Gus Potter

Yes given the size of contractor you were 20k was not that bad. When I was a Contractor I had about 10- 15 full time staff and paid about 5.0 - 10K a year for full insurance. Full contracts work... the whole shebang. Over the years premiums went up and down.. providers left the market and so on. But so long as you were marked down as an "honest broker" all in the round was ok. Now the Pi Insurance. At the moment fire is a big problem. It is happening in Scotland.. BC are having a major clampdown. English BC will follow .. but the main thing is that SE's are finding it hard to get fire cover.. the manufuacurers are pulling their data sheets big time off the internet...that is all I will say for now.

Can you report back on what your SE says?

All the best. Yes it was a long reply.. then main thing is that if you read my post I was not just writing for you really.. it was for everyone on BH.. we all pinch ideas and discuss design be it planning or all the other issues. If you want more help then post more on your thoughts. If you give a bit on BH you'll find that you get much more in return.

It is from time to time Jilly.. like a lot of jobs there is paper work/ compliance. That is less fun. You maybe have the same in you profession.. someone said to me when I was in my twenties.. if you can find a job / something to do that really floats your boat.. that you really get off on for 10 - 15% of you waking day then you are doing pretty OK. We also concluded that if you look back on say a year of your job and you had less than 5% enjoyment then it is not good for your mental health. Time for a change? Now you could say.. hey Gus you are blinkered.. but I spent a big bit of my childhood in Africa, met folk who were into preserving the wildlife.. David Attinbourgh wrote books / referenced them.. but I can tell you that all these folks worked pretty hard and had to do mundane stuff.. just like us in the UK.

No that is far from crazy.. more a good understanding of how things work and the theory. Ok SE wise @saveasteading is bang on so not crazy at all. The idea is that you make the floor beam deeper so it acts like a deeper timber. Yes you can do this on the top or the bottom of a beam..great idea from @saveasteading it's these small ideas on BH that can save you loads of cash. To make it work you need to make sure that what to add to the top or bottom of the beam is connected to it in such a way that is acts like a solid timber. The best way to do this is to use a structural glue and really clean the mating surfaces. Any dirt is a no no as the glue does not work as intended. Modern structural glues are stroger than a typical softwood.. D4 glue is NOT a structural glue specification. The D stands for DURABILITY.. not structural STRENGTH.. hey folks the clue is in the prefix.. it's a D so don't use it in a structural application and expect your SE to sign off! No point in me pointing out just the problems.. solution is use say Cascamite or similar glue.. this is a STRUCTURAL resin glue and by default meets the durability requirements. But both D4 and resin glues are very hard to clean off your hands so wear gloves! In my day job I'm reluctant to do this plating of timbers unless I really know who the builder is, that they will do what the are told and that the Client is willing to pay the builder to do what is quite a technical job. Alternatively a Client can pay me to supervise the job.. but often they don't want to pay for that last and most crucial part..I have probably saved them thousands by being an old sckool SE.. such is life. But as we are BH folk we will spend that time and attention to detail.. you are more inclinded to do it right! That lifts my spirits as it does (I'm sure) for the MODS and all the other folk that post on BH. Where the ply comes in is that you can also use ply to act like a wider flange like on an enginnered joist and that can give a lot more bang to for your buck. But you like an engineered joist you can't then go cutting service slots and holes in it. It a long storey but @saveasteading has put forward a nugget / great solution.. all you need to do is think if it suits your application. it sounds complcated but if unsure post loads of info on you project / ideas and folk will chip in on how it all could work for you.

Thanks Peter, that is interesting. On my PI I have acting as PD for about 5% of my jobs and it seems to have little impact... I wonder if it was the "Contractor element" that sent it haywire. What I can say is that everyone is struggling to get cover for fire protection design. The insurers are running a mile.. BC have been having major seminars and asking for all sorts.. the material manufactures are pullinng their fire data off the web.. In summary I have spent loads of time over the last few months sorting out fire protection..

Thanks folk for all you comments and time spent writing. Trying to digest it all at my end and thought I would respond in a way longer than you.. I have an ex council house, extended with a hybrid system. Thus new solid concrete slabs and retro fitted timber suspended floors Rads on the top floor I oversized them to keep the flow / return temperature down to promote the boiler to condensate. Ground floor has a combination of retrofitted UF on the old timber suspended floor with and extenion that has a concrete slab. It sounds dog rough but I made my own manifolds and it is really simple. Few electronics. But it is user friendly and simple to maintain. The house is much bigger now and we use less energy to heat it even though the house is much bigger. If things break I can fix it in an hour roughly.. don't know as have had no problems. Look folks.. this home automation.. have you factored in how often you are going to have to replace the different parts? Also who other than you is going to be able to fix it? You could be doing something that detracts from the house value? I'm all for technology, I'm a pretty innovative designer, love working with new materials and learning about their behavoir.. but I also as a designer I need to give best advise to my Clients and that includes ongoing potential maintenance and often environmental cost. Relpacemnt of parts is also an environmental cost.. intuitively the less parts the lower the environmental cost? I'm just asking you to think about this, I'm not slagging the concept off. I'm not kidding you.. I got a guy in to service my boiler.. he has a PHD.. but became a heating enginneer, he had the cheek to say to me you are asking me tecky questions and you are asking me to give away my trade secrets, my response.. hey donkey if you want play that game.. and this is from a guy that works with a regular contractor that I do design work for. I am paying him to be techy with me and want sensible answers.. ground my gears. The point is .. keep it simple.. yes if you want to make your house high tech.. fine but I would not buy your house... unless you can produce a full and verified O & M manual.. otherwise you could buy a pup! High tech can be an appreciation of simplicity and how you get the best out of it. Folks UFH is supposed to be simple that is the elegance of the principle. I'l say agin UFH is supposed to be simple and environmentally friendly! It works great when you design the rest of the house to suit. It's holistic design. I designed my first UFH some 25 years ago. The Scandinavians have done it for much longer. Lets just look at the cost of all the controls, flow meters, zoning, automation. It will probalbly be fine at first installation but just wait for two or three years.. then when things start to fail, getting replacemet parts.. good luck to you. Yes weather compensation works but when you look at the lifetime of the buildings and they way folk use it.. I'm not sure about how friendly it all is. The house I have at the moment has hybrid floors, all sorts of nuances but as a kick off I just built a simple manifold DIY.. it's working great, to set it up I just put my hand on the flow and returns pipes and crancked down the really hot ones. yes folk say I should not use gate valves but I did this 25 years ago.. if one leakes.. a couple of quid to fix it. To say again..UFH is easy to design, the controls can be very simple. There are some basic conservative rules. For 15mm pipe keep the loops under 75m, DO NOT over bend the pipe. MAKE sure you get plenty flow rate.. it can be turned down. It is really simple with common sense. If you are using a pug mix my own view is that you should pressurise the UF pipes to say 4 bar then pour in the concrete. Reasoning is this.. the pipes need to last for 50 years. The heating system may run at about 1.5 Bar but will expand and contract over the length of the runs. They have bends that are in the pug mix.. thus abrasion will occur. The pressure relief valve on a typical system is set at 3.0 bar.. in the round the 4.0 bar pressure at time of laying the pug mix will be just enough to compensats for the screed shrinkage and movement in the sreed plus say movement in the structural floor.. my gut feeling is that this will allow the pipe to last 50 years. To put this into context. I did my first UF system some 25 years ago, have been keeping an eye on others and had hand in others for some 30 years.. have not seen signs of abrasion in the UF pipes in a pug mix to date. To be honest when these pipes were installed they were sold as barrier pipes.. to stop oxygen ingress, I though it was a bit bollocks at the time but the boilers have held up so maybe it was not sales bollocks after all. Nice to be proved wrong. Yes if the weather suddenly warms up there is a lag time.. but all that happens is we say.. it's warm outside and the house is a bit warmer.. but that can happen on a sunny day too as we get a lot of solar gain. The thing is that in the UK UFH is great but from time to time the house may get a little warm.. it is rare.. just open a window or the door! There will probably be folk going in and out the house anyway so any heat model you make it likely a bit rough. Save your money folks and go for the most simple system you can.. have a look at the Sputnik that the Russians sent to the moon. .it had gate valves (look like Screwfix today) brave boys right enough. Think.. how much is my home automation going to cost vs a Guses "Fintstone" design.. If there are any takers I'll be happy to defend my design approach as I think this is the best environmental choice and most cost effective in the long run. There is one caveat.,. you need to make sure we are debating on a reasonable insulated external house envelope. There you go have stuck my head above the parapet. In other words.. I'm saying that for UFH go for the simple stupid, low maintenance solution. Save yourmoney and spend it on the insulation envelope.. or if you have large areas of glazing then spend you money on sinking the solar gain into an internal wall to be released later. I know folks on BH debate thermal mass.. but that is not what I'm talking about.. more the concept of how a Tromb wall works and how you start with the paint finish and store the solar gained heat from that. @tuftythesquirrel When I say simple DIY UF manifold have attached the prototype I talk about above. Yes I know it is probaly a million miles away from what you envisage. But it works, is cheep maintainable and reliable.

No need to applogise, you are asking a great question. I hope this helps. Not often I caveat what I write on BH but in this instance I do in that my following comments are without predudice. Also forgive my spelling / grammer as this is informal. In the selfbuild market and just for folk building an extension the CDM statutory legislation has wide and very onerous implications. @Post and beam I'll start with some general thoughts on how you deal with / things to think about as a self builders / say an extension and then try and offer some thoughts on what you maybe can do next. I have made previous posts on CDM but the concept of the statutory legislation (the stuff you can go to jail for) is this. The big buildiers used to kill lots of their workers. Once we reduced the mortality / injury rate rightly the focus turned to small builders / the self employed and folk building their own house / extension. Some self builds can be very substancial projects! Some small attic conversions can be partcularly dangerous as you can loose a lot of stability in a gable wall. A small gable wall can kill easily if it falls over and old buildings can be unpredictable in the way they behave... often as others have mucked about with them in the past and there is no record. Now it is actually fairly easy to comply with the CDM regulations, much is common sense. If you don't then you run the risk that you may get drawn into some thing that is no fault of your own. One example. You get a quote from a builder to do an extension. One of their employees gets hurt. HSE turn up and the employee gets a lawyer.. at some point you will get sucked in and this will probably cost you money and be very stressful. The key to avoid this is as soon as you start to talk to your Designer / Architect / builder ask about CDM? It sounds odd but CDM pretty much kicks in at the conceptual design stage. You can look up the latest RIBA advice, but the simple way is to think along the lines of.. health and safety is an intrinsict part of any project.. it is part of the design from concept onwards. Major contractors will set aside some 3 -5 % of the project cost to keep everyone safe.. this also applies to you! Ask yourself.. can you afford to build and not kill anyone.. frankly if someone gets badly hurt on your build you will find it hard to live with.. I have been on sites where folk have been killed.. it bears heavily on you. As a self builder you could rack up some big legal costs.. trying to defend even if you are not at fault. The thing is that we live in a claims culture.. you have an asset that folk can go after. While you may not be directly to blame a claims lawyer will pick the easy target. I was up at an IStructE talk.. one thing the presentor made clear was this. Folk know that SE's carry a lot of insurance.. so we are prime targets for an easy claim. You as plot / home owners are also an easy target, defending any claim is going to be horrid. Now I design a lot of wall slappings.. making a house open plan. Here it is pretty straight forward. I talk to the Client, do my Planning / SE BC drawings and calcs. The objective is to allow them to get builder's prices. But there is a big bit slapped all over the drawings that says that the Client is a domestic Client and the builder has to take on the duties of the Client also. This reflects the current HSE advice and it also works.. as often I get a heads up on who the contractor is.. I avoid if possible the cowboys. I also do a few other jobs that are larger. Here is a thought. You should factor into any build cost the 3 -5 % for safety.. ask you Contractor this question.. if they have no answer then ask.. where does the risk lie? On a selfbuild as soon as you start to talk to say an Architect / designer raise the question about CDM . They will guide you. If you are a seasoned self builder then anticipate what I will require (SE) from you before I touch your job.. how do we allocate responsibility and risk? It sounds complicated but it's not.. often we look at things and say .. if we want to build a high wall how do we brace it during construction? Often it's these things that kill folk and it's not hard to design to keep folk safe.. the important thng is to catch it early. Funnily if you think about these things early is also leads to good economic design. Sometimes the temporary works can be used to brace the building .. everyone is a winner! I have laid it on a bit thick above but in summary what I'm say is grasp the nettle early if you are self building or doing a big extension that you want to manage youself. I would go back to Potton and ask for help. Your opening gambit may be to write along the lines of... 1/ I have tried my best but I'm stuck. Just be honest.. as a domestic Client this can carry a lot of weight, mind you I write to folk.. hey your data tables are not clear.. can you explaIn.. ? Best to ask as a dafty and appear thick rather than invite disaster? 2/ I want to buy your product but just don't understand the health and saftey (CDM) aspect not least and what I need to do. 3/ I am a novice and need guidance from you about who for example is the Principle designer. 4/ I recognise that I may have missed some key stages in the design in terms of HSE planning and CDM compliance but I want to get back on track. 5/ Please can you help me. Can you put me in touch with your HSE person. Now that may get a result. It is a double edged sword.. you write in such a way that while asking for advice.. if they don't provide it or give answer it makes them potentially liable. If you don't then you can start to play hard ball. 1/ Refer back to their offer.. they should have mentioned who is the Principle Designer.. the PD.. and ask again. I would be very surprised if their HSE person does not get in touch and help you out. If you deal with the big ticket items they will probably tell you what to do with the bogs and so on.

The tolerance that the brickie is allowed in the verticality of the block work. I have an old Elu table saw, good 300mm dia blade and expect to have to rip down the door standards on occasion, facings and stops from time to time.. use old scool skills to hang a door. You can buy door sets.. like you go to Kwik fit, but if you want quality expect that a door will take an extra 6 hours to fit right and remain right for many years. I have used hard woods that are oiled hence part of the extra time. Take your time on hanging doors and forming the door sets.. in my own house I spent ages fitting them.. they just shut great, tight and will remain so.. but it takes time to get this quality job. You also need good quality ironmongery. What has made the job easier when I look back is modern adhesives and the invention of the chop (mitre saw)... but if you have a finishing joiner turning up and they don't have a sharp hand plane.. then they probably don't know what they are really doing. If you are having really traditional finishes you may not want to use posidrive screws on the hinges, to keep things authentic you want to maybe use slotted wood screws.. the slot in the screws in a traditional hinge should be vertical when tightened.. this is to stop the oils / paints from dripping and the slots should all be in aligment.. yes it's those details that matter.

In principal you can use beam and block externally. In Scotland you can (in the right circumstances) have B&B over a a raw soil solum.. i.e no DPM with solum screed. They can stand a damp environment. But there is one big caveat. As a bit of background the Champlain Towers South in Florida that collapsed, I think the documentary is on I Player. There is one school of thought. They had a swimming pool and the slab connected into the main structure. They did not realise that the swimming pool slab was "really tied in" so when it failed it pulled the rest of the building with it. If you asked me to design this I would want to play safe and say.. I want you to make sure that the B&B floor / roof is subject to no more a harsh environment that they would be say in a ground floor. In other words it needs to be waterproofed from above. One main reason is that some folk put salt on their drives and patios in winter weather. Folk may get too keen on fertilising pot plants.. again these chemicals can promote corrosion of the steel in the beams. Reinforced concrete can protest and this can lead to failure that will drag the house with it. Yes I know you may not do it (use salt etc) but subsequent owners may be unaware. For all @DeanoFromTheDock is cracking on and has a big chunky retaining wall. Looking at the photo the design looks reasonably balanced as the house is not that wide along the road elevation.. but if it was a little wider then it opens up the possibility to make big savings on the retaining wall. Here you use the house to brace the retaining wall at the top and that can be a game changer in terms of retaining wall cost. Depending on the soil you have and the loads on the ground uphill there is a trick you can deploy. We know for example that some CLAY soils can push quite hard horizontally against a retaining wall. This can be great if you are doing a passive build or eco freindly house. You are probably using EPS ayway so can get a good deal on price. What you do is to dig out more of the soil (if you have the space) and replace with EPS.. this takes out a lot of the lateral soil load, you brace against the house (If you are using ICF walls they can offer great stiff sideways/ horizontal support).. in other words you look at the design holistically and get try and get every bit to work most efficiently. Oh but it sounds like I could sell you chalk from the Downs.. but.. here is a pit fall. If you use this trick you have to be sure about how you are going to control and understand the ground water. EPS floats so you need to check for "ballast".. if not you could wake up one morning and find your EPS is now blocking the view from the windows.. not a good look if you are the designer. @DeanoFromTheDock Let us know what your SE thinks.

Great point @Annker Something looks a bit odd here. From the info you give I have understood this is definitly the first floor. On these 1930's houses you often find that the first floor joists are 1 1/2 " thick ~ 38mm. The old rule of thumb is when working on a 2" thick joist is to take the span in feet( 3.5m ~ 11.5 feet) divide 11.5 by two .. 11.5 /2 = 5.7 and add two inches for joists at 2' centres. Thus 5.7 + 2 = 7.7.. about 8". By inspection you can then say.. a thinner 1 1/2" x 8" deep joist looks about right at 18" centres. But you may ask.. why did they go to the bother of putting in thinner joists at closer centres. One reason is that the closer centre joists lets you make the floor boards thinner. In todays money we know that for domestic floor loading you need 22m thick chipboard for 600mm spaced joists and 18mm thick for 400mm spaced joists. Measure you floor board thickness and let us know. But you mention you have 4 x 3 floor joists. Yes the width is a lot more but I suspect you have a steel transfer beam hidden in the floor that you have not found yet. Even though you have much thicker joists I doubt they are spanning the full 3.5m. You may find you have an old rolled steel joist in the floor depth acting as a transfer beam. If you are able to drop the ceilings then there are a few things you can do. But you need to know about this transfer beam. For all. Lets just say you don't have a transfer beam. You want to add UFH, beef up the sound proofing, make the floor less bouncy and say make the ceiling more level as it may have sagged over time. The easy way is to just bolt and glue deeper timbers to the sides of the old timbers. This stiffens and strengthens the timber between the walls. But at the ends the new timbers don't get embeded into the walls.. you leave the walls, bearing and restraint as @Annker alludes to. But now you have created a stronger timber with a big nasty notch at the end where it bears onto the walls. When you check this you'll often find that the timbers now fail in shear at the ends and the grain wants to delaminate / split not least. You can get round this sometimes by using steel straps at the joist ends .. like stirrups. You can see this with Engineered joists where the top flange is the bearing part on the wall head, they configure the nail plates to act as stirrups. @Crowbar hero If you want post more info, a few sketches would help a lot.

Just a quick thought. Got called out to a job a few months back where the structure was unstable. Builder had got some props and so on. The key here was to stop further movement until it could all be examined and understood. The temptation is to make the props tight and whack in bracing tight. This is the wrong thing to do. Nine times out of ten.. put in props and just nip them up. Bracing.. absolute finesse it, just there and no more. If you crank up props and braced hard you can make things worse. A building will do it's best to find alterantive load paths before it falls down. If you start cranking up props hard you can lift the last bits of bearing and that often causes more problems. Most often temporary support is just there to stop things moving more until you can work out the best solution.

Absolutely! When in panic mode have something to eat, save the skin though as a real haggis has a flexible sheeps gut. On more a serious note if your are heading out to do an investigation as an SE you have two choices: 1/ You can pitch up on the job and say to the Client.. can't do that, this and oh I can only look at what I can see and I have my chocolate fire guard.. I open stuff up by myself. But when you do that you risk.. falling through a ceiling, busting pipe and cables. On a job that is structuraly unstable you have two choices.. turn round and say to the poor Client.. oh I can't investigate as we need a Contractor who I can pass the can to.. or you can just get stuck in. I'm old sckool and carry insurance to get stuck in. At the end of the day it is hard for folk to sue if you act in the interest of public safety. We are Engineers.. be confident in what you do. An old mentor of mine said.. learn as much as you can, some may sue but if you know what you are doing none / few will win..yes your will have some sleepless nights but your PI will pick up the legal costs of folk chancing their arm. I run about in an old Astra Van on an 05 plate. In the back is.. apart from my tecky and first aid stuff / surveying stuff is.. 1/ Dust sheets, a mop, bucket and cloths. 2/ 30 amp junction boxes 3/ A selection of terminal blocks / 2.5mm and 1.5mm cable and other stuff just to make electrics temporarily safe. 4/ My plumbing tool box.. stop ends.. 15, 22 and 28mm pipe.. all the stuff I need to fix small leaks.. plus a big set of crimps and bungs if I get a big burst a big pipe. here all I want to do is to reduce the flow so things don't flood. 5/ My general tool box.. and boxes of screws and fixings also a few small bits of timber. 6/ At home I keep some Acrow props and a few lengths of 6 x 2 and 4x 2 timber that I can nip back for. If a problem occurs I evaluate, eat some Haggis and all is well. No need for panic.

Not at all.. I did not read it this way. I can see where you are coming from.. good economic and practical design insulation wise. Please don't take this as being critical.. we are all here to help each other on BH. I laid it on thick in my earlier post to try and highlight the SE side of things. To touch on the technical. The regs in Scotland are different from those in other parts of the UK, tend to be more onerous. You mention various detailing of the construction.. I read this as standard stuff until I came to the bit where you were running the battens horizontally.. now that is clever. Normally as a starting point I would take a TF wall as having 15% repeating bridges, in practice a heavily load bearing kit will have a bit more than that but BC don't often complain. That said from a buildability point of view you still need the dwangs / noggings so they would need to run vertically and your average builder would probaby stuggle to fix these without splitting the timber. For me it all sound great until you look at buildability, Yes it you were doing a 7 storey student accomodation block you could educate the Contractor but on a one off small build... it can limit your options. For all on BH.. if you get too "fixated" on some detail that will save you a few mm of insulation it will work against you.. better to make it easy for the builder.. get more quotes and say.. I'll spend the saving on extra insulation in the walls ratherthan asking for complex details around windows / doors or tight level tolerances. Also for folk building you own house. This is about people management.. yes you don't want to get ripped off but if you do get on ok with your builder you want to keep them to the end.. then they too can see the end of the job and will make an effort to finish it off...their pride will often kick in if you don't get too tight with the money. I used to be a building contractor before I became an SE so speak from experience. Like your ideas about sound performance and just practical stuff like fitting pictures.. that holds weight.. cost the same to screw the plaster board.

Ok. to stick my neck out when folk on BH buy stuff from their local merchants their profit margin is 20% based on the delivered price. That can be split up between the haulage and the uplift on the material. Sounds high but you may get a big delivery and then some small ones. In terms of my work flow as an SE/ Architechural designer it was plentiful during COVID as everyone wanted to work from home and open up their house, build garden rooms / offices and so on. In the back ground I also had the industrial stuff that was on a long programme. But I can see that things are getting back to normal where we need to compete for work. The folk that have made hay over the past couple of years and not set aside money for the lean years will go bust. For self builders I think the labour cost will come down but material costs will remain fairly high due to the cost of energy and transport. It would be good to say hey.. builders labour rates are going to go down.. but fuels costs are rising (running the van), insurance is not getting any cheaper and so on. If you are lucky enough to be a builder in Scotland.. John Swinney has just increase personal taxation again if you manage to build up enough of a nest egg to consider taking on an extra member of staff.. so add that to your self build bill. In the round I think that prices may stay roughly where they are if you are doing a self build.

Good point of note. If you have a house say built circa the 1950's then please check that you don't have a separate rainwater and foul drain system.. your plumber should know this. If you put your sink waste into the rain water drain this goes straight to the watercourse and kills wildlife.

Yes but... setting aside the structural design side... but that calculation is for an individual element of the structure. You need to look at the area of glazing, the floor and the roof to make sure it all complies.. you may need to do what is called a compensatory calculation which trades off the parts that may fall below the standard and beef up other bits. Have a think about this race to the bottom folks. You may be trying to do this on a building notice / Scotland is a bit different but the jist of the rules apply. The thing I say to my Clients is this.. you may have some smart arse telling you the minimum you can get away with but if you want to stetch PD or the building regs.. fine but think about when you want to sell the house.. you are inviting grief. How are you later going to prove that what you have done is ok.. you could save money now but later you will now realise the true value of all the hard work you have put in.. and that is why it is good to get BC approval rather than doing it on a notice? To insulate properly on a raw kit costs buttons in comparison to your overall asset value. You need longer screws and you often bring the walls in a bit.. but?

For all.. Recommendation.. pick @saveasteading brains.. you could save a fortune.. but you will get true professional CE advice for free so what about chucking £50 quid to BH as a donation?

I live in hope! I design a lot of slappings in walls, to make open plan houses and so on. To do this I need to open up parts of the walls and ceilings to see where the joists run and so on. Used to be great in the old days when folk had just carpets, now there are tiles and all sorts so you can't lift floors above so easily. For all on BH.. on modern homes you find that with engineered joists and so they run in all directions and the services can be a bit bizarre, also in modern homes there are a lot more "services" .. and there is no real coordination... what is hidden in your floor depth is a lottery for someone investigating it. Also used to be great when sparks did a proper job.. ie running their cables mid depth of the joists (they know they should) with a small sag so clear of the ceiling. Got caught a few months back. Used to use an insulated plasterboard saw and sometimes don't turn off the all power.. then started using a multi tool.. makes a professional looking cut when doing a structural investigation but once the hole was open here the spark had left a coil of cable lying on the ceiling..the socket ring main. I nicked the cable. The multi tools are great but you have no feeling.. if using a hand saw you sometime get a feeling.. like driving an electric car cf an Astra van. Now it's out to the van and get my "near disaster avoided kit" to sort it as a temporary measure. I also keep in the van.. a distaster kit.. yet to be used.. luckily! Here is a thing for all on BH.. I'm an SE and you may be wondering.. what is Gus doing? I'm just being practical and trying to get a handle on how the building works and where some the booby traps lie for the builder that will have to implement my design. I could pass on all the risk to the Client but it's about getting a balance. If you don't take a bit of a risk when opening up old buildings you are designing on complete guess work and that generally ends up in tears. Yes I nicked the cable but I always explain to the Client before I start.. the more we explore now the better information we can give to the builders and this protects you. When I nicked the cable they were fine about it. It would be great to find a tool that has xray specs! Can it find cables, pipes and studs?

As an immediate and temporary solution you could modify the hopper below to stop the overspill. You'll probably need to dig a bit of a hole and need a straight coupling to connect the hopper to the existing pipe. @Nickfromwales may pitch up with a better idea so will defer if so.

Go back to basics. Look at the attic, roof pitch, have you a load of downlighters installed in the ceiling below the attic. Do you have some 350 - 400mm thickness of glass wool in the attic? If you do then check the ventilation. A modern condensing boiler will help a lot but have a review of what insulation you do have. Have you had a look under the ground floor.. what kind of solum space do you have, is the solum damp? Does the 1920's part have a cavity wall construction? not sure? I would make sure you have a very good understanding of your old house before plumping for an insulation and heating strategy. As a word of caution.. be very carefull when you are insulating and vapour checking the interface between a warm and cold roof. It can be very hard to get right.. I struggle often to detail when you have say a large warm flat roof dormer interfacing with say traditional pitched roof. Every roof is different so you can't just copy and paste details! While sometimes you can make it look good on a drawing you need to try and do something that a builder will actually make an attempt at doing right on site. If you want post more info on the construction you have, ground levels and so on.. your heat model could be horribly wrong! Best to identify the right strategy now so as not to waste money and cause a potential costly problem. Once you have nutted out the basics of the construction you will have a slightly more valid model to play with.

Spot on. Please be careful here. Like all things TF takes a bit of learning about. Structural stuff: First thing is building stability. With TF you get about a 25% contribution from the external leaf of masonry, no masonry.. debatable contribution from the outer skin. Next is insulated plasterboard on the inside. If normal plasterboard straight onto the studs you get a contribution (last resort when stuck on the sums) from that provided you are sure it is not going to get wet. Insulated plaster board.. no as the fixings tend to bend in the insulation. You have openings.. these can drastically reduce the racking resistance and if large bifold doors ect these can completely change the way the forces act.. often you need to check that the existing building can cope with the extra sideways load and pulling / tension effect it has on the existing house walls. Depending on where you have the openings a tall narrow TF panel can generate significant uplift at the bottom.. so you need to check the tie down strap nails and make sure you have enough ballast in the underbuilding to resist the tension in the straps generated by the over turning effects in the panels. Turning now to the vertical loads the studs need to carry. You can put a surpising amount of load down a TF stud when is is prevented from moving along the plane of the wall, its minor / weak axis as the OSB restrains it. But when you couple this vertical load with a wind load it has a reduced capacity.. quite a lot. You need to check the case of wind pressure bearing down on a pitched roof coupled with the weight of the roof.. often it is okunless you live in a windy spot and the roof is not flat. But if the stud length is over 2.4m in height this can suddenly becomes and issue as the TF is holding the external skin. Last but not least.. you need to look at your windows and doors.. how much defection can they cope with both vertically and horizontally. Some detailing stuff: Make sure you get your cladding details sorted. You may want to put a chamfer on any horizontal battens to channel water to the cavity where it can be properly dealt with... it's these apparent minor details that matter a lot for a durable build. Have you checked to make sure you don't have a fire boundary condition? Make sure you get the cladding ventilation and insect grills nutted out both top and bottom, soffit details and so on. Make sure you get your fire stops right and that there are corresponding studs behind. Have you decided on how you are going to do the corners of the kit (California.. don't like them structurally) how you are going to insulate and the sequence of work to be able to do it. Yes but this may be a good opportunity and avoid a howler.. why do all this work and risk that when you come to sell someone asks.. is that ok and can you prove it? The above sounds like a bit of a rant from me but you have a great opportunity here to learn loads and practice on your own house. I started out a while ago.. bought my first flat and learnt how to get started on the practical side of the building trade and earn a living. In summary if you want post some plans and elevations (rough dimesioned sketches will do as you are not tested on your drawing skills on BH) of what you propose and plenty folk on BH will chip in with advice and tips. It may be that you will conclude that it is your best interests to pay for some SE type advice.. but .. do a good job.. let the SE see you can and they may put you on their list of "good guys" and work will flow your way to boot!

Spot on. To expand on the chat I was having with the manufacturer today. They said they needed 20000m ^2 trickle ventilation on a new build . The only way to achieve this was to add a head extension to the window and fit double vents and one at the hopper.. remember window frame looses more heat than a modern argon / filmed glass unit. For a bit of fun they did a hot box test and you had massive heat loss at the vents.. but does the window need to comply with or without vents? Most trickle vents in Upvc are formed by routering out the outside and inside, have yet to seen sleeved ones on the commonly installed windows .. every day is a school day. The outcome was they said to the developer.. will be cheeper and more Architecturally pleasing to fit MVHR.. problem goes away until each occupant say in a block of housing wants to live their own individual life. My grip is this. I do a bit of work on historic structures. I make the argument to BC that they leak air like sieves and say.. my Clients are grown up.. if the buiding gets stuffy they will open a window! If you ask for big trickle vents you need to justify why.. yes you are BC but I will challenge you on these techinical matters, in particular how to you justify the heat loss and environmental impact.. that gets them thinking. They stick to the regs but you can turn this against them at times.. by saying if you stick to this part of the regs you shoot yourself in the foot on energy conservation so "tell me what to do" I wonder.. why can we not just educate the public.. if your house feels damp, you are boiling up potaoes / drying a bit of washing inside.. open a window? My Mum does that and she is 91. If it is windy then the house will air quickly.. we need some common sense in the regs rather than this blanket prescribed approach that we need to conform to because some young polititians who are over paid for their talents decide that this is the best way to get re elected at our expense.

Yes potential big changes ahead! In Scotland we have been doing TF for a long time. I remember having discussions about having to jump from a 95mm stud to a 145mm deep stud to get enough glass wool in, no insulated plasterboard, air tightness (tapes and so on) was something that we needed on the space station / for astronauts but not that much to do with us. Yes. The last time there was big step change in the building regs all the "greenies" came up with these ideas.. in Scotland they produced insulation standard details.. and they came to present to the IStructE (the SE crowd) where I asked if they had given any consideration as to how their changes may impact on the structural design and just how environmentally friendly their ideas were.. did they know about the unforseen consequences? .. say diaphragm action.. this is where we use say walls and floors to stiffen and make a building safe.. blank faces all round there! They clearly were implementing policy with no idea about holistic design. I think this will be the same case. As before some folk are going to feather their nest at the public's expense. If you want to achieve good environmental design then it takes time and thought.. unfortunately most of the policy makers are just looking forward to the next election rather than say over the next 25 years. It can be done and all the professions will adapt eventually. I am big supporter of good practical design that is of real benefit to the planet. Maybe using cold formed steel in the domestic market will make a comeback.. in which case

Hi Paul. I posted before I saw you reply. Don't panic just yet. What can you tell us about the perimeter soffit ventilation and let us know if this is an extension and if so to what kind of house? traditional masonry / timber frame. What can you tell us about how this structure joins into the existing building? Is there any funnies? say extractor fans from internal kitchens and so on that need to be considered? I would want to look at this in the round to make sure that you are not doing anything that is going to impact on the existing house.. just to tick all the boxes.