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MikeSharp01 last won the day on August 2 2023

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  • About Me
    I am a retired academic of 35 years, I have also run a couple of businesses (engineering) and had a short stint as a TV presenter - at the moment I amuse myself building a new home for my other half and I in East Kent.
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    East Kent

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  1. Welcome Jamie, I am sure there will be loads of ideas / support for a roof replacement. Just load them up and we can get you some answers / ideas.
  2. Hi and welcome Angus. I like to think that I can either spend time saving money or spend money to save time. I don't like wet trades - brick laying / plastering neither do I have a head for heights. So although I built the roof structure I had the slating done by others. When it comes to the plastering I won't be doing that and I hate painting so that's a job for my partner in life who, although now in financial services, comes from a long line of painters & decorators! Everything else I am quite happy to do myself and so far have on our build except fit the windows which came as a package. I will do all the electrics under the watchful eye of my local electrician and the ASHP will be done by others under the grant scheme although I would have liked to do it myself it's actually cheaper to get in a third party if you are getting the grant.
  3. This looks like condensation to me, so you must have dew point conditions around the in-roof GSE plastic formers - the fact that it is wet both sides supports this theory. So warmer damp air hits a cooler surface and condensation forms as the air goes through its dew point. Calculating dew point in the traditional way is a bit of a pain but in 2005 Mark Lawrence came up with a much simple calculation which gives a good approximation, above 50% Relative Humidity (RH) and not far out below. Td = T - ((100 - RH)/5.) you can read all about it here: https://climate.envsci.rutgers.edu/pdf/LawrenceRHdewpointBAMS.pdf. So you can then play with the numbers and get an impression for just when the condensation will happen. I created a simple spreadsheet to help me understand why I was getting vast quantities of condensation on the air tight membrane before the insulation was pumped in. So if the RH is 80% and your air temperature is 9oC and if your plastic unit is at 5oC you will get condensation by this calculation (and the full one). Your situation is all on the outside but it still means that at for every 5% RH drop from 100% the temperature delta increases by 1o C (at 100% the dewpoint is the temperature if you think about it!). You can look at this another way - how is it a problem? You get condensation in roof structures on the outside, the build up design is so arranged that when it happens it is dried out as soon as possible and is kept off the absorbent parts by the membrane.
  4. I don't see any walk on glazing exhibitors - there is a glass splashback company though - great re-purposing of walk on glazing though.
  5. This is classic systems of systems (SoS) territory which tells us that we are involved with an SoS when any two of the systems in the putative SoS have managerial and operational independence. (Maier 1998) It means one of three things which have already been discussed - 1. You need to keep up or 2. Do it all yourself or 3. Some combination of both! I guess its about picking your battles as you cannot avoid it all. Silly little things like a company going bust or the main developer of a product loosing interest in it. No recourse to the developer is also an issue in SoS because most of us have no control of the developer / operator and they are always on the lookout for ways to monetize the offer. Twitter used to have a free API that let you read Tweets all day long - now its paid and rate limited. Most of us, including big corporations who rely on the technology of others are in the same boat we are - no recourse and with vastly expensive teams just keeping up. Even some 'open source' stuff has a no recourse philosophy - Tasmota has this risk, it says on their web site that "Tasmota is not a commercial product and support is limited. You have to be willing to research and solve potential problems yourself." So even there you are likely as not to have to make modifications that only you will be able to follow or you get involved with the development team to support your own ideas until life expires. Node-Red very clever but it's life is limited as is USB - how much do you rely on USB?. In any eco system there is a carrying capacity the system has and we can track it with the S curve and with the S curve, well when one technology looks to supersede another, comes the two opposing mentalities - the defender and the attacker. The defender thinks their technology is fine, that they can change quickly if something challenges, we know the competition and anyway who would challenge such a well found system - Bonkers. Meanwhile the attacker has a hill to climb to get the innovators and early adopters across onto the S curve they think can beat the status quo and make them rich. Knowing when to dump all your investment, and believe me investment challenges change - big time, in a technology and get with the new one is a fine art, fraught with risk - loads of new S curves go nowhere, and it can be expensive. Personally I am hoping to keep it basically bomb proof by avoiding as many bear traps as I can while being fully aware I cannot avoid still having enough of them to wipe out a lot of bears and have fun playing with ideas while my mind is up to it. So the wiring is all traditional everywhere and at the flick of a din mounted lever isolator you can switch out the computer and connect the switch directly to the lamp - yes you get full brightness but hey you don't need to maintain the DMX dimmer, the RPi server, the switch monitoring circuitry and host of other bits and pieces. I hope to use this approach everywhere I can - as an old friend - Bill, now departed, was fond of saying - 'Mike it's supposed to be F.U.N' lets just have fun. Maier, Mark W, Architecting principles for systems-of-systems, Systems Engineering Journal, 1998
  6. We did it with 2 board scaffold both sides although to be fair we did agree with the footpaths officer to put 1 leg of the scaffold on the footpath in exchange for resurfacing the footpath - we still left it 2m wide.
  7. Welcome to THE forum for people like us. Sounds like interesting project possibilities and lets face it the journey of 1000 miles starts with the just one step!
  8. Our BC wanted the sweeps kept shallow so we do have some interesting pipework leading up to the chamber to avoid a 90 bend in the chamber. I have colleagues at the Uni doing some research work with one of the big pipe manufacturers and they are building a long drop (20m) to rest bend then into chamber all in clear plastic instrumented to death to research how these flows work, the forces involved and the challenges of transporting the stuff that regularly gets flushed that probably shouldn't.
  9. Yes we all need to keep in mind the length of @Pocsters tentacles (I checked the spelling of that very carefully) when closing in on Bristol - best go incognito or an Abrams tank! So welcome @Brizzol but beware some of the locals can be seriously 'interesting'.
  10. Hmmmmmm .. Interesting spot and one wonders if these two factoids are conflatable in the way you have. One, the latter, refers, if I have it right, to the power consumption of the fan while the other has no input power of the rest of the unit while recovering the 1257 W and I guess it will be approximately 300-420W. If my estimations are correct then the fan around 10% of the power usage of the unit at this recovery and you are right 420W / 10 = 42 so that bit is right .
  11. Here is a bit more detail. Hope it helps.
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