Visti

Good advice, thanks @Moonshine

Plan is the following setup with resilient bars, double board below and a membrane and acoustic mat above. Just hard to tell what is most suitable for the mineral wool given they vary so much in density.

I'm just about to place an order and started to think about installation of our acoustic insulation between the posi joists... The Rockwool RW5 come as semi-rigid slabs - would I be doing myself over by trying to fit these between the posit joists, or are there better alternatives? Main aim is to stick to as dense a material as possible (100kg/m3) I'm less worried when it comes to the stud walls.

Good advice @Nickfromwales. Thankfully the resilience bars are on their way so we will hopefully avoid that fate too!

Ah, got you! Mistakenly assumed timber frame. Thanks Peter ?

Holy Moley, that picture looks like it was taken from my build. Uncanny. MBC passive and internorm perchance? ?? I literally did my first wall the other day in the utility room with firmacell (1200x800), installed onto 18mm shutter ply so that made it relatively easy. Onto battens next, and so rises the learning curve. I am happy we went with the smaller one man boards. More to do, but they are easier to stagger with their 1:1.5 ratio and manoeuvre at height alone. Can confirm the screws should be threaded all the way along. The 30mm ones I have anyway. @PeterW why dryfix foam, and not just fix the reveal in place with screws? I'll be getting me some dust cyclones for certain! Anyone try the scorer? I found it to be quite underwhelming, requiring a lot of passes with force to get a deep enough groove in 12.5mm to snap off the peice. Any tricks? Going to get a cheap blade for the saw at any rate. Also for box holes, any good techniques? I've resorted to a recip saw to do the first one, but would prefer something a bit more accurate.

We made an order for our bathrooms (~£4k) between this Christmas and New Years from Megabad. No issue with UK delivery. The customs duty is a hell of a worry though, shite!

Specific heat capacity is all well and good, but useless without thermal conductivity from that mass to the rest of the house that also matches envelope losses/gains. If the conductivity is bad, you'll just have a very hot block of whatever with the rest of the house being unaffected. If the conductivity is super high, it'll dump that heat into the house faster than it can be lost. Nice sauna! Either way, it is unnecessarily complicated way of trying to setup a stable temperature as you've got to dynamically account for both boundaries over time (daily, with annual fluctuations). You're better off with a single boundary problem by focusing on the losses/gains via the external envelope alone. Then it becomes a much simpler problem of matching those losses/gains with some energy input such as via UFH or aircon. Thermal mass sounds good, but only focuses on one property of the material, where in reality thermodynamics has a lot more stuff also going on.

We're not looking to skim, just FST it. Called up the Fermacell technical line and they said it was possible to integrate the beads with the joint filler rather than skimming. So I guess that leaves both options open. Though I am not convinced. I may go with the option without a bead to be honest, much less to joint fill in. Thanks @Alex C, that is about £6.19/m, better than the £8.98/m quoted for the AGS materials!

We're planning on recessed skirting to go with our fermacell board and was wondering whether anyone has any experiance with this? Specifically whether the fine surface treatment or joint filler will work with a bead such as the following: https://www.ags-systems.info/en/skirting-boards/z-profiles/ It has the advantage we can install these after the board has been installed. If not, we're planning on going for the following profile which will work, but will have to go on first: https://www.ags-systems.info/en/skirting-boards/light-profiles/

Have a similar issue with ours! Been to ikea twice to pick and narrowed it down to two; black wood or a grey/green. Difficult! Not much help on those colours. I'd vote Carbon but then again I don't like pink nor can I see the first one (image broken)

Went with Gaulhofer 91 inline after a bidding war between them and Internorm (well, their UK distributors). Did a lot of quotes and research to find the cost vs. quality point I was happy with, then made sure I had two comparable quotes to get that bidding war started

Just about to do just that. Great tidbit!

Holy moley... I take my hat off! 1 child during my build has me at my limits, I cannot imagine a pair of twins too. Bloody good job on all fronts

Welcome to buildhub Stewpot! You will have good days, you will have bad days. You will also have very very bad days: Things will go wrong. Every day. Often multiple things a day. You just have to accept that shit will hit the fan and that it is your attitude to dealing with the problem that is key. Also, you can never prep enough. Even with two and a half years for us to prep, sometimes you just don't have the experience to know what you're missing out. Don't budget by the m2 - it is way too inaccurate and depends on 100s of choices you'll make in your build method and materials. It is useful on its own at the very beginning to convince you can do it cheaper than others! Money on a quantity surveyor up front is well spent to give you a dose of realism when it comes to cost. And your contingency? Go high. You will exceed your budget unless you know the industry. Same for your plan; expect and be prepared for it to take longer than you want it to. Cashflow is king. Those problems above go far easier if you can just deal with it right away. Else it lags, stress builds up and costs also go up. Cash is also king. Some trades will discount if you ask. Trades are not your friends. You will be desperate for them to get problems sorted, and curse them in equal measure. Some are great, some are good, others are a nightmare to deal with. Find the people you trust, and get references for their work!!! Also, review their work promptly for quality. before they get near the end of a job. Edit: I should finish with a positive note! Yes it is mad, but I would do it again in a heart beat. Same as pretty much anyone on here I bet.

Denmark used to do so, only recognising matrilineal nationalisation due to the high number of men with overseas wives. Also didn't permit dual nationalisation either! Thank goodness that has changed recently (only in the last couple of years!). IIRC, Spain only allows one nationality and asks you to rescind others unless you are from a former colony. Dual EU citizenship is out of the question for them

Danish here, Spanish partner. Both dual citizens now via UK nationalisation. Our little one has all three!

Any of you considered stapeling the fermacell? Wondering whether it'd be easier for install, but not sure how to level it like I'd do with a screw!

The model assumes a contractor to compare like for like. We're actually DIYing it now as my sister wants a gig for a few months. Convenient! I'll be going with square edge. Tapered just appears to be needed if integrated with other types of boards. I was thinking of 12.5mm throughout with a single layer, even on ceilings, to keep the m2 installed low due to size

Correct, if you compare like for like in @Dreadnaught's table, it is more than £10 cheaper. But that supplier I've found overpriced by far. Thought the realistic 10 Vs 12.5mm £ comparison still being cheaper was more striking!

Encon. Same size at 12.5mm I am getting quoted £6.48/unit, Inc VAT. That is 6.75 £/m2, nearly 50p cheaper. How many units you ordering? I'm at about 930 so volume may make a big difference.

I over spec'd I guess. I saw that standard board could be used, so I may do that instead in my next revision. It is more a representation of feeling out of control! I always do this (engineering background) so that I can feel like I am making an informed decision... I am not sure whether the results are improved following a week of evening spreadsheet of good advice @ProDave, I think that is generally the way to go. I may also get a spare box of fermacell screws for other jobs in case.

I think it comes down to value for money. The standard single layer of wallboard is cost effective, but personally it doesn't sit right with me.. neither acoustically and quality wise (I'm big, clumsy and have many holes/dents punched through and patched in my current home). The plywood backing also adds a lot of cost to enable fixings to handpicked areas. If I double up for quality, fermacell is just a far more cost effective way as it doesn't double up on labor. Doubling up also still doesn't address the fixing issue, where as fermacell will allow me to do it anywhere. I might also have found a willing laborer to do it at much more favorable rates too...

So I did the number crunching, and it looks like there is actually a good case for Fermacell if you can find a good supplier (found at £6.47/m2, making it £2.22/kg. only slightly worse than standard soundboards in my last chart). 1. Label every wall... 2. Take all the measurements... 3. Calculate labor and materials cost per m2... I've got quotes coming in at 25-33k (Double Plasterboard) - so not far off! Using only standard board I'd save ~£2k in materials. 4. Get a decent quote for Fermacell materials from here ... This is for a single layer of fermacell, equivalent density as doubled up gyproc wallboard. The labour is also an additional £1/m2 for installing these boards. The contractor also quoted more for applying the Fine Surface Treatment than skimming. 5. But what if I did just a single layer of standard wall board... This is half the density of the above except at the ground floor ceiling, and limits fixings to just areas with planned noggins or plywood backing. Using only standard board I'd save ~£1k in materials. 6. and what if no plywood backing at all... Probably the cheapest it'd get unless all the sound board was replaced with the standard board to bring it down to £11.5k.

@Moonshine - doing a review on the £/kg and it looks like the no brainer if going for acoustic performance is bog standard wallboard at 4.52 kg per £ I may as well double up on standard board which will give me a surface density of 16 kg/m2 at £3.53 per m2. That is a full pound pound cheaper per m2 than the most economical soundboard GTEC dB check, and gives an extra 3kg/m2 to boot. Why have soundboard at all? Is it a question of labour? @Nickfromwales - 100% correct on ply... a very expensive approach. I'll be doing it strategically as recommended