Gus Potter

Hi pocster. That looks like a typical lintel that may be produced by say Robslee, they call it a type A lintel which is what we call a composite lintel. It has the rod in the middle. For all they are two types of generic lintels, one is called a composite lintel, the other a non composite lintel. They are two different animals. The composite lintels tend to have the rod in the middle and a bit of prestress in the rod to keep the concrete in compression, also helps it not to fall apart while you are laying the bricks above. Long composite lintels need to be propped until the brickwork cures so read the manufacturer's instructions. If you have a good height of brickwork above they can span quite a long way if you are careful. If you think about a reinforced concrete beam. It has steel in the bottom with a bit of cover to the steel to prevent corrosion (plus often fire protection) and provide bond between the concrete and the steel rod / wire. Concrete is good in compression, steel good in tension so when you load up the beam from the top the bottom goes into tension (resisted by the steel) and the top into compression (resisted by the concrete). Now for a composite lintel you can mix up materials. You can have a rod encased in a bit of concrete, like your's pocster. If you make sure the top of the lintel is clean and put say 5 -7 plus courses of brick (see manufacture's spec) on top then you now have a deep beam.. (the top 80 odd % is of brick if you have 5 courses or more of brick) .. the depth of the lintel plus the brickwork above and that works quite well in places. In fact surprising well.. What happens here is the courses of brick above acts in compression and the rod in the lintel is in tension. The concrete in the lintel is not doing that much. In other words the brickwork acts compositly with the steel rod / wire in the lintel.. like say a SIPS panel where the sheeting and internal timbers act together and to make this work the sheeting has to be well fixed to the internal timbers.. thus the brick work has to be well bonded to the top of the lintel and the perpendicular ends of the bricks fully filled with mortar. In summary the lintel per say does not act to resist the majority of the bending effects.. the concrete around the rod / wire just acts arguably as a medium to transfer the horizontal shear forces (tension) in the bottom side of the brick to the rod in the lintel, which happens to be encased in concrete. A big mistake folk make is to put a DPC (cavity tray) between the top of a composite lintel and the brickwork above. Here you create a slip plane and the whole system stops working.. please don't do this. Now a non composite lintel acts much more like a reinforced concrete beam. The major difference is that it does not rely on having masonry above. This lets you introduce say cavity trays and put floor joists on it for example... maybe a bit of point load. The rods are more heavily prestressed and are in the bottom. They are marked top. If you can't see the mark, (sometimes the lintel may have been cut down) then look for the rods and put them at the bottom.. unless your SE tells you otherwise. Sometimes you can use a lintel upside down to create a cantilever / corbel but this is not that common. Prestressing? An ordinary precast reinforced concrete beam has say steel in the bottom, a rebar cage is made and the concrete poured round about it. It all cures and you load it up. Now steel is quite a stretchy material so when you load up the beam it drops (deflects) a bit before the steel really starts to work. The concrete is also a bit elastic so it has to "shorten" on the top of the beam and this gives rise to more deflection. Also concrete shrinks so that relaxation has to be taken up and that can manifest as more deflection. When they make lintels they don't make them one at a time. Commonly they have a very long mould and run a long wire near the bottom. The wire is put under tension and the concrete poured and cured. Then they release the tension blocks at each end of the wire and saw up the long prestressed beam into common lintel sizes. Once they release the tension blocks the wire in each section of lintel it wants to shrink, but it can't as it's bonded to the concrete in the bottom of the lintel. What happens here is that the wire compresses the concrete in the bottom of the lintel and this makes it bow up a bit.. which is good as when you build it into your house it bows back down. the idea is that the bottom of the lintel ends up about flat... in an ideal world.. just like us on BH! If you are curious if you take a longish non composite lintel.. say a 145 high x 100mm wide (type C that look like a concrete beam higher than it is wider) and lay it flat with the rods near the bottom you should see a bit of a bow upwards. But @nod some non composite lintels do have the rod in the middle!! and !!! The explanation for this is very lengthy but so have left it out. These tend to be wider and flatter. There you go.. hope this helps to give you a flavour of how the different type of lintels work and hopefully this will help you select the right lintel and use them in the right way. For me I tend to stay away from composite lintels on longer spans even if I have a good few courses of brick above as the workmanship / site supervision is often so poor these days. Yes I know the heavier non composite lintels cost a bit more but they are more "idiot proof" to some extent. Also, on self builds we often make late changes so non composite lintels give you a bit more flexibility here.

Maybe aye, maybe naw! @James traversIt would be help to know what the inside looks like. Can you see any cracking from the inside? To be able diagnose something like this you need to gather a lot of info. If I was doing this I would start by looking at the whole house and the houses round about (if you do have close neighbours) to see if the main house and the other houses are showing signs of movement. Also, I would look at the terrain, generic type of ground and so on and anything else I can see or suspect.. its a long list! Often what you do here is to get a feel for the place and try and work out what it can't be. Then work out what it could be and start to focus in more detail on that. It all sounds awfully complex but you want to make sure you have checked and ruled out say mining or a bit of weak ground strata that if you miss it will be a major clanger. Once you know you have ruled out certain things you can then say.. yes this is a localised problem and ask.. what could it be? That is a good place to start and can reveal more about what kind of movement is taking place. It's a fascinating thing to deal with.. unless it is your own house! The main thing is not to panic, once you understand what is causing the cracking you can then decide.. do we just leave it to settle down / monitor and repair the crack after a year or so.. or will it get worse, if so what can we do to mitigate this.

Often you see this type of cracking. The cracks down the wall seem to be of uniform width.. suggests at the outset shrinkage say of concrete blocks / render rather than settlement. If it was settlement then often the crack wiil be of a different width top to botom, not always, but that is a common feature. But .. where the roof meets the existing wall the crack seems to continue in the existing elevation? That raises a few questions as you would not expect to see this. @James traversPost more photos if you wish of what you have round about and if you have been slapping out walls... doing the open plan thing.. I wonder.. if you have an old house and slapped though to make the opening to an extension with good solid founds ..have the existing walls settled as you have added load locally to the old bits of wall either side of the slapping when you put say a beam in.. Look really closely at the crack and try and figure out what has moved down or up relative to the other interface. Look at the rest of the house wall and put your "Columbo" hat on. Have you had a really dry spell and the old building has dropped a bit more than the new extension? Don't always assume that the new extension is moving.. a good extension with "well" designed found tends not to.. but add load to an old found and the existing wall locally loaded for example by a beam over a slapping could well move a lot more than you think.. start at 15- 25mm for a shallow footed old building found in certain types of ground (clay) a bit less on sand / negligble on rock ! Help ma boab you may ask 15 -25mm .. but old buildings move a lot! That kind of movement is well outside say NHBC / BC tolerances but old houses are a living thing. If you build a modern extension with stiff founds that stays still these kind of cracks occur as the old building is moving about relative to your solid extension. Don't always assume that your new extension is the problem. It can be that it (extension) stays still and it's the house that moves up and down. And there is the rub.. BC want an extension built to be bomb proof with no account as to how you marry this into an old structure that moves up and down with the weather as it further ages.

You have a bit of thinking to do here. Don't go sticking a trench under where you may want to put a future driveway, you'll get caught out when they ask how you are going to deal with the run off from the hard area of the drive. You may say.. permeable monoblock or say open textured asphalt, BC will say.. but there is a drain already using the infiltration capacity of the soil under... please provide calculations. Also these things are supposed to be maintainable.. under a driveway with associated soil compaction.. thus reduced infiltration rates and so on..? Have a word with your designer about your future plans, maybe a swale with some storage capacity either side of the future drive, could even try a simple orifice plate with filter at the ends to say reduce outflow to 5 or 2 litres per second into the water course. BC etc may accept this as it is a very small scheme? If you only are predicting 2.2 cube of water then this will equate to small draft of water in a shallow swale of a reasoable length. Let us know how you get on with your SE.

Rather than a surveyor get a hold of a good roofer and pay them a couple of hundered quid to come with you. If those are the original tiles and you are doing this as a long term investment then expect to re tile and batten + membrane, you'll probably have plans for the attic anyway to try and make more space?. The nails on the tile battens will be a bit sick in places. The flashing, verges, fascia boards and chimney flashing are probaly past their best anyway. What you need to also check is the roof timbers for rot and wood worm. You need to go and see it and get into the attic with a good light. Lastly check how many habitable bedrooms there are upstairs, the width of any existing staircase and the building regs on stair case requirements for the number of habitable rooms in the attic. That may have an impact on how you develop the attic (if that is what your are thinking) and what you may need to reconfigure on the ground floor to make a stair compliant.

Barry.. unfortunately not. If you want to learn a bit more about it then get yourself a copy of BRE digest 365 link below. Will cost you £28.00 but it will give you a grounding on this. I would give you my copy but will get hammered on copywrite if I post it. https://www.brebookshop.com/details.jsp?id=327631 It takes a lot of stone to fill a trench like this, also you have to do something with the muck away, geotech membrane on top. A few rough points. The trench will probably serve to act as a partial soakaway.. good in the summer when you have low rainfall but in concentrated bursts, more pollutants on the roof from birds and just general airborn pollutants. This is when you really damage the habitat. River / burn / stream flows are low so a small bit of highly polluted water off your roof during the start of rainfall can do a lot of damage to the ecology. In the winter flow rates in the water course are generally higher so more dilution, more regular rain washing the pollution off the roof in smaller concentration. In the summer you can get really high rainfall in short spells, more so in England . The idea is that the first bit of water that comes off your roof gets stored in the trench, then as it fills it gets diluted before fully filling and entering into what you hope is a river / burn with an increased flow. The trench is filled with stone with gaps. The gaps (voids) form the storage volume.. hence the apparently large trench. Can you do a pond / retention basin / swale with storage. If you have a bit of space this could be a great addition to the garden with a bit of clever planting? Ponds don't need to be round and you can select plants that do well in both dry and filled pond conditions. Once you get your head around the theory you can use your imagination. If you have a sloping site you can create bunds to a certain extent so a " pond" can be above the original ground level once you have regraded. Clay soil is your friend here. In the round have a look at what you have got and what you could do. You may save a bit, even if you need to pay your SE for another design. Then if you can go the pond way or say a swale you'll get your money back out of the enjoyment of the garden? I hope you are not intending to put your driveway say over the trench?

Yes you could transform that. I would be minded to remove the low walling to the right. Check the split block / decorative stone is sound then bond it all out in undercoat plaster with some corner beads, plaster skim coat and square it all up apart from the inset bit around the opening. Then stand back and have a look. Think, how would it look if we continued the cornice round. Next check the flue. That looks like a relatively new house so you may have chimney with proprietory flue blocks, already fully lined. After that you can decide on whether you want to have an open fire or a stove and what inset.. could be tiles and what mantle piece you prefer if any. Lastly there is an old rule of thumb to get your open fire to draw. For single storey you take the opening area of the fire place opening and divide by 8. This gives you the cross sectional area of the flue. For two storey you divide by 9. That is all provided the chimney extends sufficiently above the roof and that you have no large trees nearby or large buildings. If so you need to check chimney height outside and select the right cowl. Hope this helps give you some pointers.

For all. We have a new bit of dual carriageway nearing completion in EK. One of the roundabouts has astro turf in the middle and nearby a big SUDS pond, probably designed by some that have not thought it through. What message does that send to the kids who go by it every day on their way to school? I wonder if when they designed the SUDS pond and the organisms you need to promote for them to work properly they thought about the micro plastics and initial filtration / first steps in the treatment train? Although of SE bent the number of sites I visit where folk are astro turfing thier gardens is noticable. That said some boy racer has already churned a bit of it up. Well done son! Will take photo and post next time I pass.

Moved to EK about ten years ago as wife's family live here. One day I left the house I had bought and got lost in EK (called the roundabout city..) and it took me about two hours to find my way back.

Simon.. yes that is the joy of Scotland.. you get four seasons in one day.. the sheep are white.. lovely to look at as they get washed nearly every day.. our central heating kicked in this morning in part of the house.. summer in East Kilbride.

Go for the simple stupid. Classic warm roof, the furring pieces are the least of your worries. Before you get too technical try and work out how you will detail the interfaces ( you need to keep the SE happy) and if you can find someone (builder) who will be able to follow the drawings and build it at reasonable cost. Also, you'll need good drawings unless you want to be on site every day. Get a feel for these costs and then look at what it will cost you to make the insulation thicker with a simple design. Your first challenge is going to be to find a builder who will take this on. Next you'll have more labour cost, a detailing cost and site supervision plus a few other things to think about, all on top of all the other day to day stuff. You mentioned C24 timber. What centres are your joists? If 400 centres have you priced / asked your SE if 225 x 75 C16 at 600 ctrs will work, maybe 200 x 75 C16. Often we look at tables, assume a certain joist size at a certain spacing.. partly because we also need to look at repeating bridges for the insulation. With a true warm roof you have much more scope to play with the joist depth width and spacing and see what is going cheep at the time.. who said it was easy!

Like your train of thought @JohnBishop On the face of it you can use vermiculite for plant pots, good for retaining water apparently. I'll defer to others on BH but I don't think it is hydroscopic.. has been use a lot in the past for house insulation. So yes it will hold water if it gets in. I suppose you need to make sure your chimney is in good order, capping, flashings, pointing render and so on. In some ways it may be good that it can hold the water, if not.. it's going to run out the bottom and onto the top of your stove or appear somewhere in the chimney breast above the stove as a big damp patch. If you have your stove on regularly it should drive off any moisture, even if just on a slow burn. The question is what else can you use to insulate a single skin liner that will get round all the contortions in a flue also given that a single skin liner when installed does not centre it's self in the flue. Folk these days want to have a stove that will just tick over but still draw.. thus you need to keep the flue pipe warm.

That's interesting. Did they explain why it leads "flue rot" and who does not recommend it? Is it because often the flues are in bad condition and they end up getting the blame or is there a fundamental reason not to insulate using vermiculite? After all it is common to line a flue if it is a bit "leaky".. in less than perfect condition. If you can find out as would like to know, Ta.

You are thoughtful. What about some acidic fruit near the top to encourage pitting, further down a satchel (fibre of your choice) with artefacts from different corners of the world.. and right at the bottom (assuming you are going to bury it standing) a Timex watch.. made in Dundee?

Roundtuit has hit it on the head and good point / thread @puntloos Any competant builder knows that 99.9% of jobs will involve some changes at some point. Maybe a starting point is to put yourself in the builder's shoes when priicing / selling the job. Do you know much about the Client? Have they got a good reputation for paying? What is their personality? Do they listen to you and what kind of questions are they asking? When you seek clarity on say a detail.. how do they respond? If technical.. do you get a quick response from their design team? A lot of domestic Clients just won't do anything to help themselves here and this introduces uncertainty to the builder. If you don't know something just ask the builder and see how they respond, don't be embarressed. An experienced buildier when pricing up a job will often spot design / buildability flaws / opportunities for improvements. Do you tell the Client at this stage? You risk getting off on the wrong foot with the Architect / SE etc or just coming over as knowing too much.. trying too hard to get your foot in the door! In other words builders are looking for indicators on how smoothly the relationship will develop, if they get the job. Good relationships often = greater security on the expected profit margin thus a builder may be a bit less heavy with the "hassle factor" element of their price. If you go for the fixed price then have the conversation about making changes. The context is important. Again in the builders shoes. Say the price was based on two storeys with say a 30 -36 week programme and you turn round and say you just want one storey and the builder knocks off a lot less than you expect. Now the builder still has the over heads, needs to find other work and so on, hence not the price reduction you expect. The otherside is you ask for say a larger hot water cylinder that can be easily accommodated architecturally and structurally and the builder says this will result in a two week delay and the scaffold needs to stay up for longer.. daft example but.. have seen some daft arguements made in the past. One simple way is to say to the builder.. look I may want to make some changes that won't impact on the critical path of the job. Give me your day rates for the different trades and what uplift you want by way of profit on any extra materials you supply. Also give me the rates if we make a change that involves a bit less work.. if we say use a cheaper slate / tile or a larger tile (thus less of them) on the roof say. Ask.. will you knock off the difference or the difference plus profit? Just ask them innocently (no smiling) how this works and how they have managed this on their other builds. Best to get this out in the open early and then you can decide if this is someone you would employ. A good thing here is it lets you set out some ground rules / bench mark should you later want to make a major change, you can refer back to the early discussions, just make sure you have it writing somewhere. If you can, make sure you have a good understanding with you design team. Even if you got just a basic design, went for the cheapest to get you this far go back and ask your SE / Architect what they will charge to keep a watching brief, be at the end of the phone. It will be money well spent. Often if the builder knows that your design team are keeping an eye on things it can be enough to keep them in check. It can avoid both you and the builder doing something that in all honesty you think is ok but turns out to have a major impact on the structural or Architectural design. Common mistakes folk make are indeed moving a doorway / window, adding extra load to a floor / ceiling by way of extra plasterboard etc. You and the builder may look up and say, no change in the vertical load so ok.. SE may say.. I was relying on this to provide sway stabiliity (stop your house moving sideways) or restraint to a major load bearing wall. Architect may say.. you have breached the fire regs, changed the daylight, ventilation, compromised an access / activity space or some other clause in the building regs and BC are going to pull you up on this etc. Lastly you mention a fixed price contract. There is a big difference between the builders own contract and a recognised industry contract! The former is to be treated with extreme caution!

Sorry if any offense caused . Did not wish to come over as patronising but have , wrong choice of words from me, on reflection would have used different language. Bet you could, it's not just the building theory you learn it's all that tacit knowledge you've gained on the way that you can't put a price / value on. All the best. Gus

Like your train of thought Mike. Having reflected on this over the years and reading the posts on BH I'm minded to conclude that professional / sage advice can help a lot if sought and given at the right time. Having been through the self build journey myself, then been a contractor building other folks houses and now a designer on reflection I would encourage all those starting out to get a bit forward under their own steam then spend the 300 - 500 quid finding someone who will tell them what they need to learn next and where the big pitfalls lie. I would not have done this at the time but on reflection life would have been much easier if I had done just that! But the reality is that the younger generations always think they have invented a new wheel.. the older generations just need to suck it up..and let the younger folk get old and learn the hard way. But unless they learn the hard lessons in life they will never grow up.. and we need the younger generation to grow up so they can pay our pensions!

Good question. You see this cracking pattern often in houses in the 50's to late 60,s where they did not put in noggings / dwangs in the ceilngs. To give confidence in the photo you have posted I would look at some other things as a starting point. Go outside and see if the outside walls have any cracks. Has the attic space if any been " converted" Are there any other cracks you can see inside.. around the window and door openings. Do all the doors and windows open and shut ok? When you walk over the floors do they feel level? Have a look at the other houses round about. Has this house been altered in some way? Often you can dig up similar house floor plans that have been on the market and compare with yours. If so post some photos. Hope this helps give you some pointers and will hopefully help reassure. All the best.

For a bit of fun.. but seriously. As a ball park on TF to start a comparison spread sheet does this fly? A joiner + labourer will make about 3-4 wall panels a day on site, some may be 4.8 m long, some 3.6m long if they have the panel drawings. The idea is that you can lift them into place with two men and brace. Say a joiner cost £220 a day and the labourer £120 / day. For your spread sheet say labour is £340 per day for 4 panels at 3.6m long .. each panel costs £85 to put together plus the cost of material. The panel consists of the timber, the ply / osb sheeting, lintels, breather membrane and crucially the poly prop straps to let the brickie identify where the nails for the wall ties need to go. But it rains and mistakes get made so allow £150 per panel. When a mistake gets made the timber gets recycled into noggings. Yes I said £85 per panel but just go for £150.00 per panel for now. To make this work you need to set up a saw bench on site, spend time reading the drawings so allow £500.00 for that. Next look at the stud height. For basic initial pricing go for a 145 x 45 (C24 grade timber) deep stud as this lets you go to a 2.7m ceiling height structurally without drama (covers most parts of the UK in terms of wind loading also) and leaves you plenty room for insulation of your choice. Yes you can go a lower grade of timber say C16 but stick with this C24 for now. Now if you have a house that is of reasonable size then you'll need some internal racking walls to stop the thing blowing down in the wind. Now two folk can erect about six panels a day by hand.. does not sound like much but there are other things they need to do.. put in temporary bracing, read drawings, have lunch..talk about things..fix it down so £ 340 / 6 = about 60£ quid per panel to erect, fix and have a fag and a bit of a think about what you are going to do next. A common mistake folk make is that when they go to get their roof priced is that the don't tell the truss designer where the the internal supporting structural walls are.. that is one reason for all the confusion on roof truss pricing. For all. When you are trying to do your reasearch on how much things cost.. try this.. start from basics. measure the perimeter of your outside walls. Just as an aside.. the truss manufacturers use a high grade timber TR26 grade ( they test their nail plates with with this timber grade) but often with attic trusses we need timber depth to get insulation in anyway.. so we can use a lower grade timber in a cut roof! In summary from following what BH folk are saying I get a feeling that the cut timber roof and stick built TF may be up for revival? I wonder if the numbers above float the boat.. of course you need the panel drawings / cutting schedule and material list.. allow £1.5k - 2.0 k (plus support and professional advice on the other aspects of the build for that and compare with the TF supplier. I think you may be in for a pleasant surprise! I have a suspicion that the TF and Truss suppliers are milking it..why.. because I have a load of my domestic builder Clients at my door asking me for stick built panel drawings and design calculations..

Great posts from everyone also. Just pondering what everyone has written about their experiences, how different they are and what you need to do to get to the completed build. One theory behind this could be taken from marketing theory.. called the FUD factor, maybe not that acceptable in this day and age but hopefully the mods will take my historic ref in the right context. See Motorola sales training manual. FUD = Fear, uncertainty and doubt. The fear comes for example when you are just about to sign with the Lawyer to obtain usually the plot.. big money commited. You know that to back out will / could possibly bankrupt you or cause big trouble. Once you secure the plot you start to become uncertain about your decision making process. Have I done the right thing? Lastly you start to doubt you own ability to deliver. Now there are a lot of seasoned self builders on BH, some just starting out on their first journey. Some of the seasoned may claim not to suffer from this but.. answers on a post card.. Reasons for self building.. well there are many. My first self build was driven by the desire to own a house that we could not otherwise afford off the shelf.. then we tweaked it to make it an "Architecturally designed house" that made it a bit more special. To insure / mitigate the risk that bad things will not happen you need to grasp the nettle and realise that there is no free lunch. You need to research, again and again. You can further mitigate risk by seeking out professional advice Architectural / SE / Contractor advice for example. Just be honest with yourself.. be willing to pay 200 --500 quid up front say.. it will pay dividends. You can spend half a day / two half days with someone who knows what they are doing and chew the fat.. then go back to work. To get the same knowledge and pointers / tips could take you weeks / months to learn. Play to your stengths. There are some that think they know it all but they are set up to either fail or not make the best of what they have.. which is.. a glass half full... The older I get the more I realise how much I still have to learn and this is part of my day job. In that context you maybe have to recognise that by the time you learn it all the ship may have sailed. If you try your very best, keep a sense of humour and so on often this will often be enough to get you over the line. Yes there is still a latent risk but there is agueably just as much risk in buying an off the shelf house. Why.. when you can by a developer house with the guarentees? I have a pal who has a pal who works for a major developer. They get a heads up for example on the houses that will be air tested! I'll leave you to draw your own conclusion.

Can you post some of the SE's drawings and a couple of elevetion drawings? Are you trying to go off piste here? Advise you don't go off and do your own thing as there is much to consider.

Hi Chris. Had a look at the photo's.. what a great project.. many challenges but the main thing is to enjoy the journey as well as the end result. Just to touch on some basics.. you may have got a handle on this already. What about things like drainage.. septic tank soak away or biodigester. Get stuck into the ground and find out what you have under the top soil. Don't quite know your exact location so have not had a look at this end but some places have deep peat (or really soft sands) interspersed with granite dykes (called igneous intrusions).. great for building on but really hard to excavate for modern sewage tanks to achieve ground porosity for soakways. Have a look about the island and ask about. Local knowledge coupled with some basic research should give you clues here. See link below. https://mapapps.bgs.ac.uk/geologyofbritain/home.html The photos of the internal render are interesting. Hard to tell from the photos but do you think they have a bitumen content.. like an early attempt at waterproofing.. like mastic asphalt? You may actually be still able to smell "oil / hydro carbons" when freshy split or put the sample in a bit of petrol and see what dissolves. Don't taste it.. stick to the whisky. I would really try and find out more about the walls, the founds, there may just be a partially failed damp course! .. could be a slate / pitch (tar) one. Also what is under the floor.. are there any solum vents? may be hidden but look closely. In the 1930's things construction methods were changing fast and costs were getting driven down so don't assume that just because it is a mission hall it will be more traditional and that it is dressed stone outer layer / random rubble with a rough stone inner skin. In fact if it was a mission hall they would have maybe aimed to get the cheepest building on the market at the time so they could spend their money on the "mission" thus this could be an ideal case where you may find that innovation has occured. Do research here on the original intended use and who paid for it to get built. You may find this in the deads.. but that is cheating! You may just be able to squeeze a quazi mezzanine / gallery up there but post a dimensioned cross section. It will need a bit of design flair and an understanding of the regs etc but don't rule it out for now. Lastly what about these out buildings.. any chance of doing something with these? Could you link them to the house? If done sympathetically you just may be able to incorperate this into the habitable space with a link concept at some stage. Is any part listed grade C say? Try and really spend time being "Columbo" now and it will pay dividends later when you come to the design of the insulated envelope and subsequent structure / finishes. Plenty folk like @saveasteading and myself for example are interested in this so please keep posting. Lastly keep a photo diary of this as it will great great interest to all both now and in the future.

Generally a single skin liner will be ok in an old brick flue that is not totally wrecked. Go for a good quality one. Make sure you install the liner the right way up, see manufacturer's instructions at all times. Have a look at the flue exit height. If you live in a town then other things may have been built round about later (taller buildings within say 200m distance, if near the Shard say in London then the vortices will extend much further) that will cause down drafts, if in the country you may have large trees that were not there when the house was built. For the cowl have a look at an "OH" cowl.. more expensive but they do work and are great for counteracting down drafts and promoting a more stable draw in the flue. If the flue is going to be long then to keep a good draw at low burn rates you can often put a single skin liner in an old brick chimney and pour in vermiculite. It keeps the flue warm so you don't cool the gases on their way up the flue. Important when you are just letting the thing tick over. Just make sure you have another baffle or rockwool above the register plate so when you service the stove the vermiculite does not all fall out. Again, ask your stove installer and find out what you think you will mostly burn in the stove and how you will be using it.. full blast occasionally or for mostly regular background heat.. big difference so choice range of stove performance is important. Best thing to do is to take advice from a registered stove installer then feed back the info to the roofer.

Yes it's essential. As we are introducing lots of insulation into buildings we need think carefully about trying to stop air with a high water gas content getting into places where it will later condense into a liquid and not be able to get back out easily. A VCL is essential.. Alutrix is one of the products you can research.

Confusion!! The glasscrete and lime screed should let the clay breathe similar to how it has done for the last hundred years. Some folk may be inclined to dig out the ground, fill it with type one or a suspended floor, field drain round the outside and thus dry out the clay. This invites the "big trouble". I think your approach is good and worth exploring. Historically the clay would have been able to breathe a bit, say if there were old flag stones with wide joints. Each season the moisture content in the clay will change and from year to year too. The glasscrete, although a modern material should not be an issue as you have the lime screed on top. It's the lime screed that I think will dominate the rate of moisture loss. The key will be your floor finish? No point in doing it if you put down limestone flags say and then seal them with oil to stop staining as the sealant works both ways. same with slate.. we put it on roofs to stop the water getting in. If you really want a breathable floor then you need to fully embrace it all the way. Now that may not suit you.. you need to think this through.. before you spend your money. As an SE with interest in old buildings the thing for me is to start with the ground.. what is outside.. trees, the natural and built landscape, then work your way up, enjoy old structures and appreciate what they are. Then explore options but always recognise that you will need to compromise and that you are just a custodian at this point in time. Then look to see where you can say uprate insulation elsewhere to "balance the books". I know it's hard to make the economic arguement but please try and design / alter your old house in a way that can be reversed later unless it is necessary for the long term life of the building. For all on BH. Many want to design in an environmntally friendy way, preserve our heritage, but we also want to make some money. If we go for floor makeups ect that rely on it breathing how do we later sell the house, do we caveate it.. such as.. the floor is breathable so no lino tiles etc.. how do we ensure that this is in the title.. few will do this.. so while it may make you feel good while you own the house what about the future?