IanR

Shouldn't? Doh! yep it "shouldn't" be too difficult.

Are you using an insulated raft for the rest of the conversion. If not then it seems a lot of trouble to go to for a 3m x 5m area, when your glass "walls" aren't likely to be better than 0.5W/m²K U value. Are you thinking frameless glass? If it's framed the detailing should be too difficult. Have you got a link to the glazing you are considering, or a section?

What are you thinking will be the on top of the EPS upstand (circled red)? and what's the profile I've circled yellow? Also, is there a DPM running up the inside of the upstand with enough free length to lap over the top of the upstand? Is it still the plan to have tiles internally? Will there be a mat on the floor?, is it a "low" threshold? How much height have you got from the top of the raft/EPS to the underside of the moving door sash? What stage are you at with installing this? is the door frame in? Is there any rain cover over this door, or can driving rain hit it? How big is the flag stone area, before it drops 150mm to ground level?

In England, if the septic tank has not been altered since 2015, and assuming there is no EA Permit, then the only additional rule you must now meet is that it must discharge to a correctly sized (to BS 6297:2007) drainage field. It can not discharge to a water course. If you are selling a property with a septic tank you must inform the buyer, in writing, all details about the system (General Binding rules sets that out) Since it's a criminal act to run a private sewage system and not meet the General Binding Rules, then when a property is sold that has a system that doesn't meet them, the parties should agree who will upgrade the system and make it a condition of sale. Do you or your neighbour have a copy of the "Conveyance of land lying to the north of the land in this title known as Mertesse dated 11 January 1971 ". They appear to have brought forward the reserved rights to the current title deed, but not necessarily the condition (covering 1/3 of costs). That 1971 Conveyance should have been sent to the Land Registry when your neighbours property was first Registered.

Please see my previous answers. What's "non-sealed" EPS? You're still not understanding the system. Talk to an experienced structural Engineer that understands and design insulated raft systems and their requirements, and, don't change the SE's details without their approval, otherwise their insurance wont cover you. There is, but not for the reasons you're assuming. With EPS on top of the DPM there is a risk of the concrete getting under the EPS if the ring beams are filled before the higher areas of EPS have been weighted, down with concrete on top. Happened to someone at the old place. The recommendation is to pour the concrete on to the higher EPS sheets and let it flow down into the ring beams. Don't pump the concrete directly into the ring beams. I don't believe Isoquick tends to have ring beams, so not an issue with their system.

No they're not. The 100mm thick areas are where there are no load bearing walls. Rafts constructed to take high loads everywhere are over-engineered and wasting the client's money. It's an optimised product for cost and performance. No DPM on the Type 1 is to avoid potential damage the DPM. You need the no-fines layer (which is just 30mm - 50mm thick) to stop water from thermally bypassing the EPS, as mentioned previously.

Layer 5 isn't Type 1, it's a "no fines" shingle/granite chippings layer and is typical for an insulated raft foundation and is only 30mm - 50mm thick. Layer 6 is more similar to what you refer, although in this case is Type 3. Water is not being encouraged to move under the foundation, it will do that if not mitigated against. Type 1 and Type 3 are porous. On Isoquick the DPM is between EPS and concrete. I assume at ~200mm thick they're not expecting the UFH to be pinned to the EPS, as tied to the mesh would position it closer to the surface. While Isoquick tend to go with a constant ~200mm thick raft, most others reduce this to 100mm thick for the majority and only go to +200mm at the ring beam, saving more concrete and further reducing the dig. Personally, my choice was cost & performance.

Ref. https://www.isoquick.co.uk/design-features

My experience in England, was that I had to be on my own meter, and the meter was at the road, so had to run a new connection to the main, install a new meter at the road, and a new pipe from meter to property (130m for me). Since I was running power, broadband and data to the road as well, I dug a trench. If you are doing water only and crossing mostly fields, could you find someone local that offers a mole plough installation. As an example from a google search: https://www.pe100plus.com/PE-Pipes/Technical-guidance/Trenchless/Methods/Installation/Mole-Ploughing-i1303.html

I have a concern for the supply side. The BUS scheme hasn't been a sufficient incentive to accelerate the ASHP uptake, so the UK is not yet on the right path to meet 200K ASHP installs a year by 2025. With the sheds starting to offer ASHP packages that your local plumber can buy over the counter is an encouraging change, but there still needs to be someone in the process that's preparing a basic heat loss calculation and ensuring the ASHP is sized correctly. Perhaps that will come with Building Regs changes for the FHS. Then we need to see a ramp up of the supply chain, prior to rules change, otherwise there's going to be shortages, and houses that can't be finished as there's no heating system installed.

I see No.10 has tidied up their press release relating to Rishi's Net Zero "re-commitment". There is no mention of any delay or watering down of the Future Homes Standard: Ref. https://www.gov.uk/government/news/pm-recommits-uk-to-net-zero-by-2050-and-pledges-a-fairer-path-to-achieving-target-to-ease-the-financial-burden-on-british-families It looks to me that the plan to deny new builds a connection to the gas grid and require a non fossil fuel boiler, from 2025, remains in place for now.

Hmm. Actually, I'm blaming the gas industry. The heating industry (boiler manufacturers) are the fools for trying to jump on the bandwagon and sell something that is of no use to their customers. The 80/20 proposal was attempted to be sold to the government as a stepping stone to a 100% green hydrogen gas grid, for heating domestic buildings. The 80/20 stepping stone only delivers a 6% reduction in CO2, at the boiler, however, since there is no green hydrogen available, even in the medium term, for domestic heating. It would be, at best, grey hydrogen (made from gas) or worse, black/brown hydrogen, made from coal, which are the current cost effective ways of producing hydrogen. Due to the processing inefficiencies, the manufacture of such hydrogen gives off far more CO2 than the 6% gas that's being saved by the 80/20 mix. The 80/20 proposal therefore increases CO2. Since the argument is now lost for the 100% green hydrogen, gas grid, just on the basis of the cost of green hydrogen, the 80/20 stepping stone is a pretty pointless adventure.

Because there's no ban yet, and those new connections today may continue to buy gas until their boilers are irreparable post-2035. Then the heating industry are fools. 80/20 gas/hydrogen mix was an attempt to bluff the government. Thankfully it has now as good as failed. Yes, the point is often missed that changes now are only in preparation for Net Zero. And while they will immediately deliver a CO2 reduction, which is positive for the 2030 and 2035 targets, it won't actually be Net Zero until some point in the 2040's.

Then they need to get their heads out of the sand, it was announced and widely reported on in 2019.

I'd read that piece last week, and I don't feel it's saying that. It's a lot of Tory bashing, predicting further back-tracking, but the statement from the Minister for Energy Efficiency:

I don't that that is true, nor has it every been. Blimey, considering we're a pretty well informed community on this subject, even this collective are confused about what's happening. (me included) So, the Future Homes Standard, due to come into Buildings Regs 2025 mandates an 80% reduction in CO2 from our new housing, and a non-Fossil Fuel heating system in order to do so. I've not heard that the FHS has been delayed or watered down. Could anyone please post a link if there is a suggestion it has. In Rishi's speech, I was only aware of the plan for EPC improvements for private rentals being delayed and the ban on replacement Fossil Fuel boilers, for off-gas-grid properties, being delayed from 2026 to 2035 (aligning it with the rest of the housing stock). If that's the case, the requirement for non-FF heating systems for new builds from 2025 remains. - If I've missed an announcement to the contrary, please post a link. Heat pumps won't be compulsory, but Fossil Fuel heating systems may be outlawed, for new builds, from 2025. If you are rural, you may be able to use bio-mass (it's not clear on what the rules will be that will allow this, "in some cases") and there's an ongoing argument regarding bio-fuels. However, for most new homes, a heat pump would be the most cost effective option.

How about another silver birch in the middle of your yellow circle, that should reduce the issue for most of the year. Otherwise you need to put in some small scale land drains. Assuming the soakaways aren't full and the water pooling is due to the slow movement of water through the sub-soil to the soakaway. From your explanation, if the soakaway is in the corner then a 150mm wide trench to the corner, with some branches off to capture the whole area should do a good job. You could get away with Ø50 perforated land drain pipe set in shingle. The trenches around 350mm - 400mm deep. Put 75mm of shingle in, then lay the pipe in and add more shingle on top, stopping it around 75mm from the surface. Ideally you'd line the trench with a geotextile material, and fold it over on top of the shingle, then the drains won't clog up over time with silt. At the very least cover the top of the shingle with a strip of geo textile and then back fill with top soil.

And if you are coming to that conclusion without costing both on the same job, then that's quite possibly confirmation bias. For you, maybe traditional founds would be more cost effective, maybe you have a network in place that helps deliver that cost effectively. Without a network in place, I costed both options for bringing in the required trades and materials. If you think about it though, like for like, an insulated raft is going to be cost effective, unless someone's adding on a big margin. There's less dig, less concrete (and or no block and beam), maybe more steel, but nothing exotic, cheaper insulation (EPS in lieu of PIR/PUR) and no screed. But, you do need to pay an SE to Engineer the foundation system. Yep, all the manufacturers do of course say their product is better performing, but I'm talking about calculating the thermal performance for PHPP. There's a lot to do to a traditional foundation to get it close to being thermal bridge free, but for an insulated raft it's inherent in the design. ie. the exterior walls are sitting on the raft, which is insulated from the ground. While insulated rafts remain niche in the UK, they are more-or-less standard in Sweden. It's a well proven technology.

Is the trench with 50mm stone not capturing the ground water and taking it away to the nearby ditch? If it was only taking away the surface water then a surface drain would haven been sufficient. If ground water doesn't move through clay then French drains would not work in clay (apart from removing surface water). The biggest yield improvement we saw on our arable farm, which is/was on Essex clay, was when we started mole draining in the late eighties. That wouldn't work either, if ground water didn't move through clay.

I appreciate you do not understand this system. It's disappointing that your lack of experience with it would have you challenging the knowledge of the Structural Engineers designing the system, rather than considering your knowledge is incomplete. It does. Seen it with my own eyes. Had I not been sure I would have caveated my response. No, that would put the DPM at risk. FFL would typically be 150mm above GL, so 350mm - 450mm The water table at my old house was 100mm below the garden level, unless it had recently rained. You are coming across as if you are. "Ultra-cautious" would be opting for a 250mm reinforced raft with loads of steel, and spending a client's money on unrequired concrete & steel and extra dig depth. If you take some time to look into insulated rafts you'll actually find that they are, in most cases, Engineered for the actual loads they take and the ground they are sitting on. The one system that does follow more of a "one-size fits all" approach is the Isoquick system that is the subject of this thread, but it still out performs traditional foundations and is comparable in price (when apples are compared with apples).

If there's either water moving through seams in the clay, (after rain) or a high water table, which brings the water up to the EPS level, then water would move between the sub-base and the EPS and in between the EPS layers (below the DPM). The EPS under the ring beams will likely be around 500mm - 600mm below FFL, and for the majority of the floor area around 400mm below FFL. There are quite a few companies now Engineering these insulated rafts, and (at least when I looked) they were all using a similar build-up.

The "no fines" pea shingle or granite chippings are there to be free draining and the French drain is to lower the water table so the bed the EPS is sitting on is kept dry. If the EPS is sitting in water (up to the DPM) then its been thermally bypassed. ie. if you have 3 layers of 100mm thick EPS and the DPM is between the bottom two, with the water table above the lower layer, then you've effectively only got 200mm EPS.

There's no harm in zoning. Houses are a thermally dynamic environment, effected in different areas by solar gain, occupancy levels, open windows etc. Zoning reduces the effects across the house from a change in one area and provides better control to have different areas at different temperatures, ie. bedrooms v. living spaces. Be aware though, if you use zoning to significantly drop the temperature of, say, an unused area, then this may cause your heating system to be less efficient due to it running at a higher flow temp, and end up costing more to run.

I've used Airflow Airflex, with Airflow manifolds, terminals, joints etc and all went together very well. Best price I could find was via Travis Perkins. They're a distributor for Airflow, but don't seem to know anything about what they're selling, so you need to give them all the part numbers for what you want.

Can't say it's best practice, but what worked for me was cutting out the damaged pipe and inserting a new piece with some couplers. I was sure the UFH pipes were nowhere near the shower wastes, so was confident cutting around them to make space for the trap. I guess you can't keep your eye on a couple of km of UFH pipes....