Gus Potter

Hiya @Amateur bob Have raked back through you posts and made random comments for your digestion and general discussion. Reach for the Rennies if need be all. Your posts, generally copied, are in italic. “I’m looking at a different house design” Good.. different does not mean expensive. I would go back and really write down you requirements. For example I built a house for us that had three large bedrooms near Biggar. Other houses locally on the same footprint had 5 bedrooms but we always designed for there being just two of us living in it most of the time. We knew that potentially it could reduce the value as it was not really a large family house. When sold we got a substantial premium over and above a similar 5 bed as the folk that bought it were retired and wanted this type of house. Why does everyone not do stick build if its cheaper? A number of reasons. One is speed and speed often translates into the release of funds by a lender and valuation. Speed.. well roughly two joiners will build three accurate panels a day give and take. Some panels can be long, some short but I would price on 3 a day. You also need a good working platform and space to store the panels you have build on site. Take your average external panel as being about 3.0m in length to be safe. Internal non load bearing panels are just erected later on, often once the ceilings are up. The non load bearing panels need very little drawing effort. Internal racking panels are the same as external panels but with no vapour barrier. Two good joiners who know how to build kits on site £ 250 -275 each per day. That will get folks attention in the Central belt, my Mum lives in Dunning. To build a kit on site you need the panel drawings. I do panel drawings for Contractors I work with that do stick building as I’m often doing the whole design so all the cad / model files and so on are already set up with grids, levels and so on.. you need a bit of practice to do this well and most importantly you need to know what kind of joiner / contractor you are design for as one part of the job is to play to their strengths. It can be difficult initially to find joiners who will take the job on. That said I recently did a 250 sq metre + single storey house with complex roof where the Client specified stick build as this suited his preferred contractor. Cost to do the walls panel drawings about £1750.00 with a bit of prefabicated roof truss specification /detailing chucked in. Once you have the panels up you can then shop about for insulation and so on, you can change your mind! Stick building gives you more flexibility and choice. “Thanks for the reply so this design is fairly cheap to do if i dont open any of the downstsirs rooms up? Could you give me a rough cost for a house like this, average/basic spec” Would love to but prices are all over the place. The main thing is not to get to hung up on the timber kit. PeterW and plenty others on BH I think (and I agree) suggest that the super structural frame is only 10 – 15% of the cost of the job so even if you pay more for the kit in the round it’s not a disaster. “yes he budget is tight but would i not need joinery skills and time myself to do a stick build?” To build a kit for the first time DIY you’ll need to be fit! You’ll also need some joinery skills and an understanding of wood.. post for another day. “so a standard joiner can built these stick frame houses up to the spec of the kit providers?” No they need to be familiar with TF construction, know their way around the types of metal fixings and how to fix. Etc. “Our original design was 2 storey box shape as it was an easy design but refused, the next application needs to be materially different so i thought lowering ridge height would help planning and roofs in roof would be cost efficient, are those designs I’ve shown quite expensive? Dive back and review for example the Scot Gov permitted development rules, then see where you don’t comply and address as you can. It may seem like basic stuff but in doing so it will increase your confidence and allow you to get the best out of this. “They basically commented on the size and visual impact so i thought lowering ridge height would be a good place to start? no real limitations to plot size” Have a day out walking about the area, see what else is out there. Imagine you are a planner! Good you have plenty land as this is a real bonus. Also, when you walk round and about your land you can get a better feel for the shape, contours and so on from a distance rather than just standing in the middle looking outwards. ”This would be a cheap design as no dormer windows and use of roof for upstairs? “ Old rule of thumb.. allow 3- 5K per standard 1200 – 1350 wide dormer if new build. If attic conversion folks.. the price can be a good bit more. “Thanks for the feedback, is there any way to avoid these big steels for the vaulted ceiling? steel is not cheap just now” Don’t get too hung up on this for now unless you are going for daft / pretentious vaulting and huge spans. Concentrate on the layout that suits you. Your big construction savings often come from setting the building at the right height with respect to the existing ground, foundation design, drainage design, access, services and so on. The immediate value comes from getting the house to meet your dreams... just a great home to live in and.. in doing so you make it energy efficient, sit well in the environment for example. If you do this then the house will also maintain its long term value. All the best.

Hiya @notreadyforthis I don't want to cause you undue concern but I would again urge you to get your SE round for a look in the interests of safety and to set your mind at rest. Diplomacy is probably at the top of the list as you seem to be getting on ok with your builder? Interestingy the steel packer plates are probably not a major issue in themselves, but they provide a slip plane that your SE may not have designed for. What it suggests to me though is a possible lack of skill / dilligence in setting out / your builder not reading the drawings. It looks like you are taking a chunk out the corner of the building. When you do this it introduces a lot of overall building stability issues and it is really important to follow the SE's drawings to the letter. If the builder wants to make even what appears a minor alteration it can have a major impact on jobs like this. The builder should always ask the structural designer first if it is ok to deviate from the drawings. "Thanks for taking the time to comment. It gives me things to ask the builder about. I'm sure he'll have a good response but I can usually get a good read on whether he's trying to wing it. The beam where there appears to have been a cut is interesting as it didn't get delivered like that. i also note that the bolt holes aren't centred as they are in the drawings. These steels should have been ordered according to the structural engineering specification. I've got the docs which have all the calculations - none of it makes any sense to me though. The building regs guy has also been around to check it out - would he have raised any of the same concerns as you have or do they not check those sorts of things?" Don't rely on BC to be a Clerk of works.. it's not their job. Also the points I make re the connections and stability are of a more specialist nature that are more in the "wee world" of SE / steel fabricator / steel contractor types rather than BC. Cut BC a bit of slack as they can't know it all, just as SE's say don't know it all. Hope this helps.

I would urge you to get this reviewed by an SE say before you go any further. I can't see quite enough from the photos but.. That connection in picture two where one beam is framing into the web of the beam that seems to extend outside is highly questionable. It looks like someone has made a mistake and been cutting, altering the connections on site. The bolts look like M12 diameter, possibly undersized.. not just to carry the vertical loads but also to prevent other things from twisting. The beam has an unexpectedly large notch. You have some top plates on the steels but the spacing of the welds looks quite large. Also, you seem to have a couple of beams in the depth of the floor above. This coupled with the steel section sizes suggests you are holding up a fair bit of load and that the load is not always centred over the beams. In picture three the beam seems to extend outside so can't see how it is all supported. I know it's not finished yet but it looks like the works are quite extensive. I would at some point expect to see much more tying together of the steels, timbers and masonry so that the overall assembly is stable and safe globally. The padstone supporting the steels seem to be cast in place. This is often acceptable and can be advantageous at times, have done this on my own house for example as it can really help tie the brickwork below together. However I would also want to have a look at these in closer detail. Sorry about the above but I would get this checked out professionally by an SE for example.

Hiya. Yes I think your SE has put a bit of thought into it. Can it be changed? On the face of it you would move beam 9 to line up with beam 12 and that would open up the stair well. But the load from beams 9 & 10 would move from roughly the 1/3 point of beam 8 to its mid span so the bending forces not least in beam 8 may increase, I'm not sure though how much they may increase if that much as you will have to support less floor area. I can't give you a definitive answer as I don't have all the info.. but ask your SE the question as it may be simple to change. They may be a bit peeved as I think they will have put a good bit of effort into this.. so you may need to part with some cash. But if you don't need the floor space the extra light may offset any aditional SE fee. But perversly if you are going to sell the house on the every sq metre of floor could count.

@RJHumphrey What a stunning looking place. This rendering.. do you really have to do it, even if the other walls are half or a bit worse you will knock value off it, not just financial. It would be a real shame to render a beautiful place like that. Technically if you render some walls then you'll have to design for a wall that breathes and others that don't. The interfaces at the corners will be complex to say the least. As an over view always look at how you are going to say wire and plumb the place. Work out how you are going to do this and maintain / alter at a later stage and the practicality if you have insulation placed hard up against the stone. Remember for example that electric cables placed in insulation need to be heavier or need shorter cable runs which may be hard to achieve. It's not easy fitting 4.0mm cable into a 13 amp standard socket. Yes there are different views on whether you insulate these old buildings with an internal frame, a cavity between the walls and the stone or an insulation system with no cavity. But structurally you often need to tie the old walls into say a mid floor.. often with a chapel and this means complex penetration details at these levels which are hard / costly to achieve. Yes if you have an internal frame with a cavity you to some extent create a bridge layer when doing you U value calcs.. but in practice you are talking about a cavity with trickle ventilation not a howling draft. In the round you may want to take the hit on the reduced U value if you have a cavity but the buildability savings especially at the corners and floor often off sets this. Use these savings to load insulation into the floors and roofs where it is easy to do, more buildable? The key for me.. if that place was mine..well it's not.. but I would look first at the pointing, external drainage and the general weathering details. Pointing is the key as even wind driven rain will be mostly shed by good pointing. If you want to experiment find a bit of that river stone, dry it out in the oven and put it half submerged in a bucket of water. See if the top gets wet and the split it in half. Observe. In summary when you insulate you make the stone wall cooler. Generally the humidity is higher inside the building and this air that contains water gas gets into the wall. At some point in the wall the gas turns to water.. called the dew point. Now the dew point in an old wall is hard to predict as it is a natural material made up of a mixture of random rubble and dressed stone. But you can be sure that you will shift the dew point inwards when you insulate. From a buildability point of view it is very quick to put up an internal timber frame, at the worst case it is also a reversible process and easier to intervene if a localised problem occurs. Look at this in the round.. you can create an energy efficient house but energy efficiency and eco friendly is also about making it easily maintainable and adaptable over its 50 plus year intended life span.

Back on topic. Probably telling my wife that our alterations would take 2 years to do worst case 3.. in 2017.. still not finshed. Not overspecing (putting in more) the insulation.. just got the latest fuel bill in from Bulb.

1/ Non vat registered. Well the current vat threshold is £85k and equates to two or three modest extensions a year for a builder if they do nothing else. Now if a builder is experienced in extensions they should be doing a few more than that. Ok if they are not vat registered then questions need to be asked... such as.. are they a limited company.. if so be very careful before you part with money up front. If not limited find out if they own their own house so in the worst case you have an asset to go after. However they may be starting out on their own but do have sufficient experience so don't rule that out and take care... but generally there is no free lunch here. Its a red flag this for the unwary. If you have to make up front payments only risk what you can afford to lose. No vat / cash = more risk for you. 2/ Your SIPs panels have to sit on a pretty level base and can't be altered. Watch your payment schedule to the ground worker as unless you are absolutly on top of the found setting out and levels then you are inviting a lot of grief. 3/ Word of mouth recommendation. Ask not least your Architect and the folk that are putting up the kit. They maybe will know who builds good bases / underbuldings and who to avoid. All the best.

Hi all. I can't quite see where all the supports are to the steelwork but there are plenty things that could be going on here and the SE looks like they have spent some time thinking this through. It's looks quite elegant really even though you have a bit of cantilevered floor that with hind sight you may not have chosen at the Architectural stage. Let's start with the basics. A steel beam is designed for "pure bending" called its moment capacity (Mc). This is often where the steel starts to yield and fail but the beam does not distort or twist sideways. Beams can also fail in buckling where they just twist and distort and collapse suddenly. Often you find buckling (Mb) is the governing criteria. We call this (Mb) the buckling capacity of the beam. Long beams buckle easily so what we do is to fix floor joists, floors or other beams to them to prevent them from distorting / twisting / moving sideways and thus we increase the buckling capacity as we shorten what is called the effective length.. that is simplistically the distance between restraint positions. If we do this well we can in cases increase the buckling capacity up to the Mc capacity and thus get most bang for our buck. Lets start with beam 8 and lets assume there is not much restraint from the floors as the joists span beam 9 to 7a. The SE may be using quite a stiff connection from beam 9 to 8 to stop the twisting / provide torsional / twisting restraint to beam 8 thus increasing it's Mb (buckling capacity) significantly. If you don't do this then often you need a heavier and deeper beam. They may also be using beam 12 to further reduce the effective length of beam 8. As you come up the stairs on your left hand side there is the stringer with spindles above and behind the stringer there is a space before you seem to find the first potential support. It actually looks like the end of beam 11 is supported by beam 7a. Thus beam 11 spans from 7a to beam 10.. it is beam 10 that is holding up one end of beam 11, 7a the other. Now for beam 10 to hold up the end of beam 11 it needs to act as a cantilever off beam 8, but if beam 9 was not there then beam 8 would just twist and it would fall down. I think the SE has designed a very stiff connection between beam 10 & 8 and 8 & 9 so that 9 & 10 act as a continuous beam, supported at one end by the outside wall and by beam 8 at the joint. Lastly you also find that where beam 9 rests on the wall the SE has made sure there is enough back weight to stop this end of beam 9 lifting upwards.. like ballast in a boat. That looks like one possible hypothesis but a caveat is that we have not seen all the info, support detail and the global structural design. Lastly the diagonal bracing. I have touched on a few but not all the facets of this but you can see that the steels will be doing a lot more than just carrying the basic loads. Everything will be wanting to twist, bolted joints will slip here and there so I think the SE has introduced the diagonal bracing to stiffen things up. Also the diagonal bracing may be providing global stability to resist wind loading. In summary don't remove beam 10 or any other for that matter without asking your SE! Also don't let your fabricator / metal worker change the SE's connection design in any way without asking. If you have read this far then thanks. Gus

To excuse the pun. Rather than interfering with your neighbours tiles can you create a rain screen effect. Here you would fix maybe a metal channel type section to the good bricks, could be timber protected by dpc. The rain screen would belong to you but over sail the neighbour's tiles. You could run Code 4 lead vertically, say in 900mm lengths so manageable and easier to fold neatly. That may be enough to solve any problem and allow air up behind the "rain screen" lead? If you are using lead don't forget to coat with patination oil on both the front and back of the flashing. You would need a wee nifty bit at the top but if it looks promising in principle the you should be able to devise some kind of capping flashing?

One of my mentors was Professor Ian MacLeod of not least Strathclyde University. He taught me about the importance of having a robust energy mix that could withstand environmental and geopolitical shocks. He has been lobbying the Scottish Gov for years about this.. fell on deaf ears. It's often overlooked but folk don't realise that natural gas is used to make the precursors for things like plastic.. heart valves and so on. Ineos at Grangemouth in Scotland is prime example. Wind turbines make electricity but no byproducts for say your electric cars.. that need also needs a lot of plastic and faux leather. Coal fired power stations make fly ash that we use in low carbon concretes and as a retarder! So we now buy fly ash from China.. who are building apparently a new coal fired power station every week..

Great comments from all. Interesting to read all the views. For the budding loft converters a few observations. As a designer your starting point is to establish what folk want out of their conversion, what will meet their primary needs and then, aspiration. Next is to get down to brass tacks. You have planning constriants; ridge height, eaves alterations, what you can project from the roof.. dormers or Velux or in some conservation areas.. mme. From a BC compliance point you look early on at how you get a stair up and fire protection. A critical dimension is to see if you can get the clearances for the stair in terms of head height. Lastly you have a look at what kind of headroom you can achieve in the rest of the proposed converted loft. If your Clients are all six foot six plus then you need to say.. hey you are quite "blessed" but you ain't going to enjoy this even if you comply with the regs. On the other hand you can be "blessed" if you are of shorter stature. Everyone on BH is blessed! Next you delve a bit more into how you may insulate, do you need to replace the roof, get any drainage to work and so on. You look for booby traps that could burst the ball. Now have a look downstairs and where you can support load by means of load bearing walls. What are the Client constraints... do they want to live in the house or move out say. This then gives you a flavour of what to explore structurally. Once you have got this basic information you open your SE tool box and see what will work best, not just in terms of pure structural design but also what will best fit the local contractors. Good design is also about designing something that is elegant and buildable at a reasonable cost. That is the art of structural design. Next you iterate and go back to the Architectural side of things and this lets you design Architecturally in the knowledge that what you are doing has a sounds structural footing. Now you may then want to use Glulam beams..maybe an oak ridge beam for a feature if you have enough height, use sistered joists, steels, cold formed steel.. sometimes very little structural "extras" are required and this feeds into the Architectral design. which is the bit you see at the end of the day. In summary your starting point should be as above and as each attic and floors below are often different it is almost impossible to say "this is the way". If anyone wants some pointers then the best thing to do is to post some sketches thah show for example the span, height to the underside of the ridge, walls below. Rough it out on a bit of A4, take a photo and post. Don't worry if they look a bit rough.. you want to see mine! Lastly while some materials may best on paper to use.. say steel, glulam, cold formed steel the design decisions can be driven by the type of builder you have available. Say you know a great joiner that buys a lot of wood and gets a good price. You may want to play to their strengths and use Glulam that they can buy using their regular account, rather than steels that they may have to pay "punters" prices for. At the end of the day this can work out cheeper for you.

From an SE point of view that house look reasonable structuraly efficient = lower cost and fairly buildable. There are good few cross walls on the ground floor so easy to stabalise the building. Floor spans are modest and so on. The gabled parts of the roof will probably need girder type trusses but there is plenty available support for them. If you like the design then you could start to tweek it but the structural cost will start to rise significantly if you really want to open it up. And if you do that then you need to go back to the drawing board and start afresh. There are plenty ways of doing a 1 1/2 and 1 & 3/4 storey house. Enjoy the journey.

Ha ha.. you are not supposed to tell folk that I'm an SE.. cats out the bag now.

Hope this gives you some pointers. Lets start with the abbreviation.. ICF.. insulated concrete formwork. For walls the insulating blocks act as a shutter (formwork) to hold the wet concrete in place while it sets and then cures. The blocks themselves for walls make no contribution to the structural stength of the concrete wall. The choice of insulating wall medium has no bearing on the strength of the wall to resist the vertical an horizontal loads. The choice of block has no real bearing on the amount of rebar you need in the walls. Not quite, but let's keep it simple for general costing purposes for now. Some complex behavoir can happen at the bottom of the wall, depends on how and if it (the wall) is positively fixed to the floor slab. However it when it comes to the floor slab things change a lot. If your insulating blocks go down the walls and continue under the structural floor slab then the building is supported by the insulation, which rests on the ground below. What SE's do to design this is to look first at the ground.. how squashy is it, one property they look at is it's elastic modulus... a property of squashyness! Next step is to look at the insulating blocks.. how squashy are they. Hopefully you as an SE find the insulation is more squashy than the ground below. If so plane sailing. You design for the most squashy layer which is the insulation, there are other methods but this is the most common and practical for domestic design. Thus if you have an ICF block rated at 300 kPA at 10% compression (30 tonnes per square meter at 10% compression) you first say how thick is the insulation? Say 300mm thick so 10% of 300 = 30mm settlement to get your 300 kPa out of it. Now 30mm settlement is too much to tolerate normally. Also, you may have insulation that creeps a bit over 25 -50 years.. bit of a worry. Lets go for a figure of 2% compression and see what load we can put on the ICF blocks. Thus 300 * 2% / 10% = 60 kPa = ~ 6 tonnes per square metre all nicely spread out. Closer but we need to watch out for point loading and so on. Now there are many ways of carrying out the next steps to determine the shape and form of the supporting slab that sits on the insulation. But basically you strike a balance between the thickness of the floor slab and the amount of rebar you chuck at it. The easy way to get your head around this is to think about a bending a ruler. If you do so the top is in compression, the bottom in tension. Thus the thicker the ruler the less force on the tension side. Now concrete is good in compression but poor in tension so we use steel bars which are bonded into the concrete to resist the tension force. Thus for your ICF floor slab if you make it a bit thicker you'll often need a bit less rebar. But there is no free lunch as you'll need to pay for a bit more concrete. But the secret is often in reducing labour steel fixing cost, reducing complexity and avoiding on site errors. Lastly designing a ground bearing slab on ICF is not the same as designing a concrete slab that you may see in a multi storey carpark. The slab interacts with the ICF and ground below and thus the design approach is different. In summary @Ben100 if you choose a higher stength insulation under your floor slab you'll maybe use a bit less rebar and concrete, but you'll lose some of the insulation properties so will then need to make it (insulation) thicker to achieve the same u value.. and making it thicker will result in more movement.. who said self building was not fun! The best advice I can give is to seek out the most practical and buildable solution for you. Always start with the simple stupid. See how much that costs and then if you have spare cash explore further. Your simple stupid option is your bench mark. The weight of steel you need will much depend on your slab and another of other factors. To get the best out of this you'll need to post some pretty comprehensive drawings so folk can see what you are proposing. All the best.

Hiya. Yes if you can post some drawings then folk will chip in with value added comments. The main thing is to post so folk can see the roof space, plan view and sections and where the load bearing walls are below. You probably have plenty options but to get some practical SE type input then the drawings are required. Also let folk know if this is your "forever home". There is probably lots you can do at this stage so now is the time! maybe?

And there lies a potential problem. That is a big opening. When the wind blows on the glass the frame around about need to resist the loads. The central pane of glass is vertically spanning. The bottom rail prevents it from moving in and out. At the top there is a gap and the fixings are subject to a lot more bending force. For fixings to realise thieir full capacity they also develop a "second order" tension effect. They can't develop the tension as the compriband compresses and the frame at the top will bend upwards / twist under wind loading. One thing that stops the movement and saves the glazing companies is that the plaster board, masonry check outside / or the mastic lasts just long enough to make it very difficult for the home owner to complain. Bifold doors can be even worse as when they are open they rely on the top part of the frame to stay rigid, it does not have to be windy to cause a problem. It's a dilemma once you start to delve into it!

Nod.. see when you are sticking on the external corner beads for rough cast do you mix in a bit of old gypsum plaster to flash set the dabs on the beads?

No, whether they barrow it in or pump it the final result will depend on the quality of the mix design, the weather and internal temperature on the day, good compaction and a dilligent workforce. These are the things to focus on. Oh and in the old days you they used to say.. don't buy a car made on a Monday of Friday as folk were still hung over on a Monday and wanted to go to the pub on Friday.. corners were cut.

Is it veneered door? The discolouration could be due to this.. where the veneer has caught a bit of the sap wood. Or something to do with the glue type?

Just a thought.. well a couple. SBR is not the same as PVA and they behave in different ways. If you let SBR dry then stuff has less of tendency to stick to it. You can make things worse. SBR is generally meant to be left until it gets tacky then you apply gypsum based or other cementitious materail to it so it forms a chemical bond. Have a look at the SBT technical data sheet before using it to be safe. It's on another thread but the "green plastic" has it's benefits provided you get the rest of the details right and control the quality of the whole job. Up here in Jockland if you turn up to say a domestic loft conversion and ask where are the tapes are they (the Contractor) may suggest you need a deep fried mars bar to rewire your brain. Maybe they do the same in Yorkshire? For all. If you are getting your local builders to price this kind of stuff then be mindful that complex air tighness comes at a cost. If you are new to self build or extending start with the simple stupid, the things you can be comfortable with and able to control quality wise yourself on site. Make it as simple as you can even if seems initially like a comrpomise. Once you get the prices back, if you get many at all, then consider where the weak spots are.. service penetrations, the real howlers.. movement in the structure as it beds in.. can easily be 10 - 15mm and so on if you want good long lasting air tightness. If your aim is just to get a good result at the beginning then why bother going to all the hassle?

Hiya. Hope this helps and for a bit of fun (please excuse my grammer / spelling) I have added in some other stuff later to do with timber framed structures and thickness of ply / OSB boards in a structural context. Internally.. towel rails.. future provision for grab rails in bathrooms etc. The Scottish Building Standards talk about robust details. Below is a screenshot from clause 3.12.3 from the domestic handbook. 18mm ply is considered to be robust. Next turning to timber frame and what the structural sheeting does. Your vertical timbers generally hold up load. But at the top and bottom they are often just nailed with 2 to 4 nails to the top and bottom rail. Thus if you put up a TF panel with no sheeting it's easy for the wind say to push it sideways.. your house will then fall over. If you nail a sheet of ply to the frame it stiffens it all up. The sideways (horizontal forces are transferred from the timbers through the nails and into the sheet. The sheet then transfers these loads to another part of the sheet that is connected via other nails at the bottom say and back into the timbers. The sheet acts like an exoskeleton. SE's call this diaphragm action. The nails carry mainly shear ( sideways loading), they do other thinks but I'll leave that out for now. Now remember where the load goes. From the timber, into the nails, into the sheet, into other nails and back into the timber. Now if the sheet is thin it will buckle and also fail where the nails are transferring the shear loads. To mitigate we can make the sheet thicker.. thus spreading the shear loads at the nailed connection. Below is a screen shot of part of a TF panel design, one I made earlier today in the oven. Its a bit abbreviated and there are some post and later calcs that go with it. Also I have manipulated the calcs to suit this panel so please don't do this at home. If you are browsing then please don't read on. If keen then the following is a fly through to give you a flavour of what it is all about and the things you need to look out for. The above is based on BS 5268.. it's a bit less lengthy than the Eurocodes. Rows 529 to 533 are the basic parmeters showing the basic strength of a typical TF panel. You can see here that you can add another sheet of structural board on the inside. Row 531. We do this if we get stuck.. BH members like to put big holes in walls and fill them with glass. Now we take the basic strength and start to modify it depending on the following: Row 536 to 541. Here we are looking at the spacing and diameter of the nails. Be aware the nails and spacing are important! At row 543 we take into account the board thickness. The base line for this code is a 9.0mm thick sheet. if we make it thicker we get a positive increase in resistance. Rows 549 to 551 take into acount the shape of the panel. A long low one will carry more horizontal load than a tall thin one. Row 554 takes into account the size of the windows / doors. Cut openings in the panel and it get weaker. Row 561 looks simplistically how many other panels are attaching.. this requires an essay / book to explain. Row 566 recognises that the TF and masonry interact. Row 575.. if the applied load is less than the resistanc we crack open a beer! Lastly you'll see that this panel appears to be over designed. It's not as the later checks on global stabilty are the critical ones.

@Rebel80Good to see the slender vertical glazing bars. They look great. They look like true sliders rather than the lift and slide type. We have the Origin ones and they run pretty smoothly with similar sized panels. The locks are discreate as are your's. Like them. I think the break in the bottom rail is a potential issue. Your building is going to move under that bottom rail. You need to make sure that the drainage track channels the water outwards.. that's not going to happen once that joint opens up and translates sideways. Also as they are true bottom sliders you'll notice the bump as the bearings run over the gap in the stainless running bead. I have found ours are really sensitive and even a small amount of dirt on the running bead is noticeable. If these beads come out of alignment on plan then you'll be even more disapponted to say the least. If it was me I would be minded to ask why did they not put the joint under the centre pane and fit a coupling piece under to ensure the water is channeled outwards at all times. The track will attract a lot of water when you get some driving rain against the glass. Interesting to see your steel over. Who designed this? I wonder what is above in terms of load? The packers over the head look tight on that span particularly over the fixed centre pane. I ask as am curious how the installers have managed the deflection in the centre of the opening.

Sleep well! You probably have enough masonry over the opening and to each side to form a properly butressed arch. Thus if you "very conservatively" project a 60 deg line up from the edge of the opening you form a triangle of masonry. This is the bit the steel needs to carry. If say brick and the perp ends (the vertical joint at the end of the brick) are fully filled then it will almost be self supporting over a small opening width. @Caversham Build"I also have a 6mm plate welded to the underside of a cantilever beam beam to support around 100 - 150kg of masonry over a span of 4 m " Cantilevers are a very different animal as are top bottom plates welded to beams as they can introduce significant buckling effects and torsion (twisting) effects respectively. It's a long explanation but if you have any concerns don't hesitate to raise this with the SE.

Yes, have seen this myself Nod. Have seen a couple where you can actually wring the water out of the insulation into a bucket. But when you investigate further you often find that this is a symptom of a problem that lies else where. For example, water vapour is getting in round the sides, leaky pipes, sparly ducting conduits sloping back into the wall.. it's a long list. Also take a timber frame, if the trickle vents to the cavity are blocked then the moisture is more trapped. Sometimes the breathable membrane is installed to wrong way round.. ! Yes designers are aware of the risks and in the short term if you let the building breathe both ways then it will probably have more of a chance except in say family bathrooms or in heavily used kitchens. Probably the stir fry is you friend as the grease will seal the gaps? Interesting you cobservations. Yes, this cropped up a couple + decades ago when timber frame really caught on in Scotland but at that time while we knew about the "reverse dew point" we discounted it as a serious threat. Now however the insulation levels are significantly increased and air tightness is now a consideration. In the early days we got away with it as although the timber frame houses were comparitively much warmer than the existing housing stock they were still draughtyish compared with what we are building now. But even back then we know that the more insulation you introduced and the more you controlled the air flow then an increased risk of condensation would follow as a consequence.

Plus one to the above. There are few nautical folk on BH. A lecturer of mine used to use this term when he was teaching us about how to find a solution that initially seems very complex and unachievable. You point your boat to a position you know you can get to, then when there, complete the last leg. He actually explained how this was a good commercial approach at times as if we wanted to get a job we needed to know that money does not grow on trees. If self building is at the top of your list then can you move / rent in your preferred area? Keep you ears to the ground and mix locally. Maybe try and cut you teeth on a small renovation, make some builders contacts, you may find something falls into your lap... that is my attempt at aiming off. All the best and keep posting.