, for rapid construction and limited longevity. But it still had features that, while un-needed in the end, would have proved a boon to patients and doctors that were not in the original spec.