I'm impressed with the level of restraint employed.  That must be one of your smallest hammers 

Not really a sensible suggestion, but if you look at 2.23 on this video, you'll see the chaps 2 post lift which also lifts the roof.  A metal deck roof on a frame would be well suited to moving up with the car, you just get a bit more ventilation when the lift is up.  The lift in the video must be rated to, or maybe just capable of, an impressive weight as that's not a regular SD1...  

That all sounds very sensible to me.  Couple of comments are that max surface temperature of most for finishes is 27°C 29 at a push.  This is not water temperature as there will be a temp drop through the screed, 40°c to the pipes is probably a bit high, but i suspect you mean 40°c to the manifold, where it will mix down.  Insulated floors are significantly less common than the EPCs would tell you, so you'll be ahead of the curve.  The first bit of insulation is the most important, it's diminishing returns the deeper you go. 20% saving is ambitious from a boiler, but if it goes from non condensation to condensation mode, you run the room at a lower temp, and you're adding insulation, you might get there 👍

Shacktune = James Shackford, who is pretty well known in the saloon world. He was also TR Enterprises gearbox specialist for many years. Almost the entirety of the suspension setup I have for my 2000 has come from James, and I have driven his MK1 and can happily confirm it works! He is also one of the sources of the bearing spacer kits for the small chassis front bearings. I'd be strongly tempted to give it a shot, if you wish John I have a number and email for him I can send (via PM)? Phil

Just a heads up regarding the Honeywell Evohome system - I run this in my house (and I recall there is another forum member here using it?). However it is not as cheap to install as you might expect. Well, actually the system isn't cheap at all, but the way it converts an existing parallel getting system into zones does make for substantial cost savings with regard to running costs. However, I've had my system for almost 10 years, and I have already had to replace multiple radiator controllers (HR92's) and also the main controller once! So whilst it is a good idea and when working is a fantastic system, it is most definitely let down by poor component quality. Ohh, and if using the HR92 radiator controllers, keep a decent stock of AA batteries on hand! Phil

Thanks, although I'm pretty sure it won't get done by Christmas, I'm only aiming to get the screed poured and the gas pipe relocation finished. But already feel that might be too ambitious without burning through all my holiday. From what I've read yes, there is an efficiency gain, the heat is released radiantly from below over the whole room instead of via convection from the side. The body perceives this as warmer for a lower room temperature. The large surface area allows for lower flow temperatures, which increases the efficiency of the boiler as condensing works best at lower flow temperatures. For means of comparison, I'm targeting a UFH flow temperature of under 40c, but currently we run the old inefficient single panel rads at 75c (the upstairs ones are also earmarked for an upgrade to modern K22 radiators). I've seen figures of around 20% efficiency improvement quoted, but hoping for a little bit more than that given the current handicapped nature of our heating system due to lack of radiators. The heat loss through the floor is allegedly not much, there are even companies that will groove an existing non-insulated screed for UFH pipework with a special router. Some say a lack of insulation in the floor is not a big deal, as the ground will function well as a thermal store. But for responsiveness of the system (UFH is already very slow to respond), it's better to isolate from the ground as much as possible, so I want some insulation, hence removing the screed, planned build up is: Glue down LVT (~4mm thick) Thermal liquid screed with 16mm Pert-Al-Pert UFH loops (40-45mm) Vapour control layer (to protect PIR) (~0mm) 50mm PIR boards Damp proof membrane (~0mm) Existing concrete slab. So new total build up will be around 95 to 100mm. Existing build up with the multiple layers of wood was about 70mm (40mm screed, 10mm parquet, 20mm solid oak), an increase of up to 30mm which will necessitate new doors and the like, but isn't awful. Modern houses typically have 100mm+ of PIR, we can't get near that without digging out the slab, but U value calculators suggest we will go from U value of ~1.5 to a U value of ~0.3, which is a decent uplift.   Yes exactly, UFH upstairs doesn't seem worth the hassle. I will replumb the combi to be S-plan, with zone valves for the UFH and upstairs radiators (pluss an auto bypass valve for pump overrun). The UFH manifold I've bought has a pump and thermostatic mixing valve, so it should be happy with any input temperature a few degrees hotter than the set point. I have OpenTherm control for the boiler, and I've purchased Honeywell's UFH controller and EvoHome OpenTherm smart controller so hoping it can modulate the boiler to only run as hot as is required for the zone that is calling for heat.

A huge pre X Mas project. I assume you will have a mixture of UFH on the ground floor and Radiators upstairs (we have that in our House) Thus you will need two separate controlled   pump cirquits because Radiators need a higher water temperature than UFH.

Wow that’s a big job.    Hope you still get on with the neighbours !!

thats a lot of work and Christmas is only a month away! how are you going to insulate under the pipework, most new builds seems to have very thick layers of insulating boards? Are under floor heating systems more efficient than having modern radiators?

@mpbarrett hmmm, if Dad does the machining tonight, and I get the final bits on order, and the software tune just works, then technically it's possible to make it, but I'm not that optimistic!