Gus Potter

Like that. Of course if you go down that route then it leads to more.. can you do passive stack ventilation.. can you use the adobe floor to balance and control moisture levels. Can it be used for example in historic buildings? Take an old Church you want you renovate and turn into a house. To comply with building regs you need to stuff in loads of insulation thus often shift the dew point in the walls detrimentally. If you have a moisture sink in the floor can you use these properties? Clay can absorb a lot of moisture. Is the adobe more enviromentally friendly, the processing can be I understand, but not always, less energy intensive (embodied carbon) than say making cement. I totally get the idea of low temp floors and passive house.. I'm a big fan of PH.. also a practical designer. As a designer of homes I think about making it a home.. it's not an office. Imagine you are unwell or your kids are off colour, an old person to look after.. it's good to have the option to crank up the heating and sod the bills. I know myself, how much and how good it feels to walk on a floor that is hotter than the norm. Build in that redundancy.. it's a luxury at not a big cost. Also, when we get say a "beast from the east" it's bit embarassing if your house is cold when guests come? yes.. the passive house is great normally but you can borrow my fleece and sorry the food is a bit cold and the red is a bit below temperature, and the old folk just want to go home as your house is bloody freezing. If you are a dog owner then you need to create cool spots in the floor for them.. I used to have a German Shephard and kept a couple of cool spots so the dog was not uncomfortable.. he was part of the family and we all shared the same space. These are the types of things you need to finesse to make it a home for all the family. Putting my SE hat on.. bouncy concrete structural slabs are a no no. Saying that for normal domestic applications your starting point is to say can we get a 100mm thick slab to work with the UF pipe, where do we need movement joints and that also drives the zoning of the UF loops.. another good reason to get your SE in early. Even with the best designed UF layout it is almost impossible to not get the odd hotter spot in the floor as the pipes cluster when nearing the manifolds. If you try and avoid it then there is no free lunch.. you probably need to compromise elsewhere in terms of floor layout.. you end up chasing the dream... the builder turns up and does something completely different! I take your point but they do work well if designed taking into account the anticipated floor finishes and the home owners expectations. Ok for me to profess but when you are in the thick of it as a self builder easier said than done when you probably have much bigger issues to deal with.

Ta @Nod thanks for the heads up, much appreciated.

Welcome to the world of garage conversions. I do a few of these and BC often ask how do you support the outer leaf of brickwork even the ten or so course below what is often a window above. Many of the jobs I do are on relatively new builds. Now the obvious solution is to get a hold of the "as built plans" that show whether the found is running continuously under the garage door opening. In practice this can be a challenge. If you can get this info and it shows a continuous found then the easy way is to excavate down and build off the found if niot too deep and it gives you more of a vertical zone to get drains past. But you may have a piled found.. can be a little more complex but best to try and find out now. If you can't then you can often span the gap with a lintel as you say. One secret of garage conversions is to make it easy for the builder to get stuff off the shelf. Steel lintels are problematic as say Catnic lintels are not design for below ground use.. so you need hot rolled steel.. then maybe an SE to design / check it and it needs to be hot dipped galvanised. That all adds to the cost and how much running around the builder needs to do. Ok lets put some numbers to this. How heavy is ten courses of non load bearing brick? The window is supported on the inner leaf. A standard course + mortar is 75mm high. 10 x 0.075m = 0.75m. Brick density 20 kN/m^3, say facing brick 102.5mm wide. The working load weight you need to hold up is 0.75 x20x 0.1025 = ~ 1.5 kN/m run of wall.. say 1.6 kN/m. Now if the door opening is 2.7m wide tops...the total weight of the wall is 2.7 * 1.6 = 3.2 kN ~ 320 kg just for a bit of context. For fun .. a 15 stone person weighs about 100 kg so we are talking about three folk standing on the beam. I think a Sumo wrestler weighs more but so does an elephant. "Interestingly" SE's have a number of bibles and an adult group of elephants impose a load on a floor say of ~ 320 kg per square metre of floor. Below is an extract from a concrete lintel manufacture, Robslee. The values shown below are what is called the permissible load, a working load, thus I have not added safety factors to the calculation above. A clear spanning type C concrete lintel (145mm deep) can carry a uniformly distributed load of 6.53 kN/m which is greater than the 1.5 kN/m we have calculated above. Now that looks like it works, provide that you drains are not clashing with the lintel as you can cut a hole in that. Ok the weight of a concrete lintel that long. Well you'll need 150 mm rest each end so the lintel you need to buy is going to be 3.0m long so weighs about.. 27 m of lintel = 1000kg. Thus a 3.0 m length will be about 3/27 * 1000 = 112 kg. In terms of price and availability the concrete lintel now looks attactive, easy to get a hold of and something the builder is used to working with. The good thing is that the concrete lintel generally works below ground.. provided the ground is non aggressive.. not full of acid soil and sulphates from power station ash say. . I'm just making caveats in case folk start to use my example for things other than a typical garage conversion say. @Kenc Things to check.. 1/ Your ground levels and DPC level. 2/ Where does the existing floor slab of the garage stop and can you put the inner skin on that.. requires another post. 3/ Do you have a gas membrane.. BC are certainly tightening up on this in Scotland so you need to make sure that if you have one it is detailed out. Hope this helps.

Spot on, mull things over, let us know, ask questions. But later if you make this work (all moved in and comfy) you need to come back and tell folk how you did it! That is the asking price!

Good for you and good thoughts! For a bit of context I have been experimenting with different solutions over the years. First go was on a self build with suspended timber floors some 30 years ago. It worked mostly.. but lets say I could have "done better" as I did not know then what I know now. I have to say.. this sort of thing crops up in my day job from time to time and I don't experiment on my Clients. I have been doing up my own ex council house. I added an extension, laid some hard core, insulation, DPM and then a 100 mm thick concrete slab with A142 anticrack mesh... yes it is still the structural slab. I tied the wet UF heating pipes to the mesh. Then laid a layer of I think about 3.0 mm thick foam and floated a good quality engineered flooring over the top. I wanted a floating floor as opposed to glueing it to the concrete so I can lift parts if it ever get damaged, say by water or me doing something daft. It has the give..and a bit of a spring.. me too am a big fan of bare feet in the house and a massive fan of UF. If you have a leather sofa then it's warm when you sit down as heated from below. In another part I had the old timber suspended floor. Existing joist depth is 150mm. What I did was to get 50 x 50 timbers and fix to them 100 - 120mm wide rippings of OSB with plenty glue. The solum space is tight so then put plenty glue on top of the 50 x 50 (OSB on the bottom side) pilot drilled the joist at an angle and cheek screwed the 50 x 50 from above to pull it up hard against the underside of the joists, leaving a 150 mm ventilation space under. I had to do it this way as there is not enough room below the joists to a battery drill in to screw from underneath. Now I had a 200 mm effective depth of joist with a ledge of OSB protruding. I then cut lengths of OSB nearly the width of the space between the joists and dropped them in so they rested on the OSB ledge. Next I cut 150mm PIR and fitted it tightly in between the joists. I went round any gaps with foam and then use silicont to really seal between the insualtion and the joists. Fixed to the insulation was the UF pipes, then a pug mix then the chipboardd flooring. This is to be a bathroom so from BH have been following folk like @nod and plan to use a decoupling matt for large format tiles. Going to have a stab at laying these myself.. if it goes well will let you all know.. if not.. maybe not. Now the down side of me renovating/ preparing an existing supsended floor was that is was very time consuming and to do it right requires a lot of attention to detail that a builder may not be that keen on. In other words it a great way for Build hubbers as a DIY project. Now technically I know that the foam layer is an insulating layer that reduces the effectiveness of the UF. But I took the view.. the heat has to come out eventually. In both cases I put extra perimeter insulation around the edges. Pratically I have learnt that it's a good idea to over spec the UF by way of closer pipe centres or larger diameter pipes, does not cost a lot. Reason is that my wife is a big fan of rugs and designer stuff. These rugs and their insulating effects far outwiegh my 3.0mm bit of foam. @saveasteading has got a lot of info and knowledge about this so have a look at past posts. He also knows a lot about perimeter insulation and how it can really improve the heat loss performance.

Hiya. Your proposal is technically feasible. A few thoughts. On the plus side.. you have an eye for detail and I assume your are familiar with things like; logic, sequencing and programming events in terms of timing. Also, you probaly have a good idea as to how you assess risk. Hate to say it but the Rumsfeld quote is applicable.. the things we know.. On a personal level I think you may need to have a certain personality. Remember that you are not always dealing with other professionals. You have to be able to work with for example great trades folk who are terrible at communicating (they will do your head in from time to time) , sales folk, the whole gambit. Can you do this and not end up doing yourself mental harm? Can you cope with that over a sustained period of time? How are your IT skills? Do you think or can you work or learn to work a cad drawing package, just simple one. Something that you can use to convey construction concepts to others? You have time.. but if you have not done this before you face a very steep learing curve with the associated risks. I would go right back to the beginning and review what you know, how did the planning go?, what did you learn from that. Then look at the site you have, do your own desktop study so you understand the ground.. learn the technical terms and language used, you can find examples on the internet. The objective here is to get a handle and understand the things you know you know.. this builds your confidence. All the time you are doing this you end up reading around and gathering tacit knowledge that comes into play later. If you have a pretty good idea of how you want the Architecture to shape up then you can probably get quite a long way.. but you will make unforced errors.. that is why Architects take at least 7 years to train! If you want to get the likes of MBC and others to produce work packages then you need to know what they are omitting and what they are basing their design on. It's the gaps between the work packages and folk using different design criteria that cause big problems. One suggestion. Do the leg work, put together a document that summarises where you are. Imagine you are using this document to sell your project. Next try and find a local SE that is interested in the kinds of things you are interested in implementing. Remember SE's also do a bit of Architectural design. Or you could find an Architect who knows their way around the SE stuff.. the two professions cross fertilise. Some SE's will say.., give me 300 -400 quid a day and I'll not just give you SE advice but a whole load of other pointers about stuff they have picked up over the years and how you can design all these flashing details etc. It does not have to be an SE, could be a surveyor etc.. but all builds start in the ground and the structural concept.. particularly the horizontal stability system. Yes I know I have slanted this in favour of maybe an SE but.. The above is the best advise! Other than to add you need to find folk you get along with and can build a rappore and trust. Here you get it all for free and can explore without losing your shirt!

Yes your are right but in the round and to give folk a flavour of the things that occupy our minds..

Too right! Hi Alan. Hope this helps... there is a lot of prep work you can do.. seems like you have already started raking out a borehole log so well done. We call this a desktop study, often folk slag this off but what they don't know is that it forms part of the BS design codes to site investigation and good practice. Try and find out as much info as you can online, look at the BGS viewer to see what kind of bedrock you have and superficial deposits. Speak to the neighbours (very good to do as we weave this local knowledge into a site investigation report), well I do as it carries weight.. believe it or not. Ask say about flooding, were there any landfill sites, was it in a bad corner of a field that the farmer filled in? .. think of the things that might be relevant to your site, be friendly and get them talking. Sometimes they produce old historic photos and give you pointers, history of the site and real nuggets of info that can literally save thousands later on. Other stuff.. have a look at the services, if rural... then where are they, what services will you need.. drainage is a biggy. If in the town.. where do you think they might be and how deep to the sewer in the street, if rural have you available space for say a soakaway or easy access to a water course that does not dry up in the summer.. Next thing to do is to have several walk overs of the site and wander round about. Try and understand how the topography has been formed and importantly what has been changed over time. Are there culverts, how does the land drain, where are the water courses, are there big trees, if so which way are they leaning.. If you see the power company / water folk digging up the street stop and ask them about the ground! many of them are keen to tell folk what they know!.. sleep on stuff for a while.. be curious.. think of everything you can and try and work out why the things you observe are the way they are.. and write it down. The objective of the above is to try and encourage you to look outwith the site and understand what is going on round about. Do your best here and put all the info you have into a document with some photos. Now you have the makings of a desktop study and off the back of that you then plan the intrusive site investigation. Your SE and investigation company will meet you with open arms if you turn up well prepared and won't make a fool of your efforts.. if they do then find another SE GI company pronto. If you come to me and say Gus.. I want to build this house.. I'll say.. to do it right and do our best to avoid things coming back to bite us we need to start with the above. This way we take all reasonable steps to mitigate the risk to you and we can then focus our effort on the different designs knowing we have started out doing things the right way.. done the leg work. The above is the starting point of planning an intrusive investigation that reduces the risk of wasting money while at the same time providing useful design information that can unlock options for the building / basement.

Very good advise given here from @saveasteading

That is a very good practical question! If you have a cavity wall and using twin beams under each leaf then you can use M16 or M20 threaded rod in the web. The rods need to go as close to the top flange as you can so the nut clears the root of the web. You get the web drilled and then align the beams so the holes line up. Weave the rod through and wind on nuts so there is a nut both sides of both the webs... then you fiddle about progressivly tightening the nuts. Now you can only do that if you have a reasonably wide cavity and beam flanges not too wide as you need to get a spanner in between the beams. OR you can be really clever and bolt the rods to the first beam with a nut each side of the beam turned up tight, measure exactly where the inside of the other beam web needs to be, wind on two nuts and turn them in opposite directions so they lock... a locking nut. Then the second beam can be slid sideways onto the rods and you put the last nut on. But all this needs good planning as there are probably props etc in the way. The other easy to do it is to put a flat plate over the tops of the beams and bolt that down to the top pre drilled flanges. The plate acts like a strut. The objective of both methods is to prevent the top flange buckling sideways. Rods can be a bit of a palaver but if you have set your mind on mitigating cold bridging rods work well in this context as their cross section area is a lot less than flat plates. I'm sure there are other ways to do this? but that is some..

Yes looks like you have some good soil to work with plenty spare capacity. You can get rafts (strip founds to a lesser extent) to work well below these values. Here is a thing for all. If you get a ground investigation done you may see the soil descriptions. Maybe written like this CLAY with sand or.... SAND with clay, silt etc. The word in capital letters denotes the dominant component of the soil. Now if we are working in soil that has a dominant CLAY content we are interested in the swell shrinkage potential of the CLAY as that is driven by proximity of say trees and where you live in the country. Up north it rains more so excepting trees the founds don't need to be so deep, but down south you need deeper founds as the drying effect penetrates deeper. Where you have a dominant SAND content we are much less interested in the swell shrinkage potential but very interested in where the water table is and where it might be in the future. The soil investigation may give us a bearing capacity of the SAND. Sand gets it's bearing strength from intergranular friction between the particles and this is driven by the density of the sand and what is above it adding load. But when the water table rises the water reduces the effective density of each sand particle so there is less friction. In practice if we start with a bearing capacity of a SAND type soil of 100 kN/m^2 but find the water table may rise to within the pressure bulb under the found we then often say we are losing half the friction between the particles so we will half the bearing capacity to 50 kN/m^2.

Yes spot on looks like good engineering. These are really important as if you have not followed the SE's instructions to the letter re the bolts you have cause to worry as the beam capacity could be reduced by some 40 - 60% as a guess..

Ok, thanks for that.. every day is a school day.

Post overlapping here. Good point about the Hornbeam. Have had a scant back at the ground report, seems to be a confined site and access. There could be a lot of ground water flow or negligable.. depends on the lenses of gravel / sand and the topography, water regime. But the elegance of trench fill is that even if 1/3 is rubbish you still have plenty gas in the tank.. where as piles.. especially screw piles.. taking lateral load.. does not float my boat. Also don't yet know how high the structure is that is going on top. But in the round I'm thinking trench fill, cantilever slab say 300 - 350 thick with 20m rebar in the top and associated anticrack rebar.. that will carry a good load from a house? My thoughts are to make all the stuff about the trees become a mute point, make any party wall agreement easier to negotiate.. mitigate risk as the site seems to be lower than the surrounding buildings. In Scotland the rules are a bit different but same principles apply. For me it's looking at the job in the round and not getting hung up on piles.

Yes agree but when the customers back is turned.. ? In some ways dabs are not that bad as it allows the dabs to dry more so when you get frost there is less water for ice crystals to expand?

Just a thought.. have not really examined all the detail but.. what about this line of thought.. You have a confined site, trees, it is in a bit of a hole, probable ground water and neighbours close by that could be "touchy". Good news is you have refusal at 2.6 m so lets say that is where we have something we can work off. But we need to know more about the ground water.. and how fast it will flow will you do trench fill. Could we do a test and use a sump pump? I would explore doing a trench fill 1.0 - 1.4 m in from the boundary. You look at the stand up time of the excavation, you are working in a safer zone (further away from the boundary and loads beyond the boundary / unexpected things that are more difficult to control) as not to close to the boundary so if things start to move you have more time to recover as opposed to getting complex by working right on the boundary. Also for example it takes you further away from the trees, primary roots etc and you have a "soft zone" to run all services around the outside. What you then do is cantilever your structural slab out to the boundary / where it needs to go and put the superstructure on the edge of the cantilever. We do this a lot when we are fitting a commercial building into a gap site. I have no objection to using screw piles myself but they are not so good at carrying sideways.. wind loads.. a good circular pile has more lateral bearing area against the soil. But I would alway look at the simple stupid first even if just to rule out.. like trench fill and a cantilever slab. Is this worth exploring for you?

Good question. My thoughts and a bit of tecky stuff. The capacity of the ground to bear the load is probably not a major concern. I think this hinges on the thickness of the hardcore you have underneath and what is below that. Monoblock is quite forgiving in that if one or two blocks move about you won't see it. But when you start using large format tiles they can protest. There are two things here to consider. Does the underlying soil dry out in the summer, say if you have trees near or just live down South. If the soil dries unevenly (say at the edges of the patio what happens? Is it clay that shrinks, chalk that shrinks much less or open textured gravel that is good in this context? Next is frost.. where do you live and how cold does it get and for how long does that cold persist. Persistant cold can result in quite a lot of frost heave in clay type soils, a bit in soft chalk and less in gravel. Say you have your new tiles.. they may well be laid on mortar dabs, then some hard core.. say all of that is 30mm for the tile + 40 for the dab (average) and 100 hardcore that is not succeptible to frost. That gives you 170mm before the heave potential ground. Now the NHBC require founds to be 450mm below ground level for frost heave for a house designed for a 50 year life span. But this is a patio.. what next? Have a look round and see what vegitation / trees you have. Are the roots going to be growing under the patio? If so they will increase in size.. cause heave and dry the ground between winter and summer, shrinkage and swell. Solution.. manage the garden. Frost heave. At shallow depth you can get differing amounts. But if you have say an open gravel ground, low / minimal ground water flow small ice crystals will form and then stop. But if you have ground, say a clay / silt mix that has a slow flow of water this allows the ice crystals to grow larger as they are fed by the water and cause a lot of heave. The solution to this is to provide drainage around the outside of the patio but not too deep as you don't want to suddenly do something that will upset the house founds. Normally we would never have bothered about this but modern patio finishes are now a big investment so they need a bit more thought. Hope this info helps.

Hello all. A bit of technical stuff and a few tips on self building an insulated Kore (say) slab. Yes spot on. For a bit of fun here is an bit more of an explanation as to why and what is more important (in my view) for insulated raft design and construction on self builds. Roughly the plate load test involves a stiff metal plate, usually 300, 450 or 600mm square, a jack and a strain gauge and a load gauge (ring). The plate goes on the ground, and you jack against something heavy. You can create a big cradle weighed with kentledge.. expensive for smaller stuff or you can use a 16 tonne excavator to provide the kentledge. Excavator is the easy way as you drive it about.. if you have the room. You start to jack measure the amount the plate sinks by at what load, plot a graph etc and from that you derive what is called the CBR ratio (California Bearing Ratio) based as a percentage value. The CBR value is a number that is often desired for highway design. In a domestic context we may want to know this if say we are building a few houses and the shared access is to be adopted by the Highways agency or for some reason the fire brigade have a particular requirement for access during a fire.. they need to know the access will not sink under the weight of a turn table ladder.. you would have to have an exceptional site for this.. but just to mention anyway. Another time you may need to know the CBR ratio is if you are doing piling, need a heavy rig and need to design a piling matt for the rig to safely get in and do the job. The piling Contractor will do due dilligance and often ask for this number especially if they are designing the mat. If you find you get stuck on this there is the option of proof rolling. Here we may run a roller with a dead axle weight of 5 tonnes over the ground.. if it moves about like pastry then we know it is not promising. Now a key thing about the CBR (plate) test is that it only gathers good information down to 300 to 600mm, much depends on the size of the plate and the ground you are testing. The pressure / stress the plate exerts on the ground is roughly the shape of a slightly extended (droopy) light bulb (incandescent). Lastly it is possible using some rules of thumb, charts to roughly convert the CBR value to a value that is roughly equivalent to how elastic a material is called the modulus of elasticity and this is good as we now have units that are compatible with our hard core, slab insulation and concrete slab above.. not quite but closer. But on an insulated raft we are probaly using an insulation 300mm thick on 150 - 300 mm of well compacted hardcore. These spread the load a lot so the underlying formation ground is much more evenly loaded. The CBR value is now not really that useful any more to us on BH. What is useful is the value the SE puts on the soil they see in the hole as this gives them the allowable (presumed) bearing capacity of the ground. Often you see a value of 100 - 120 kN/m^2 in decent clay soils. That value equates to you being able to put about ten tonnes per square metre on the ground with the expectation you might get some 15 -25mm settlement in a clay soil. Houses are designed to move about a bit. Now if we know the allowable bearing capacity of the underlying soil, know we are using good well compacted hardcore, know what kind of insulation thickness we need and roughly what kind of concrete slab is going on top we can then design all these layers for the loads. What 99% of the time drives the design (Kore etc) is the slab loadings (slab point loadings / spread out loads) and how these interact with the insulation directly below. This is the critical bit as it drives slab thickness, amount of rebar required and the complexity of the slab / rebar and that is one place where money can be lost. The SE then iterates the design to get the most economic slab by balancing rebar, concrete thickness, concrete strength, concrete shirinkage (movement joints, water bars if applicable) and the underlying layers of insulation etc. OK. Things some you can look / think about when doing an insulated slab to set you on your way for a good job. 1/ When you excavate out the ground to the level that you are going to start from.. called the formation level look after the virgin ground surface, be quick to get a covering layer on it if say clay or friable chalk to stop it softening in the rain / frost or drying out too much. remember that value of 100 kN/m^2 .. if you soften the top 50 -150mm that bit it will move later. The last time that soil may have seen daylight could be some 100k years ago so treat it gently. 2/ Lay your hardcore in thin layers 100 -150mm thick and get a good whacker. Take extra care at corners.. try and get the compaction even.. no soft spots but also no really hard spots. Hard spots can break the back of a foundation.. strip foundations can suffer in particular if you have say a big boulder that does not move. What you are trying to go is to create a platform that moves up and down in an even way. Rafts are less succeptible but never the less. 3/ Often you need to run drains under and that involves excavating a trench and back filling. The objective here is to try and backfill so the filling is about as squashy as the ground next to it. If you were to say backfill with a lean mix 10N concrete you create a really hard spot on a line that invites a floor slab to crack, if you chuck disturbed clay back in that has got wet you'll now have a nice soft line under the slab. Hope this helps someone.

It's a dilemma that lot of new folk encounter on BH.. Do I post stuff that I'm not sure about.. folk worry they may seem daft. What I can tell you is that you are on the right road to getting a lot of help here on BH. Not just on the design stuff but where to buy your materials and so on. I had a quick look at the plan drawings you posted. All good with dimensions. But as an SE / Designer I need to see the elevations you are thinking about. There are a lot of folk here on BH that are great designers. Some are actually Architects, Civil Engineers, Heating Engineers, Electrical Enginners, self builders / extenders the list is long so forgive me if I have not listed. Also I learn new stuff on BH every time I log on so we are all on a learning curve. M sugestion is this: 1/ Provide the elevation drawings. 2/ Put gridlines on your drawings so folk can say .. see that beam on gridline A1 suggest do this.. a lot of Architects don't do this.. but the good ones I work with do.. and just hide the layer in their drawings. It makes it easy on BH to identify what we are talking about. Also when I detail steel work it can relate to the grid.. time spent now will help later. Get the gridlnes into your head and that will make it easier when you are talking to the builder. If you can do the elevations then that will help to complete the picture for me and probably for other BH folk. At the moment I can't comment as I don't know what you are trying to hold up.

Good thread. But for the younger members from an "old crusty".. may save you money.. choice is yours. My thoughts and a bit of back ground. I worked at Torness Nuclear power station, and have designed stuff for the decomissioning of Bradwell Nuclear Station so apreciate the decomissing costs. Mostly now I do domestic stuff.. Part of my Masters was to do with the energy supply in the UK.. I started out as a local builder.. so did not go into Uni right away.. I also had a spell at designing farm buldings with 40 kW pv when the grants were good. Yes I was right into it.. how the grants worked and so on. Have to say one at least went on fire as the invertor did not do what was written on the tin. Lucky for me I was not in the firing line.. but it burnt well and no one got hurt. Yes, I'm near sixty but I still practice so have not quite turned into a fossil... and can't see me going woke any time soon. Anyway my thoughts are.. Marcro and from an SE / designer point of view looking to the future. If you are an environmentalist and into PV.. or any other home automation just to be blunt you have a living in a bubble. For the following macro reasons not least: 1/ China are becoming dominant to the extent that they are going to influence what happens in fifteen/ twenty say years time, unless they invade Taiwan.. then we will have much more to worry about. 2/ The stuff that we rely upon comes from mostly China and the "belt and braces" and most importantly hegemony that they have fostered. I also grew up in Africa and follow how the Chinese have weaved their way in that continent.. and some think the British Colonials were bad! 3/ All this stuff we are introducing.. electronics.. EV cars requires for example, mining and invites destruction of the environment.. 4/ Have you thought about getting replacement parts and how much these are going to be in say 10 - 20 years time? Remember washing machines don't last that long.. you MHVR is intrinsic to the house so should be able to preform in the long term. Do you honestly expect that you MHVR is going to last the design life of the house? You'll be lucky if it works for five years and each ear yoy need to change the filters.. Look folks you have to wake up and realise that while we are trying to save every extra penny in the UK other countries are shafting the environent and the global eco system we need to produce the "air we all breathe" You also need to recognise that you are buying filters, the running cost.. and inherant redundancy. Get your head round this. If you think strategically... The best thing we can do is to try and adapt our building systems to use the materials we have in the UK. We have lots of clay.. if we supported our Farmers and brick industry we could have bricks and wool.. good for insulation in the right combination. Also all locally sourced and provides jobs... I could list more but we have in the uk many of the things we need to protect the environment without haveing to ship in stuff. Look there is word that in the south of the UK they is Lithium for batteries.. in Scotland we have the wind to charge them up. Just maybe we could start to think.. hey... see in the south of the UK our houses are getting a bit to hot in the summer.. can we pinch ideas from Adobe houses that rely upon passive stack ventilation. Yes there is a bit in the building regs about this but if you think about it.. it's a controlable chimney. They do it in Spain for example just here BC don't help. Anyway.. kids need fresh air not filtered air.. just think about it if you are a parent. Yes you may think I'm off the mark here.. but see in ten years time when you can't find replacement parts for you MHVR and home automation other than from China. I'll get the last laugh.. if I'm still here. If not well you made you own bed. I have a house with UF and some nice bells and whistles.. but these come at a cost.. there is not a couple of weks that goes by when something does no break down.. You'll end up saying.. the house was great for the first month.. but there are loads of things not working and it is getting on my tits. When I go to see a Client I point out the good bits and the bad.. For example just this weekend two dimmer light units have failed out of about 16.. and that is in the first 18 months of installation .. and they have to come from China. I can fix this myself but what if you are not OK with diving into electrics.. how much is the spark going to cost you? To finish.. I'll appeal to your wallet. Do you think that having MHVR is a good or bad selling point? Can you demontrate to a buyer that it all works, what value is a Surveyor going to attach to it.. is it like a dodgy gas boiler... at least a gas boiler has a Gas safety certificate .. your MHVR just has.. cowboy written all over it!

You'll get great help here on BH and support. I'm an SE / Designer, do a lot of domestic stuff but can only really chip in a bit. What I can say is that the breadth and depth of knowledge on BH is astounding, and it's right up to date in real time. The great thing for me is that there are loads of folk just starting out and are working hard. One of the reasons I responded to you was that I felt that you have put a lot of effort into reading the regs and to get your design as far as you can. If you do post your drawings and thoughts your big problem is going to be how you digest the feed back you get! But if you can it will save you money and you may get something you may thought you can't afford at this stage.

Posts have over lapped will read yours now.

I would love to chip in more but need more info to give a reasoned response. You are right in that any vertical load bearing beam needs a structural support. You may not need the return masonry.. the buttress. If you can post your rough scheme and let's see what comments that generates. Then we can look at the whole thing in the round.. we can all have fun helping you and that will hopefully give you the info you need to move onto the next stage.. better informed. You'll get loads of info here on BH.. I learn new stuff all the time here.

I would go galvanised. If you think about it Catnic and Keystone for example cold formed steel lintels are galvanised. Also they are probably over some nice door / windows.. the last thing you want is to spoil the effect. SE wise.. external steels.. lintels for example can cause big problems if corrosion sets in.. it lifts the masonry.. not good. Now galvanising comes at a cost. You can try and use special paints / treatments.. but avoid on a self build.. you find it's load of practical trouble. To do a good job you have to have the tools to prepare the steel to accept the coating. Here is a thing.. you can drive down the galvanising cost. First let's say you you live in.. Oxford.. your steel fabricator may have a choice of steel fabricators and they will have a choice of galvanisers. Some small.. some large. The big galvanisers have 6.0 m long or more galvanising baths. The smaller ones 4.0 m long.. they do say a lot of gates for farmers. Now if you have a 4.0 m long bath you can dip an 8.0m beam.. they dip one end at a time... called double dipping.. normally not good in a social context but good for us on BH! But I think you'll get the best price from the smaller galvanisers as the big baths are for big jobs.. not the self builder. If you live in Scotland then your choice of local galvaniser's is limited., you can send it down south but you have the extra transport cost. You'll need to be a double dipper if you have long beams. Now let's say you have a big house with a 9.0m beam, rules you out on getting competetive quotes from the small galvanisers. But you then say to your fabricator and SE.. can we split the beam into two or three? If you do this you need to have beam connections.. but that can work in terms of cost. For a bit of fun.. your big beam may be over an expensive set of bifold doors that are sensitive to deflections. If you start to splice the beam then the connections can move if say you use 16mm ordinary bolts.. they get drilled in 18mm hole. Thus you could get potentially 2.0mm of slip. Some SE's say bolts need to be high strength friction grip.. needs the right tooling and expertise.. comes at a cost and your local builder will not be keen and add on a bit to the price. It's not really the price.. builders and fabricators don't want the hassle. A practical way is to say.. lets build the structure, load up say the roof.. get all the deads loads on the thing we can.. get the SE round for a look. If I'm doing this.. for a bit of drama.. but also recognising that we are using the cheeper ordinary bolted connections that can slip I get a heavy hammer and give the steel whack., some times ( not often) you get a bang and it shifts.. but that is the bolts bedding in. It's also a great way of heading off the really keen SE / BC checker. Now we can measure up for the glass etc. Often we look to keep deflections over bifolds say to less than 4.0 - 8.0 mm .. nice to know that you have addressed some of the potential bolt slip.. and it gives you ammunition if the glass door folk start to argue later on if the doors start to stick.

Fantastic.. it's great fun, sometimes frustrating but sounds like you are putting a lot of thought into it and reading up, reading around and expanding your knowledge. You'll reap the rewards of your efforts. The best thing you can do is to post what you have in mind in terms of conceptual design. Don't be embarressed if you think they are rough looking (you want to see some of mine!) and you're not under examination. If you do this you'll get loads of help, ideas and suggestions.. then you can pick out the best bits, discard the ones that don't suit. For all... here are two key points: Many two storey modern houses have big open plan spaces on the ground floor and big glazed openings. While this is ok and can be designed for SE wise if you don't want to break the bank then there are a couple of things (not least but start here) that you want to aim do. Try and avoid a layout that results in the roof loading landing over / near the middle of the big glazed openings unless it is spread out. With big open plan spaces you often have a floor (maybe another?) above that may need to have long spanning joists thus you may need to split up the joist span with a transfer beam.. try and avoid transfer beam end loads landing over glazed openings. You can do it.. it just cost more as you need to control deflection. Also big openings reduce the amount of solid walls you have to stop the building moving sideways as per next point. This other key point is what we call lateral (global / overall) building stability.. we need to design the house so it does not move sideways in the wind. This is different from "buttressing" covered in the regs for small buildings. Yes.. if you add up all the small buildings guidance bit you could well end up with every wall being structural.. and then find that non of it works anyway in terms of point loading from transfer beams and global lateral stability. The above said you are on your way (well done you taking the time to study) by recognising that the individual wall panels need to be braced to stop them from buckling sideways, out of the vertical plane. The buckling effect is commonly caused by two things.. the fact that the vertical load from above does not sit directly over the centre of the wall and by addition of wind suction / pressure loads. And you have movement joints.. it's quite complex to arrive at a reasonably economic solution and all this changes depending on the type of construction.. masonry, timber frame, SIPS, ICF. Roughly concrete blocks shrink after laying and clay bricks swell over a long period of time. But both move about depending on the temperature. Generally I get nervous when a block wall gets over 5.0m long.. and if I was designing using a traditional English clay brick I would not stretch it to 9.0 m without a movement joint on a self build unless I new exactly what brick you were using and had control over the mortar. Basically it's self build and the brickie may be hand mixing so there lies the risk. Good point.. at the right time you can detail this.. you let the lintel slip at one end and put a small movement joint above. Now that has made me think.. You are right.. but both the English and Scottish regs are kind of giving rules of thumb, small building guidance... maybe also called deemed to comply.. if you do this and provided there is nothing "odd round about" it will be ok.. maybe.. In terms of the regs in this context a lot of them were written a long time ago.. call it tacit knowledge but also a lot of thought has been put into it.. by some clever folk.. and each reg has to be read in conjunction with all the others. They also get updated so let's take them as current. My thoughts on the 6.0m thing is that beyond that you may get a lot of defection in say a joist / steel beam. That causes the end to rotate more.. the guidance assumes a simple support at the joist / beam ends. The rotation introduces (springs to mind) two deterimental effects. The first is that it shifts the centroid of the bearing closer in span.. thus you get an eccentricity of loading on the wall.. introduces a bending moment which masonry is not ameniable to... it can significantly reduce the load bearing capacity of the wall. The other one is that if you are using timber joists (if you could get them to span that far as you say) then you'll get concentrated load and crushing of the timber. Or if using steel you need to check for crushing at the inside face of the block.. well you don't as you design the steel beam to deflect no less than say span / 360 (12mm is a also good number... but not over glazing) so you reduce the beam end rotation and the problem goes away. Yes keep posting and loads of folk will chip in.. then you will be in the best place to make informed decisions as to how to spend your money.