Mr Blobby

Slabbies (is that a thing) are coming out to measure tomorrow. Good point about the slab support within RSJs. l'll ask them about this tomorrow😉 ... going back to my original question @Conor, do you think there would there be any benefit in making that RSJ longer to be better supported by the padstone? It just seems to me to be on the edge and longer would be better. Or am I being a bit OCD here 🤪

You mean this: That'll be about 180mm Hollow core slabs. But this RSJ supports further beams that in turn support more hollow core slabs so I think this bit may be quite important 😬 Tell me about it 😩 .. The RHS in the first photo is ok-ish, its the LHS that's a bit on the edge I think.

I think steel beam marked with 2300 should be longer so that it is supported by more of the padstone. Should I get it swapped out?

The plan is to use solitex plus breather membrane to wrap the ends of the hollowcore slabs for airtightness. From what I can find online, this is what others have done and acheived good airtightness scores <= 0.6. What I don't get though, is that Solitex doesn't seem to be airtight. So why use it as an airtightness membrane? Are there any other robust membranes that are also airtight? Any recommended products here?

Thanks @Conor It sounds like you have the same insulated screed my builder is suggesting. From alpha flow screeds in Omagh? Did you then poor a standard screed on top of the UFH pipes? How thick? I think we're looking at 30 insulated screed and then 50 ISH standard screed on top.

As it says, I have the option to run a couple of UFH loops in the FF bathrooms, which are above the kitchen diner in our passive build. I figure it would be handy for cooling as much as heating but as far as I can tell, the clip rails would need to be attached to insulation and then the screed on top. Can I attach the clip rails directly to the hollow core slabs? My builder and plumber were appalled at the suggestion, but I think because of the labour required, not because it is a bad idea. Has anyone on this forum ever attached clip rails directly to the slab? Is it impossible? I only expect to install two loops for the bathrooms and a bit of landing so not a massive area, about 30 m2. To install FF UFH our builder has suggested a 30mm insulated screed under the UFH pipes to clip the rails to as it is failrly maleable for a number of days and easy to fix to. And he says it gives a sturdy and level base for the rails. The screed then goes on top. My concerns with this are the extra weight of the extra 30mm screed. Has anyone ever installed UFH on insulated screed on the FF? Or should I just stick to PIR. Or is it just a cr4p idea to install the UFH on the FF to cool the hollowcore slabs above the kitchen? Maybe the current heatwave is affecting my thinking 🤔

We have an MVHR plan originally from our M and E guys which I think is OK, like this: The unit is in the loft under a warm roof, in the centre-ish of the house. The external vents are through a North facing gable end wall. The first floor heat exchanger will probably be replaced with a bit of UFH upstairs, but apart from that, is there anything fundamentally wrong with the layout and ducting plan? The third diagrm shows more extract than supply vents. Is that an issue for balancing? I ask because a leading MVHR supplier refuses to engage with us and give us a quote until after we pay them a fee to (ostensibly) rewrite the ducting plan.

If 3-phase is close to the cost of a single phase connection, then get 3-phase, just to future proof extra car charging, or whatever else. Three phase will make it easier to have more PV on the roof as well.

Good question! I dug out our old quote and it was for 30 kVA so by my maths thats 75 Amp per phase. I think this is just below the threshold at which NIE tut and shake their head. It is unlikely you will be charging three cars at 32A simultaneausly and even if you were then chargers like ZAPPI and the Tesla wall chargers can do load balancing to make sure you don't exceed you grid supply limit. Without load balancing you could do something simple like 1 charger 3-phase 16 amp, 2 at 32 amp single (different) phase so that would be a maximum load of 48 amp on two phases and the remaing phase with 16 amps demand from the charger could go to the ASHP and the hobs and stuff and still not exceed 75A. But then reducing to 75 Amps may make no difference to your quote in your circumstances, but worth checking with your DNO just in case.

Is that 100 amp per phase per property you are requesting? That seems like an awful lot if it is. When I first enquired about our 3-phase connection last year the DNO told me there is a threshold that I should not exceed in my request. I forget what it is now, but I'm pretty sure it was less that 100 amp per phase. Maybe talk to your DNO about resubmitting your application with, say, 79 Amps per phase.

Reading other threads on this and it looks like 28mm in armaflex through 80 mm conduit build into wall. How does that sound? What about the power, another conduit through wall to the isolator switch outside? What diameter? So three holes then. Is there any value in positioning the ASHP on the East wall instead of North to get some sunlight in the morning? I have options here.

Thank you very much @Thorfun for the link to Powell blinds. We are about to order the Trojan AV90s from Powells that have Z shaped slats. Are you still happy with your blinds? I take it there have been no issues.

Thank you for your helpful responses. Chief brickie did say he'd put in a "sand brick" every few blocks so he could clean mortar out of the cavity. I did wonder if he was perhaps a bit mental, but now I'm reassured. Next few days will be interesting...

What is the best way to minimise mortar buildup from droppings inside cavity walls? I read on here somewhere (can't find it now) about removing a corner block and sliding lath up the cavity to remove droppings. Is this feasable? What have others done? Brickies didn't laugh when I said I wanted clean cavities so there's some hope...

And did you weather seal it on the outside? (Sorry if this is a stupid question)

This has become a bit of a hot topic this week between myself, builder and architect. The architect recommends the cavity closer to be supalux board but at a U value of 0.17 W/m K is not great as it will bridge the cavity. Supalux does however carry an 'A' fire rating. The alternative, bosig phontherm has a much lower u value at 0.08 and is marketed as a cavity closer. https://www.ecologicalbuildingsystems.com/product/phonotherm-200#technical-details ... but phontherm is, AFAICS, not fire rated. The builder would usually push some PIR into the cavity with a block return. Great u-values but hardly fire-rated. (and how would this be plastered over) I guess this is, in part, a building regs question around fire-rating of cavity closers. Do build regulations allow the use phontherm board / PIR to close the cavities?

And the winner is... Though the wall. We were originally going to follow the plumber's recommendation of both pipes through a single 160 long range bend but in practive the bend radius was massive and would mean the pipes emerge too far from the exernal wall outside. Questions: 1. Should the conduit (we will be blowing balls into the cavity) be built in or core drill the wall later. Building in seems better, is it? 2. How high up? (I assume about 40cm) 3. Two holes or one? I see @Conor and others did a single 100mm conduit for both pipes then foamed it. I guess two 50mm conduit would be ok too, and easier to build in.

This week I am mostly worrying about reveals and windows. I would ideally like to install our windows pressed against the outer leaf with compriband as the weather seal on the front face of the window frame. Reading through the various threads on here about check reveals it seems that most have done this with a brick facade but we will have rendered blockwork. Can I install the windows like this with a render facade? I took my kid's markers (we called them felt-tip pens when I was a kid) to draw this masterpiece: I have omitted air-tightness detail and foam for clarity. Rendering to the window frame is, I think, standard practice here in NI. So, questions are: 1. Can I install windows as above? If not why not? 2. Assuming the block reveals are square and vertical, then what thickness compriband tape, the 3-7mm? 3. Will the window be pushed back into the cavity about 5mm if a 3-7mm tape is used? 4. Can the compriband be rendered over? 5. If rendering over the compriband/gap to the window then should a plaster stop bead be installed on the window frame? Have I missed anything? Do I need to think about anything else?

Exactly. I can't see what harm it is doing, but KORE and the SE recommend it is removed. Why? I think to allow water runoff, but I've not heard from SE or KORE any reason why it should be removed. Taking their advice at face value, the top two thirds of EPS upstand is now in the skip. The next question now is, do I water proof it? The minimum is that the DPM will cover it, but is that enough? The site has good drainage and priming and tanking it will not be a small task 😩

Are they Hallmark Trojan blinds? ... and I quite like the prison window, a nice contrasting feature I think.

Fair point, and I reckon this is the reason why. I emailed KORE this morning, but not not heard back from them yet. KORE customer service have actually been very good. Some of the foundation was actually cut wrong, and after some head scratching on site KORE accepted the error and recut and couriered up new peices. Which was pretty good if a little stressful. I guess being 2 hours drive from Cavan helped. Two chaps from KORE also visited the site last week to show a prospect round, which I was quite happy about, as it gave us time to ask lots of questions and they were really helpful. We asked them about this perimeter and were advised to cut a horizontal line not too far down and remove the top part. KORE also advised to remove it before the concrete had set too much because then it is a bugger to remove. He was not wrong but darling wife had a birthday last weekend, when Sunday would have been the optimal day for the perimeter upstand to come off. Here's some pics. It was sunny all week, which nnever happens in Northern Ireland. Maybe the big church on the other side of the road did some miracle stuff. ... and here's that upstand...

Unlike TF construction, for cavity masonry foundations KORE recommend the perimeter upstand be removed thus: ... which is fine, except it is realy messy and time consuming. Given the EPS is below ground level then why can't it remain in place?

Indeed it is! And it's being installed this week. I'm not tense at all. 😕 The KORE installers have seen this detail before so it looks like a common enough approach but obviously a bit more work is needed to make the concrete pads.

The SE drawings for the slab include two sections where the EPS 300 is replaced by perinsol blocks, and the perinsul blocks are in turn supported by concrete pads. I guess some extra support is needed here. It looks like this: In the end we went for Partel CF200 instead of perinsul. The problem with the CF200 is it is eye-wateringly expensive. I reckon a single thermalite 100 block on top of a single quinlite block would have similar performance for a fractoion of the cost but the SE approves the CF200 and its easy to get hold of.

Thank you @Gus Potter for your detailed explanation. I sat down with a fresh cup of coffee and read every word. As I had suspected the builder (not my builder) who visited the site and told us we needed the PLT once the hardcore was installed was talking out his backside. He'd seen it once before so had jumped to the wrong conclusion that it was compulsory for a raft-type foundation. This is good to know. I had thought the SE trial-pit investigation was perhaps a bit of a waste of time, but now I am reassured that it was a very worthwhile exercise. I went back to read the SE report again in light of what you have written above. Our SE report says that we have sandy boulder clay with bearing capacity of 150kN/m2. Which sounds pretty good to me given the desired ranges you list above. It looks like we are blessed with good ground conditions, though I did suspect it would be pretty rocky after trying, and failing, to install an earth rod some time ago 🙄