Gus Potter

You have to start from somewhere, so try an Architect first if inclined to do so. Let us know how you get on, you have got some tips / hints so far on BH so that should aid your discussion. As always, try and enjoy the design process, it's not a competition! Keep us posted.

Have a look at the building regs. On upgrades I often have to have a discussion with BC in terms of what is "reasonably prcticable" In your case as you don't seem to be increasing the building foot print or the volume then this supports the "in so far as reasonably practicable" approach. The key to this is as you have clocked it is to maintain good ventilation, the more insulation the more ventilation you need, that's a rule of thumb. The other key is to tightly fit the insulation and use tapes to stop convection currents bypassing your hard work installing the insulation. Last is to install a good vapour barrier on the warm side to stop water gas getting into the insulation layer in the first place. Moist air does liittle harm.. the harm arises when the gas temperature lowers and you get water condensing out, we call this the dew point. The best way to get increased performance is to use insulating plasterboard on the underside but this may reduce the ceiling height. This works as you don't have the repeating bridging effect of the joists. Below is a link to Kingspan. You can play about to see the difference between insulated plasterboard and insulation between the joists. https://u-valuecalculator.com/gb Hope this helps and you have a bit of fun playing about with it.

Welcome to BH. D & G is a great place to live. You have a journey ahead, main thing is to enjoy it. You'll get plenty help and suggestion here and BH is a fantastic resource.

A structral requirement of the BC regs is that the windows and doors need to be positively fixed to the structure. Detailing this is difficult to meet the SE requirements. I'm not singling out anyone in particular as this problem is common across the board. We see loads of details but few that show the fixings and their capability to resist the wind loading on the glazing while accounting for head deflections and thermal bridging. In other words I think... first thing to do is to make sure your glazing is fixed so it does not fall out and hurt someone. On large openings check the head deflection from the structure can be accommodated so it does not jamb the doors. Then think about the outside weathering detail and then last the thermal performance in terms of cold bridging. I know it's not not de rigueur but what do I know? Well I can tell you.. if your glazing is not properly fixed then no SE sign off. Here is a suggestion. Accept that you have to compromise, live with a bit more thermal briging and add a bit more insulation elsewhere. You will be not happy if water starts to leak in driving rain so that is why I put weathering as my second point. Threshold details can look great on a drawing.. but you need to make them idiot proof as few folk will keep out leaves, moss etc. You also need to make them buildable which many details are clearly not. Has your Architect put themselves in a builders shoes? How do you achieve this on site and how do you water proof the ends? If it's too complicate you'll likely end up paying more for something that probably won't get delivered on site.

Thanks for posting, its a refreshing topic. Fundamentally, on the face of it, what you are doing is not that difficult.. the technology and designs are well proven. Where it becomes difficult is when folk don't reasearch or question the advice they are getting. But you are, so hat off to you. For me (SE hat on) I would want to understand the Architectural design; how is it supposed to work, how is it supposed to look, how does it marry with the house, garden and how does the space get use in terms of circulation, when you have a party / entertain. Then delve down and look at the choice of materials and why they have been selected Architecturally. Once I get a handle on that then I can start to think about how you engineer that to stay within the Architectural envelope and material choice you the Client desires. This is common when you have a high water table. The piles more often than not are not subject to a lot of tension in normal use, but if under designed with a high water table then the middle of the pool slab can tend to lift up first when you fully empty it. This causes cracking which over time leads to leaks and so on. This gets worse over time, but by then the contractor is long gone. Then if things are bad the whole building can float up and out of the ground! Tension piles and restrictive maintenance clauses can vary, in other words pool design can be a bit like the second hand market, prices can vary a lot, so you have to be really careful that what you are buying is going to do the job you want with the life span you want. When we have chlorine SE's will usually err on the safe side and treat this as an aggresive environment. The thing is that while you may control it the next owner may not. This comes under our Civic responsibility. At some point you may want to sell the house, a surveyor may say.. how much is this pool going to cost to maintain over the next 40 years. If there are too many caveats then it may put a buyer off. The extra cost of protecting your asset is often not as much as you think. For me I'm interested in your ground conditions. @markc knows a lot about this stuff, probably more than I! Keep up the good work posting!

Hope this helps. The design of these things needs to start with the ground. This is a large investment. One way of thinking about this is not just in terms of the weight of the structure on top, nor the weight of the pool when it's filled with water, as water often weight less than the soil you dig out, but what happens when you want to empty it for maintenance. If the ground water is high then the "pool box" is going to float out the ground, we call this buoyancy. Just say your overall excavation with insulation under the base of the pool is 2.2m. The buoyancy will be about (very roughly) (29m + wall insulation, say 29.5m) x (7.0 + wall insulation, say 7.5m) x 2.2m (pool depth + floor + insulation) = about 487 tonnes! From that you deduct the weight of the walls below ground + the wieght of the structure on top. The type of structure you have is not likely to be heavy enough. OK, you may say, well I'm going to dewater it when I want to empty it. But as you're close to the neighbours the dewatering may cause a problem over the boundary or cause a problem with the existing house. Then, as others have pointed out, you have a chlorinated liquid in a building which is not a great fit with many common building materials. This takes time to think through and you do need good professional advice.

But how would you have known that? The only reason that I know is that I've been in this for a lot longer than most folk on BH, I'm also a self builder, an SE, past Contractor and know how things can go wrong. I kind of have a bit of an advantage, call folk out but try not to be too much of a smart arse. That said the previous just sounds like I'm a smart arse! Ok for all. the motto is, build in redundancey into your UFH pipes, loop CAD etc is nice but don't forget the pipes over lap for example, so don't go for a too thin a screed. The pipes will over 50 years get a bit of furring, so pipe up anyone that can claim otherwise.. come on.. be brave! Or are there any folk that think that UFH should only last 15 years? What then? By all means go for weather compensation, home automation.. but just remember that when you come to sell your house a surveyor may not appreciate your fancy and possible rapidly outdated controls and software. Yes you may have done calculations but what happens if the new owner puts a rug on the floor! moves the furniture.. Basically what I'm saying is that a lot of UFH heat loss calcs are pish ( most are just a guide as to how it might work in real life) as they don't take into account the life cycle of the house. If you want to get teccy then we need to look at the soil dumpling below the insulation, the floor perimeter insulation, a large sofa does block heat which does tend to play havoc with weather compensation, I can pick faults in this all day long.. Much of UFH is about practical design, like foundation raft design, part thoery and part an art.. Close up the pipe centres below large areas of glazing, run one pipe under kitchen units just to stop condensation for example. Just imagine if it was your kids that then go an buy the house and it turns out that the build had been designed on two retired folk that never have kids opening doors etc! and there is a bunch of home automation that no one can work or even if they can get replacement parts. UFH can be great but is the best way of designing it is first to recognise that is in a blunt instrument, on / off and keep it simple.

You need to cough up and pay for an SE / Designer who knows about this stuff. Try and find a designer that can hold your hand and walk you through the things that need to be considered, how you design the different bits so they fit together and work. They will also help you put together the different work packages so you pay a fair price. The design and execution is much harder than you are probaby aware of. I have this on my website from Ruskin but is is worth a revisit. “There is hardly anything in the world that someone cannot make a little worse and sell a little cheaper, and the people who consider price alone are that person’s lawful prey. It’s unwise to pay too much, but it’s worse to pay too little. When you pay too much, you lose a little money — that is all. When you pay too little, you sometimes lose everything, because the thing you bought was incapable of doing the thing it was bought to do. The common law of business balance prohibits paying a little and getting a lot — it can’t be done. If you deal with the lowest bidder, it is well to add something for the risk you run, and if you do that you will have enough to pay for something better.”

No, because I feel if you want to save money then you need to put in the leg work first, there is no free lunch. Your starting point is to learn how you put together a timber frame, how the lateral stability system works and so on. If you make a good go at your TFand post your drawings then I may chip in as an SE / designer to give you some tips etc.. but I'm not going to share my intellectual property with you until I'm sure you have done the leg work.

Good comment Mike. Yes, when it gets that hot passive stack can struggle. My blunt appoach is intended to encourage, at times my views may seem challenging and not what folk really want to read. But as I work all over the UK I take a broad brush approach to upfront installation cost and long term costs / liability of UFH. At some point the house often needs to be sold and if your heating is dodgy then it detracts from the value. The more complex the system the more risk for a valuer, or they just say "nothing to do with us" thus passing the risk to the lender / the purchaser. For passive stack to work when we get these temperatures we need windows and doors that can open on the cool side of the building.. to let the cooler air in and that promotes the convection of hot air out the roof. This is brilliant John and what UFH should do! The reason I often challenge is that folk are desinging the pipes in the floor with no redundancy, or recognising that what gets built on site may not actually be what is shown on loop cad for example. The extra cost is marginal. Split UFH into two parts, the bit under the floor you can never change (without great cost) and the bit above the floor that you can change just say when your heating source get out of date.. and when the software rapidly gets out of date! Technically true but this is the building trade we are talking about. That is why I advocate for shorter and more loops, one can fail and often you can live with that. I wonder if say in 10 years time if we can find a house insurer who will offer cover for this as a new product? In summary though I think UFH is fantastic!

Can I ask, did you buy this at auction?

Yes. 1/ Invest in a good Co monitor. 2/ Check your flue. 3/ Accept that if you have not run the stove for a few months you will get a "funny smell" as it dries out the surrounding structure. 4/ When was the last time you replaced the door seal to the stove? bet you have not! 5/ The flue vacum will change as the chimney warms up.. you are chasing the dragon here. If you check the basics then come back to us describing the problem in more detail. Why are you indulging in this? Have you not got something better to do? The flue pressure will change a lot depending on which way the wind blows! I know this as I'm an SE. The reason I'm being a bit rough with you is this. Young and new self builders may look at your posts and get worried that self building is so hard these days, it's not worth the effort. I think it is the best thing you can do, is to build your own house! I'm here to encourage young folk as they are the future! But they do need information from folk like myself to enable them to make informed decisions. Make no mistake here, many of my posts are intended to inform.. it up to you as grown ups to decide!

Ah philistine here. Why on gods earth are we designing systems that are not passive in the UK to cool houses? Why not design our doors / ground floor windows to provide purge ventilation and say put Velux windows in the roof to promote passive stack type convection with a bit of cross flow ventilation. You can achieve this even on a single story building. Again I'll come back to this. I've been designing UFH as a designer and as an SE for decades. So I kind of know what the long term costs are. And no one on BH has stepped up to this plate.. yet.. I'm alone in my view it seems. But the thing is.. I'm pretty good at maths, have installed and designed UFH when most of you were in short pants, I know the economics! and to boot I'm an SE so know how you integrate UFH structurally. So get that up you and lets see some evidence about long term maintenance costs on UFH and the introduction of complex controls.. Oh and if you can make that basic argument then have a go at cooling. If you want to make your arguement then explain how pipes in the floors work over the design life of the house first. Work up from there. Go on and give it a go! I'm willing to learn.

I've seen a lot of changes in the merchants business over the last 40 years ago. One thing that has driven this is that is it a lot harder for them to take cash and not really put it through the books. The other is that the increase in dodgy customers who don't pay their bills has also increased.

That's a bad show. Hope this gives you a few pointers, some points you will already be aware of, but this post is also intended to help others that may be in a similar position to you. You are not the first to have an extended project so take heart from that. I've recently had a Client who started a project under their own steam, but their financing arrangments changed and they needed a warranty retro actively for lending purposes. But you are specifically talking about an insurer. Is that just say for public liability, contents etc. But say, for all on BH this is for warranty (10 year) purposes, like an NHBC warranty. In your case I think the starting point is to show that what you have built so far is ok. You are going to have to do a bit of work! Gather together all the site record photos you have, invoices and so on, itemise who did each part of the work so far. Put that in a big folder, even if it looks spurious! This is your evidence base. Next step is to contact your original design team and ask if they can help. You should indicate that you are willing to pay for this service. Sound them out, even if you offer say £200 quid for a quick consultation. Be proactive with the cash! Now they may not want to get involved. Very occasionally I do this, but only if I'm going to get a fair days pay for a fair days work. But when I do I give it full pelters and you need to be willing to pay about £ 275 - £300 quid a day for my time. So if you take my rate then anticipate / compare that your design team may charge similar. Make no mistake, I'm not touting for work as your design team already have a head start. When I get involved I look at two primary things. First is what evidence do we have that what you have built is ok and how do we package that up so a broker / insurer will be interested in quoting for something that carries a higher risk. Have any site inspections been carried out by the insurer that has stepped awy from this? If you have record then this is good evidence. As an SE I'm very aware of risk, as are my insurers. It's about putting something together that insurers can quickly understand and engage in the detail that leads up to a quotation you can live with. You can almost insure anything. In your case the premium will likely increase, but if you present well you may find that more than one insurer will be interested. As a final word of encouragement. A recent Client got the run around from Protek admin, but once we elevated that to director level they were great... but we had to do a lot of leg work first for them to recognise we were not trying to take the piss out of them. I bet they don't..there will, I suspect be all sorts of agreements, maybe some NDA', side marketing and product placement deals.