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Hi all I stumbled on some articles on heat pumps and thought this would be a useful group to join, to hopefully get some direction as possibly add things I have learned along the way. We have been living in Rural France and have found it impossible to get reliable people to finish work, be it electrical, plumbing, building etc. Much of this is a language issue, but even for the locals, they have similar difficulties - so doing what I can, myself. It is turning out to be quite a learning curve, which can be quite daunting as well as rewarding. Anyway looking forward to the ride

Folks, We are on our self-build journey, we selected timber frame then short listed 4 suppliers and in the end chose MBC. They erect our medium complexity house in 8 working days - very impressive. I think MBC's strength is their experience which shows in the detail / thought in the design office and the efficiency of their erection teams. Our site is constrained so working out the order to deliver materials, how things are stacked, the order that things are lifted by the crane is complex. The team didn't seem to make any mistakes and just kept working, rain or shine. [To confirm I'm just a paying customer and have no other association with MBC]

There is your answer. the conduit is probably crushed by a stone somewhere and sadly useless. For anyone reading, only use a much larger smooth sided rigid conduit. 50mm absolute minimum.

OK, an update: I stuck my heels in and called their bluff, surprise surprise they haven't initiated a small claim and after more ridiculous attempts to justify their position they have agreed to write off the cost of replacing the cracked tiles and have suggested we split the tower scaffold hire 50/50. So, progress, but I would still be paying £750 for the hire of something that I wasn't told about and didn't need, so I'm going to push back. Also, their threat not to do the electrical safety certificate and not honour their 12 month defect warranty still sticks in the throat a little. They want me to settle whatever is owed and then only will they return to do the certificate. Our relationship has understandably deteriorated a little, so I would still like to hold the cost for this back until it's done, which seems reasonable to me. How are things normally settled at the end of a contract like this - normally would ALL work including certificates be done then a final invoice, or is asking for payment first then completing certification the norm?

Have you read up on the bloke on here with the extension that just will not get warm, and looked at all the issues he has. read it and get a good grasp of what is right and wrong. pretty painted walls and nicely fitted architrave doesn’t make a good building.

A couple of pictures of my efforts on the upper floor so far. I have so many of these aiirtight box's to make, so so many.

I've got half a dozen books from when I designed and built my own house. I don't use them any longer, so if some or all are of any use to you I can send them to you. If you donate a tenner to BuildHub that would cover P&P. The titles are:- Building Your Own Home by David Snell The Green Building Bible 4th Edition Volumes 1 & 2 by Keith Hall The Green Self Build Book by Jon Broome The Energy Efficient Home by Patrick Waterfield The New Autonomous House by Brenda & Robert Vale

I'm assuming that the brickwork in this pic is the external skin and the blocks are the inside? If so then you've a 10mm+ gap between the insulation and internal skin... Cold air will circulate through this, negating a large portion of the insulation. I.e. it'll be cold. It's needs to be rectified.

Couldn’t find one to quote as we have overhead wires which prevent crane use. Besides, I’ve an impact driver. What could possibly go wrong?

I’m glad you have said this, because I’ve been thinking it for a while. This is exactly what I’m going to do. I pressed the trigger on a professional alarm today. I know that a more cool headed approach would be to save money and go the self install route, but I didn’t want to be responsible for a bad installation, and I also wanted it done quickly. The burglary hit us bad. The scumbags came back a few days later and stole the car too. Luckily I recovered that thanks to a tracker. Now I’m preparing for the fight with the insurer. Can you believe they have sent their “agents” to my house to check my locks and entry points THREE times. They haven’t caught me out yet though, and I’m not about to start letting them by declaring an alarm.

In that case I would have expected them to build the inner leaf first and then set the insulation boards clipping them tight to the inner leaf. How exactly are they fitting them at the moment? In my view they should be foamed to the inner blockwork, to eachother, around the wall ties, the foam trimmed and then all joints and exposed edges taped with foil tape. I've never seen it done though.

As people correctly say: "Where are the pictures?"

MVHR is one of the best things I did, wouldn’t like to live in a house without one. Self installed for less than £2k.

Thanks. It was definitely flowing uphill! Got him to angle it and clip it correctly.

Yup. 100% solid. Are there joints underground? Or a single pipe run? This stuff is crazy hardy, so I’d be shocked if you’ve managed to damage to pipe. Are you testing wet or dry? Best to just connect it to the mains and let the leak show itself.

You really want a gully trap. The amount of crap that comes off a roof is impressive. We've two at the front of the house that connect to 110mm pipes that just open in to the gravel backfill around the house. Having the gully and the grid means none of the leaves and sycamore seeds can get in and clog up the outlet.

Where is the trap situated to stop the smells coming up that pipe. if you are thinking of fitting a waterless trap behind that appliance then you need that to look at the diameter of it. I can see a way out of your problem, but I do agree with everyone, it’s a bit farmed up and the pipe should come up in the cupboard next to the appliance. will the back panel on this island be removable. I think you need to answer the bit about the trap first and the possibility of moving the appliance first before we start looking for a method of hacking that pipe into a better position.

I cant find this requirement in the definitive MCS document which is here. The BUS rules say that the system must be capable of providing 100% of the space heating requirements, but say nothing about rooms You might reasonably argue that the guidance (but not the actual requirement) of Part L of the building regs requires separate heating of each room so you might want to take a careful look at this (note that most of the document is guidance, the actual requirements are just a couple of paragraphs.) DHW is frequently heated to 48 with an ASHP If you heat rads to 41-45 then your flow temperature will have to be be 41-45 with mixing down for UFH, so you lose the efficiency advantages of UFH. You want a design where the space heating is one flow temperature only (with weather compensation obviously). The towel rail in my bathroom is hopelessly undercapacity according to the calcs (because it wasnt upgraded from the DT50 design). The bathroom is nice and warm from the adjacent hall and, when its in use, steam. I would go with those who say find another installer/designer.

As an aside 3G, Airtightness and MVHR were always going to be included for the comfort, noise, air quality and building health aspects. Payback was considered but it wasn't really ever up for discussion given the other benefits.

We are really pleased with our MBC house. The installation team did run over and it took almost 7 weeks in the end but it was quite a complex build.

Its nearly 20 years old, at the end of its serviceable life, are you not better off starting from scratch with a modern heat pump and redesigning the heating system as best you can.

Get digging, I'm afraid. We had the same issue with a electrical conduit. At least you spotted this before flooring! Another reason to install kitchen before flooring.

As a full time wheelchair user this kind of b******s really p****s me off. I came across the incredibly restrictive stuff in part M4(3) about kitchen design (worktops capable of being raised and lowered, no cupboards under a sink or hob etc.). This is rank 'ablesplaining' - able-bodied people deciding what disabled people need. Fortunately, our planning consultant and architect say we can ignore part M4(3) as we are not specifically designing a "Wheelchair User Dwelling" even though its going a be a dwelling occupied by a wheelchair user 🤔 On topic IANAE* on building regs obviously but I can't see anything in part M that says you cannot have a WC lid. I suspect it's an invention by low-lifes who think they can sell a few more shabby cut-price loos by calling them "Part M compliant". Rant over 🙂 (* I am. on the other hand, an expert on wheelchair use and I would always want a lid on a toilet.)

Don't fit UFH in this situation. Your overlay boards will not have anything like enough insulation to sit directly on an uninsulated floor. If you do proceed expect a lot of your heat to go down and very poor performance.

It probably is.

A bit like the screws & bolts question. Sorry to hijack but this is fun.....

I think that's actually the right way up, the intake sucks air in at the bottom and spits it out the front. Not much, but hopefully better than just slab cooling, esp in bedrooms with solar gain and carpets on the floor. And we are in Northern Ireland where it rarely gets above 23C on a summers day. I'm getting the impression that pelmet is the way to go here 🤪

It’ll feck your MVHR flow up quite a bit? You’re suppose to recirculate the air in the room, boss Last one I did this on I installed 2x 92mm Ubbink radial runs to letterbox sized extract points (22x 225mm) with one in each far corner of the room vs 100% of the airflow at the one vent (for sound mostly, but also for more even flow of the cooled air throughout the room). The bedrooms with direct cooling had a communal attic space with vaulted ceilings, so the idea was to have the FCU grille in the vertical wall direct off the FCU, flow the air in at the top and let it blanket down, across the whole bedroom, and then exit via the 2x letterbox grilles (I installed these at socket height to blend in a bit). Using a transfer grille in the landing outside of the bedrooms could see air from bathrooms being pulled towards this, with positive air being forced out of the MVHR inlet. Not. A great idea to not have these properly recirculate, and I wouldn’t do this if it was my own job. Maybe create a pelmet, and use that as the hidden extract point? Without being there it’s a bit sketchy to advise obvs…

A "Bulb" is something you plant in earth and it grows into a plant.

https://www.cotterillcivils.co.uk/blogs/guides-to-flood-management/how-to-install-soakaway-crates?srsltid=AfmBOoohgOP6ReHBhn3MNaLCNlKWv0QntWy-0RO-CJBHyVViWn_e6_77 We didn't use crates at all, just slotted 110mm pipe in crushed gravel, geotextile below and above. The pipes were covered with more gravel then geotextile.

Hang on. Has someone worked out how much more in resource terms these so called eco but actually short lived led bulbs (that’s what John Lewis calls them so I’m sticking to that) cost vs dead simple and resource friendly filament bulbs cost? I know filaments use more lecky but is it enough to justify all the plastic and precious metals that get thrown away?

Good to have your approval Nick!

The double boarding is to allow getting the height done the precise amount so that the top of our tiles comes to the exact ceiling height. Its a shower room so sound not really an issue. May go with 300mm as small room so may as well make bombproof.

Bear in mind that the planners often want you to be able to go in and out in a forward gear, so you will need space on site for turning. You may do well to extend the driveway / parking areas.

400 or 600 12.5 boards on 400 If you use 600 centers you can’t use 12.5 boards Only 15 mil

You simply refuse to pay anything with the reason being that the job is incomplete due to defects in their workmanship. That’s it. Separate the Scaff claim, that would get binned in the first 60 seconds. Part out the original contract and pursue that uniquely. They sound as thick as 2 short planks tbh, so I doubt they’ve sought 3rd party legal council yet; if they had then they’d have been told that they’re Donald Duck’d.

It is linked to your ADHD

You need parking spaces and turning for (looks like) 4 spaces, it doesn’t matter if they are on the drive or in the garage. You can extend the turn on the left to allow for another space if necessary. The LPA won’t care.

You don't need to do anything. The only issue may be if you have parked cars in the road and the council become involved.

Is the garage flat roof or pitched? Could be space in the roof area for some kit. Also, general feeling on here and talking to architects seems to be that Planners don't care what happens after they've given approval (unless a neighbour complains) and BCOs don't care what the planners say, so...

Yes, wood is an insulation compared to screed. Screed also gets full contact with pipes so maximum heat transfer.

yep normal enough. If you've room to fit an EGO one in, they last a bit better in my experience?

Ha, looks like just asking it bog-standard questions might work better in this instance than using Deep Research! I wonder if we should start some sort of UK open source document template repository for self-builders.

No glue required - they're just cut a little over length so that they gently wedge themselves between the walls. Short lengths will stay in place until you put the studs in place, or you can slide the batts behind the studs, or a mixture of both - slide just one end of the batts behind a stud, put the batts in place, then the rest of the studs. It depends on the situation. In this photo there wasn't much space to slide them behind the studs so, as there were walls either side to hold the batts well, it was easier to fix the studs afterwards. Plasterboard and gypsum plaster are vapour-permiable, so no problem. Vapour won't move through them over the course of a few hours, but it will over the course of days, which is enough. But but it is necessary to use a vapour-permiable paint over the top - see https://forum.buildhub.org.uk/topic/41776-breathable-paints

Provided you use semi-flexible insulation batts you cut them a little oversize and compress them a little, so that they push gently against each other from floor to ceiling and wall to wall, holding each other in place when supported by the studwork... Just found a pair of images to illustrate the above. This is hemp insulation on a wall about 1m wide x 2.6m high, self-supporting (left) before I put the studs in place (right). The batts here are 100mm thick, but the lowest (out of shot) was sawn through to about half that as the wall behind was out of plumb.

Once again to emphasise. Diffusion is absolutely insignificant compared to air leakage and obviously liquid water . I would go so far as to say, that so long you have a mechanical ventilation system and don't use impermeable materials, you can completely ignore it.

Vapour diffusion is a thing, but it's the scale VS airtighess that gets lost on people. In this example a 1m² piece of wall allows 0.5g/M2/day to diffuse through it. Meanwhile a 1m x 1mm gap on a day with a gentle breeze will pass 1600 times more moisture through it. A badly sealed layer of Intello will do little to nothing for airtighess and that's the big battle you are fighting.

Stand the studs off the wall a little. If you're feeling really picky you can jamb a little fluf behind them, but the batts will fill the gap, espically if you space the studs close enough as they're a little hairy at the edges. The batts will just stay there all by themselves if you get the spacing right. Here's one my mate is doing at the moment. These batts are only 50mm too. Even where they're 2 batts in one bay they stay there fine. Use a slightly thicker batt than the depth of your cavity and it'll take out the imperfections. Wufi and other programs are only as good as the data they get and renovations of old houses are full of incalculable variables. Beware manufacturers will typically spec a buildup that achieves two things. 1. An "on paper" safe buildup that, 2. Uses lots of their product. For example try any of the PIR manufacturers and they'll oblige but I hope my lengthy video might have explained why I think it's a bad idea. The fundamental points are that it needs to be able to not get WET. Think airtighess, and it needs to be able to DRY. Drying onwards is no issue so long as you manage the ventilation, an imperfect VCL is worse than no VCL. Your plan is sound. Keep the course.

It's a very poorly understood topic. Unfortunately it's a common misconception that the moisture that causes an issue comes from outside. Assuming you have dealt with gutters + pointing etc this is never the case. It comes from inside the building, from breathing, cooking showering etc. This airborne moisture condenses when it reaches a cold surface. It is carried on drafts and air leaks around the house. This is why PIR is bad news unless you are prepared to hermetically seal it (Airtighess!!) If you leave a hole the size of half a penny that allows damp air to leak consistently you will get dampness behind the boards. As it's cold and sandwiched between a layer of miniscule vapour permeability (foil) it'll be forced into the exterior walls. Bad news. The walls will be much wetter than before the interior insulation. A flexible more vapour open airtightness layer like lime parge will be much more resilient as the walls will still have a drying route into the room. Mineral wool and gypsum are still massively more vapour open than foil faced PIR. 10 mm Lime render has a SD value of 0.1m. 12.5mm of gypsum is the same. Aluminium foil on the face of PIR is about 200m. In other words 2000 times worse. Lime parge, mineral wool and gypsum will allow the wall to dry inwards. Theres many way to skin cats and many wonder products but if you get a handle on the actual numbers the you can make an informed, financially balanced choice.

Any stainless brackets I used to have made, I'd ask for them to be "pickled". An acid was applied to remove discolouration and any scale from the welding pieces. Back in the day the part was dumped on the ground and nitric or hydrofluoric acid poured over it. Soaked up by the dusty yard and neutralised when it rained. Happy days!