Gus Potter

That gusset plate at the top of the column with the oval hole looks interesting. I was wondering if someone has been looking at lifting and handling hence it may be a lifting point. But putting my SE hat on the strength and stiffness of that connection has been significantly reduced to the point where I would want to revisit the calculations and explore the "design journey" that connection has gone through.

On our own house we went for the Origin sliders. They have a 20mm wide mullion in the middle so very little frame to obstruct the view. They are not the lift and slide type, just have a small locking handle, all very neat and elegant. My own view is that bifolds have a lot more moving parts and are more sensitive to structural movement and deflection, looking ahead for say 5 - 10 years.. parts will wear and so on, can they (bifolds) be fixed.. easily. The sliders we have open from both sides so that offers up the opportinuty to rearrange the furniture in the room in some ways. They have some roller bearings on the bottom and although pretty big and heavy they run well provided you run a cloth over the running rail at the bottom from time to time. On the down side the sliders are probably less air tight as they have brush seals where as the bifolds will have compression seals mostly. But over time the compression seals lose their flexibility anyway. My choice would be to favour sliders first. Dilemma or what!

Being a philistine (maybe like @ProDave) here but also greatly appreciate the thermodynamic knowledge of everyone and learning a lot. In the not so old days on big houses we had a hot water cylinder. The water was heated by the boiler via a exchanging coil in the bottom part of the cylinder, when the boiler broke down we had electrical heating elements, one near the bottom and one about 2/3 to 3/4 up the height of the cylinder that could be deployed. About 200mm from the top of the cylinder we took off the main hot tapping, this was to partly reduce air getting into the system as we are talking vented (gravity fed) cylinders not mains pressure, say up to 3 bar unvented cylinders. We then run a loop of pipe around the house, often called a secondary loop and this was really well insulated. We installed a secondary pump that circulated the water around the secondary loop, but this pump was on a timer set to run when the house was mostly occupied and hot water demand was most likely to occur. The kitchen tap was off the top of the cylinder as this is where the water was hottest and if you got a bit of "air" so be it. The secondary loop acted like an electrical ring main. Each bathroom was tapped off the ring so when you turned on the hot tap the hot water came out nearly right away as it does not have far to go, or if you ran a big bath the hot water remained at a constant temperature. Now my question is. Can you marry up these old principles with the new, just install a secondary pump to circulate the water to avoid statifcation? But of course the secondary pump needs that valuable electricity / energy we are trying to make most use of. Maybe in the round this is a simple way to do this as too much complexity often leads to higher maintenance costs etc?

@Barryscotland Hi Barry. If the trap is holding water then the seal is maintained. But you may be getting vacuum in the system. This often happens when you flush the toilet or use another sink say. The "plug" of water either fills the pipe to full or nearly full bore and that sucks the water out the shower trap as it creates a vacuum behind it and thus the smell comes out. These types of shower trap often have a very shallow water seal depth. 40 - 50mm as opposed to a kitchen sink washing machine trap with a 75mm water seal. Look outside to see if you have a soil vent stack. Has the top come off and/or birds been nesting in this? Is it cranked and some bits have fallen off and it is now facing into the wind or on the leeward side say. Next try first filling the shower trap. Then go around each sink/s and toilet/s one at a time. Use them in the way you have been doing and get someone to listen to the shower trap, or smell. Sounds weird but the first objective is to look for the simple stupid. Don't rush this, be patient. Now some sinks have an anti syphon trap fitted. It may be that one of the anti syphon traps is sticky and not letting air into the drain to relieve the vacuum. The objective is to find the appliance or the thing that has changed in the system as it was working ok before. Working up you may have a 110mm drain line that is like a branch line in the house. It may have a 110mm air admittance valve, a bigger animal than the small valve on say a sink trap. That may be sticky. Try this and let us know how you get on.

Yes they are an important component. The standard wall starter kits Catnic / Sabre fix mostly work in horizontal shear. In other words when you build an extension with the extension wall at right angles to say the back wall of the existing house they stop the wall from moving horizontally in the plane of the existing back wall. They don't contribute much to stop the extension wall from moving away (tension effect) from the existing house wall and leaving a gap. This can happen due to a little settlement of the new wall, shrinking (concrete blocks shrink mainly) and swelling (clay bricks) as it ages, moves season to season with temperature changes. The same roughly applies to what @johnannik has. The starter kits are intended to primarily stop the new wall from moving horizontally at the junction between the old wall and new one. You have some pretty solid looking walls there, particularly the new one, laid block on the flat? Give your SE a call and see if the new bit of wall will work as a stand alone column or something to that effect. then all you need to do is deal with the shrinkage / swelling between the old brick and concrete block. It may be that all you need to do is to put a couple of plaster stop beads on the outside to create a movement joint in the external render.

That is a cracking and interesting job you have there, especially for an SE. Have had a brouse through the posts and the drawings and it looks like there is a lot to get your teeth into SE wise. The SE drawing you posted looks like a preliminary sizing drawing to give the Architect a feeling for the structural envelope. Maybe there is a lot more detailed information? On a job like this, to review and value engineer, if there is only preliminary sizing information available, I would probably look to model in 3D the ground floor primary walls on the two floors to see how things all line up and the vertical load paths and just as importantly check to see that the building stability system proposed looks adequate. Nothing special, just enough to check the loads paths and get a feel for the structure. This gives you confidence that what is supporting the roof is ok and nothing serious has been missed. This would provide the platform for the roof design and associated steel work in detail. The 3D software is then used to generate the sections, particularly the bits where that are really hard to draw in 2D and the steel fabrication drawings. The great thing about this is that the model is in basic colour so you take screenshots and put them on the construction drawings, if the joiners have a "picture" to look at life is easy for them. You can turn the model into a file that can be spun round using a laptop and say using Navis Works (free viewer) on site to help the joiners visualise where all the bolts go, the awkward timber cuts and so on. Question.. What level of drawing and design information do you have to work with? As this is a new house it could be worked up in a lot of detail as there is much less uncertainty compared with say a renovation in terms of dimensions for example. That would include all the connection details, steel fabrication drawings, timber connections and all the tricky bits. Is it the case that the Architect and SE have included a lot of "contractor designed elements" and left it to you to figure out the construction / steel fabrication details and sequence? Below is a small trussed rafter roof screen shotted out the software with some quirky angles and cuts. Joiners love the visual aspect and can then easily understand the dimensioned 2D drawings and wind bracing system Keep us posted and posting as very interested, wishing you good luck too!

Argree @CharlieKLP There is no free lunch in this world. No contract the more risk the customer takes on board. Contracts written by builders themselves tend to favour themselves. It's a big and emotive subject.

If you look at the plate sizes you can see that they are not standard. When designing stuff like this you want to think about minimising cutting. The plate shown is 360 x 260. But what you want to do is to cut the plates out of standard flat bar widths if you can. Standard widths each side of 260mm are 250mm and 275 mm at 10mm thickness. Now to fabricate this connection the plates need cut at an angle to form the gusset down to the valley. You can get really clever and really reduce the amount of cutting if you don't mind the appearance. For a small order like this you may find a price for the 6mm fillet weld comes in at £30.00 per metre run. Then spray paint it yourself with galv spray... in your own taste of tint / colour.

Interesting, but if you don't want to use an industry recognised form of contract (often gives you the most protection) then don't forget to inform your home insurer. They may for example insist that your builder also has contract works insurance. Builders can purchase what is a called an "all risk" policy that is intended for small jobbing builders for example. This is different / over and above public and employers liability insurance. Employers liability insurance is a statutory requirement. Say your builder / roofer goes away for the weekend and you get a burst pipe or water ingress that floods your house. Who pays? If you want to not use a recognised form of contract then at least check to see if your builder owns their own house, it is not a matrimonial home, is not a limited company, then in the worst case you may have an asset to go after but that is to be avoided if you can. You can find info on the net about contracts, I have written some stuff as have others on the internet. You may be paying in cash.. I've written about that too. All the best, but continue to be cautious.

Looks like you may have a bit of a "disconnect" between what you actually have and the drawings so can see why you are raising some queries. Starting with the roof. Looks like you have prefabricated fink trusses which are resting on the timber frame with a stud thickness of 89 -95mm. I'm guessing at the span of the trusses from the photo but over the existing window you'll have maybe have a timber lintel made up of 2 no 145 or 170 deep timbers or a Kerto beam (some composite) of a similar size. The soffit is level all the way round so that tallies with a standard kit. The timber frame is the skeleton of the structure and holds the masonry in place although they both interact to resist wind loading. With that type of roof detail I would not expect to see a lintel on the outside masonry leaf. Now when you widen the opening you get much more deflection, bifolds are very sensitive to this hence the flitch beam. But the flitch beam looks too deep! How do you fit the doors and what is under the concrete lintel shown? I would ask someone to go in the attic and check to see how the eaves are formed and then make sure what is drawn can be built and hold the roof safely wthout excessive deflection. The steel grade of the plate suggests that this may be an old generic detail that is recycled and not maybe applicable to what you have as does the lack of a bottom truss chord in detail D1. That said I can't see all the drawings hence it's just suggestion.

@Onoff Like the veg patch. Would advise your mate to give the "shed" idea a rethink using these sections. Also could be false economy.

Hello @Marlin That's a good first go at a concept. I see you have picked up on the inline purlins.. for a domestic type application that makes sense particularly if the frame is to be kept on the warm side of the insulation envelope. There are many reasons for this, some relating to the Architectural design some to do with the structural design and a lot to do with insulating and detailing. There are certain nuances that apply to domestic design. Long story so won't explore in depth just now. Structurally you seem to have a suspended ground floor, there are other options such as a ground bearing slab. What you have there structurally is a half way house between a true portal ( two columns / two rafters) and a tied portal ( two columns / two rafters tied at the eaves joint) which is a different animal. One way to think of what you have is akin to a portal frame with an integral mezzanine floor. This too behaves in a slightly different way but it's no great drama. Your soil type does not appear to be a big issue so standard pads under the columns look to be the likely outcome. I can't see your bay size but it looks about 4.0m? A 140 deep purlin looks on the ball park. You can play with the thickness. Also you can play about with the number of frames you need, maybe larger bays to fit the intended openings? For me, if I was designing this for you I would want to look first at the Architectural intent, planning constraints, then have a quick sizing of the sections, foundations and any key detailing that is off piste. Iterate the design process.. then do the final structural design and detailing once you have the go ahead prom the planners.

A few random thoughts. I'll start with what may be going through you SE's mind and their thought process. The 100 x 100 lintels tend more often to be what we call non composite lintels. In other words they act like steel beams say that "stand alone" and don't rely on having masonry above that interacts with the lintel / beam to create an arching / deeper beam effect. The 65mm deep lintels work in a different way, often compositely and they need to interact with the masonry above. In other words they are two different animals... but look very much the same. Now if you don't have say 4 -5 courses of brick above the lintel then you often need a non composite lintel. Also, on alteration work no matter how well you repoint the gap over the lintel you'll never get the same "bedding effect" that you get when you are laying the wall for the first time. You new mortar will shrink away so the brick above won't interact with the lintel to develop the composite action. In other words you can rule out a composite lintel on most alteration work. The difference in load bearing capacity is a lot so don't get caught out. You SE has probably also thought about how you prop the wall when you are doing the work and how much space you have to do this. They have probably also thought about what is above.. are there point loads from floor joists, maybe other stuff above, a door over lapping the opening, all sorts of permutations.. and that again rules out a composite lintel.. hence the 100 x 100 that is a non composite lintel. The 100 depth is say enough to carry the final loads but shallow enough for you to prop it? Before you go ahead mull this over. Be very careful about putting in any lintel orientated in a different direction from the manufacture's intention.. trouble ahead! Your weird 20mm cavity! What you probably have there is what we call a collar jointed wall. The two leaves are tied together with brick ties at much closer spacing than you have in a normal cavity wall and the gap between the leaves is filled with mortar... the gap is usually 10 - 20mm to allow for variations in the brick widths.. hence the 20mm you are observing. This allows you to design the wall using it's full thickness so you get more bang for your buck. In summary it looks like your SE has put a bit of thought into this. I would lift the phone to your SE before you start deviating from the design.

Good solution Mark. +one

That is a stunning photo of the ground! Me too never seen such clear definition of the layers and the distribution of the particle sizes. Looking good Nod.. the rain will stop! Dave.. you are a bad man!

Hello Marlin and welcome. You'll get plenty help here. There are a few folk that have joined since this thread was started. It's a guess, but some will be along shortly to contribute in terms of how you design this structurally for a domestic application and a few tips and hints on the insulation details and so on... and many more. In terms of structural design the main difference between agricultural design and domestic design is the deflection limits you work with. In terms of detailing you have a bit more work to do to reduce cold bridging, detailing around the openings and damp proofing, all surmountable though. Think of it like an office building.. meets the same standards very much as a house requires in terms of environment and insulation. Ok. To get you a bit further what about posting your sketches, make sure you dimension them; include the roof pitch, show windows / doors and the heights you want internally, where you want the openings and how big you would like them to be. Also show the ground levels as this impacts on the column height down to the found as that is one key parameter when determining the steel section sizes. What kind of ground do you have, clay / chalk / rock etc. If you want.. provide your location. You can give just the first part of your post code. Then we can see roughly where you are in the country. Also provide the site altitude and if close to the sea.. if next to a cliff or at the top of a long exposed hill let us know that and then we can get a handle on the wind and snow loading This will allow for example for folk to give you a rough steel size for the main portals and a ball park size / spacing for your steel purlins and wall rails. There are many variants but you need to start somewhere! For your steelwork you can go the whole hog and work all this up to a full set of fabrication drawings, material and bolt list with numerical control files and then start farming that out to fabricators. All they need to then is to fabricate as they have no design input at that point. The numerical control files are a text file that is accepted by the software on most advance cutting and drilling set ups. Having these lets you go to big fabricators for a price too. But the NC files are not essential as most smaller fabricators just want a good set of drawings. A good set of drawings comprises. General arrangement drawings. What are called assembly drawings.. these are drawings that show say beams with their end plates say and the weld information, a plate and shaft set of drawings. These are drawings of each individual plate and beam. Small fabricators may buy in the plates and shafts and make their money on the welding / painting/ supplying the bolts and so on.. again many variations on how you can go about this. Now that is a lot of drawings but we use software to do a lot of the heavy lifting and drawing production. In terms of PDR the planners are interested in what it looks like from the outside rather than the skeleton of the building which is often covered? Keep posting.. interested in your ideas.

@Ben Weston 1/ Take everything the brickies say with a pinch of salt. If you have large bifold doors say then you could have point loads and need at least something with a bit of strength under areas of localised loads. Your average brickie is not going to spot this. A few may do but it's evidence you need not "blarney". Question.. do you let the brickies advice take precidence over BC and the SE? 2/ To get the best economy you need a really level found to build off + /- 5.0mm if you only have a couple of leveling courses before the masonry becomes visible. In practice this does not often happen. 5.0mm is too tight a tolerance for practical day to day site work on concrete founds in the domestic market. It will be hard to achieve a level bed for the engineering brick with only one course of trench block and still comply with the maximum and minimum mortar bed thickness required by the codes. 3/ Practically and cost wise your founds are unlikely to be flat on the top. Expect in real life a variation of some + / - 15mm often more .. if you get a hot day then the concrete won't flow so well, a really wet day and the folk laying it will want to just go home. Solution. Use 7.0 N dense blocks laid flat and bonded to get the coursing right and a level bed. Then put your Engineering brick on top.You will get a bit more play in the mortar bed and this will make it easier to level the coursing before the engineering brick. It may be that the engineering bricks are forming a damp resisting function particularly if matching into an existing building that has no DPC but blue / engineering brick as the DPC. If this is the case then they could be decorative and it needs to be spot on visually. To realise this you need to give yourself as many points of adjustment in the mortar beds under the ground as you can = more courses. In summary forget mixing and matching, stick to dense concrete block and concrete bricks if need be if it turns out the top of your founds are not quite where you expect them to be... they probably will not! Forget the one course of 3.6N trench blocks. It is false economy.

What is the mesh required for? Generally the A type meshes are to control cracking only rather than acting a true reinforcing bars like you would have in a reinforced concrete beam or floor slab in an office floor. You'll often see on a drawing A142, A193 or A252 meshes specified. If this is the only mesh shown on the drawing and there are no other individual bars attached to the mesh then it is likely for crack control only. The are other types of meshes called structural meshes and these start with the letter B. If you have an A type mesh then as @saveasteading says explore using plastic fibres as you could save a lot. Post more info if you want to investigate option further.

@SteamyTea Great link to the book. Ta.

Yes it is standard stuff, nothing wrong with it. In fact most of the big TF companies seem to use it. On the practical side if you are a self builder then you have to be more accurate to fix plasterboard to a 38mm wide stud than a 45mm wide stud. In certain windy places or if you have slightly higher walls (longer studs) it can work out economically if you use the slightly deeper 95 x 45 timbers as this lets you keep a 600 centre stud spacing rather than going for a 400 centre stud spacing. It's not just the extra timber as when you have 400 centre studs you get closer repeating bridges which impacts on the insulation performance. The main thing is that an 89 x 38 mm stud has different load bearing and wind resisting properties compared with a 95 x 45 size. Would be a shame to do a lot of work and BC knock you back. Best to check first.

That looks interesting. You may have to put a bit more thought into how you make it safe and comply with the accessibility requirements, especially if it is a new build. It's not just the stair on it's own but also what you have at the bottom / top of the stair / corridor widths and so on. That is why maybe why you find folk backing off a bit in helping you with the stair design. You need to provide the whole picture in terms of top and bottom landing space / doors in proximity at the top and bottom of the stair / opening direction, the size of the landings at the top and the half landing and so on. A few things to check are for example in Scotland: Are there gaps more than 100mm between the treads and between the handrail balusters. Is the hand rail / baluster assembly climbable? What space do we have at the top and bottom of the stair, where are the doors, are there any fire / smoke protection measures required, can we fit hand rails and where do we need them and what width of stair is required. If a new house then disabled access requirements will apply. Basically in Scotland you need to make provision for a future stair lift. The regs require space at the bottom of the stair and at the top to park / access a standard stair lift. But you can now get ones that are self parking so that makes life a bit easier. Stair lift technology has improved a lot over the last few years. I would try if you can to put together something that shows more information, maybe that covers the above and see how you get on. You can always test the water by posting here on BH. Don't worry if you can't understand the stair regs at your first attempt.. very few, if any, do, myself included.

Hope this helps a bit. Just watch the timber thickness.. as in an 89 depth it is often 38 mm thick as opposed to 45mm thick that you get with grade C16/ 24 95 x 45. Please ignore the branding, it's just a snippet I have in one of my data sheets, makes for easy reading though.

Wishing you all the best. Looks worth the effort you are putting into this. Keep us posted!

What about this? Have attached a very rough sketch. Notch bottom of rafter< 25% Use JHA Simpson hangers wrapped over as you have shown. These take the shear loads. Buy some flat galvanised restaint straps 2.5mm thick or round about. Get a vice and a spanner and gently put the 90 deg twist at each end where you need them to be or if you want the full bunnah get Simpson to make them for you. Try if you can to get at least 6 no square twist 30 x 3.75mm into the rafters maintaining a 20mm edge distance to the timber. Much will depend on the rafter angle, the shallower the more meat of timber you have to play with. The twist strap will sit flush with the bottom of the Glulam and tie them together at this level. Get 3 - 4 sq twist nails nails up through the strap into the underside of the Glulam. If you put the strap over the top of the timber you'll need to scab extra timber to the side to fix the sarking as the strap will foul the sarking nails. Food for thought?

@SarahGThat is a good place to start. Often if the builder knows that someone is keeping an eye on things for you then this encourages a good standard of workmanship. Also, if you set it up right and say to the builder that you have engaged someone who is fair minded, even handed and impartial then it gives the builder confidence that if they get a bit stuck they can call on your advisor for guidance... feel able to lift the phone and be able to discuss say problems / unforseen issues on site. It's about working as a team. This to some extent this de-risks the job for the builder as if say there are extras they may feel that they will be paid for them if justifiable. It also de-risks it for you too in that the builder will know that any spurious extras will be resisted.