SteamyTea

Probably is. https://en.wikipedia.org/wiki/Vapor_barrier You need to get the gm.m-2.day-1 from the makers. Moisture Vapour Transmission Rate, MVTR and this.

Not for me. It really needs grinding down to the GRP substrate, cleaning and then reapplying. Polyester resins generally bond to other polyester resins quite well, before they are fully cured (a day or two). After that, they are not to good as the free styrene has boiled off, even as low as 10°C. This is partly why self-etching resins were created, it made repairing boats easier. Wax additive, which makes for a nicer finish, is paraffin based (usually) and works as a release agent. A light sanding will, initially, seem to be good enough, but generally, over time, delamination will take place. I used to make steam room from GRP. Steam and thermal cycling is how resins are tested for longevity (with UV lights). Took me quite a while of seeing failures before I got a decent combination of resins that could be cycled reliably, every day, for a few years. When I left the company, the guy who took over decided to change just one component, failures started in weeks. I am still smiling about it over 30 years later.

Only a bit of a (expletive deleted), not the full marsey.

Thermal movement maybe. Parents had a new house that had a banging roof when the wind came in from the west. They sold it to a TV news reader. Always wondered why she looked tired.

It will soon be winter and in darkness for 15 hours.

I see your business is up and running (expletive deleted) me, I gave you that phone number for emergencies only.

I would hope that any PV system works well this time of year. Better to report back later when you have October 21 to March 21 numbers.

Ideally you will want to use a self-etching polyester resin as part of the top/flow coat mix. You really do need to remove most of the existing top/flow coat. Unless you know what the 'flavour' is i.e. make and mixture. Proper repair work is often harder than redoing it.

How the (expletive deleted) did it go from an economics topic to tooling up CATs.

http://www.tonyshouse.readinguk.org/tonytray.pdf Any help?

Maybe, but simple arithmetic is simple for a reason. I suspect that most self builders have 'earned' the money through property inflation, inheritance and occasionally good fortune at work. So it is not really correct to compare a tradesman's price with cash saving. We occasionally see people join here with great plans, not enough money, buckets of enthusiasm, then vanish. They usually work in IT management. Arthur C Clarke once said, the advantage of electronic engineering over mechanical engineering is that, with electronics, you have easily available, standard parts, while with mechanical engineering, you can wait weeks for a simple casting, that then has to be machined accurately so that it does not fit.

When I did my toolmaking apprenticeship, we combined machine amperage and an assigned tool life so we knew when to change the work bits. Mayne you can do something similar, say 4 months and 50W.

That looks like a relatively small transformer. DNOs love it when customers pay to upgrade their old kit.

PU/PIR sheets will shrink over time, the only way to stop the edges becoming thermal bypasses is to use a very low foaming adhesive, properly applied. This sill not stop the sheets becoming slightly thinner of the years, but as the thinning is a percentage of length, thickness thinning is not so much of a problem. While tapes can cover any gaps, that is all they do, and again, they have to be properly applied. I love expanding foams, I made a living out of making the tooling for them, but you have to know the curing characteristics and limitations of them. Curing can happen for months after moulding and natural temperature variation will cause 'off gassing' that further changes the ratio of the material to void matrix (bubble size effectively).

I think the problem is two fold. How much electricity do you use. What percentage of the PV yield can you utilise. There is a third/forth option and that is your personal views on environmental issues and aversions to power cuts. So it really boils down to each individual having a different formula.

Really. Is that tons of refrigerant? 1 ton = 3.5 kW.

I think last month my standing charge was greater than my usage charge.

@Kelvin When it gets dark and cold, I get a candle out. When it gets really dark and cold, I light it.

It is hard to believe a screen can be lit for so little. Here is my lifestyle.

@DamonHD lifestyle

I have loaded up my mighty spreadsheet of my energy usage, and looking at the last full 4 years, my breakdown is as follows. This is for an all electric house on Economy 7. Day Mean Power 0.09 kW Delivered Power 0.18 kW % Zero Power 58% Night Mean Power 0.89 kW Delivered Power 1.1 kW % Zero Power 44% The greatest power I have drawn, over a half hour period, is 8.9 kW. During the cheaper night rate, considering there is 3 hours (185 minutes) when no power has been drawn from the grid at all, and I have a 100 A supply, charging batteries would not be at all challenging. When I look at just January, February and December, when I am usually heating the house: Jan Day Mean Power 0.14 kW Delivered Power 0.23 kW % Zero Power 52% Jan Night Mean Power 2.63 kW Delivered Power 3.14 kW % Zero Power 32% Feb Day Mean Power 0.11 kW Delivered Power 0.2 kW % Zero Power 51% Feb Night Mean Power 2.19 kW Delivered Power 2.67 kW % Zero Power 33% Dec Day Mean Power 0.14 kW Delivered Power 0.23 kW % Zero Power 51% Dec Night Mean Power 2.52 kW Delivered Power 3.02 kW % Zero Power 33% So to power my house during the winter days, by charging batteries at night, I would need a battery system that can store a deliverable 2.5 kWh, and deliver a peak of 10 kW. I currently have a 20p kWh difference between day and night rates and looking at my latest bill, which was waiting for me when I came home, I have used 1281 kWh on the day rate and 4538 kWh on the night rate. Those have to be halved as that is for two years, so 640 kWh day, and 2269 kWh night. At current rates that is £215 on Day Rate. If that was on Night Rate it would be £86 a year. So a difference of £130 (with a bit of rounding here and there). Now I have no idea what a suitable system would cost to install, but being generous and assuming that there are only 5% losses during each charging and discharging cycle, and that after 5 years, 90% of the capacity is available, a 3 kWh storage system would be needed and a 10 kWp inverter. Anyone know what that would costs, or to put it another way, it would have to be less than £1300.

Quite interesting the constant power draws that some people have. While I am not a financial fan of battery storage, if your constant loads are high, they may make financial sense, though it does depend on the cheap, time of use, electricity price.

Try this if you want something really lethal. https://dhmo.org/facts.html

Would it not have been easier to fit a ventilation fan?