Gus Potter

As a cursory inspection that won't get past a UK SE. The wall fixings into your proposed blockwork will fail drastically and the wall stringer is too flexible. The diagonal tread bracing is a straw man. Keep up with the ideas, something that suits your budget will come to light. How much have you allocated in your budget for the stair?

My timing, spelling, grammer and choice of language etc is often well below the mark, but thanks for that. But have a look again at your roof make up, just in case you have missed something fundamental. The last thing you want is you SE turning round and saying, we never signed off on that. I do like how you are taking the time to get your U values and material build up sorted and it's clear to me that you have put a lot of time and effort into this, I admire you. If it turns out you need to resolve an SE issue then you will be able to adjust as you have already put in the hard work. Onwards and upwards, you are on the right track! I love your idea of external blinds, easy to maintain, passive over heat protection. You could retro fit when your glass units start to fail? I was on holiday recently in Lake Garda and stayed in an "ECO hotel" They made much use of external blinds.. which were not that Architecturally unappealing. Yes it's a different mind set but cf the cost of special coated glass and the inevitable replacement cost then it seems like not a bad deal. For all.. see when you get fancy glazed units.. the warranty is often 7 years.. so ask if they fail how much is that cf some external blinds, brise soleil for example. Bet your house is roasty toasty, a joy to live in and won't be falling down any time soon. A house like yours could still be standing in two hundred years or more if maintained and kept dry.

Yes they do and I put this on my drawings and specification. You will find the nailing schedule and nail type, durability etc on any SE fixing schedule. The nails holding everything together are just as if not more important than the timbers say. It is fundamental to the SE design as different types of nails have a different performance. Ring shank nails have a different load capacity from a smooth nail, length and diameter of the nail is vital as is their coating for durability. From time to time I get asked to verify that what I have designed has been built.. I check the nails on site as the performance can be 30 or more % different! Lots of builders cut corners here and use the wrong nails, they don't follow the edge and end distances that are specified on most SE drawings. They think they know best.. but they don't. Look, you ask your SE to do lean design.. then the builders comes along and says they are talking pish! At what point do you think.. hey this is more risk falling on me.. and I'm paying for all of this! So in the context of buying a nail gun. Buy one that fires the nails your SE is specifying and make sure you / your builder executes what the drawings say. I have this on my website but take a little time to read this by Ruskin. “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.”

Ok this is good, design is often about ruling out the things you don't want and that lets you focus on the things you do want! So you have precast treads... do you envisage these being cantilevered? I think you have to go back to the drawing board. I get it, it's a major design decision. Keep posting, don't give in, loads of folk on BH are able to help.. But don't forget.. you are helping others that will come after you might read this thread!

START HERE! You might be as your SE may be relying on the sarking boards to stiffen the roof. Just ask your SE if the sarking you propose is compatible with the building stability design intent. If your Architect has not picked up on this then you have options, but ask the question now and direct these to the SE, rather than leaving it to later. If a loft conversion say this could blow the gaff in terms of clearance height when you go up the stair and so on. If your SE has relied on the boards on top of the rafters to stiffen the roof then it's probable that your Steico boards are not providing enough stiffeness, and then you need to rearrange the roof make up.

To add a bit. How industrial do you want say the welding to look if going for the stair in my last post? @ETC here we are considering the important detailing and finish. How that interacts with the tread appearance, the balluster and so on, even the pitch and tread length of the stair is important to get an appealing looking stair which is often a main feature of the house. @flanagaj as an SE so long as the welds have an adequate strength then all is good. But the ripple weld is more industrail.. good steel fabricators can do both and all you need to do is tell them, please do this type of weld. Next is paint finishes (if any, could be a clear varnish but we need to check the fire protection) and what goes well with timber treads and balustrades. All this does not need to cost the earth but to get best value it takes thought time. You have enough on your plate to get your self build underway but the KEY is pick the structural design of your stair in the context of what you need to build now and then have fun later on the detailing and choice of glass or what ever handrail / glass and so on you want. Don't forget that your design may evolve and what you are thinking now may change.. keep your options open, appreciate that this is one of the benefits of self building. What I can tell you from my own experience is that the design will evolve so try not to tie your own hands too much at the moment. Last thing is don't forget the building regs.. any gap roughly needs to be less than 100mm! So a lot of these stairs you see are non compliant including the one I posted above!

Does this sort of thing float your boat, it's stand alone, you can make it as industrial as you like. I made a post earlier about your cantilever stair but what about this.. it can be free standing? The great thing about these is that the steelwork is not too expensive, they get churned out by fabricators day in and day out and depending on your budget you can pick and choose the treads depending on how much money you have left as you near the end of the build. @markc earlier knows a lot about this kind of stuff and how you fabricate them so have read back on his posts. He has talkedf about in past about how these type of stairs twist a bit due to welding heat an so on.. but that comes with the "industrial look" BIG point.. these types of stairs need a strong support at the top and bottom (to stop twisting) so you need to plan for that early on. Good thing is that you install near the end of the works to mitigate damage risk. SE wise they are easy to design but the connections at particularly the top need some thought as you need to get the stairwell trimming sorted out so it take the twisting (stair torsion). The bottom conection is often easy as you have a base plate that can take some twisting. There are lots of posts on BH where folk have discovered late in the day that their stair top trimming is lacking strength and robustness and that causes lots of grief. These stairs can look great! You have the tread detail, then how you do the steel paint finish, how much you want the welds finished, the balluster / glass detail. You have many options from high end to totally industrial look.. rough as.. The best advise I can give you as a past self builder and designer is make your mind up now about the way the stair is going to work structurally. Build the support structure in and then as you near the end of the job see how how much you want to spend on the stair finishes (glass, quality of the treads etc) and how that fits with the other budget constraints you discover as you have gone along. It's a hard decision as the stair is a main feature of the house.. the first thing folk see when they come in, been there and worn the tee shirt.

Make sure you get one that fires the nail sizes and type your SE specifies, could be ring shank.

That's a nugget! How did you find that out?

Agree. Good bit of lateral thinking Nick. Sounds like hard and risky work and you'll need components that are not cheep to buy if you don't have economy of scale. Ok lets look at this stair @flanagaj as per you link. My thoughts are; for buildability, ignore any contribution from the glass and hand rail. This works differently from a traditional tenement stone staircase as the treads are pure cantilevers. My next step is to ask what is the function of the wall and how does it fit with the overall structural design. Is it for example a vertical load bearing wall and does it also serve as a racking wall (shear wall) that stops the building moving sideways? Then have a rough look at the forces the wall needs to resist from these loads and from the stair treads. Now review the proposed wall contruction. @Nickfromwales starts to introduce this concept of using a different material, steel. Here the thing that will goven the design is the stiffness of the tread to steel connection and the tread deflection. Hence we are looking at welded connections in the first instance as opposed to bolted connections. Thinking In terms of buildability. If the wall is not carrying lots of vertical load, say just a bit distributed load from the floor above is it possible to complete most of the build and temporarily prop. Now often in self building we change our minds as we go, this method keeps your options open for longer and this type of work really needs to be put off until the place is wind and water tight and most of the messy work is over and done, see how the budget is holding up and so on. I like @Nickfromwales's idea of a steel framed wall. Try and imagine building in vulnerable treads into blockwork, the risk of damage or complex connections. My gut feeling is aligned with Nicks, the wall is probably better built in steel framing, put together on site and tailored to fit, in a clean environment and made to fit what you've actually built. Ok some techy stuff! Let's have a look at the tread material. Say the treads were 100mm thick oak and the stair not too wide. Now these will carry the loads, and not deflect too much. We need to watch the differential deflection between the treads as you walk up the stair so we don't burst the glass (that will be driven mostly by the end connections and flexibility of the wall studs) and if we have glass to timber connection that have too much tolerance we will end up with a wobbly hand rail. Now given the forces and the timber grain direction any connection to steel is potentially tricky. Timber also shrinks so a big consideration and so do concrete blocks. Often what we do is to inlay steel to the underside of the timber treads (easier to make the connections) or go the American route where we construct a steel / rough timber stair and then veneer with high quality timber once the majority of the work is complete... again buildability and taking care of you final finishes. @flanagaj You might not need vertical steel posts at every tread. I've not reached that point of analysis. They key thing in a stair like this, my own thoughts, are it needs to be appreciated not just in how it looks but also in terms of how it feels when you walk up it. It needs to be a bit "dynamic" so you "feel" the engineering" but not too much so it feels unsafe and cracks the glass. Great idea, send them your drawings and ask if they can design the wall and stair for you as a package.

Love this. Ok, first thing is if double glazing often the spacer bar will have a mark and date with the BS code, sometimes the year of manufacture of the unit. So you can bench mark that with the historic U value of the unit. If you can find that then we might explore more.

@flanagaj That was a bit of tough love but go for it if you can. Post more info and some drawing details and if I can help I will, for free! Others will chip also as there are folk on BH that know about this stuff, have construction experience "boots on the ground" but are reluctant to post in case they get a slagging. To be blunt you have access to a great resource on BH so you need to give a bit to get something in return. Your floating stair really interests me and I would love to help but I'm not going to do that unless you share enough info that other BH members can benefit from. Just maybe you'll get some tips and you can go back to you SE and say.. I've read some stuff on BH and here is how you design it.. what do you think?

That is a good honest response from you SE and I often wish for this where folk say "it's not my bag" . As an SE from time to time I'll say the same, I don't have the expertise to take on this. This is a condition of our SE registration. To provide a bit of cost context to this, say you came to me and said would you, Gus design and sign off on a floating stair? I would first want to have a look at your drawings and see if there is a fighting chance of making something work. I would charge you £200.00 quid for that as there is no free lunch. If I think, yes I can make that work then the calculations are pretty straight forward if using natural stone, but if concrete they are not as you then need to design and detail the rebar which is a lot of work as you have torsional effects. The main part of the work is in the drawing detail and making sure you as the Client don't cut corners and that the drawings specify the construction sequence. I have to do that as if you cock it up you will might want to take me to court! My proposal is. If you want to pick my brains then you need to pay for that. I'll then walk you though and discuss how we might go about designing,constructing it in a buildable way . Then I will be able to give you a fee quote based on us working together. So long as you pay me a fair rate for a fair days pay then that is reasonable?

Ok, that sounds like a valid reason. You have a height restriction. That's flag if they can't take this in their stride then oh dear! Radon is assocaited with granite rock. My gut feeling is that you are not paying your SE enought. Phone them up and have a frank conversation. Don't be afraid to step on your Architect's toes. Just say they ask you for an extra two or three grand to hold your hand. All they need to do is to save you a week of two men's skilled time on site + expenses. And how much are you going to spend! Then she should have told you to be the bad ass and knock heads together.

Agree John. There a loads of folk that use ICF as self builders and sometimes I look at ICF designs and think.. that does not stack up cost wise. It's forgivable as often folk convince themselves that it's right for them, but with my hard nosed hat on I know that's not the way I design as I can see it more expensive. But other times ICF is absolutely the right way to go. As a designer I often look at projects and think, how can I get this built at the budget? It takes experience, it's not that hard though. One of my key principles is to understand the Architectural design intent, identify what is important in terms the Client requirement, what matters to them, and then check to see if that fits with the planning requirement. That's the way I design as an SE and general designer. The big problem is that folk just don't want to pay for this skill. One skill a good SE should have is to be able "knock heads together" , bring discipline to the design process. Architects are not good at this in general. Because that is a Client requirement, what is wrong with realising your dream to have something that is different and a wow factor. Now fair enough, it might turn out that the detailing and buildability is going to be prohibitive cost wise but you have to explore all the design options. In summary folks if you are thinking ICF also look as how much extra performance you get out of it for a bit of extra rebar. It's almost free money!

A basic DPM gives you basic protection, it's taped anyway to stop damp. Where are you building? Why are you replacing the existing concrete slab? Myself and @saveasteading often look to see if we can retain the slab with a bit of clever engineering. You should by this time have an SE fully on board giving you practical building advice and showing you where the costs lie in terms of buildability, working closely with your Architect, guiding them and encouraging design discussions.. unless you want to lose money.

This is interesting from a design perspective. I clocked this as it's a good span in ICF.. and then we have a steel beam. My thought process is roughly as follows: ICF is basically an insulated reinforced concrete wall with insulation. Reinforced concrete, if you have a decent height of concrete over an opening can be really efficient structurally. The wall can't be too thin but say it's "normal" 150mm. We don't know what the loads are from above but the 457 deep beam is likely designed for deflection (critical design condition) rather than strength. So the SE has introduced steel. But I then think as designer.. what about fire protection, insulation detailing, cold bridging, insulation fixing to the steels, differential movement between the materials and impact on the external and internal finishes and buildability. All that is going to add to the cost. This is where you really need to think things through. Scenario.. often the SE, (after Grenfell) will pass the fire protection to the Architectural Designer and then they will put some random note on the drawing for the ICF folk to make it work and they will pass it on to you as the Client.. you see the problem? My gut feeling is to understand why you need steels. If you have a two story building then sometimes we can hang the beam over the door from the ICF wall above, even if there is a modest window above. If only single story then is ICF the right solution? And 8.4 m door is going to be big bucks so head deflections are critical. To finish. Your design team need to get together and say.. this is a big area of moving glass so let's start to talk to each other and produce a well thought out design. For the technical minded: On concrete buildings we can use a principle called a Vierendeel girder where we look at the whole wall say on a two story building. This is where ICF has advantages over say a timber frame. If it all looks good SE wise you then need to make sure someone can built it and ideally save money. Again the SE stuff for the steel is probably straight forward but the detailing is where is could all fall to bits. ICF is simple in this respect.

Ok in the round you can look at this in a few ways. But one is that the planning and building control function subsidises other public services. A BC officer told me that BC make a profit but that gets "hived off" to pay for other "stuff" that you may not have voted for at your last council election. To be fair, if you are going to pull folks trousers down you need to tell them what needs to happen to be able to pull the pants back up. But they don't even bother to tell you that.

Hi Steamy. I've written a PM to you but can see you have PM's turned off. Can you PM me with your contact details? Gus

Much of this is above my pay grade.. but as an SE I can report the following: I'm using it as a tool to give me prompts in SE design. Prompts can be; suggestions and links to research papers, design code links and so on. This saves time thinking.. I have this info but can't find it in my large library of info. I always check the facts. I tested AI against some basic beam design, then pushed it a bit, chucked in some geotechnics.. which is a dark art. Again it served up a template that a student SE would get taught at uni. But it fell short of what is required of an SE which is the "art and craft of design".. but it still saved some time. I then thought I wonder is AI will write me some VB code (not just macros) that lies behind some of my excel spreadsheets and it made short work of that. If I have the will to live I'll ask it to write the VB code in excel that does a structural stiffness matrix which includes deflection. I wrote this a while back in excel for myself so I could check commercial SE software. I other words.. write me a basic frame analysis package in excel. Now you have a free basic SE frame analysis package! My better half is using and pushing AI a lot in complex areas and getting good results. For me, if you look at Grok it seems to be doubling in power every 4 to six months. That said, I feel AI is milking me for my craft so am wary that when I go off piste as an SE I'm in no hurry to give away my secrets avbout how you actually execute the art and craft of design.

Welcome to Buildhub and well done for posting a great question. What you have is a little different. Is your house circa 1950 to 1967? Here, after the war there was a drive for "non traditional construction" and the house builders were experimenting with leaner design. Conner, good spot! Agree with Conner in that this tie could be holding the external wall head in place and the toothing is there primarily to turn the internal wall into what we call a shear or racking wall. I can't say much more at the moment but if you want post a photo of your external elevation and put a line on it where you want to take the wall down that would generate more comments that might help you. Also changing the size of the opening in the external wall will lickely have a marked effect on the wall stability.

I think it's debatable. Both a low or tall radiator will still set up similar convection currents in the room. My own view is that the position of the radiator is more important and in a principle room appearance and position of the furniture will often lead to a compromise. Ok for a bit of fun to size a heating radiator system in the old days (35 years ago) when I was a building contractor .. still can apply when at the ball park quote stage. To get the customer interested I used to take them round the house and say... Imagine you had a one bar electric fire in this room ( 1.0 kW) or a two or three bar fire (3.0 kW) working on and off. Think of your Grans house. In this day and age we can use the equivalent of a fan heater. Most folk can relate to this. You run round the big rooms and as you go you say.. hey big window here and a draughty door say in a big hallway. You want to be able to make this room nice and hot if feeling like a duvet day? Now you add that up and with a bit of experience you can feel for the size of heating system you need. As an SE I use rules of thumb to size floor joists and steels and this is no different. OK so you now have a well insulated modern house. Take the above preliminary size and half it as condensing boilers work better at lower return temperatures.

Go for somewhere in between. Think maintenence and roof penetrations. Where you have eaves you need to think about roof access (and gutter damage) , something solidish to stand on. Verges, keep away from them as any disruption here can cause the roof to leak. Think about what service penetrations you might want in the roof. This could be a soil vent stack, any fan vents and so on. Keep a good margin around thec penetration flashings. If using tiles then think about the tile width so you don't end up with a funny width of tile.. the detailing is going to be hard and it gets harder when you have fewer tiles between the panles and the verges as there is less room for adjustment on the width as you lay them. Be careful folks as if you have not thought through the detailing and maintenence cost (risk of breaking things when you go on the roof) then it will come back to bite you. Remember that your house will not go up perfectly plumb as it will get built to a tolerance.

Local topography can vary a lot. On my self build, Qouthquan, near Biggar we had Tinto hill and the upper part of the clyde valley that would move the "local" weather about. Yes, you will get a lot of different weather, four seasons in one day. You will no doubt be appreciating how dynamic the weather is at your house, but one thing... it's not boring! Parts of the south do seem to be suffering from a long term decline in the main aquire level. That said it could just be that the performance of the borehole has dropped off, got clogged. Some boreholes don't last forever and that I suppose has to be factored into the long term (maintenence) cost when buying a house with a borehole.

It's interesting. I hope I'm not identifying Kelvin's site but I've been there. About a mile or so down the road is a farm that I have a family connection to. This used to be a highly productive soft fruit farm and if you wander about you can still see the bases of the prefabs that armies of berry pickers would come to every year. The key thing is that this farm sits in the rain shaddow of the mountains but also the geography then further splits the weather and that doesn't get picked up even in the local weather forcasts. Go five miles further up the road and I think you would get a different output from your PV.