Dreadnaught

Yes indeed. They had cross my mind too. Will be quite a challenge. I imagine my frame will require the smallest of everything: the smallest skip, smallest concrete wagon and pump, the smallest crane, the smallest forklift or telehandler. Hence I am proposing to use a smaller frame dimension too. At least that's my current thinking. The neighbours are all quite lovely (they might be reading this)! Actually, it is generally quite neighbourly, with just a few "exceptions". The boathouse opposite my plot is being rebuilt at present and I have a good relationship with them. I have offered them the use of my plot during their build and they have indicated they will extend help to me when it is my turn. A challenge is that the access road gets plenty of use, by the small silver car shown above, by boatclubs with boat trailers, and by hordes of students heading to the river to row at the crack-of-dawn. Beneath all that lie my utilities, all of them.

Thanks @JSHarris. What a sight! And then I imagine you had a big crane for the offload, like @vivienz had? I suspect neither is a possibility on my site, which is why in their quote to me MBC allowed two entire extra days for the necessary manhandling.

Regarding access, here's a view down the access road towards my plot. The gate to my plot is under that (slightly brown) chestnut tree at the end past the small silver car. Hopefully in the event I can convince the various neighbours to temporarily move their vehicles on frame day. As you can see, driving a digger around may be challenging.

Good point. Thanks. My architect mentioned this as an advantage too. I forgot to mention it. Oh, interesting. Why so when the U-values are comparable? Was it decrement delay and better sound insulation? Did you have a direct comparator to draw the comparison I wonder?

Thanks. Yes, Peter. I have a quote from them (and visited two of their builds). I must say I rather like Touchwood's system. And they would also offer me the advantage that their frame team are relatively local (Hertfordshire I believe) so would avoid the expense of local accommodation. Disadvantages are that, as far as I know, they only offer a full Passive-House specification product, which is inevitably more expensive than either MBC's passive option, let alone the 140mm-open-stud MBC option that I am now considering. And they don't offer a in-house foundation solution (although they do seem to recommend AFT for foundations).

Building on your comment further, @Russell griffiths, I think I am lucky to have chosen a good architect. She is a certified passive-house designer and is experienced with designing timber frames (she has, at various times, even been retained by frame companies to do their designs). And I feel I have excellent working relationship with her. The only disadvantage in choosing her is that she is not at all local, she lives many hours away from my site. And she not overly keen on wielding spreadsheets for some of the more detailed building physics work. My choice of architect has presented me with a puzzle to solve about how I should structure my build team. I could do with somebody local (to Cambridgeshire) to compensate for my total inexperience, to have a rolodex of local contractors (and mental list of ones to avoid), to attend weekly onsite meetings and advise on quality, sequencing, and resolving problems. It would seem to be that that person would be an experienced old hand but ideally someone who appreciated the importance of airtightness, etc. Is this a good idea? It did cross my mind that I could all but rely on BuildHub (BH) to act as this party. BH has been hugely valuable to me thus far. But am I being unrealistic. I would welcome others views on this. As some others have said (was it @recoveringacademic?) I am huge fan of building empowered teams filled with trust, but given me short (and no doubt unrepresentative) experience thus far in self building that does not seem to be usual culture. Or am I wrong? Its a hugely steep learning curve (which I am secretly rather enjoying).

@Russell griffiths, good question. No I hadn't. I started by assuming that I would go for an MBC-style factory-built frame. Its only when I received their details and quote did I first think about deviating from the standard passive double-stud wall. Open stud is new territory for me. The advantages of going with someone like MBC are that its quick to get to weathertight compared to a stick build. And they do the foundations too, giving the impression of reducing the build riskiness. And companies like MBC also give the impression of easing the path, providing reassurance, being easier for a novice like me. I can easily appreciate that for someone with your level of experience and ability that a stick build would be attractive (I suspect you'd do the build yourself). I am much more wary as a beginner but possibly without good reason. I suppose it depends on whether I could identify a pair of chippies I truly trusted, no easy task as I am already finding that trust-filled relationships can be few-and-far-between in self build. I have already had the impression from some parties that I am viewed as a meal-ticket-on-a-plate. Having said all of this, I intend to devote plenty of time to being on site. And I am also keen to be as involved as much realistically possible given my total inexperience. Hmm, food for thought. Thanks for the comment.

@lizzie did you use Habito everywhere? What about ceilings? And, for example, in the utility room? What about bathrooms, don't they need moisture resistant board?

Thank you @lizzie. Good point. Your comments are very helpful. That would be Gyproc Habito I believe. Certainly superior but, as I understand, sometimes cursed by installers?

Yes. Your and @lizzie's comments both support my hunch on where best to spend limited funds to maximise sound proofing. Funds are best spent on a triple-glazing upgrade and airtightness and not on replacing Earthwool/PIR with blown-cellulose in a (thicker) double-stud wall. But its only a hunch; I don't know how to support this guess with calculations.

Ah, makes sense. I will have vaulted ceilings throughout so highly relevant. Thank you.

Oh I clearly have so much more to learn about. I had not realised that.

Interesting. Even in a living room? I had thought such lights were only for kitchens or bathrooms: more utilitarian spaces needing bland flood lighting.

I looked into mezzanines briefly because the seller of my property wanted to prevent me from having one (long story). Could there be a building regs issue in relation to the minimum ceiling height needed for both the mezzanine space and the residual space beneath it. In my case this was my clinching argument for my seller. I could not feasibly squeeze in a mezzanine while meeting minimum ceiling height requirements, so he was content with my high ceilings. How high is the space you will be dividing (you mention 5m)? What will be ceiling heights of the new space and the space left beneath? (I am new to this building lark so could be completely wrong.)

@lizzie thanks. Can I just check that it is 400mm of blown-cellulose insulation in your roof? Did they come along with the blowing machine and cut disks into your ceiling to blow it in? Its not some sort of cellulose batt that they used? It does seem a bit odd to me that they would go through palaver of bringing the cellulose blower to site just for the roof. Good point about the ceiling service-void and downlighter. I must remember to watch out for that.

Thanks @Thedreamer. Yes having read a little about it, Protect VC Foil Ultra does sound like a good product, assuming of course that it is well installed and not punctured. It has embedded tapes at its edges but the manufacturer recommends it also be taped at the edges and joints (double taping) to ensure even higher levels of airtightness. I have asked MBC if they routinely do this.

Fair challenge @Nickfromwales. Personally, sound proofing is important to me. I like peace and quiet and the location of plot is prone to occasional raucous May-Week and bonfire-night parties, etc. And when I heard some time ago @JSHarris saying, presumably half in jest, that he would struggle to hear a Chinook throbbing overhead through his 300mm of WarmCel, I liked that the sound of blown cellulose very much. And I do concede that the timber studs that bridge directly through the Earth wool to the PIR will be channels for sound conductance. However, as well as the PIR in the section above there is 140mm of Earthwool in the walls too. Isn't that like Rockwool, which is used for sound insulation in internal walls? Moreover, is not the main source of sound ingress into a home that which comes from the windows rather than through the walls? Wouldn't upgrading from double to triple glazing have a bigger impact on sound proofing £-for-£ than spending 30% more on Warmcel in the walls? And wouldn't attention to good airtightness (which I understand has a big impact on quietness too) also make a big difference? I am happy to be contradicted.

Your usual observation is very welcome. Through your repeated emphasis on the such matters I have learnt so much. Here's the conundrum. In my design, most of the walls of my bungalow will be shaded by an overhanging simple pitched slate roof. Thus, sun's energy that could risk overheating in the summer predominately falls on the roof. Now here's the key part. The section I showed above is only for the walls, the roof is different. The roof system that MBC specifies to go along with the 140mm open stud wall system has 400mm of blown-cellulose insulation (see below). Thus, I am putting the cellulose in the place it is most needed for enhancing decrement delay, the roof. Thus I am getting the best of both worlds, while also reducing panel bulk, and saving the 30% price premium. Am I right? From MBC again …

Yes, @PeterStarck, you are exactly right. I suppose the advantages of the 300mm double-stud over the 140mm open are: Improved decrement delay, as @JSHarris rightly says above. More on that in the next post Improved sound proofing In some nebulous way that I cannot put my finger on, less cold bridging. (I am aware that a U-value (as compared with, for example, a λ value) should take into account but I have feeling I am missing something here) Less carbon embodiment Have I missed anything?

Oh, if only! It is an admired tree in a conservation zone, and nigh-on worshipped by the neighbours. It has already been trimmed: a crown lift by a proper tree surgeon and guided by an arboricultural method statement. Yes, one of those baby telehandlers might just fit or one of these off-road fork lifts:

Good point about steels. Have not got to the detailed frame design quite yet. I guess that will be in about March.

Quite right, @Russell griffiths, single storey. But I lack the glorious expanse of your truly lovely site (nor to mention your vast and wonderful wildlife pond)! On mine, the first limitation is that there is nowhere to site a crane as it is surrounded by buildings, trees and crotchety neighbours. The second is that the entrance gate is obstructed by the low branches of an overhanging mature chestnut tree. The third is that there is little manoeuvre room inside the gate nor, crucially, on the outside in the access road. Having seen a telescopic forklift being (skilfully) driven around @vivienz site, I doubt even it would fit in the cramped confines of my site. I can easily see the lorry carrying my frame stopping at to the end of the service road, some 40m away, and then each panel being carried or wheeled on dollies (possibly forklift) down the road and squeezed through the gate on to site, with the height restriction being the limiter. I had one frame company come to site and another looked carefully at it on Google street view, supported by some of my photos . Both were concerned about the access. One upped their quote by a few thousand because of it, saying they could find a way by making panels smaller, etc. The other did not quote. Anything I can do to make the panels smaller (by choosing 140mm over 300mm, for example) helps I think.

Here you go (from MBC) …

@vivienz haha. OK: The reasons for choosing 140mm wall system over 300mm twin stud: My site has restricted access and the craning of panels is likely to be severely limited and may be impossible, at least with a big crane like the huge one on your site. The panels will likely need to manhandled into position. The 140mm system is far lighter and less bulky A frame using the 140mm system is about 30% cheaper (excluding foundations) and my build is being planned with one eye on saleability

I wonder, has anyone here used the MBC open panel 140mm wall system (as compared with the 300mm twin stud)? I know quite a few on here have used the MBC 300mm passive-house twin-stud wall system but for a range of reasons* I am thinking of specifying the open panel 140mm wall from MBC instead with external-wall upgrade to U-Value 0.11W/m2K. I have some questions about the airtightness with the open panel system using the Protect VC Foil Ultra airtightness layer. (* If anyone is interested in the reasons I would be happy to explain.)