Temp

In Fig 1 there are two pumps. 1). One on the left circulates water from boiler to/from the buffer tank. 2). One on the right is on the manifold and circulates water around the floor loops. On some manifolds this pump also draws water from the buffer. In brief - the mixer controls how much new hot water is drawn from the buffer and how much is recycled from the return loops. However not all manifolds work quite the same way. Sometimes a other pump is required to circulate water from the buffer to the manifold and back. You will need to check with the supplier of your manifold to see if another pump is required. Not sure what size buffer to recommend. Probably 100-150? Tables on the web suggest the expansion vessel should be around 8% of the total system volume.

I don't see any down side to a close pipe spacing apart from material cost. I suppose if you had very large rooms that might mean you need two loops in one room as they recommend each loop is less than 100m. That means extra ports on the manifold but not a big problem. I would certainly consider a buffer tank because oil boilers can't modulate so they can only cycle when (for example) only one loop us calling for heat.

There are several ways to add a buffer.... https://blog.heatspring.com/2-pipe-versus-4-pipe-buffer-tank-configurations/ Figure 1 is what I have... In my case the room stats control the right hand side via a wiring centre. The wiring centre performs a logical OR function to control the manifold pump. The boiler/left hand side is controlled by a stat on the tank (and an optional timeclock). The left and right hand sides work independently from each other the only common thing is a Switched Fused Spur that powers both sides. However there are alternative ways. The two port system in Figure 4 is claimed to be more efficient but I've no experience of this approach.. The idea with thus approach is that flow from the boiler can go direct to the UFH. The buffer only takes "excess" water that the UFH doesn't need (for example if only one loop is calling for heat). I think this approach is better for ASHP systems as they have lower flow temperatures and this approach helps maintain the flow temperature.

Im not entirely convinced that's correct because the mass flow rate will be higher.

What was there before? If the path replace paving that was there before the law changed I would reply "No new paving, only replacement of existing'".

It might be possible to dig it out of there with a knife but not sure how I would replace it. A regular sealer gun wouldn't fit in the sink. Would need something like a right angle nozzle ?

We have an undermount sink and granite work tops. Terrible problem with the sealer going mouldy. Needs replacing really but that would be a lot of work I think.

Screwfix has some festool sanding supplies.. https://www.screwfix.com/c/tools/sanding/cat6270002?brand=festool

I think that's OK but it's different to how many systems work... Many would have the Nest control the pump between buffer and UFH. Then the stat on the buffer would control the boiler, firing up the boiler when the buffer goes below the set temperature. That's how my TS system works. The down side is the tank is always kept at the set temperature even if the UFH is off. You can add a timeclock to fix that.

We use cylinder gas for our hob. Cost in terms of £ per kWH its high but in absolute terms its not expensive. A 47kg cylinder lasts at least 18 months. We have two cylinders feeding a 6 ring hob Britannia range with electric oven.

Solid uninsulated walls on ground floor ? Stick with mains gas.

I think that might be being confused with.. https://www.planningportal.co.uk/info/200130/common_projects/43/outbuildings

I'm not sure if that's a hard rule. Some people have built outbuildings close to their house and the planners have won and lost appeals. They use words like "there must be a material gap" without defining what that is. One option is to submit plans with an Application for a Certificate of Lawful Development. This would be checked against the rules for Permitted Development rather than the more subjective Planning Policies that a Planning Application has to meet.

How wide is the green extension? The grey "PD here" is limited to half the width of the house.. Page 22... (j) the enlarged part of the dwellinghouse would extend beyond a wall forming a side elevation of the original dwellinghouse, and would (I) exceed 4 metres in height, (Ii) have more than a single storey, or (Iii) have a width greater than half the width of the original dwellinghouse

It's brave buying bricks before approval. We choose some hand made bricks and the planners rejected them.

Not all manufacturers approve their render for use below the DPC. Check before buying.

I think its a more complex design than it appears.. The large open plan living/kitchen area means large spans for the first floor (9.5m). Not helped by the large patio door/window in the gable end and balcony above. The room-in-the roof design means the roof can't use simple trusses. Nor can you easily use a structural ridge beam because there is nothing for the western end to bear on (windows in gable wall). The flat roof dormer and roof light (snug and stairs) also complicate. At the front there might be an issue with the amount of water flowing onto the roof of the porch from three roof pitches. As my SE said.. You can do anything with a bit of steel so I think its all solvable but this is the sort of thing that can add to the cost.

or mirror the whole house so chimney is on the north side?

See The Guide to the Party Wall Act. https://www.gov.uk/government/publications/preventing-and-resolving-disputes-in-relation-to-party-walls/the-party-wall-etc-act-1996-explanatory-booklet Unfortunately it can get expensive if they don't cooperate as its you who pays for their surveyor as well as your own. It's worth noting that there is no penalty for non compliance with the Act, however if you cause damage and it ended up in court the judge would take a dim view of you not being in compliance. First check if the work is even covered by the Act or if you can change it so it doesn't.

But not by much. I suspect old sockets with weak contact springs might be more of an issue for overheating. I probably wouldn't leave everything running while you are all out.

Equations are correct. P = IV I = P/V for a 2kW heater.. I = 2000/230 = 8.7A Two of those easily over 16A as others have said. The wire gauge of extension leads can vary a lot. +1 to what @ProDave said. I cant see the power rating for the dehumidifier anywhere on Amazon. One person suggests 420W. You should be OK if you put one 2kW heater and one 420W humidifier on each extension lead. Ideally plug the extension leads into different rings or at least check if there is anything else that will take the ring over its rating (typically 30A).

The technical guide here.. https://www.gov.uk/government/publications/permitted-development-rights-for-householders-technical-guidance says height is defined as follows.. and Building is defined as.. So it seems clear its measured from the highest ground immediately adjacent to the deck.

12 year old thread but... https://khub.net/web/planningadvisoryservicepas/forum/-/message_boards/message/6222126 so unless more recent appeals have gone the other way you measure it here..

Check ends of joists as they may tell you if there is any water in the walls they are resting on.

It looks on the small side so I guess EWI is preferred to IWI ? It looks like there is a reasonable roof overhang and neighbouring properties are rendered so a possible candidate for EWI. If you have the budget there are brick or stone slip solutions used a lot in Europe that might look better than render. https://prostone.eu/stone-products/exterior-and-interior?gclid=CjwKCAiA55mPBhBOEiwANmzoQkAfH0HZYfsHORmwV3uLu30KFc9boDZe1-NBjqVuSJAllNUg61mqDRoCfZ8QAvD_BwE Any sign of damp low down on walls? Perhaps behind furniture? Any evidence owner has painted over it? Perhaps consider installing a MVHR system to provide good ventilation.