Gus Potter

You don't need to. For all: The following assumes you are not in the building trade, have all the advantages that that brings. It's intended to appeal to folk on a budget, possibly first time self builders that are willing to learn and invest time. As I've said before, in the old days self building was a great money spinner even if you were a complete idiot. Property prices were achieving a year on year 10% at a minimum increase in value. Thus on a two year build the land just alone would increase in value. The game is changed now. For a while it worked where you could go to a TF company, say Scot frame etc, AFD foundation design were doing a lot of really great stuff, Tanners Structural Design were chipping in etc. for example and others for "work packages" and it still stacked up, the profit was less for the novice self builder but still worth a go. You still got a return from "managing the project" One of the main problems I see at the moment is not just the regulatory stuff (Planning and BC), it's actually the idea that you can put different work packages together without dealing with the interfaces, where the hidden cost lies. We could describe this as "day works", expensive! The "work package" providers are now taking too much cream, there is little left for the self builder, and the risk remains the same. Designers are certainly not helping. Few if any take the time to help you coordinate, some of this is bad practice, but also, there is tendency for folk to think good designers are like washing machine engineers, we are not here to fix your washing machine. In the round all the cream is taken out the project before you get a shout. One fundamental key to a good self build is to not pay too much for the land. A while ago you could buy a nice flat grass plot, easy services and so on. But these now are less attractive as they command a high price. What is attractive is a cracking site, great views, but brown field. In other words maybe a bit contaminated, hard to service for example. if you crack that nut you can get it cheep. The big developers are not interested, your local builder with say 10 men is not interested as they will have to pay for professional advice, they look for the easy route. This puts you in a pretty good negotiating position if you can identify what's wrong with the site and explain to the seller, this is is a good offer I'm making, and here is why. Now just say you could get a 100k plot for 70k by explaining to the seller, you are selling a pig in poke. To do that you need to just bring forward the professional fee advice. It's not going to cost you the full whack, an advisor may give you this advice for under £1.0k. My own view is that it's now time to go back and consider old school stuff, say getting local ground workers in to do the founds, joiners to stick build the TF, slaters for the roof. You buy the materials, you then own them, eases cash flow. I think this can deliver a good bit of profit! In summary I do think self build can be profitable, we just need to go back to old school stuff and the basic laws of business. But adapt with a view to say modular construction. @Square Feet has some thoughts on this in fruition.

Possibly not! Have you commissioned and run your UFH for a few weeks? If I was working for the flooring contractor I would be aware that the underlying structure also has to condition, move about a bit, it's not just the screed. They are just getting paid to lay the floor? But maybe being sensible. If something goes wrong then think about it from their end, put yourself in their shoes and work back from there. They could be faced with a massive hassle trying to prove movement is also related to the structure and not their fault. To be blunt, the suppliers of flooring and the installers have so many caveats, not least min and max floor temperatures, which are hard to achieve when you have congestion of UFH pipes. Sometimes you have to make your best guess. Anticipate where movement will occur in your particular self build and lay the flooring accordingly. To make things a bit harder, it's often the summer that modern highly insulated TF house expands as the UFH heating has been off, particularly if on say a concrete slab, this is counter intuitive!

The soils are just above the plasticity A line, not much to worry about. Lots of rafts get designed with an L shaped building, we design joints for this and make sure the super structure can cope with anticipated movement. The allowable bearing pressure is good at 115 kPa, a standard benchmark of 100kPa is a good comfortable reference point. Where does the water table sit? You probably need to post the full SI for the best feedback, there will other stuff buried in it that you may not have the experience to be able recognise it's importance.

You did, no offence intended! I layed in a bit as AI is more dangerous than not if you try and get it to do SE stuff.

Great post, very informative!

Now by now you should know that there is no way any of us that can take a punt on this. Post your geotech info, a site plan etc. You know the rules, the more info you provide the better quality response you'll get.

Reading a lot of these posts it's pretty clear that that many on BH don't have a high opinion of folk like me who design as a day job. I can see many professionals have lost their compass and are not delivering value for money and are not that good at running a business, hence the poor service delivery. I've been in the construction industry for over 40 years, 20 spent as a contractor running my own business' , did my own self build, really pretty much all by myself on the tools ( took me three years) then off to uni to be an Engineer, now for the last ten years I wear two hats as an Engineer and Architectural designer. Thus have a fairly rounded view of the in and outs of this. I can say that in the last 20 years there has been a race to the bottom, not just from designers, but also say the timber frame suppliers, ground works designers ( UFH and rafts etc) and designers who think that if they curtail their design brief, caveat it a lot the money is going to flow. But in the long term it doesn’t, as often the key to good business is repeat business, recommendation, even in the short term cutting you brief down often leads to problems, queries, design mistakes that just eat into your profit and leads to potential claims or Clients rightfully withholding money. Ok, lets look at some financials. The bottom line for a new self builder ( not someone who works in the trade with contacts) is the tendency to split each element into work packages, say foundations, timber frame and roof ect. Each package supplier takes the cream out of the job, leaving nothing for the self builder. Then you have planning and BC regs on top not least, that all adds to the cost. I work on a lot of projects where I'm involved holistically. I work very closely with the Client, not just as a designer but also do hand holding and participate in all of the design. Now to be blunt. Say for a self build the design fee is £10k. An experienced chippy ( joiner may cost you £250 a day, a labourer £150 as day, total 2.0k per week. All I have to do to wash my face is to save you a few weeks, just on the labour alone and I have well and truly washed my face! The pendulum is swinging back where folk are clocking that we need to "go back to the old days", but now you need someone like me who can cope with the modern code requirements for example, and the modern way of doing business., much less trust and more hard arse stuff. I get this kind of business where folk are happy to pay me a bit more as I can guide them, hold their hand and most importantly we all have fun, we do whacky designs that you only get to do on self builds! We also tend to avoid " work packages where we can, say from MBC et al and keep the cream to ourselves. This also often helps cash flow and gives the Client more control on day to day site activity. Now in the round if you want to make some money then try and find a designer like me that is local to you, with good contacts.

In my day job I sometimes ask AI for it's calculations for a bit of fun! A lot of the time I find it's completely wrong! I checked a beam design against AI and found it to be a factor of ten out, on the unsafe side. One of the bits it missed was the destabilising loads ( an unrestrained load applied to the top flange) loads, the lack of adequate lateral restraint and the support conditions, all that lead to is being miles unsafe. Now AI aggregates information, you could have ten undergraduates all uploading their student projects and AI thinks.. this is right, but it's dangerous bollocks! There is good reason for BC to reject you! If you want to use AI to generate calcs then you have to be competent enough to make sure it's not rubbish. By all means use AI to do the donkey work for you, but unless you know what you are doing, have the knowledge to understand what the calculations mean then you are an idiot!

You know the answer don't you! You have two choices, let the render progress, but the window frames may not be fully sealed. In reality, have you checked your window contract fine print as to what length of guarantee you have on the glazing units. If you use good mastic the frames should be ok..pragmatically. But again look at you warranty, often now the sealed units are not warranted for the same length as the frames. If you get a failure in a sealed unit your warranty may be rejected if you have not fully sealed the surrounding frame. There are no friends in the desert these days, check the fine print on the window warranty!

In the"old days" A first time self builder with no experience could save at least 15% on the build cost of a house. Now in the old days the market was rising, thus the value of the property also increased by on average, say 10%, over say a 2 year build time. You had to be a complete idiot to lose money on a self build. So even if you were not that good your self build could return a tax free return of up 25%, but nine times out of ten you would not lose your shirt. The market has changed a lot. @saveasteading who has decades of experience pointed out.. and I agree, much of the profit for the volume builders now lies in the land transaction, the actual building of the houses are not the main profit element, the house building is just a means to and end, basically a bit of a hassle! Now if you buy a serviced plot on one of these serviced schemes, the seller (developer) has already taken off the cream of the profit, you as a self building then are looking at marginal profit, but carry much more risk. Self building in this case is not going to make you lots of money, it may give you the house you love though and if that has value for you then it's viable. Now say you do a house that sells for 300k. You'll be lucky to clear 20k after all the taxes etc if you sell it on , if your motive is to make money, you'll have to risk dealing with a builder, a huge amount of personal time.. etc.. the reality is you are likely to be better off if you just do a Saturday morning shift in Aldi, you may even get a pension contribution! I've had the good fortune to talk and meet with @Square Feet who has some ideas about how we get back to making self building more attractive, not least financially. It's early stage ideas, will take time to develop, but looks promising. The reality at the moment is for your average self builder the financial risks are high vs the rewards. There are still a good few very well off self builders who don't really mind if they make money of not. But the whole idea is to encourage young folk to self build and improve their financial health which results from their own hard work. But as above.. it really is the case.. you are better off at times doing a Saturday shift at Aldi!

Your proposal invites discussion, that in itself is healthy. I think it's fair for you to ask the question, most of us on BH won't take a negative view of this as you are exploring if you can benefit the self build market, and if you can make a living out of it and a bit of money then your are justified, a fair days pay for fair work. Here is bit of context and bit of my background. The first 20 or so years of my career were spent being a builder, some of that was building houses for self builders. I had generally 6 -8 full time staff then sub contractors. Depending on the time of year I may only have had four subbies, then at times up to about twenty folk working on one site. To keep them all working I would normally run one big project and say a couple of extensions, attic conversions at the same time. This allowed me to manage resources, deal with changes, cash flow, maybe planning and BC delays. You should be pretty familiar with how this works given your background. When I got to near 40 I could see the writing on the wall personally. My wife and I parted, my German Shephard died and I was left living in my lovely self build on my own with this huge weight on my neck of the business and my duty to my employees. I shut the business, paid all my staff the redundancy, phoned my competitors, told them I was chucking in the towel and pleaded for them to take my lads on. Some did! Now I also squared up all my builders merchants.. some told me, even my accountant.. you are limited Gus, if you walk away you'll be at least £100 - 200kk better off. But I paid the money as I knew my personal reputation can't be valued. Now I was lucky as I sold everything just before the 2008 crash. I then trucked off to university to become a Structural Engineer, graduated, trained and now my consultancy is in October this year going to celebrate it's tenth anniversary. But part of my success is my contacts from the old days! I am still in contact with my old suppliers, they give me names of good creditable builders, as they remember I squared them all up. One of my ex employees is now a BC officer in my local area, his wife, who used to inspect some of my project is now a Senior in BC. They are consummate professionals and remember me as "not a chancer". In summary, my own view is that if you want to build a sustainable business in the construction industry it's going to take 5 years living on the edge, another three years to stabilise, it's really only in the last couple of years that I've felt I've arrived, lots of repeat business and a huge amount of experience under my belt now.. 40 years! Ok, the above is not a rant.. it's intended to let you see there is no fast buck here in the construction industry. Developing an app is not going to work long term, unless you have lots of contacts and an already established business that brings in the bread and butter. Let's say you are digitising and facilitating via an app the procurement and build process, that's just using modern tech, the game remains the same and the profit loss sheet still stacks up the way it pretty much has over the last 40 years. The tek has changed, but the fundamental principle of turn over is vanity, profit is sanity has not changed, you may also want ( I suspect you may not) but just look at Ruskin the common law of business. But the bottom line is that it looks like you want to project manage, use your QS skills.. with a fancy app. To make a living out of this, you need do the basics very well, get repeat business, you'll need to have lots of contacts, cash in the bank, be legitimate, have insurance etc, and be very good at what you do to be able to justify your 10%, your app ain't going to cut the mustard, the app is your potential cream, your USP that delivers that extra profit. I think you need to have look at your business model in term of the app. But if that stacks up for you then it would be welcomed by not least myself and folk on BH.

Great post and lots of info, well done you! Spend time finding the right SE, that has deep knowledge, is pragmatic and understands holistic design. That means they could swap hats and be an Architect not least. An SE like this is going to cost a bit, but it will be the best money you spend! SE's like this also act as an advocate for you, will hold your hand and guide you through all the other regs and sorting out a builder etc! Try and find a local SE, not me! as I'm too far away from you to be able to come to site on short notice, not least!

Thanks mods for removing my drawings with the Client info, you have saved the day at my end! Reposted below, redacted:

Here is the roof plan. I've screen shotted it, you won't be able to read the detail but can see the shape. Each cold formed cee was a different size, but cf providers can handle it provided you give them a schedule. All for £1552.00! The schedule looks like this, but if the walls are parallel then it is much simpler as all the cees are the same length. I would explore using cold formed joists, creating the fall can be really easy!

You'll only learn this kind of nugget stuff on BH from the likes of Nick. You may think.. well I'm not going to let the floor socket "take a drink" but.. The spark may also want to change the cable rating anyway as it's not say in a wall. Electric cables are sized partly on not just the load but also if they are surrounded by insulation, or near to say UFH. Fundamentally we don't want them to heat up too much. Thus what Nick is saying also make sense when we look at the electrical design holistically, and that can save cost later on. Thus, why not adopt Nick's suggestion, as the spark will insist that the wiring up to the floor socket is to spec anyway? It's just that last nuance that Nick is bringing his experience to bear.

I appreciate your desire for level and diligence. Have you considered. If you have an existing house. How level and undulating all the other floors are? If a new house then it is going to take time to bed in, settle. To provide a bit of context. Often as an SE I'll start by designing a house to settle no more differentially by 25mm! Then refine depending on the finishes and how tolerant the structural frame is going to be in terms of differential settlement. A Swedish log cabin might shrink by 75 - 100mm! I would give the floors you have laid so far a "walk over test" not by you, but by visitors. Ask them if they notice much level or issues with flatness. Glancing light is always going to show up even tiny changes. This is building, not eye surgery!

This is really a bugbear I have with folk who are less experienced Architects, it's even more of a wtf are you doing with Architects who are set in their ways. I wear two hats, SE and Architectural designer. Design is about communication of information not least. At concept design stage if you stick on a grid it lets everyone see how the floors and things line up. On BH most folk don't have access to say CAD or more complex design packages where we can overlay floors etc. It lets us all see what goes where, get a rough handle on things and communicate well. If there is a grid we can say, say on teams, go to grid intersection 2A, and a bit to the left or 300m up on the drawing, there is no dubiety and that stop wasting time trying to identify what part of the drawings we are looking at, it avoids error and folk getting frustrated. Later when we come to the detailed design a grid is essential to allow the builder to set things out. Why not start with a grid at the beginning, grids help reduce error! Now Architect's like their drawings to look good, when I draw stuff in cad I'll change line weights, emphasise at time depending on whether I'm trying to show a Planner, a checking Engineer or how the kitchen may look to the Client. Funnily I work with quite a few highly experienced Architects, they have embraced my suggestion for putting grids on drawings! It's the future! Architects.. For pure visual presentation, just turn the grid layer off and stop being so precious.

It is. The reason behind it is that the building loses a lot of sideways stability. The steel work is also designed to stop the building falling over sideways. This is often the main challenge as an SE, not just to hold up the vertical loads but also to maintain sideways (horizontal stability). You also need to maintain your thermal breaks / mitigate thermal bridging etc. This makes the SE work harder as in the old days we just tied everything together! That all has to come together and then needs to be detailed (just as important), with the propping sequence thought through, so it's buildable by an average (hopefully) competent builder at a sensible cost. I deliberately put lots of detail on my drawings where I want to explain to the builder what is expected of them and thus by inference what they should include in their price.

Good link. My own view is that the glue, if the right glue is going to out perform the timber. If you take a structural glue, like Cascamite, invented about 1940 it's well proven. It's relatively cheep and easy to use, just keep it out your hair, arms etc! You ain't going to get it of with a bit of Fairy liquid! Sometimes I want to glue stainless steel plates together, here the glue is a bit more specialised, maybe @Alan Ambrose may chip in. Buckland mention the end grain. The critical bit is to make sure the end of the cut timber is treated. But I can tell you that 99% of the time on site the joiners cut a bit of wood / trim Gluelam and don't treat the exposed ends. And then all the theory turns to manure! It's good though to see Buckland investigating this, it can only help inform.

Always helpful Thus the rebar has to have adequate cover and be surrounded by well compacted concrete. This concrete is at the start of the next lift, well down the shutter. Very difficult to achieve. The only reason for continuous rebar between floors is if you have particular fire or disproportionate collapse requirements. Less onerous on the standard ICF build. In fact.. if you add rebar into the ends of Hollocore slabs and tie that into the external walls then you start to create a moment / partial stiffness connection. You then introduce an extra bending force into the walls, thus you need to design for that, it potentially causes problems with concrete core thickness. Disagree, a lot, not really applicable to self build when using ICF, you are mixing up platform and core lifting with ICF which is a different animal. If you give your Hollocore slabs full bearing on the ICF core (say 150mm) then this often satisfies the tying requirement on a low rise buildings, like self builds. My advice stands. Recognise that on your second ICF lift it's going to be hard (impossible actually) to get adequate concrete compaction at first floor level when you have to get the poker all the way down the base of core if there is more rebar congestion. Keep it simple, extend the Hollocore out to the external face of the core. Always check with you SE in case there are funny point loads or lateral bracing requirements. My advice is general, but intended to be practical in the first instance.

Good spot, thanks for looking at my stuff. There are three fin plates, one at each end and on in the middle marked F4. The end ones stop the angle rocking on the external leaf of masonry. The centre one halves the effective length of the steel angle. Over a 4.0m length the angle will fail, in torsion and buckling. The members marked 7 xB8 are the first floor joists that rest on the inner leaf beam. I've added more drawing to let you see what I've been up to! Remember thought these are screenshots of part of my drawings. While I'm happy to share some stuff I do I need to protect my intellectual property to some extent. It is after all my day job also. The stuff you see is only part of what is a much larger drawing set. This is big bug bear I have. Architect's nine times out of ten don't put a grid on there drawings at the concept design stage. Thus it makes it right from the get go hard for a Client to line stuff up. As I wear two hats.. I just can't see why they don't do this, it's bonkers or arrogance?

Your SE is trying to convey to you some very difficult / complex structural behaviour, in lay terms. To put this into context. Working from left to right. The first two diagrams show a Cee section. It takes about 3-5 years after graduating from uni to even get you head round this, to be able to design something buildable and cost effective. Your SE has made a pretty good go of the diagrams. Option 3 works, up to a point span wise, much depends on the span / size of the angle. Angle sections are prone to twisting. Your SE later may want to also restrain the angle in places to stop it twisting. Below is a cross section though something very similar to what you have. Buried within the insulation you'll see two bolt heads. below is a screen shot of the steel GA details. If you look closely you'll see a steel fin plate in the middle of the angle span. Here I'm shortening the effective length of the angle and stop is twisting over the doors below. The fin plate method is a small local thermal bridge, but an effective way of getting a relatively small steel angle to work. Yes there are still thermal bridges, but this is not a new build rather a retro fit into an older house. Below is the proposed rear elevation. The clear opening width is some 4.0m. The steels over the opening need to carry first floor and roof loads. I've only posted parts of some of the drawings, hope enough to give you flavour of some of the things we need to think about.

As a suggestion for granite walls call: https://masonsmortar.co.uk/ The link to their website is above. This is a completely different animal. I'm assuming as it's in the centre of your house it is an internal wall? Try and post some drawings, maybe some photographs, often most helpful and describe what you are trying to do / why and your thoughts.

Hope you are enjoying BH, we have lots of fun here. Remember there is no such thing as a stupid question! As an SE I often look at bearing lengths for say Hollo core slabs. Generally on masonry standard is 100mm, on concrete (ICF) min 75mm, I then deduce your SE is taking into account construction tolerance, hence the 80mm. That's a good sign! The bearing length is vitally important as the floor slabs often act as diaphragms that tie the house together. But now we need to look at your pour sequence. Normally we would cast the first lift up to underside of Hollo slab, set the slabs, then carry on. A standard ICF domestic core is 150mm of concrete, sometimes a bit more. Now if you have a 80mm rest on your Hollo core that technically leaves 150 - 80 = 70mm of concrete before the outside skin of insulation, and that bit is going to be very hard to compact properly as it's going to be at the bottom of the next shutter lift. Have you considered extending the Hollo core slab rest to the full thickness of the concrete core so it sits flush with the outside edge of the concrete core? Then you'll have much better tying and can foam up the Hollo cores to your hearts content as they will be easily accessible? If you really want air tightness you can seal off any gaps within the floor depth as the end of the Hollo slabs will be flush with the inside face of the outside insulating layer of ICF,, that's a tongue twister! I may have missed something here. You SE may have introduced some extra floor to floor tying rebar, hence the reason for the 80mm bearing? Can you post the details you have? To finish, good question and hope you enjoy BH, folk chipping in, but also remember that folk that come after you will learn from your posts and experience. For me, it's also my day job, I also learn from your innovation, so thanks.

Very good question, looks like you are on the ball! Below is a typical Strongback detail: If you want to make a hole for a duct in these you'll likely have to add some plating detail or the like. It all looks quite doable..if your ducts are not too large. Can you dimension up your sketch / photo and mark on the hole and diameter you need to make? Plating with ply each side with glue is an easy option if your duct is not too large a diameter. There are plenty ways of getting around this, but we are looking for the simplest and cheapest option. I say glue as if you just use nails when you calculate the forces you often need lots of nails and the nail edge and end distance just takes loads of time to detail. The nails are just used to clamp ply until the glue cures.