Gus Potter

Me too, not a day goes by where I don't learn something.. problem I have is that older I get the more I realise how much I don't know! I went to University at forty, best thing I did as it gave me the tools to teach myself. Interesting background you seem to have. You're among kindred spirits here on BH, mind you be careful what you wish for. Seriously though, if you've done a few of these before post some photos on how you did it, the tools you needed, what is going on at the supports etc.. that practical stuff.. so new folk can see how it's done properly.

That's a good description.. reverse percolation test! Clay soils can be quite variable. In a site investigation report you'll often see that they captilise the dominant component.. like.. silty sandy CLAY. The clay in capitals means the dominant component is clay. Also when you are sampling and doing boreholes you sometimes see a blank bit in the site bore / sampling record.. often described as "no sample recovered".. this is a big red flag in some respects, mainly as it relates to the design say of a basement and how you stop it from floating like a boat.. what is it (the no sample recovered part of the log) and how much water can it convey. On the other hand it could be a gift than can be taken advantage of in a drainage design if it is indeed a permeable layer of soil. Now there are soakaways that we a famiiar with. You dig a trench, fill it with gravel and a perforated pipe and the water goes downwards never to be seen again.. problem solved. But sometimes you can design them so that the water goes sideways and mixes with the natural ground water. This can work well where the additional flows are low. Often less so for surface water unless you can attenuate. Funnily I did this on a self build on clay many years ago where I just added the water from the septic tank to the natural horizontal ground water flow. However you need to install it really carefully and it may some maintenance later.. it's often not a "do and forget solution". At the back of my mind is that the climate is changing.. more rain coupled with long dry spells so anything you do needs a bit of future proofing rather than just doing something that will pull the wool over the eyes of BC and the Environment agency say.. that a lot of folk are inclined to do. To be able to design a "sideways" soakaway you need to establish the hyraulic gradient over the site. Simply if you dug 4 holes and took levels of the ground surface and the static water line in the holes after say a week you can plot that on a drawing to give you a rough 3D idea of what is going on under the ground... the hydraulic gradient. Yes you may have say ditches nearby but they won't give you all the info you need. Alan.. To test this principle before embarking on detailed investigation.. what if you fill the hole you have dug from a bowser to bring the standing water up by say 200mm and then see how long it takes to revert back to the standing water level you see at the moment? It's not something that we could rely upon but it would let you see how something could work? Now if you have that "no sampled recovered" bit in the site investigation log .. it could be a great permable layer at a decent depth that you can tap into to get rid of your water. For all.. on a technical note.. I use the word permeable. This describes the overall behaviour of say a layer of soil. Say you have a layer that is made up of quartz gravel and sand / silt. The particles themselves are not porous.. like granite stones in a wall ("rising damp").. it is the gaps between the particles and density of compaction that is important and when we look at the layer as whole we call this permeability. Now the same principles apply when we are designing concrete for a basement so it is watertight. We want to reduce the cavities and the crack widths in the concrete. We reduce the cavities by selecting the right mix of concrete and reduce the cracking by using rebar and that makes the concrete more impermeable. Often if you have a house that has no basement then the problem can be decoupled. But if you have a basement then you need to make sure that you are not going to channel water back towards the basement which is in effect a large sump.. that you will have to pump out or drain in some way. Also..if your water from the septic / digester tank / car parking area ends up (although diluted) next to your basement wall then you could alter the soil PH and sulphate content and that could cause a problem as when we design concrete under the ground we consider sulphate and PH value. Never mind that.. you don't want stinky toilet water against your house .. often happens if your visitors / relatives behave badly in the bathroom. In the round if you look back over Alan's thread he is taking time to investigate and plan each step. This is good design.. you learn a bit.. review what you know, plan and execute the next step. It takes time but it's the best way of spending you money wisely. In the round if you have a flat site say Norfolk / Linconshire or up in Scotland round about Stirling for example where you have these types of non consolidated clay soils (the list is quite long) then while you can get the structure to work you have to get the design to perform holistically. No point in say an SE doing a basement or a heavily loaded found just for it to get messed up as you can't get the drains and services to work. For all. Alan's job I think is a good example of how if you work through the issues step by step in a holistic way then you don't waste your money. A duck pond! I built a few for my self build and kept ducks.. etc. Some of the ducks were negligant mothers at times at times when broody so we would take a few eggs and stick them in the incubator. Once hatched we stuck them in the bath to help oil their feathers up, then later introduced them back into the adult population. It was great fun. The point here is that there are often solutions to rain and foul water disposal that can be fun. The SUDS guidance can be flexible once you get your head round the seven or so hundred pages! The pond provides attenuation, dilution, habitat, a potential hydraulic head to drive water downwards and you can have a flow / oriface plate to regulate say discharge to a drainage ditch. For me I'm an optomist, on a self build see what the options are that compliment say the type of garden you want, planting etc and how you want to live.. sometimes you have to live in a different way, learn new stuff and that can be fun too.

Conner is pretty much right, many roof structures don't need much if any fire protection.. but there are some cases where this rule is not applicable. If you look at the building regs you'll see a bit that says roughly that if an element of structure is contributing to the stability of an element that needs longer fire protection then that bit too has to have the longer duration protection. I've had this "experience" when working in and around party walls and boundary walls / walls close to boundaries that need say an hours protection. Past "unjoyfull moments" include attic conversions and adding and extra storey onto a single storey garage attached to the house.. I have sat down and worked out a structural solution, made myself a coffee and felt quite pleased with myself.. until is dawns.. oh no!.. I need that bit to have a longer protection.. bubble gets burst and it can be expensive (for the Client) and time consuming (for me) to sort that out. To finish it's worth trying to understand, if you can, how your building stays up.. it needs to carry vertical load but also all work together to stop it falling sideways either in the wind or by just being a bit off the plumb. Quite a lot is common sense.. a lot of folk have intuition. If you think about houses you have been in that have open spaces and say high ceilings and walls.. you just get that feeling that things look a bit too slender or the upper part of the building just looks too heavy / catches too much wind to be sitting on what is below?

Probably not much.. depends on the loading. Good to see you have made a few in the past, they are elegant in their own way and are one of the solutions in my toolkit. For all.. in principle how they work is great for teaching material behaviour. We know that steel is stiffer and stronger than timber. But how do you how much load the steel plate carries and how much the timber? What we do is to recognise that as the timber and steel is bolted together then they must both bend by the same amount and thus we can work out how much load the timber and steel is carrying respectively. The detailed design is quite complex, especially if using the Eurocodes. There is bolt slip, bolt bearing, timber creep and list of other bits to consider in all the calculation. The timber creep adds complexity. Over time the timber creeps.. like a ceiling in an old pub and this "relaxation" needs a bit of thought as the apportioning of the loading changes as time goes by. Post a photo of the finished article! All the best.

I think you need to have a more in depth conversation. What about cavity trays, maybe cranked solum vents, weep vents, return corner details, some lead flashings, maybe working around some steel beams etc.. all the tricky bits that take up time. Going on a sq m rate for something like this is maybe not quite enough. Also sound out.. I'm a self builder. what happens if someone else lets me down.. will you cut me some slack? how do you see that working if there is delay etc? Your starting point is to say.. hey I don't mind paying a fair rate.. it's just I need to know how we deal with reality on a self build.

Good question to ask. My own view is that it is healthy for your builders to query the design and I can see why they / et al ask as using a column (UC) section as opposed to deeper and narrower universal beam section (UB) immmediatly flags up.. why is the SE doing this? It is a long span and other posters are making suggestions as to alternatives. But I'll go with your SE and that makes me think.. why the UC or not say Glulam etc. I suspect that at the top of your stairs you need 2.0 m head clearance and the SE has struggled to get the structure to fit within the Achitectect's envelope that is available for structural members while maintaining BC compliance. Thus to make the structure work within the given envelope the SE has had to use a UC section that is inherantly less efficient for this application in terms of steel weight and assocaited conection cost. You'll see on the drawing you posted that there is a splice in the beam stated at 1/3 point. At 1/3 points there is often still a fair bit of bending force in the beam and that can add to the connection fabrication cost. I try and go for 1/4 in for the end splice as the bending forces are less and can simplify the bulkiness / cost of the connection. Now I mentioned the connection cost. If the connection requires a full strength weld (full pen butt weld) then some smaller fabricators need to get an inspector in to check the full pen weld .. this can add £300- 500 quid to the cost of the steel on a bad day! Or you can go to a larger fabricator who may get the inspector in at a lower rate or have in house staff who can do it.. but you pay for that in house service.. So you need to ask the question can we go for a 1/4 splice (with simple fillet welds) and also ask the Contactor if they can lift a 3/4 length beam instead of a 2/3 length beam. If so what is the steel price now? Sometimes DIY / BH folk get a steel price and wonder what the difference is.. it can be just down to a connection and the way it is specified / welded up on a small domestic project!

Good first try but I think you're out of your comfort zone here. Flitch beam design is a bit of an art and to execute this well you have to have a good understanding of how the timber, steel and bolts interact and the support conditions. To put it another way.. this sort of thing is not taught to graduate SE's doing a masters course at uni, it is a bit of a specialist subject. Personally I like a flitch beam as they can be an elegant solution.. they are a bit "old school" but there is a place and a time for them and they can really suit the self builder / small Contractor, good for you having a look at this.. but it needs refinement.. well probably quite a lot! Yes you can get Kerto beams etc off the shelf but sometimes they don't have enough poke unless you make them bigger which defeats the purpose. What you have drawn with the steel off the centre could introduce twisting effects not least.. to be avoided. The easy way it to centre the flitch plate and use timber packers to frame out the beam. Sometimes the makes a void that you can stuff a bit of extra insulation into. At my end if I find a bog standard timber lintel isn't working I start to work my way up the timber grades. Ok we have C16 and C24 grades of timber. But a lot of Contractors I know are buying in prefabricated roof trusses and the truss folk use TR26 grade timber. Often I'll have a word with the Contractor and say... look we need 2/ 3 lengths of TR26.. get that tacked onto the order.. also a good timber merchants can rattle this up and buy well using their clout if it's part of a larger order. It may be that if push comes to shove TR26 could work rather than introducing a steel plate and the bolts.. the bolts heads clashing with other stuff etc. Now if you find say TR26 is still not enough then you can go back to C16 but 63mm thick with a steel flitch plate.. this helps centre the flitch plate.. makes the twisting often go away. Your 190 deep timber is pretty standard but you're 5.0mm out on the machined size.. normally the actual size is 195 deep for the C16 and C24 grades. The TR26 sizes are a little different so watch out for that as the sizes are "bespoke" to the truss folk, not much mind but just be aware. In terms of buildability... don't have the flitch plate on the outside.. bury it in the middle of the timber flitch beam and leave timber on the outside as this is much easier to fix other things to! Yes, can't say much more at my end either until we have an idea of the load the beam is carrying. Mr Punter has highlighted an intrinsic and key point that is in the design code. The timber shrinks, the steel plate doesn't so that is why we make the steel a bit less deep (aim for 8 -10mm) than the timber. So it is the timber that bears on the support rather than the knife edge of the steel plate. I mentioned earlier that flitch beam design is a bit of an art! Now buried in the design codes and design guidance is a tiny bit that says you need to check the grain of the timbers each side of the plate for the grain direction / orientation. If you have a timber joist often they way they are cut leaves timber on one side that is younger so it shrinks more than the older timber on the opposite side of the vertical face.. this causes the timber to "cup". For a flich beam with the plate in the centre you put the inside bit of the tree on the outside away from the plate so it cups away from the middle. The bolts on a flitch beam are staggered away from the horizontal centre line so that when the timber cups it doesn't split along the midline. Takes a bit of getting your head round all of that! Ok to sum up.. Don't be put off by my technical comment.. rather.. think about it from a buildability point first, material cost / time, who is going to do the work and how you are going to fit insulation / plasterboard to what you have.. I kind of hope you're going to do this yourself as you have taken the time to think it through.. and you'll probably take more care and end up with a better job than a Contractor would do.. the result is you'll get do something that is supposed to do what you intended for the money yiu have spent. Hope this helps.

Agree with George above.. I would look at the benefits of a box frame before ruling out.

Help ma boab.. looks like I have had an IT breakdown and posted an unedited version and a woke one for the faint hearted. Never mind.. if you dont like one read the other. Any complaints PM me and I'll sort it out. BRE Digest 251 Assessment of damage in low-rise buildings.pdf

Hope this helps a bit. Have attached an old document that explains a bit about structural cracks. Have a read.. it will be the best thing you can do. Before you attribute all the blame to the tree you need to look at other things that could be exacerbating the problem.. it may be that you can address these and leave the old tree to do it's thing. Often this type of solution just transfers the problem to another area as you create a stiff point that doesn't move so the movement happens at the end of the stiff point and often makes things worse. With this sort of thing I think.. ok things are moving about.. many historic buildings behave this way but is the building a safety risk.. going to fall down? If not then let's see how we live with it moving about and do something that reflects that. Internally we can force the movement (once understood to say a shaddow gap in the interior decor, externally concealing by some clever movement joints or say a planting trellise.. with maybe some careful cutting of stress relief joints.. first let's to see if the whacky and sympathetic ideas work first before going the full Bhunna / sledgehammer to crack a nut. Structurally we maybe want to do some flexible ties that lets the thing move but not fall down in the wind.... here we are saying.. yes it needs some bracing to deal with the movement. This could even be some tensions wires like you see on sail boats.. that can work well if you want to give a room a Nautical feel or something more contemporary. As a rough guide a 6.0mm stainless steel tension wire with some connections to the wall will set you back say £500.00 quid, wire and turnbuckle / fork end is about £150 then the builder and resin anchor fixings takes you up to the £500.00 quid. I would dig well into my box of tricks before considering cutting down a tree like that. Once you cut the tree down there is no going back. I suppose it boils down to this.. are you happy enough to live with the tree and enjoy what that brings.. shade ect, a bit of life that attacts nature and in doing so accept that you have a bit of semi concealed movement inside and out or do you want to have a house that does not move and sacrafice the tree? If you go abroad to say France or Spain or other parts of Europe.. their houses move all the time.. in the UK we tend to worry more! You mention you concern that things may get worse. But if the tree is that old is it going to grow much more and the root ball expand? .. why not just say we are all of a certain age and lets live with each other.. as we get older and wiser? Be careful though as if you cut off one source of nutriants that old tree could get a dose of Viagra and send out other roots that may cause you another problem! Did your experts tell you that? BRE Digest 251 Assessment of damage in low-rise buildings.pdf

Give me a call on the phone or PM me. You find my phone number on the internet, text me first so I know it's you as I'm a bit deaf as in deaf as a post. Happy to spend 10 min having a chat. Any spammers.. every day is a school day..

Bit of an IT disaster at this end as I keep loosing what I have written and folk I have quoted. @Thorfun thank you for the kind words. Yes busy with the day job here, also my Mum is 92 and has just bought a house close to me so trying to get that in order.. Have to say though BH is great, love learning from others and seeing new folk coming on board with new ideas.. younger folk willing to learn, older / experienced folk passing on knowledge and adapting what they do know to the lastest ideas from new members etc, also older folk revisiting what we thought was ok in the past but maybe less so today as materials, fixings and analysies techniques evolve etc. There are good few professionals on BH that do this sort of thing as a day job like myself... Contractors, Designers and folk that have other technical background.. I appreciate their knowledge and will be the first to say.. thank you all.. as I have learnt a lot from you all. @Thorfun Have had a look back but can't find it just at the moment. I've tried to google it but that post is not coming up. From memory it was basically showing how the forces in ballustrade fixings can be pretty high! I've had a quick look through the thread. Lots of good technical comment from you all which I appreciate, it makes me think also! Earlier today I turned down a job for designing and doing the steel detailing for some extra stairs and landings for the Glasgow Hydro Arena (~15k seat capacity) as I don't have time to do it. The main thing that stopped me from doing it was the time you need to spend coordinating all the fixings and checking that everyone else involved in the process knows what they are doing, they often do within their field.. but have no clue about how the design works holistically and if it can be built safely and in a cost effective way.. Here it gets dangerous in terms of safety, that also means you in a domestic setting. It is also a big business risk for me as there is mention of collateral warranties. This means I can do say 10k of design work and steel detailing but expose my insurer / myself to a disproportionate claim.. excuse the spelling. It's not that I'm being difficult.. I'm just doing what I was trained to do..initially as a Civil Engineer.. which means I have a social responsibility to society. I mention this above as in the thread folk seem to think you can swap one fixing for another or change the principle of the design even if they are of the same diameter and length the ductility of the fixing may be different and thus could behave in a diferent way. I think there was a suggestion of fixing through the flooring.. but the flooring needs to be able to move about a bit.. so you no longer comply with the flooring manufacture's spec..let it move about.. no point in complaining later that gaps have appeared in your expensive flooring if you have clamped it at one end so you can get your ballustrade fixings to work. I think there was mention of fixing into the tops of posi joists etc. But if you are introducing significant forces (particularly bending forces) into these then you void the posi joist warranty as I'll guarentee you'll compromise the web etc connections..not least in terms of your nail / bottom track fixings but also nail their plate teeth connection and edge and end spacing. If you don't believe me phone up the manufacturer! Now I may seem like I'm ranting a bit but just say a BC officer asks the same question? For me.. I can see that lots of folk are face with the reality of the self built / renovation market. Fundamentally there is a lack of designers that are avialable to guide say folk on BH. At my end I win work by saying to Clients.. yes I may be on the face of it be a bit more expensive.. but I bring a lot more to the table.. One thing I do do is to sit down with my Clients and find out what they know.. I'm often surprised just how much they do know but just need someone to put a bit of structure to it all and give them a bit of a confidence boost! In terms of the OP. Go back to basics and try and simplify the problem. Fix the primary structure to primary structure and make sure the primary structure won't twist. If it does you'll end up with a bendy handrail etc. @Thorfun I've not look that closely at your detail as had a horrible day trying to sort out a parapet detail.. will try a bit later to see if I have any suggestions that you can chew over.

@George.. What is your gut feeling on this one? Do you fancy stepping up to the plate? Unless the SE et al has been paid enough to the design and detail job properly it is not going to work out well.. you know it.. I know it! The Architect has to sit back and let the SE sort it out. For all..there is no point in trying to hide behind fact. SE's like us have been cowed in recent years... the result is that out Clients are not getting a good service as we are not sticking our guns. @joe88The SE needs to get their arse to the site and make sure it can be built at a reasonable cost if at all? And the Client @joe88 needs to understand the financial risk of not doing so. @joe88 Please take my advice.. you won't lose anything from testing my views but you could lose a lot if you don't. It may be that you need to pay more. I'll direct you to Ruskin here and hope. Quote below. The below was written a long time ago but still applicable in the modern age.. I see this day to day where folk are get ripped off.. it's getting worse not better. The professionals that are supposed to be helping you are more concerned in covering their arses. I stick to "old sckoool" stuff and have a niche market but my fees are higher.. but in the round I always aim to save you more than you pay me and will ensure your house is safe to live in. Ruskin mentions "lawful prey" take note! There is hardly anything in the world that someone cannot make a little worse and sell a little cheaper, and the people who consider price alone are that person’s lawful prey. It’s unwise to pay too much, but it’s worse to pay too little. When you pay too much, you lose a little money — that is all. When you pay too little, you sometimes lose everything, because the thing you bought was incapable of doing the thing it was bought to do. The common law of business balance prohibits paying a little and getting a lot — it can’t be done. If you deal with the lowest bidder, it is well to add something for the risk you run, and if you do that you will have enough to pay for something better.” @joe88 this is part of my day job so I'm not shitting you!

Oak shinks less than soft wood. Thus if you have an oak frame it is not "scary" ! All you need to do is identify where the shrinkage will take place and detail for that.

Advise you don't do this.. you'll make more of a mess and it is not worth it. Find a local digger driver who knows what they are doing and is used to working with your soil type. Pay them well and they will give you all sorts of other tips about drains etc.. the founds and with a couple of bacon rolls even more. They could also tell you what ground workers to avoid and who is good locally. I love working with local digger drivers etc as they are doing this day in and out.. they hear what past SE / Goetec Enginners have been telling them and can "feel the ground and see" with their machine. Why not rely / take into account on their local knowledge? It's a no brainer for me! I always want to work with an experienced local machine driver when doing say trial pits or doing founds.. they have saved my bacon on occasions! I know you are thinking you may make a saving getting a machine yourself.. but look at this holistically and the advice you may get.. also you'll get a found in the right place. Digging founds is not easy as you have have a digging strategy.. so you don't box yourself in. Also if you want to have a go yourself then there is a soil bulking factor.. what you dig out grows a lot and if you don't stockpile it properly and seal it ( a skill) then later you'll have a harder job to handle that.

True story and I have the calcs / drawings to prove it. I did this job for a company who renovate supermarket trolleys. They build big new shed and we had to limit run off into the local water course, from memory it was 5 litres per second. We designed some storage capacity (attenuation) to hold the water and let some of the pollutants settle. As they could weld etc we fabricated an orifice plate.. a bit of metal with a hole in it. But for this to pass EA / SEPA you need to screen it.. we used the old trolleys as a screen and put in place a maintenance schedule (also good to present).. it all passed and happy bunnies all round. If you have a look at the cost of a Vortex flow control valve.. you'll see it's a possible cost effective option. Hint.. next time you are shopping take the trolley home.

Worded that the wrong way.. there are plenty competant Contractors.. this was a new one. @joe88 A few things that would help a lot would be to get some gridlines on these drawings so we can see how things line up. I would say this to all budding Architect's.. put some gridlines on your drawings when sending to the SE, the builder, QS etc. If you don't it just wastes all of our time. Your job (Architects) is to communicate essential information in a way that is easy for others to follow, it's a skill that you need to develop, oh and it's good for self checking drawings. On the other hand SE's, QS etc need to reciprocate. A lack of gridlines demonstrates etc that either you don't care or don't know what you are doing. @joe88.. it still looks a mess. Are there some existing walls under the line of B1 and B2? Your image of the existing ground floor plan seems obscured by the side bar? A lot of folk say that a box frame is more expensive.. in terms of steel cost.. it can be but on a job like this it may not be as it adds stiffness that saves beam weights, reduces connection costs, makes it more buildable etc further up. Your SE says you need an extra bit of found.. trench... but.. why the beam B1 & B2 in the first place? To be honest I've not spent the time trying to line stuff up on your drawings and trying to second guess. If you have some existing founds the soil under they will tend to be more consolidated (more bearing capacity).. say each side of a window. The bottom of the box frame in the middle of it's span tends to act to stiffen the structure above in terms of.. in layman's terms the bottom member of a box beam doesn't put that much load on the ground near the middle of the span.. hence we may put crawl holes here for solum space access and ventilation. I mention ventilation as it is a classic bit for getting tripped up by BC. Just glancing again at what you propose.. Column C2 is to be bolted to the wall with resin anchors.. does anyone know how that work will be sequenced and how the steels will be measured by the Contractor so that it works and can be built? Beam B9 spliced at third points.. would be interested in seeing the welding on this connection and associated cost. My gut feeling is 20-25% in from the end of the span so it becomes more of a shear type connection. and thus cheaper. If you see anything like "full strength weld or "full pen weld"" annotated on the drawing then that needs tested. It could add £800- £1500 onto the cost of the steel if a small fabricator has to get the inspector in. The third splicing rule is always a flag.. could be a lazy Engineer and is worth examination.. or could be due to getting say beams into a confined space. A lot of folk say that a box frame is more expensive.. in terms of steel weight cost.. it can be but on a job like this it may not be as it helps stiffen every thing above and reduces the associated stress and deflections. I could go on but you have a complex project that is fraught with difficulty. From experience you could end up paying for things that won't get built on site. It all could end up in a massive argument and spoil the enjoyment for you. Before I was an SE I was a Contractor for 20 years so can see this from both sides. If I was you I would start talking to Contractors and finding the ones that know their stuff. You can then feed back that info to your design team. Even if you offer to pay a Contractor to visit you it will be well worth your while. I'm sorry if I come over as a bit harsh but it's worth grasping the nettle now. On a job like this you will need a lot of details.. fixings./ guidance notes that tie in with the Architectural side... so you get what you are paying for.

We all start out in life / DIY .. being a builder knowing not a lot so you're not alone. I still learn something each time I come on Build Hub. A good wall paper paste that is designed for sticking to say a vinyl wall paper or similar surface is your starting point. In terms of tools. A bucket, sponge, a wide brush and a sharp pair of kitchen scissors.. the most important thing is to read the instructions on the wall paper as the method of applying the glue changes. Don't go sanding it all down in case you later change your mind! Just one last thing. A roll of quality wall paper comes with a batch number on the label inside the roll. Photograph that in case you later want to put more of the paper elsewhere.

Take a pragmatic view. You want to build a house and by doing so you stop the rain from slowly permeating into the ground in a natural way. If you cover the ground with a roof then water runs off quickly and that can flood houses down stream. Thus get your head round the fact that you can't morally, not least, do this. Now 2.0 litres per second equates to 2.0 x 3600 /1000 = 7.2m cube per hour.. which is actutally quite a lot of water off a domestic roof. over say a period of an hour. My question is how big is your roof and how much water are we talking about. You may find that this is easy to comply with. If you can tell us how big you roof is and where the site is then some folk on BH may help you out.. but recognise that it takes a bit of time to do this so a donation to BH may be in order..

I maybe need to take a hit on this one as had no idea that there was so much stuff going on above and the loft is getting converted. I'll eat some humble pie as promised. I'm minded to make a box frame at ground floor level.. after that.. the drawings just show some beams. The box frame at ground floor will help what is going on above. In terms of buildability and cost I can't say anymore other than.. You MUST get your SE to site, let them take their measurements and open some stuff up, your SE needs to put forward a buildable, sequenced and cost effective solution to this. It's not the Architect's job nor the contractor's job. A job like this might need 20 drawings with details on each drawing. You then may want steel fabrications drawings.. a full set of these add another 25 -30 drawings that go to the fabricator. A fabrication drawing package has drawings that show all the beams with the bits welded to them. These are often called Assembly drawings. To make up an assembly you often have a beam ( say called a shaft) so it has its own drawing showing holes ect and then you have plate drawings ( the end plates / stiffeners etc) Thus each assembly has sub drawings. Now all of that may cost you say 6.0k - 10k plus structural calculations. But if you skimp on the design information (that forms the contract) and you lose a week on site for three men (2 skilled + 1 labourer) that could cost you 2.5k.. now you can maybe see the value of the professional service? On the other hand you can produce too much design information. Contractors are people too and if they think they have some nutter of an SE / Architect overseeing the job they will just add on more. It's a people business also. You'll maybe need to pay the SE more and if they don't engage and it becomes apparent that they have no idea on the cost /buildability of things then need you then sack them pronto. Yesterday I went to a job and met a highly competant Contractor for the first time.. say @saveasteading they vetted me (as an SE) just as much as I vetted them! Get a good builder / contractor to meet with the SE and let them fight it out while you watch, listen and learn.

Good advice. You should get an SE to come and have a chat about this as it could really drive the design. It may be that if you add on a bit which will add further sideways wind loading then that could be the straw that breaks the back of the building. On the other hand if you add on something that contributes more to the stiffeness of the building then that could be a good thing. Get an eperienced SE or someone that understands the forces and go from there. An experienced timber frame designer will also know about this and the pitfalls and long term performance.

To refine a bit you can buy tubular beam spacers off the shelf. See link say below. https://esteels.co.uk/structural-steel/universal-beam-twin-chs-spacer-touching-separate/ But often the walls don't have a consistent width of cavity.. good design when say knocking holes in walls is about anticipating some of the things that may not be built the way you think they are and generating as many "get out of jail free cards" as you can. The next stage is to note this on the drawings so the Contractor who is pricing the job can see that someone has put a bit of thought into it and tried to derisk it.

Great tip! Very obvious once someone explains it so simply.

Copy and paste your post to Masons Mortar of Edinburgh and take advice.. these folk know their stuff! Off my own bat. The stone you have looks like much what we encounter down the east coast of Scotland.. not well "sedimented" sandstones or more likely "conglomerate" in other words they tend to not weather well. These houses were built by the gentry for workers, they were not good quality. You need to get your head round the fact that these houses are what they are.. they were built as cheaply as possible for the land / estate owner so they could extract the most they could from their workers.. they are basically shite structurally / in terms of workmanship and let water in! Get it out your head (if you have had that thought) that they are quality buildings...they are not. @Tapster my post is encouraging later. You are trying to now make a silk purse out of a pigs ear!. The Scottish gentry lived say in Edinburgh / Glasgow and built in Ashler commonly ( oh! yes it was the Scots taking advantage of their own! nothing to do with the "English" or the "Welsh" or the "Irish" it was a "big boy" that done it and run away for those who are seeking factual history) .. faced sand stones.. the best.. I'm happy as an SE (and have done so) to convert these Edinburgh Ashler buildings all day long.. You'll see this in most Fife and Ayrshire coastal towns where the middle of the stone has weathered and the mortar is sticking out and that just drives water into the wall. Sometimes with a bit of thought you can recover the situation and live happily ever after. You need lime mortar.. you'll see often recommended a NHL3.5 lime mortar, bin that idea and go for a NHL 2 lime mortar which is supposed to be used for internal work only. But on this type of stone it's the angle of the pointing to shed the rain outwards that matters and acceptance that it needs regular maintenance. The idea is that you use a soft lime mortar that erodes faster than the stone.. you maintain that.. like cleaning your gutters. Eventually the stone will erode and need replaced.. hopefully it won't happen during your tenure.

Great to have you chipping in. You may get a bit of slagging off.. but just stick to your guns. Stick with it. BH can be great fun and rewarding if your are happy to give pro bono advice. Gus