IanR

How does that meet your x4 simultaneous 20l/min showers for 20 mins + apparently hot feed to washing machines and dishwashers? If 300l @ 65°C with a 3 hour reheat time meets your requirement, then just have a 500l UVC heated to 50°C by a 12kW ASHP and have a 60 min reheat time. Pretty standard, if a little on the larger side, but able to store plenty of excess PV when the sun is shinning.

Sound quality is no worse than an analogue phone, supposedly better if both ends are VOIP. I've found the Service reliable, apart from the handset occasionally not ringing, but that's likely my own fault for trying to route a single user account to multiple devices. The options and configuration available (if Service provider makes provision) far exceed an analogue phone service. For instance, Voicemails are held on providers cloud, available from anywhere and I receive a reasonable voice-to-text translation, via email, directly after any message is left.

A 50kW gas combi could perhaps get to 18l/min of 50°C water, so blended down to 38°C could get you to perhaps 25l/min. With just 2 you'd still be +30l/min below your target. I'd suggest it's not reasonably practical to meet your unusual requirement with an ASHP, so go with Gas.

Is this for a domestic install? +80l/min of 40° water must have taken some setup if that's what you are used to. What boiler did you previously have? How frequently would x4 showers be running simultaneously? It's an unusual requirement.

The codes are staying, but they're already becoming less meaningful. I moved to VOIP a couple of years ago and ported my landline number, which rings on my mobile phone wherever I have a signal. I did look at an analogue adapter (~£50) for the house when I moved over to VOIP, which could be a solution for alarms dialling out and keeping your existing phones. Needs to be on a UPS, along with the router, to keep it working in a power cut. Some VOIP Services will set up the adapter box and/or new VOIP phones, if you purchase the items through them. In the end I went with a 3rd Party VOIP Service (Yay.com) and now pay £6 / month for a "landline" with 100 mins of inclusive UK calls, incl. mobiles, and cheaper call rates than standard BT. I bought a new Grandstream WiFi VOIP phone that works off the existing house WiFi, so no extra base station. It was easy to set-up and does generally work well. I've not yet worked out why, but occasionally the handset won't ring for an incoming call, so I now make sure I power off and on every week to keep it connected. It may be that I've also routed the line to a couple of mobile phones, but I've never got it to work robustly and have all phones ringing on an incoming call. It does make me wonder if an adapter box would just sit there and work, or whether regular reboots would be required.

While the external materials and finishes are very strongly "Suffolk Barn", I don't see that from the form. Roof Pitch on both main roof and mid-stay porch, need to be steeper, in the 45°-50° range, and for a traditional timber structure it appears too wide. Max width of the main structure would be 6m. To get to 10m wide would need a lean-too. I imagine you have a height restriction to combine the current width, 2 full stories and 50° roof pitch. For me the form would appear more in keeping with a modern, portal frame style barn, but that would mean walking away from the Suffolk tile, black cladding and red brick plinth.

Correct there is no DPM, or any membrane under the upstand or the lowest layer of EPS. It is OK for the EPS to sit directly on the Pea Shingle. The Pea shingle (no fines) is free draining, so combined with the perimeter drain, removes any water from under the raft. Yes, 100mm is all you need with Mesh included. A deeper ring-beam under the external wall is unlikely to be needed with the loadings for a garden office. The setup I've shown is for EPS not PIR. I don't believe there's a PIR/PUR approved for ground bearing (happy to be corrected), so for this the concrete has to go under the insulation as per @Moonshine's option, and is no longer an "insulated" slab/raft.

Here's my go at an over-engineered insulated raft, for a Garden Office. As per @Iceverge, ground should be around 150mm below the finished floor level. No separation layer needed for EPS. To do the chamfer detail on the upstand you'd need to make up a hot wire cutter. If not then a thinner upstand (25mm) will do. Upstand can be stuck and screwed to the base layer. You could, almost definitely, do it all in EPS100, rather the the EPS200 I've shown under the ring beam, as you won't be having a heavy roof finish on that 5° pitch.

Hi @fatgus, and welcome. I really like the simple form, the contrasting graphic and material choice, it gives it an agricultural aesthetic that should fit well it what I assume is a rural setting. Working against that though, imo, is the fenestrations. Windows and doors are a little too busy for me, especially as it contradicts the agricultural aesthetic. In part this has come from an equally busy interior layout. What's the overall sizes? It does appear that a little too much has been fitted into the available space. The 7 different sitting areas (outside of bedrooms) for instance, the additional laundry room on the 1st floor, the Shower in the Utility (for the dog(s)?) as well as the WC & Shower on the utility, the narrow passage to the Cinema room etc. It's a shame this has then left only a small space for a compromised office and only one bedroom with en suite bath/shower room.

Hi @matt-me, and welcome. Are you using a PIR/PUR or an EPS SIP? and do you know the effective U value of your SIP Roof Panels, once the timber fraction is taken into consideration? I suspect once the timber fraction is taken into consideration, the U value of the roof panels will mean that your unheated loft area will be cooler than the rest of you house (except under sun loading on a sunny day). Since the hot moist air from a shower-room at say 24°C with 85% humidity has a dew point of 21.3°C it would be advisable to insulate the extract ducts. Unless you are considering adding cooling to the supply air, there's no reason to insulate the supply ducting.

Hi @russellfeeed and welcome. Congrats on the planning. Photos are always encouraged....

The bottom right corner (Between A & D) needs to drop 67 mm. If you are not extending the sides to the correct length, ie. side D to 5800, then perhaps only move the bottom right corner down 60mm, to half the error. Not aware of a specific App, but use a free piece of CAD software to draw it out.

There is often confusion, even within the industry, with regards geothermal and ground source. The terms are starting to become interchangeable, but I remember when Geothermal required at least a 500m borehole, and probably more, to get down to rock that was being heated by the earth's core, rather than solar energy. Unless you happen to have a hot spring emerging on your plot, when you could go without the borehole. Ground source is of course absorbing energy from the ground, or water that is heated by the sun. Typically GSHPs have lower day-to-day running costs, but are much more to install and a little more to maintain. With the demise of RHI, I can't see there ever being a cost benefit of GSHP over ASHP. Only if the ground arrays are incorrectly sized, which does seem to be the case with a reasonable number of early installs.

The discharge to surface water rules have a contradiction. While there is a clear rule (19) stating you can't discharge to a water course "that does not contain flowing water throughout the year, unless there is a drought or an unusually long period of dry weather", in rule 20 it then allows a partial drainage field that permits waste water to soak into the ground, when the ground is dry. With this rule 20, the partial drainage field is still considered a discharge to surface water as long as the perforated pipe used between the treatment plant water course is no more than 10m from the water course. You previously described a "land drain" installed by a previous tenant of your plot. Is this a piped drain? Could you replace a section of this with perforated pipe, if it isn't already perforated, and then discharge directly into it. For my install BC made no checks on the discharge pipe. I supplied a drawing and stated the installation is covered by the GBR and that satisfied BC. The Environment Agency would only ever get involved if there was a pollution issue.

If you are only drilling a few holes then HSS should have been fine, but at Ø16 you should slow the drill down and take your time. Even a little fairy liquid under the drill may help. If you are drilling a lot of holes then you may want to go with a cobalt steel bit or black oxide bit.

Areas precluded from the GBR for discharge to a surface water are specifically listed as: biological sites of special scientific interest (SSSI) special protection areas special areas of conservation Ramsar wetland sites designated bathing water protected shellfish water freshwater pearl mussel population Are you believing ground water protection zone 1 is covered by one of the above list, or have you got a reference elsewhere that precludes it? I'm not saying it's allowed, just haven't found the rule you are likely referring to.

If there's not an "authority" that owns the drainage adjacent to the road, I doubt it's going to be part of a larger surface water drainage network. Sounds like previous land owners, or perhaps the council, have taken local measures to put underground what previously ran in ditches, but probably caused some occasional local flooding. We have similar in our road, where a neighbouring farm allowed a ditch to be diverted under a corner of their field to give surface water an easier exit to a larger ditch then into a river. If they were all still "ditches", there would be no issue discharging into them under the General Binding Rules as long as, at the point you were discharging, it remains "wet" for the majority of the year. Or are you saying the fact that you are in a "groundwater source protection zone 1" disallows this? I thought it stops the drainage field, but discharge directly to a water course was allowed. Just because surface water ditches have been re-routed underground, it doesn't change their function, so they should be able to be treated as a water course in General Binding Rules terms. It would be nice to know they won't get blocked though.

As long as I've explained well enough. A 4P buffer is a different use case, ie. if you want/need to run separate heat/cooling system (wet duct MVHR or fan coil heater/chiller) and you want to run that at ASHP Flow temp, for as long as possible when the ASHP is not running, then you need a 4P Buffer. If you "just" want to increase the volume of available fluid to the ASHP, then a 2P Buffer in the return line. Yes the Buffers are available pre-insulated, and there's no harm adding more. For my MVHR Wet Duct? Because I tee off the flow line before it gets to my UFH group manifold, which holds the UFH pump. So to get flow through the MVHR wet duct heater and back to the buffer, I need a pump on that loop. I had to do it like this as I wanted to be able to shut the buffer off from the UFH and just circulate the UFH water to re-distribute solar gain from the warm side of the house to the cool side. So this is rather specific to my installation and there may have been a better way of doing it. A condensate drain. So I use a wet duct chiller for mine which either heats or cools the MVHR based on what's in the buffer. Mine are Hunter Douglas external venetians and colour match very well to my Alu-clad Internorm windows. Good point regarding your location. And maybe your shading to the living area. I wouldn't take a risk on this though and I'd get it modelled. I'd recommend PHPP even if you don't plan to build to a PassivHaus level. Costs for me we're offset to some extent by not needing such expensive internal blinds/curtains. In my living areas I having nothing internal on the windows, and in bedrooms I have internal roller blinds. When my blinds are retracted they are entirely concealed behind the cladding In 2017 the 5m window blinds were £2K each and I have some 2m windows that were £1K each. Internorm wanted around £1K per sash, but they do add a 4th pane when they include integral blinds.

Yes, buffer always in use. A 2 port buffer is less efficient due to standing losses of the buffer. A 4P buffer is less efficient due to standing losses + an extra pump that may not otherwise be required. Neither are huge inefficiencies. Standing losses at ASHP flow temps aren't huge, and even less at ASHP return temp (hence put the 2P buffer in the return line), plus you're only paying for one third of the standing losses since you have an ASHP heating the water. For a 4P buffer the extra pump that you may be able to avoid without it, may cost £20 - £60 a year to run. Your capital investment is also higher, of course. I have mine tee'd off the flow line, before the UFH group manifold, but I then need yet another pump, and use it for heating and cooling. But, energy transfer via MVHR is low, due to air-flow rates. I doubt it would make sufficient difference unless you have very low energy losses, ie. PassivHaus class. No, HP in cooling mode will definitely not be enough. Bris Soleil is a minimum, but more control allows you to make more use of the solar gain. What was the issue with shutters? I have external venetian blinds, that are not visible when retracted, and controlled by the HA so that the slat angle matches the suns positions to maximise visibility.

The Installer manual will hopefully state a minimum volume of water that must always be available to the HP for heating. My Nibe F2040-12 states 80l Min, although I have a 200l buffer. If you just want to increase the volume of available water to the HP, then a 2 port buffer in the return line is generally the most efficient route. There are situations though when a 4 port buffer may be appropriate, but it does require an additional pump that may be able to be avoided without one. While air flow rates can't deliver that much heating or cooling via the MVHR, in a well insulated home there are quite a few heating days that the 1-1.5kW an MVHR can deliver is enough. A correctly sized 4 port buffer allows for an MVHR wet duct heater/chiller to use water, at ASHP flow temp, to trim house temps. I have similar and didn't fully appreciate how powerful solar gain is within an well insulated home, even though PHPP analysis told me exactly this. Thankfully I fitted external blinds to all the larger windows on the South-East and South-West elevations as they are used regularly for 9 mounts of the year to stop over-heating. In Winter, on the coldest days, which are normally the sunny days, I'll need no heating at all. I'll just let the solar gain warm up the rooms that benefit from it, then circulate the UFH to distribute that energy to the rest of the house. It does mean allowing the "sunny" rooms to get to 23°C or 24°C, but it seems nobody complains when the house is a bit warmer in winter.

2.5 ACH seems an odd target to me. Depending on building proportions, 2.5 ACH is in the region of 3m³/m².h @50 PA infiltration rate, which is the threshold at which whole house mechanical ventilation is deemed required as there is insufficient natural ventilation for reasonable internal air quality. At that target, you have to install mechanical ventilation, but receive no benefit and therefore no pay-back for the cost on the install. There's a lot to save from better air-tightness, but if you are to go better than 3m³/m².h @50 PA, then shoot for 1m³/m².h @50 PA (approx. 0.6ACH), in order to get a return on the MVHR investment.

I'm surprised the NFU wouldn't continue to insure you until the build started, but they don't cover self-build insurance. I used www.tradedirectinsurance.co.uk for self-build, NFU before and https://www.frontierinsurance.co.uk , now it's a home. Frontier should insure before the build starts, they're very flexible with outbuildings etc. I've actually moved all our buildings insurance over to them, from the NFU.

I'm in agreement with you and made the same point myself. But, you are being called in to repair corroded columns, so that's what you are seeing. While I made the same point, I didn't have this issue with my own frame, but have seen it in others. I did "square up" a number of columns that were 2" - 4" out of plumb though. It needs to be checked, preferably before purchase, or needs to be budgeted for if it can't be checked. ...but it can be the ticket to a residential property in a location that there is no other route to gaining permission. Such a shame that there is not a legislated route to a knock-down and rebuild development if there is no architectural/heritage/historic merit in the existing structure.

Just to reinforce what others are saying, I have 421m² of UFH for which I paid £5,500 for in 2017 including help for 1st fix install. I paid a premium at the time as it was added on to my insulated raft package and came from ThermoTech in Sweden who aren't the cheapest. It included system design, a group manifold and mixer + 2 further distribution manifolds, 1800m of Ø17 pipe and x20 electronic proportional actuators That makes just over £13/m², although didn't include commissioning or controls. As for Infrared v. ASHP. ASHP, no question. 300% more efficiency, DHW included and cooling if you want it.

Why is PassivHaus levels excessive? 150mm PIR doesn't even meet the proposed 2025 Building Regs. With a 2,600 ft² footprint, I'd be concentrating my insulation on the floor and roof.