Temp

If you are subject to the CIL get your exemption paperwork sorted before starting any work on site.

Are we sure the DHW tank isn't being used as a buffer for the UFH? I think some systems put hot flow into the tank and take it out to send to the UFH via the same pipe when the boiler is off.

Got to wonder why they didn't get pp in 2019 to change it to an separate dwelling? That ight make it more valuable and it could still be let out. My guess is they were advised they wouldn't get it. Beware. If you do manage to get planning permission while under offer whats to stop them pulling out of the deal and selling it to a third party at a higher price? To prevent that you could talk to your solicitor about an option to purchase contract but that might cost as much as you could loose if they bail.

Partly vented.. The boiler - store - UFH circuit on mine is vented but it can be dosed with chemicals to prevent legionares. The mains - heat exchanger - shower run is mains pressure and flushed with fresh water every time its used so i figure there is no time to grow bugs. Its no different to an electric shower I think. The burner in an Oil boiler always runs flat out. For some reason they dont/can't turn the size of the flame down (aka modulate) like a gas boiler does. To reduce power output to match the load an oil boiler has to turn the whole flame on and off instead. This is called cycling. Rapid or short cycling can be inefficient (ike driving a car in stop start traffic) so to prevent that I have the dial on the boiler right up and run the boiler to store pump quite fast. When its working right the store calls for heat and the burner makes one long burn until the store is satisfied.

Kingspan withdraws insulation fire test admitting it is 'not representative' of product on market for 15 years. https://www.insidehousing.co.uk/home/home/kingspan-withdraws-insulation-fire-test-admitting-it-is-not-representative-of-product-on-market-for-15-years-68461 "Kingspan last week wrote to the Building Research Establishment (BRE), which carried out testing on its Kooltherm K15 product, to withdraw test reports it has used in its marketing since 2005."

Problem is boilers can cycle for different reasons. Its unlikely to be due to the weather. Its usually because the boiler is too powerful for the load. For example when just one (or two) UFH loop is calling for heat. That can happen when the house is upto temperature.

Ours is an oil boiler and we had cycling even with a 300L store. My solution isn't applicable to a gas boiler without a store. What i did was turn up the boiler pump speed so it extracted enough power that the boiler never reaches the temperature set on the boiler dial. That means the burner runs continuously until the store is satisfied. It also reduces the flow temperature. If the minimum your boiler can output is more power than the load needs then the flow temperature must increase until a sensor somewhere makes it cycle to reduce power output. To prevent it you either need to reduce power output somehow (Smaller jets? Smaller boiler) or increase the load (thermal store or buffer tank). Another possibility might be to link zones so that you always have at least two loops calling for heat. However you get less control that way.

I believe Clearview have a direct air kit for some of their stoves but last time I looked they had two vents on their stoves, one on the bottom that could be fed from outside air and one on the door that took in room air. This might have changed as its been awhile. Ours burns room air.

The Clearview Solution 400 fits with both old and modern styling. Love ours. Its possible to control the air so you get lovely slow flames and the glass doesn't tar up as fast as other makes. Ours is in a traditional recess with the chimney to one side.

My feeling is that you could do with a pump speed between medium and slow. Not so fast that the flow is too cold. Not so slow that it cycles.

I have a similar system but with a bigger boiler. I run my store at about 60C to keep the return to the boiler low enough to be in condensing mode. My understanding is that the knob on the boiler sets the peak flow temperature .. the burner runs until it hits that temperature then shuts off. It will cycle lon and off like that if you let it until the store stat is satisfied. My preference is to not do that. I turn the boiler right up and increase the pump speed up until the boiler never quite starts cycling. Then when the store calls for heat the burner runs until its satisfied without cycling.

Try hinting you work for HMRC, perhaps as a VAT inspector ?

See the table column "Pence per kWh (after boiler efficiency)". https://nottenergy.com/resources/energy-cost-comparison/ They still reckon oil or gas is cheaper than an ASHP but its possible to argue with their figures. How much do you pay for electricity? They assume 19.4p/kwh.

I'm guessing many old houses have 25, 30 or even 40kw boilers and may need them in cold weather. Are there ASHP that will deliver say 30kW at a COP of at least 3 when it's 0-5C outside? Do you have to buy two 15kW units?

Just curious but is there a typical maximum you can install with just a single phase supply to the house?

Is the basement going to be a heated/habitable room or just for storage? One option is to build a beam and block floor over the whole footprint and put insulation and screed on top.

Are you in a CIL area?

Ignore the prices but Mick George have two versions of limestone on their web site with photos.. https://www.mickgeorge.co.uk/50mm-down-limestone.html?tax_display=2&gclid=CjwKCAiAnIT9BRAmEiwANaoE1RdOnbQN0HDdkNj2Rc4FU4pjbNnlM3uofChsbIDzQpEZLz-MzL9eXhoC9gYQAvD_BwE And https://www.mickgeorge.co.uk/50mm-clean-limestone.html?tax_display=2&gclid=CjwKCAiAnIT9BRAmEiwANaoE1SsBsKxcggt5zHzC1EGAXsQulvL_7okY5eMMW7KtYcxCH8_vw1WqrhoCk0gQAvD_BwE Think ours was somewhere between the two in terms of dust.

I don't think I have a photo but the stuff was yellowish rock covered in slightly sticky dust. Once laid and driven on the top layer compacted to form a very hard layer that was a bit slick when wet. If I remember correctly MOT 3 is meant to be permeable and the regular MOT 1 can be but isn't necessarily permeable.

We used limestone hardcore as a temporary driveway and it developed a sticky layer that filled in the holes between the stones. That then set up like cement. Unfortunately we had a planning condition that required a porus driveway and the planning officer pointed out that Limestone MOT wasn't considered porus. I guess washed limestone might be ok but i think I'd avoid it..

I guess it may depend if it's a former piped ditch or something the Highways built for their own purpose.. https://www.suffolk.gov.uk/assets/Roads-and-transport/Flooding-and-drainage/Riparian-Ownership/2018-12-07-Riparian-Ownership-in-Suffolk-Booklet-FINAL.pdf

Google found.. https://www.herefordshire.gov.uk/downloads/file/16062/guidance_on_landowner_responsibilities.pdf I don't know what happens to riparian rights when a ditch of the second type is piped and covered over.

PS If it was once an open ditch I believe you may have a right to allow surface water to run off into it if the land slopes that way? I didn't investigate that aspect though.

Yes we did. When we applied for PP there was a condition requiring us to submit plans for surface water drainage. Our only option was a "piped ditch" that runs along the verge of the road. Decades ago it would have been an open ditch but was piped and covered by tarmac when the road was made up decades ago. I proposed putting surface water into the ditch and the planners forwarded my letter to the EA. They responded saying that they "wouldn't want us to make local flooding worse". The planners simply forwarded the EA letter to me. In response I proposed a rainwater recycling tank with overflow to the ditch and the planners agreed it (possibly without asking the EA again). That despite a rainwater tank not providing attenuation when its full.

Is the plot big enough to dig your own pond?