Iceverge

Well done great news. Blown cellulose?

In John Cantors Heat pump videos he made a good point that as the monoblock is a factory sealed unit there's less risk of a refrigerant leak, which could wipe out any CO2 savings over the life of the heat pump. On manufacturers that insist on packaged tanks etc I'd be keen to avoid as it might mean it's impossible to repair when just one component breaks in future.

What standard of workmanship are you intending to employ?! Anything can work. You just need more "drying" than "wetting" The big one with internal insulation is airtighess, most moisture gets into a structure via airpaths from inside. Not diffusion through materials. You can do PIR internally and expertly isolated any part of the cold external structure from the moist warm internal air and you'll be fine. However do a slapdash job with insulated plasterboard and you're asking for trouble.

@ProDave did a suspended I joist floor with a screed on top. Search his recent posts. Added to his external woodfiber layer it should have excellent thermal bridging characteristics. Or like @Thorfun says just shove lots of insulation on top of block and beam. Perimeter thermal bridges are pretty straightforward to deal with for timber frame anyway. What's your planned wall build up.

Thinking about it some more and looking at some you tube videos cellulose is a different beast. It comes in fairly compacted bags and needs the agitation of the blower to fluff it up properly unlike EPS beads. I think the blower hire would be better for this .

Or to confuse things further how about an air to air heat pump. Or to really confuse things keep the oil boiler and plough all the money into extra insulation, air sealing and mechanical ventilation. Preferably with heat recovery. It might end up making more environmental and financial sense.

What's wrong with just back filling with soil and compacting it in? Otherwise maybe a "rice Krispie" concrete mix so that water isn't trapped by the post rotting it away.

The plastering isn't immaculate but without seeing it from different angles it's not too bad. The light oblique from the window is making it look it's worse. Open the curtains or take a picture from below and it'll look better. If you hold a torch along any of our walls they will often appear with ripples. As much from my spray painting as anything else. And we had really good plasterers. It's just a fact of any hand made product. Imperfections will be there. I have no idea about your other pipe issue or what even is wrong sorry.

If you want to make up volume then 270mm isn't really that much. 200mm of EPS would do the trick nicely. From the top down. 70mm screed with UFH Pipes stapled into EPS with long staples. Slip membrane. 100mm EPS 70 DPM wrapped up the walls. 100mm EPS joints staggered to the top layer. Sand levelling layer £11.33/m² is the cheapest I found after a 2 minute Google for 200mm and a U-value of about 0.18 W/m²K You could go even thicker, say 225mm to save the screed depending on the minimum required thickness of that.

I love hammering nails. As I understand it they are less prone to sudden sheer failure than screws. You can get special screws now that are fit to replace nails in joist hangers for example. These might be the "high" quality space screws mentioned above. As for the BCO disregarding the SEs design, they will probably become believers after the screwed joint is still in place in 50 years. Frustrating for you but that's the way most knowledge on building seems to become accepted.

I have 2 preferred engineering methods. 1. Observe what has lasted and what has failed on the farm after 60+ years . 2. Jump on it and add more reinforcement until it feels strong enough. For connected members I would say a good dollop of glue and some nails would be more than adequate if the timber was to remain in a temperature stable environment. You would need to let the glue set before adding any load mind you.

Off topic but I know you have an ijoist suspended floor. What's the total build up just for my own interest?

The only way to get good quality work done is to get good quality people, give them a good brief, adequate supervision and treat and pay them properly. Bringing a complaint against his previous work, and then letting him loose on a bathroom to be expected to work for free was asking for trouble, I won't go so far as to suggest sabotage but I could understand his motivations if that was the case. Beware if you get a reputation for being an unfair customer it may be harder to get other people in time to come.

Pics please. I was all for multiple drawers everywhere. Then I saw the price.....

PIV with some good filters would work. You can make your own pretty cheaply. You'll need a few bits of ducting too. Suck in front the garden and allow the air to be expelled via the bedroom vents. No heat recovery but at least you'll have filtered fresh air.

It would be fine for a comparison I'm sure

Nice one. Can you do any kind of test before and afterwards to see the difference?

I assume you want to isolate the noise from the floor below and have no access to the ceiling underneath you? How bad is the problem as is? Firstly seal all air paths with acoustic sealant. If it's a solid concrete floor you will have plenty of mass so mass loaded vinyl is a waste of cash. You then need to work on decoupling, specifically for impact noise. Doing this from above means some kind of squashy backing to the engineered flooring if you want to minimise height. However floating floors are pants. We have LVT floating and it feels loose. Carpet on your floor in higher traffic areas and a "no shoes" policy might be as effective as anything.

We leave the window in our bedroom for much of the summer. I support we could turn the MVHR off but it's so cheap to run and as it guarantees fresh air regardless we don't bother. Despite my statz-esque approach to kids leaving the entrance door open I try to remember a house is there entirely for our benefit and and enjoyment and not as a science project.

Having tinkered with a little auto wiring I would say absolutely nothing about house wiring is nearly as involved. Can you put in a resistive heater as a stop gap and dedicate 2 days of your holidays to this later on. You'll be well able.

This post says a tremendous amount. Passive standard gives fairly random number. The complete purist who wants only to heat their house to exactly 20⁰ with a MVHR post heater doesn't exist in reality. Most of us are happier a little colder or warmer in reality. Passivhaus ignores this. Copying someone else who has done all the hard work and arrived at the best solution is a trait that should be applauded. It's a great use of brain power. Cheap ASHPs make perfect sense. A low cost insurance of UFH pipes for the "just in case" is well worth it. Also despite best planning and hopes life changes sometimes. It's only a house in the end, don't worry too much about it.

Like lots of low energy builders I got completely bogged down by deciding on a heating system for our passive house. In the end I said "stuff this" to all the salesmen and opted for no heating. We use an electric resistive rad. I put some pull string patio heater style heaters in two bathrooms and a fan heater in the other for a bit of post shower comfort. I have no regrets about not opting for a full central heating system. However electric UFH just under the tiles would be nice in the bathrooms for little cost. I should really have made more provision for "just in case" but I had lost patience with the confusion and cowboy prices. That means: UFH pipes, Pipes for radiators, UFH resistive wires, a duct for an ASHP, a wall duct for A2A, A fused spur for a storage heater. Do one or two of these and then pour every other penny into the fabric and airtighess. When the house settles in 2 years you'll be able to make an economical and effective decision. We're putting in an A2A to cut the electric bills a bit.

Don't get hung up on the density of insulation for sound proofing. The main job of fluffy insulation is to dampen the reverberations or "drum effect" in a cavity. Concentrate on sealing each and every air path. Perimeter, board to board, wiring holes. Downlights are a disaster. The add some fluffy insulation for reverberation. Then add mass. Denser insulation of course helps but it's an expensive way to add those extra kgs. Standard plasterboard, soundbloc and OSB are all about the same price per kg and mug cheaper than insulation. If you're feeling really cheap sand in bags or plasterboard off cuts will all help if shoved between joists above the ceiling. Finally decouple the floors although this is more important for impact noises. Strips of carpet or rubber above the joists and resilient bars underneath.

Do you have the original proposed drawings showing the metal hangers? Thermal bridging is really important once you get to high levels of insulation. I would encourage you to download THERM and have a play. It's not too user friendly and won't give you accurate results like @ADLIan says but it does give you a good feel for the situation. I suspect it'll put your mind at ease once you see how little point connections like wall ties matter and how much difference even 25mm of insulation makes to break a thermal bridge

I think I've seen this somewhere. Before the finale of Grand Designs the producers arrive with lots of cushions and potted plants to disguise any exposed wires or abandoned breeze blocks.