Redoing an attic

[Garald]

Another possibility (thinking of the ground-floor neighbors on the other side of the backyard, who may lose some light if my wall just becomes 4.5m higher, though windows would help):

 

Is this sort of thing ever done? Is it feasible?

 

Alternatively:

 

 

Edited December 27, 2024 by Garald

[saveasteading]

Start with this very accessible book and see how you get on. About £5 second hand.

 

Maths is essential for Engineering, but not vice versa. Of course there is a big overlap where the Venn diagrams cross.

3 or 4 years at uni then min 3 in the real world to get qualified. There's a lot to learn, but knowing the principles and the right terms is a good start.

 

 

If I remember, there isn't much Maths in this, but principles.

 

The New Science of Strong Materials (or Why We Don't Fall Through the Floor)  by J E Gordon

 

 

 

 

[Garald]

2 minutes ago, saveasteading said:

Start with this very accessible book and see how you get on. About £5 second hand.

 

 

The New Science of Strong Materials (or Why We Don't Fall Through the Floor)  by J E Gordon

 

 

 

 

 

I already read that (excellent) book, and I have its by now half-read sequel (Structures, or why things don't fall down) by my bedside. Now it would make sense for me to get a crash course with maths in it (which I expect to be easy, but might be interesting for all that I know).

[Gus Potter]

Thanks for the heads up. I'll mull it over.. see if I can come up with a anything that may be worthwhile, most of you have already claimed the good ideas and given sound advice in my mind.

 

For all. That's the great thing about BH.. the sharing of ideas, a bit of maths, design principles, Architectural, Goetech, Electrical ( long list) design, innovation and not being to afraid to be off the mark from time to time. I always appreciate BH as if you're a bit off or say something silly you don't get ripped to death.

[joe90]

7 minutes ago, Gus Potter said:

That's the great thing about BH.. the sharing of ideas,

Which is why I am still here after finishing my build and no chance of another but find the ideas bounded about in a subject I love inspiring.

[Mike]

22 hours ago, Garald said:

 

Is it feasible?

 

Yes, either could be done in principle, and the vertical part of the 2nd one could either be constructed in masonry or timber.

 

However once the roof gets steep like that you'll need to check out the maxinmum inclination of the pantiles; either slate and zinc could be used instead & would fit with Parisian style. You'd also need to check & enlarge if necessary the capacity of the left hand guttering, as it will be taking much more of the rainfall due to the longer slope.

[Garald]

3 hours ago, Gus Potter said:

Thanks for the heads up. I'll mull it over.. see if I can come up with a anything that may be worthwhile, most of you have already claimed the good ideas and given sound advice in my mind.

 

For all. That's the great thing about BH.. the sharing of ideas, a bit of maths, design principles, Architectural, Goetech, Electrical ( long list) design, innovation and not being to afraid to be off the mark from time to time. I always appreciate BH as if you're a bit off or say something silly you don't get ripped to death.

 

I know - I just opened my mouth on reddit asking for pointers to structural-engineering resources that would be useful to a mathematician, and all I got was an amusing pile-on by disgruntled engineers who detest 'arrogant STEM people' (... I thought E was for engineering?).

Speaking of which, can I ask exactly that question here, viz., what to read up? J. E. Gordon is a world of fun but he tries to keep the maths to a minimum (though not lower). The one useful recommendation on reddit was a textbook (Hibbeler's Mechanics of Materials) that looks like what I imagined a good textbook for first- or second-year engineering undergraduates would be like - an easy read, full of pictures, apparently short on theory, and 900 pages long. Surely there has to be an "espresso" book for mathematicians and physicists who want to become less ignorant, aren't scared of maths, want to know the underlying ideas, are used to terse exposition...? Not that I am remotely pooh-poohing real-world experience (or engineers) or believe that maths gives me super-powers.

 

BTW folks on reddit's structural_engineering (Americans I take) were shocked, *shocked*, that engineers haven't formed a holy coven (of people who have to be held in awe) in France; an engineer in France is just a graduate from an engineering program. I didn't tell them that the top engineering programs are particularly prestigious in France (to the point that people on the bus resent Polytechnique graduates a little). I'll probably be best off asking colleagues who have taught in or graduated from ENS Saclay (was: ENS Cachan) whether they know anybody good from the civil engineering program there who would find this little project to be fun. The fact that the selection to get there is maths-heavy probably helps.

Edited December 28, 2024 by Garald

[Garald]

1 hour ago, Mike said:

Yes, either could be done in principle, and the vertical part of the 2nd one could either be constructed in masonry or timber.

 

However once the roof gets steep like that you'll need to check out the maxinmum inclination of the pantiles; either slate and zinc could be used instead & would fit with Parisian style. You'd also need to check & enlarge if necessary the capacity of the left hand guttering, as it will be taking much more of the rainfall due to the longer slope.

 

Right, the vertical side or the very steep side would clearly not be tile. And yes, had just thought of guttering. In fact I have to do something related to guttering on that side at some point. I don't know whether I mentioned it here, but during my recent birthday party, someone rung the door during dinner - no, it wasn't a late guest, it was a random person who informed us that hot water was pouring out of my apartment over passersby like herself. A few days later, the plumber came, and told me it was no biggie - I just have the same illegal plumbing as about 1/4 of the population of Paris: the water leaving the kitchen doesn't go to sewage as it should - it joins the eavestrough. The joints in the eavestrough were not watertight - in fact, the plumber said, they are not even meant to be watertight. The eavestrough got clogged with leaves and other random roof stuff, with the result that the output from unusually massive dishwashing flooded onto the street. The plumber just unclogged the eavestrough with a little vacuum pump of sorts, and told me to just make the plumbing legal the next time I "break my kitchen" (an unromantic expression for that modern vice, kitchen renovations).

[saveasteading]

8 minutes ago, Garald said:

engineers haven't formed a holy coven (of people who have to be held in awe)

 

It's in the nature of Engineers to do the job rather than play for power.

 

Plus as a Chartered Civil Engineer we have vowed to put society first. client next ( and by implication ourselves lower).

 

 "maintain lifelong competence, assuring society that the infrastructure they create is safe, dependable and well designed."

 

I don't know about other Engineering professions.

[Garald]

12 minutes ago, saveasteading said:

 

It's in the nature of Engineers to do the job rather than play for power.

 

Plus as a Chartered Civil Engineer we have vowed to put society first. client next ( and by implication ourselves lower).

 

 "maintain lifelong competence, assuring society that the infrastructure they create is safe, dependable and well designed."

 

I don't know about other Engineering professions.

 

Sounds good to me. I'm not going to let a bad reception on reddit sour me on engineers anywhere, obviously.

 

What I meant was (a) the attitude in reddit was not great, (b) I just learned that there's no chartering or licensing for engineering in France like there is in the UK or Germany; a French engineer is just a French engineering graduate.

 

Not to harp on the same story, but I think I scared the bad old pseudoarchitect (note that architects *are* in an Order in France; she wasn't, as it turns out) when I mumbled something about Hammurabi's Code.

Edited December 28, 2024 by Garald

[SteamyTea]

6 hours ago, Garald said:

a French engineer is just a French engineering graduate.

 A British engineer is anyone that wants to call themselves an engineer.  it is not a protected term.

 

We had our automatic sliding door belt break, the company that made it sent 'an engineer' with a spare, toothed rubber belt and a step ladder.

Half hour later, and with £800 in his pocket, he left.

[saveasteading]

2 hours ago, SteamyTea said:

British engineer is anyone that wants to call themselves an engineer

And any groundworker can paint 'civil engineer on their van'. 

 

Same to some extent with 'doctor'. 

An extended degree in anything would get a doctorate.....but I think the NHS and public know the difference.

 

Strangely 'Architect' is protected even though the aesthetics of a building won't kill anyone. But the profession sells itself strongly.

 

I don't always correct being called a Structural Engineer, (I kept to the Civil path,) as there is some recognition.

 

Ask the public what is a Doctor or Architect, and all will know. Lawyer? Structural Emgineer? I think so.

 

Mechanical/ electrical/ chemical? 

 

The same applied to trades of course. Electricians at least have standards with certification but I know this gets abused.

 

 

 

 

[Garald]

3 hours ago, saveasteading said:

And any groundworker can paint 'civil engineer on their van'. 

 

Same to some extent with 'doctor'. 

An extended degree in anything would get a doctorate.....but I think the NHS and public know the difference.

 

Strangely 'Architect' is protected even though the aesthetics of a building won't kill anyone. But the profession sells itself strongly.

 

Right, same in France (pretending to be an architect is actually a crime, yet, to judge from news items, fake architects are very much a thing.)

 

The doctorate issue is confused by:

(a) use of the doctor title by academics is actually older than among physicians (some academics will insist, correctly if obnoxiously, that a doctorate in medicine is actually one of the "little doctorates", like a doctorate in law - it doesn't require original research);

(b) (UK, Switzerland, etc.) "Prof." is restricted to what Americans would call full professors, and so 'Dr.' becomes shorthand for "I am an academic who is not a full professor (yet)"

(c) UK surgeons actually insist on being called Mr.

 

Actually, what is the difference between civil engineering and structural engineering? In the earthquake-prone zones of South America, we just assume that civil engineers have been trained to build earthquake-resistant structures. (Actually, that would seem to be the main thing that they learn, given that the large majority of Chilean, Peruvian, etc., engineers would seem to not even know that there is such a thing as thermal efficiency.)

Edited December 29, 2024 by Garald

[saveasteading]

9 minutes ago, Garald said:

what is the difference between civil engineering and structural

Well. I've got a few minutes.

Once upon a time there was Engineering. Making war engines such as trebuchets and battering rams. And associated stuff like tunnels and defences. This was Military Engineering.

Extending this to non military use was then known as Civil ( ie not Military) Engineering. That would be drains, roads, bridges. Perhaps castle-like buildings with big open spaces.

 

There may be some unis where you study a degree in "Structural Engineering". (Others will tell us I expect.)

Mostly, uk at least, it is called Civil Engineering and you learn the lot. Experiments with materials and hydraulics, structural theory and design, drainage, roads, geology, management of construction.etc .

Mine included building science which i enjoyed most.( heat,  light, noise, airflow)

 

Later in real life you are likely to tend toward Civil or Structural specialisation. You can study and be examined after s dew years, for one or both institutions.

 

In my case I designed structures and pipelines and buildings as if an SE. 

The examination for SE though was high end maths without the books and colleagues to refer to. My very clever ISE colleagues took 3 shots at it because their subjects didn't come up.

So I stuck with Civils. Civils also tends to include more management. I presented a real life structural project, and the exam was essays and a heavy interview on design efficiency and the morality ethos of the profession! 

 

So I am qualified to design and to approve structures that I would struggle to understand. I maybe did once but I'm out of practice.

But I don't, and that's the point really. To the extent that I employ an SE when necessary, but only one who will tolerate my interference. Hello @Gus Potter

 

Hence. Most practices say that they are "Civil and Structural Engineers".

 

Coffee finished. Up to the loft!

 

 

[SteamyTea]

@saveasteading

I find you civil.

(Always wondered what your background was)

[Garald]

On 27/12/2024 at 09:25, Mike said:

This would probably be the better option in terms of added value, as it would change the Loi Carrez floor area (the area higher than 1.8m) - worth verifying that with an estate agent?

 

Seeing things strictly from a Loi Carrez perspective (... which is a bit crude from some real estate agents' perspective, but it does give you a main term):

 

The current width of the loi Carrez area in the attic is about 160cm (well, a bit more because of the skylights, even once you discount the stairs, I think; also, these measurements are from the faketitecht's plans - I should verify them myself). The house minus outside walls is about 825cm wide.

 

a) Under the asymmetric plans we started to discuss, the total loi Carrez width would be 825/2 + 160/2 = 492.5cm

b) If the attic were scrapped and made into a place with straight walls (not so likely; wouldn't slanted walls from a lighter material be better?), the total loi Carrez width would be 825.

 

Hence we are looking at a ratio of (825/2-160/2)/(825-160) = 1/2. Hah, we could have also got that without computing anything, just given that the house is symmetric.

 

In other words, from a crude Loi Carrez perspective, the 'sophisticated solution' a) is preferable to b) if its cost is half or less of the cost of scrapping and redoing everything.

 

In reality, it's probably rational to prefer b) (if done well) for 60k eur to a) for 100k eur (both figures may be optimistic - and both require me to wait some time to save first). One also needs to add 10k+ to redo the roof insulation no matter what.

 

Either plan puts me above 150m^2, which probably means an architect needs to be involved - bummer. The solution, I guess, is to find a good engineer who works at architectural studio, so that someone in the order of architects could sign off on the thing. There's such a thing as engineer-architects or architect-engineers in France (apparently there's a difference), but Wikipedia tells me they are rare.

Edited December 30, 2024 by Garald

[Mike]

4 hours ago, Garald said:

Either plan puts me above 150m^2, which probably means an architect needs to be involved - bummer

Yes, unfortunately that is necessary - though even below the limit your copro might require you to use one as a condition of giving permission.

[Garald]

30 minutes ago, Mike said:

Yes, unfortunately that is necessary - though even below the limit your copro might require you to use one as a condition of giving permission.

 

In principle, yes, though the copro is tiny and the only people who ever vote are the president and the secretary. One of them is one of a couple of very nice retirees and the other one is me. I actually forget who is which one right now.

[Garald]

To return to my question: J. E. Gordon recommends several books at the end of The New Science of Strong Materials, but he says: "Equally, it is not possible to interpret many of one’s observations without the aid of books and, unfortunately, it is not a subject particularly well served by books which are not excessively specialized and mathematical. However, the following books are open to anybody with a knowledge of elementary algebra." I need the opposite - a couple of books for people who most likely know the maths they will need and find it a natural language. Someone recommended a standard textbook to me (Hibbeler) but, while it seems very accessible, it reminds me of the book I was given to teach ODE to first-year or second-year engineering students twenty years ago - prolix, colorful and more than 900 pages long. (I've also heard it said, fairly or not, that it tends to skip the reasons behind the formulas.) Surely there has to be an espresso version?

Edited December 31, 2024 by Garald

[SteamyTea]

19 minutes ago, Garald said:

To return to my question

When I was at university (both as a student and a lecturer), the local public library had a very good selection of engineering books (mostly about mining as I am in a mining area and CSM was based in the town).  Might be worth a visit to your local library (when I worked in London, my local library was the British Library, and I managed to con my way into the Bodleian in Oxford as well).

Failing that, you can always borrow a Jean-Paul Sartre.

[Garald]

12 hours ago, SteamyTea said:

When I was at university (both as a student and a lecturer), the local public library had a very good selection of engineering books (mostly about mining as I am in a mining area and CSM was based in the town).  Might be worth a visit to your local library (when I worked in London, my local library was the British Library, and I managed to con my way into the Bodleian in Oxford as well).

Failing that, you can always borrow a Jean-Paul Sartre.

 

Right - I should have no trouble going to the library of the architecture school that is two blocks from my office (in fact I've already been there). I hope they have the right engineering books - otherwise, that's another sign that I should keep the company of civil engineers and not that of architects!

[Gus Potter]

On 31/12/2024 at 17:59, Garald said:

Right - I should have no trouble going to the library of the architecture school that is two blocks from my office (in fact I've already been there). I hope they have the right engineering books - otherwise, that's another sign that I should keep the company of civil engineers and not that of architects!

I admire your tenacity and interest in sturctural enginering. But here is a bit of tough love.

 

It will take you about 20 years to become competant to design this kind of stuff economically that you are wanting to do. Find and pay for an SE that likes doing the things you are trying to acheive and you will save loads of money. Your chances of producing a set of calcs that can even begin to back up what you are doing is close to zero. You will have to also learn about wind and snow loads not least. Then you need to trace all the loads down to the founds, prove the load path / building stability / fire protection and check everything below that!

 

Yes you may be able to read books and work out the forces in the members. That is good fun and will introduce you to the tehcnicsl terms. Anything you do is time well spent.

 

But you'll need to know how to work out the wind, snow and gravity loads. You'll then need to establish the deflections. Next you will have to quantify your connection design. This is going to be harder as you are marrying into an existing structure.

 

To put this into context. I was a builder for 20 years, then went to uni at the age of 40 to become an SE. I'm now 60 years old and now reasonably competant in this kind of structural design. But every day I learn new stuff..

Give it a miss and spend your time researching insulation / sourcing materials.

 

Sorry to say it. If you fancy being a Structural Engineer then it is a great job. My journey has taken me into the Architectural and Conservation side so now I call myself a Structural Engineer and Architectural Designer. But seriously it's taken me some 15 to 20 years to develop my basic skills and that is off the back of me being a local builder for 20 years before that! Now I'm no thicky on paper. I have a Masters degree with distinction and won the best all round student prize at university. Frankly you can become a Surgeon faster than an SE! but that goes back to how many folk you get to kill in one go! see below.

 

Per say it is a very responsible job. It's the kind of job that keeps you awake at night! I often say.. Doctors generally get to kill one person at a time but an SE is able to kill lots in one go! If an Architect makes a bit of a bollocks of it then your building may leak water / be cold / condensation or look as good as you expect.. yes you may lose some money but you won't get killed!

 

If there are any teenagers (parents) reading this or folk that are stuck in a dead end job.. My advise to you is choose a study course that teaches you how to teach yourself. @SteamyTea et al. Probably the thing for me was that the folk that taughtme enabled and gave me the tools to teach myself. I love cooking. I could have pursued something completely different.

 

When I was a builder I did not know how to teach myself! @SteamyTea @MikeSharp01does this make sense to you?

 

 

 

 

[Garald]

38 minutes ago, Gus Potter said:

I admire your tenacity and interest in sturctural enginering. But here is a bit of tough love.

 

It will take you about 20 years to become competant to design this kind of stuff economically that you are wanting to do. Find and pay for an SE that likes doing the things you are trying to acheive and you will save loads of money. Your chances of producing a set of calcs that can even begin to back up what you are doing is close to zero. You will have to also learn about wind and snow loads not least. Then you need to trace all the loads down to the founds, prove the load path / building stability / fire protection and check everything below that!

 

Yes you may be able to read books and work out the forces in the members. That is good fun and will introduce you to the tehcnicsl terms. Anything you do is time well spent.

 

But you'll need to know how to work out the wind, snow and gravity loads. You'll then need to establish the deflections. Next you will have to quantify your connection design. This is going to be harder as you are marrying into an existing structure.

 

To put this into context. I was a builder for 20 years, then went to uni at the age of 40 to become an SE. I'm now 60 years old and now reasonably competant in this kind of structural design. But every day I learn new stuff..

Give it a miss and spend your time researching insulation / sourcing materials.

 

 

This is all good advice. Don't worry, I'll spend my time on my actual job - I think I've already learned enough about insulation thanks to the good people in this forum.

 

At the same time,

- there have to be at least mildly interesting mathematics involved in SE (certainly compared to insulation or even the Carnot cycle!) - after all, Euler and one of the Bernoullis were involved. I see this as a bit of a general-culture thing.

- I'd like to:

* decide which SE to hire, be able to make suggestions before and during the work on the project, etc.

* know what to want. A good SE will be able to tell me whether a structure is possible and safe, but will they tell me whether it makes sense to want a certain kind of structure? All my perspective right now comes from what I know about insulation, really basic geometry (keeping a surface small and the volume large), solar exposure, cross-ventilation (note: I don't actually know enough about that - I'd love to learn to model it and gain some intuition), really vague notions of architecture - so it's an unbalanced perspective, in that structural engineering is missing.

 

So, I thought that, while I should obviously focus on my papers and my book (not least because I need to wait a bit to earn the money necessary to change the structure of the roof) I would also learn some of the maths involved.

 

Of course I risk annoying an SE by 'double-guessing', but OTOH I completely agree with your philosophy:

 

> Find and pay for an SE that likes doing the things you are trying to achieve  [my emphasis]

 

and my intuition is that a structural engineer that would actually like this project would also be unlikely to dislike working with me in the way sketched above (I'd hope).

Edited 1 hour ago by Garald

[saveasteading]

44 minutes ago, Garald said:

have to be at least mildly interesting mathematics involved in SE

Oh there certainly is, especially in steel.  In the day job we mostly look at tables of the properties of materials. Someone has done the complex maths, combined with experiments, and the properties of standard steel sections, for example, is already done and published.

That save lots of time.

 

If you want to look at the principles of everyday steel design, I have a book in front of me  Structural Steel design to BS 5950 by Morris and Plum.  It was published in 1988 so you might find it second hand and explore the maths...Gus will know if it is superseded.

It is very accessible but uses the published tables.  Behind it is much more complex maths which you will find if you want, but it is the stuff of academics and not used as everyday.

 

BUT I studied this stuff and am qualified. But I have forgotten most, and so only work on simple beams and subcontract to people who do it as the day job.

 

Then there is concrete, which is done more from first principles because of the infinite variety.

Actually I am wrong. First principles involves serious calculus and again leads to tables that are used for real stuff. And, for example, the Sydney Opera House is not out of books at all.

 

Buy a couple of books I say. You will look at beams and portal frames differently.

 

Oh and another difference is that a surgeon works in a familiar environment with a fairly standard subject.

But every construction site is different, even for a repeat building. and wet and windy or hot and dry.

 

 

This sort of stuff?

Elastic section modulus

Equation (9.10) may be written in the form

σx,1=MZe,1σx,2=MZe,2

in which the terms Z_e,1(=I/y₁) and Z_e,2(=I/y₂) are known as the elastic section moduli of the cross section. For a beam section having the z axis as an axis of symmetry, say, y₁=y₂ and Z_e,1=Z_e,2=Z_e. Then, numerically

σx,1=σx,2=MZe

Edited 51 minutes ago by saveasteading

[Garald]

1 minute ago, saveasteading said:

Buy a couple of books I say. You will look at beams and portal frames differently.

 

Very good - recommendations welcome!

 

Assume the reader is a mathematician who remembers some physics and would love to learn some more (the last course I took back in the day was quantum mechanics, which I didn't really learn, but did teach me how important and natural Hilbert spaces, normal operators and spectra really are - lesson to be learned here).

 

I imagine that, for this little project, it will all be timber, with perhaps a few steel components involved at a crucial place or two.

 

> It is very accessible but uses the published tables.  Behind it is much more complex maths which you will find if you want, but it is the stuff of academics and not used as everyday.

 

Well, that's likely to be the interesting part, isn't it.