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I'm extremely glad to discover that this forum has been set up since e-build closed down. I'm a Structural Engineer by trade, with a personal interest in self build and off site construction, and you can find me answering structural engineering and publishing questions at Quora.

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Welcome. I shall be following your posts with much interest.

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59 minutes ago, StructuralEngineer said:

and off site construction

I also have an interest in this and have tried to stimulate thinking on it here, to little avail at the moment, because it is a no brainer when it comes to solving the housing crisis, can't quite understand why it has not been forced through / enabled / incentivised by HMG - must be a vested interest I have not spotted - oh the house builders I suppose!

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Welcome to the forum. Structural engineering seems to many to be a dark art, even down to the remarkable variations in prices that people are quoted for the same job! :)

 

Looking forward to your contributions (which I see you've already made a start on).

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Prefabs periodically reappear as solutions to the "housing crisis" since the second world war, if not before. They aren't a solution as the problem is the availability of affordable land that is in areas that people want to live, closely followed by the enormous bureaucratic delays.

 

Actually building things isn't a problem.

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Posted (edited)

Welcome

 

I am interested, purely from an academic point of view, about foundations.  We only tend to hear about them being a problem, but not the science behind them.

Seems to me that they are often very over engineered.  Is that true?

 

@MikeSharp01 My very first post 'over at the other place' was about open source house design.  A decade on and still not much is happening.

I find it hard to believe that we still use labour and energy intensive building materials and techniques on site.

Edited by SteamyTea
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3 minutes ago, SteamyTea said:

Welcome

 

I am interested, purely from an academic point of view, about foundations.  We only tend to hear about them being a problem, but not the science behind them.

Seems to me that they are often very over engineered.  Is that true?

 

 

 

Welcome, I share @SteamyTea's curiosity.  As a former scientist I started out from first principles to design a large gravity retaining wall, made some measurements of the max allowable soil bearing stress, knew the underlying ground conditions well (we had a water borehole drilled, so had a detailed hydrogeological survey) and then realised that, just to keep BC and our insurance people happy an SE would need to replicate the design. 

 

I went through the copy of his design calcs, and they were much the same as mine, but his final design was significantly more massive, with a margin that very much exceeded Eurocode 7 requirements.  He was very good value in terms of what he delivered for the price though, it's just that his design used a fair bit more concrete and steel.

 

Over the years it seems that foundation design in general has become increasingly more complex/costly, and I have a suspicion that some of this may be down to the "London effect" where so many houses built on London Clay decades ago have needed remedial foundation work.

 

I'd be very interested why, apart from a natural desire to err on the side of conservatism (something I can understand - I used to design and build light aircraft as a hobby) this is so.

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17 minutes ago, billt said:

Actually building things isn't a problem.

Not sure I can agree with this. Two bits of evidence in support of my disagreement. Firstly just up the A2 from here they are working on the Ebsfleet Garden City and they have room, and permission, for 15,000 homes but they are being built at a trickle pace, there must be an underlying reason for this pace. The land is there and the demand is there, 17 minutes from central London on the fast train. The builders have a number of excuses but I suspect the rate is controlled by economics not housing need. Secondly, on the other side of the equation, if the houses were prefabricated on a large enough scale they could be assembled on site in no time at all, weeks instead of the the year which looks like the average lead time of more traditional construction, and thus bring the build rate up to something like what we need. Sadly we all know the old maxim that 'investment challenges change' so if you are invested in one method of construction switching to another does not appear to be in your interests until, as happened to stone age man (& woman) they get overrun by the bronze wielding hoards. Talk to my children's generation they get it, or rather they don't get the housing opportunities we had. Although owning your own property makes you 'heavy' it also gives you some security of tenure that is not available elsewhere.

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Thanks everyone for such a warm and encouraging welcome! If you're trying to win me over you're going the right way about it :) (the other way I can be won over is good coffee).

@Dreadnaught Likewise, and I hope we can benefit from one-another's expertise and experience.

@MikeSharp01 Certainly it looks like there are reasons other than engineering/construction/cost that tend to dictate the situation, and as an engineer I find that as frustrating as the next man. There are green shoots though. For example, staying single storey, financing without mortgage, building on flood plains, or under "other" jurisdictions(e.g. waterways, Scottish "hutting",  mobile or park homes). I'd be interested on your and other's views on this.

@jack

Quote

Welcome to the forum. Structural engineering seems to many to be a dark art

Indeed! I'd say it was a mix of structural mechanics and historical precedent, and while the former can be straightforward the latter is hard to come to terms with as a "science" professional, especially when your peers sometimes trump science with precedent. This problem is greatly compounded by the fact that there is little or no feedback loop -- so if a surgeon operates on 5 patients and they all suffer complications, they can look at what the underlying issue is with their method. If a SE designs 5 buildings, they never get to see any of them again. This is partly why I'm here -- to get realtime feedback!

@billt

Quote

Actually building things isn't a problem.

Try telling that to any self-builder who never worked on the tools. Just using a measuring tape can be a real challenge for some, and I say that sincerely. I personally think anyone should be enabled to build their own house, and that it's an essential part of masculinity that is denied to men today.

@SteamyTea  Foundations - see also the above paragraph - are the worst to get data about, in that they're buried and hardly ever see the light of day again. 99.9% of the time if there are problems another Engineer will be dealing with it, maybe 20 years in the future. However, the source of the "over engineered" perception is probably because of NHBC and building control, who often specify enormously deep trenches, and inexperienced/insecure/browbeaten SE's who blindly follow. It's vexing because most SE's I know see it as their utmost duty to save the client money. BTW. I'm more of a coffee man, but each to their own!

@JSHarris Thanks for the case study. Conservatism is probably a good thing when it comes to foundations, since a bit more concrete amounts to £85 or so per m3. Like you I've noted the tendency for trench-fill being over the top (see comment above) and have for years been advocating for a pad and beam approach or using mesh reinforced rafts. Also you may be right about the London Clay effect -- where loss adjusters have picked up on "clay heave" and apply it where it doesn't apply. Only last week I was shocked to see another SE who had specified 3m deep trench-fill with clay-master to two sides as underpinning... 1.5m away from a mature broad-leaf...

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1 hour ago, MikeSharp01 said:

Not sure I can agree with this. Two bits of evidence in support of my disagreement. Firstly just up the A2 from here they are working on the Ebsfleet Garden City and they have room, and permission, for 15,000 homes but they are being built at a trickle pace, there must be an underlying reason for this pace. The land is there and the demand is there, 17 minutes from central London on the fast train. The builders have a number of excuses but I suspect the rate is controlled by economics not housing need. 

 

I'd suspect this also. To preserve value, the supply is deliberately constrained. Also they may not be willing to invest in the workforce and other logistics to build at a faster rate. Lastly building slowly may help ensure quality, but I doubt this. 

 

Reminds me of when  a high profile act announces one or two nights at a top venue and it sells out immediately. Then extra dates are incrementally announced 'due to demand' as if they venue and artist had and empty week in their schedule. Ensures that each night is packed and all inventory is sold, even the lower quality seats.

 

Great to have a SE in the forum - we used an all female practice for our basement and associated works and was amusing to hear every trade default to 'he' when referencing the SE, and I'd always correct them to 'she'.

 

On foundation design, she designed quite a sizeable ring beam / slab foundation for our garage as we were building on made ground from the backfilled basement excavation and I remember that frost related heave was given as a reason. 

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There are clear examples around here of developers sitting on land and waiting for the "deliverable homes target" time to expire, so they can use that argument to gain PP for more land, before they've started building the homes that they got PP for two or three years before.  Looking at the times scales it's pretty obvious that they game the system all the time, but then it's perfectly legal for them to do this, all they are doing is maximising their profits by exploiting the existing regulation.  The margins in house building a pretty damned small, with most coming from the uplift in value of land when it gets PP, so, from a purely business point of view, who can blame the big developers for just exploiting the system?  It's no different in principle to F1, where every trick in the book is used to stay "legal" yet gain a winning edge.

 

One problem is that we seem to expect developers to have a social conscience, just because they are in the business of building homes.  I've no idea why this is, but it's clearly a nonsense.

 

I think the one thing that annoys me more than anything else is that we don't do enough to incentivise the re-use of existing developed land.  It's often far more expensive to develop land that has been previously developed, so developers will naturally prefer green field sites.  Around here there are lots of former light industrial and agriculture related sites that could be developed, yet instead we see the green fields alongside them having large developments built on, whilst the derelict brown field sites stay empty.  Seems a bit of a nonsense to me.

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Hello & welcome,

I am sure your input will be gratefully received on this forum.

I would have been great to have someone to ask questions of when our foundations were being designed.

I would say ours are certainly robust.

1 hour ago, StructuralEngineer said:

think anyone should be enabled to build their own house

+1

1 hour ago, StructuralEngineer said:

and that it's an essential part of masculinity that is denied to men today

:/

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2 hours ago, StructuralEngineer said:

... that it's an essential part of masculinity that is denied to men today.

??

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2 minutes ago, Hecateh said:

??

I may reply to this when I have finished the housework :D

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18 hours ago, SteamyTea said:

I may reply to this when I have finished the housework :D

@SteamyTea I'm not with you. My point about masculinity doesn't make any reference to anyone's femininity. For me and many men, building a home with our own hands is part of our masculinity, from the dictionary  "possession of the qualities traditionally associated with men." I'm happy to discuss if you feel I'm wrong.

 

 

 

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2 minutes ago, StructuralEngineer said:

I'm not with you

You will find that the humour on here can be a bit strange and pop up in the most unexpected places.

And a lot of teasing goes on too. @Ferdinand has the best lines :D

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Posted (edited)

+1 on the humor!

 

I do agree with you that there's nothing quite like going at it with your own hands (with a little help from the power tools!). It's a shame that the UK has lost the attitude still held by the germanic and nordic states in their balanced view towards the physical+technical trades vs desk jobs. Apprenticeships and collage courses should be seen as an viable alternative route to Uni, rather than a 'backup' ¬¬

Edited by Visti
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6 minutes ago, Visti said:

Apprenticeships and college courses should be seen as an viable alternative route to Uni, rather than a 'backup' ¬¬

 

Absolutely. For some reason, we think that there's some status associated with sitting in an office rather than going out and actually doing/building/making something. 

 

My kids are pretty bright, but even while they're young we're drumming into them the idea that university isn't a given. If what they want to do needs it, we'll be with them the whole way. If something more vocational or entrepreneurial suits them, that's what we'll be supporting and encouraging.

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On 12/03/2018 at 11:27, StructuralEngineer said:

I personally think anyone should be enabled to build their own house, and that it's an essential part of masculinity that is denied to men today.

 

There are a few women on here who have the dream too and you will find lots of banter / humour on here :)  

 

Years ago I spoke to a Belgian friend who told me that every Belgian man was born with a brick in his belly so the dream of building their own house was part of who they were. He had built his own house already. The other thing I observed was the number of houses built next to the owner’s business, so a mix of residential and commercial premises side by side. Clearly very different planning regulations from those in the UK. 

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I don't differentiate between my kids when it comes to DIY. Both are quicker than me! 

 

P3240026.thumb.jpg.842db0e11f77878f08b781923731b8cf.jpg

 

 

 

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30 minutes ago, Onoff said:

 

I don't differentiate between my kids when it comes to DIY. Both are quicker than me!

 

 

Get them on the case with boxing in then! And payment in Haribo has to be good value :)

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1 hour ago, Onoff said:

I don't differentiate between my kids when it comes to DIY. Both are quicker than me! 

 

P3240026.thumb.jpg.842db0e11f77878f08b781923731b8cf.jpg

 

 

 

 

 

No disrespect but I think this may finish your bathroom quicker than you

 

image.thumb.png.0f9a99efdf956ffacc5d00c08f5fe561.png

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8 hours ago, SteamyTea said:

You will find that the humour on here can be a bit strange and pop up in the most unexpected places.

And a lot of teasing goes on too. @Ferdinand has the best lines :D

And I have the best avatar !

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19 minutes ago, pocster said:

And I have the best avatar !

Pop-up Pocster, all very scary, there are cartoon characters on this site B|

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2 hours ago, Onoff said:

I don't differentiate between my kids when it comes to DIY. Both are quicker than me! 

 

P3240026.thumb.jpg.842db0e11f77878f08b781923731b8cf.jpg

Plus they have the advantage of being able to walk safely on the downstairs ceiling plasterboard.

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