Great_scot_selfbuild

We used this stuff to screen our heras fencing. Just secured it with zip ties. £44 for 50m (2m high) - saved me £££ over the proper screening stuff. Can look thin (if you get right up to it), but if that’s a concern you can always double it up. As for wind, if you can, put it on the upwind side and it’ll put less stress on the zip ties. Weed Control Membrane | Heavy Duty Ground Cover Fabric | UV Stabilised Weed Barrier | 2m x 50m | 50gsm https://amzn.eu/d/9iYC2IZ

@flanagaj I can highly recommend Adam Chandler - https://chandlerhp.co.uk/services/house-builds/ (based in Basingstoke) Best of luck, stay positive!

Yes - planning to do this with the internal walls and. There will be a void in the ceiling (small flat section at top). All these comments are very useful reminders - I’ve thought about many/most of them, and am creating a checklist but I’m looking at one aspect there’s a risk of forgetting another!

Yes, it'll need to be ventilated. No matter how many times I mention that we need a mesh installed, this seems to be something that is actively ignored and it looks like I'm going to have to go and add this to the list of stuff I need to do myself! (has anyone got any recommendations for mesh they've actually used? I'm sure I can find some, but no doubt some products will be easier to use and handle than others, so I'd like to hear some first-hand experience)

@JohnMo your reply her (along with others) has prompted me to spend quite a bit of time over the last week doing some reviewing of previous quotes, get a couple of them updated, as well as investigate sourcing the ASHP and DHW myself without the grant and have a plumber install it. The majority of them quote between £12 - £14,500 before the grant, resulting in near to £5k after the grant. I've a quote for the supply and commissioning from an MCS supplier for ~£5,500 before grant and so the only cost would be our install cost (the quotes typically have the install broken down as ~£2,500 - £3,500). What do you think of this Cool energy HP? (this would 'only' cost us the install costs). To me, the numbers appear to suggest it modulates up a huge amount (9kW), but not down very well; I'm still on a steep learning curve with all this. I'm attracted by having an installer who is familiar with the make/model of the HP as so many threads are associated with poorly set up HPs. I looked into the Haier one - my main reticence with the less common makes, or going it on my own it the support for them afterwards. Thanks

@saveasteading this is helpful. I’d been so focussed on my arch tech’s previous reference to intumescent material I was overlooking this. However, as @trialuser says, the horizontal one will need to be ventilated.

@Nestor appreciate the pic - thanks

The entire upstairs is within the roof void. We have a steep pitch and a short wall height before the steep pitch starts. Having reviewed our lighting and power plans, we have no need for a service void on the sloped ceiling, and losing 37.5mm for the sake of it would be noticeable to the headroom and useable space in the room. I’m wanting a sanity check - is there anything I’m missing? The sloped roof will be all boarded with airtight pro passive board, and I would assume we would screw the plasterboard to it as ‘normal’ (should we be aware of / consider any other way?) Thanks

I like it. This matches my preference for always offering a solution to a design that I can make work, rather than someone else coming to me with an unworkable one. Do you have any recommendation on product? I need it to fit behind the counter battens (I have a 25mm gap)

I could write you the response I'd get from my BCO: It's for your Principal Designer to define where it goes, I just check it's where they say it needs to be. (I'm assuming this is now the common approach to all BC questions?)

I sometimes wonder why I bothered nominating a Principal Designer and Principal Contractor. The PD hasn't made clear on the drawings where fire stops are needed (though I've done my reading and understand the principles), and the PC hasn't asked about them before rushing in to install the battens for cladding. I've read this helpful thread - (surprised I couldn't find many more tbh) In short: I'm going to have to notch out of the battens space to install fire stops around each window and at the first floor level. Our build is, fortunately it seems, a Larsen truss wall filled with cellulose, which leads straight into the roof trusses (without a break or void), which appears to solve that worry. We have shingles fitted to counter battens and so only have a 25mm gap to be able to fit a fire stop in line with the vertical battens (or cutting across them for the horizontal break between ground and first floor). I believe I need fire stops around each window, at the break between ground and first floor, and literally just above this, at the top of cladding under the eaves. Inside, because we have a warm roof on the flat roof, I expect we need a fire stop above the wall where it meets the flat roof joists - but this will involve cutting it to fit the small gaps between the joists. What I need advice on is: What fire stop material have people used behind a timber cladding?

@HanleeHouse did you ever get any resolution to this (from elsewhere) I'm just about to post on the same topic and was doing my due diligence of seeing what other threads had been started - very surprised to see so few threads on this topic. I like the design btw!

This is an excellent suggestion (just the idea I was missing!) - to add to it, I'm thinking that rather than jigsawing, the pilot hole could be used with the pilot drill on a hole saw.

@Iceverge This is the space I'm in atm, it will remove an inch of useable space from each wall, which on the end walls would bring it down to 888mm wide. My main specific challenge from a sequencing perspective is the following: Timber frame is a Larsen-truss wall, from the outside: Breather membrane 12mm medite vent board 350mm cellulose insulation 12mm Pro passive board (assuming I keep the service void) 25mm batten 18mm hardwood ply (fermacel/similar?) @crispy_wafer @JohnMo @G and J @MikeSharp01 @Russell griffiths @saveasteading So, I need to drill/core holes for the MVHR supply & extract ducts (~210mm dia hole). I've been pondering the challenge of drilling all the layers - I don't trust doing this by measuring, so I'd want the ply in place first, then I figure I would: Drill the ply and pro passive board Remove the ply so I have a (little closer access to reach through to drill to the outer medite-vent board. Once the duct is installed, I can then seal around the pro passive board, then re-fit the ply over the top and then think about painting / finishing. QUESTION: How do I drill through the propulsive board and then bridge the 350mm gap to the outer board? (for info, it is highly likely the insulation will have been installed already, though I'm going to see if I can delay this)

@Russell griffiths This has given me pause for thought - although I would like it a nice painted, clean room, the practicalities of slowing everything down for this room (when I actually like the natural finish of the hardwood ply) is something I'm weighing up. I also already realise I've built the garage before the house and if I tell my wife I'm going to board and paint the plant room, before we've guaranteed the kitchen and other family bits of the house, I may not survive the build! 🤣 Do you have any photos of your plant room for inspiration please?

@Benpointer those windows look great (love the colour too).

Was this recently? When you say you spent £7500, was that on materials, or the plastering?

Great to know. @NestorI think I've been reminded that we will need more light and so need to paint our ceiling. That said, I really do like what you've done. What fixings did you use (I can't see any trace of a pattern of fixing points - lovely job!

@Russell griffithsI hadn't thought about that detail for window reveals (the walls are really well insulated, but window reveals will naturally be an area of less insulation - really like this prompt. I must start a log somewhere of things I shouldn't forget...

@Benpointer thanks - I plan on laying the pipes myself and having someone lay the screed. We're on full cost-saving mode now, having had most of the build so far involve work that I simply couldn't do myself (not if I want to actually get to live in it during my lifetime).

The intention for plant room is that the 12mm green PPB has 18mm hardwood ply board nailed directly to it, then items will be installed into it, with screws going through both. My main concern is if screws are put in and then later removed (items moved), then how do I maintain the airtightness. All of this is, of course, easy to keep an eye on when I’m doing it myself - my concern is once I have the electrician, plumber and others involved who don’t get the significance of ‘its just a screw’. So, how important is it to fuss over this level of detail - am I right to be so picky? (Possibly my ‘default’ approach 🫣)

@ProDave Thank you so much for this suggestion! We had some offcut Medite vent board do the same as it was left to one side. This is absolutely within my ability 😁

Useful to be made aware of this sort of detail - TVM. Is sounds like you’re suggesting that all XPS boards are cement-faced, or are you just highlighting the need to check whether they are cement-faced?

Thanks - once the battens are in place and give the final radius I was thinking about getting a board to test out options. I hadn’t been aware of the tile backer board for this purpose (just had it recommended for going under electric UFH mats, but wondering if it’s really needed there - that’s a different matter entirely). I’m wondering if the cuts/scoring can be made in the other boards (20mm is very deep).

Hopefully I’m overthinking this, but having read about the impact of small gaps in mortar on airtightness I just want to check… Situation: Timber frame build. Internal face of stud wall is Pro Passive Board. Intello airtight membrane used to lap joints and maintain airtight layer where PPB won’t fit. Timber frame company has a proven reputation for achieving better than 0.6ACH. They will install PPB & service battens, that’s where we pick it up from. Plant room: This is the first area where I will be installing 18mm ply throughout to give us a solid fixing for all the equipment that goes in here. I’m thinking that we can do away with the need for a service void here because all the wiring, piping, ducting etc is going to be on show anyway. I’m very keen to see how others have done their plant room fit-out. My questions are: 1. Should I still keep a service void in the plant room? (Why?) 2. When screwing through and into the PPB (which would be the case with/without a service void), this will pierce the airtight green coating on the PPB - will this affect the ACH performance? 3. There will inevitably be cases where screws are put in and then taken out, having gone through into the PPB layer. Will this affect the PPB? How significant can these piercings impact the air tightness performance? Photo for interest. This is ‘the big one’.