jack

I doubt mixing is going to be the way forward, as it will affect the way loads are transmitted. As I understand it, no fines means that the larger pieces will lock together under load. I wouldn't speculate about something as literally fundamental as this. Hilliard is a really helpful guy. He knows your house and your ground conditions. Give him a call and I'm sure he'll set you straight within a couple of minutes.

Notifiable by whom though? Is this likely to be the owner's responsibility rather than the supplier/installer?

Just checked our spec and it's actually 30-50mm. Not sure where I got the 28mm lower number from!

Give him a couple of weeks' notice so he can allow some growth for you to hack at. Buying a plot without planning permission is a minefield. If a plot doesn't have planning permission, you have to ask why the current owner hasn't sought it, given the huge uplift in value that planning permission provides. In my opinion, buying such a plot without really (really) knowing your onions is a recipe for a lot of stress and delay at the very least, and a significant loss of funds at worst. And welcome to the forum.

The network rail stuff is, as far as I know, what some including me have used as a replacement (with Hilliard's blessing) for the specified 28-50 (from memory) angular no fines material. It's been a while, but I seem to recall that this is an unusual spec in the UK, which is why recycled rail ballast became of interest. If you can find a source of hard, angular, no fines material with a slightly different size range, I'd just give Hilliard a call and ask whether he's happy with it as a replacement. Not sure whether a revised formal spec will be required - worth checking with your building inspector.

I'd be concerned about significantly changing what BPC have designed you, without checking with them as to whether the changes will unbalance things. If you increase the extraction from the kitchen, you'll have to balance that with more supply elsewhere. Have you taken this into account? That's my experience too. We have a single run and a double run for our roughly 6m x 6m kitchen/dining area, and even on full boost (400m3 per hour) it isn't enough to keep the kitchen clear if we're doing something really smokey. I think it's partly because we have high ceiling (nearly 3m), which means that smoke can disperse somewhat before it gets anywhere near an extractor.

I emailed my D&A statement to Ed. Our architect wrote ours, and it's a lot like a planning consultant would have written. This was for two reasons. First, our house is very contemporary in design, and our local council is deeply conservative (in more or less all definitions of the word). We wanted to telegraph to the planners that we understood the framework within which the planning system works, and that we had considered each and every relevant rule that applied in the circumstances. Second, our local plan was in the process of being rewritten to bring it into line with the new national planning policy framework. Until the local plan was approved, the national framework needed to be applied. The framework is a lot more pro development than either the old local plan or the new one that was in the process of being drafted (aside, that local plan was eventually rejected and our local council is only now, years later, about to submit a new local plan for approval). While I'm sure the planners knew that they should be applying the national framework in the circumstances, we again wanted to make it clear that they knew that we understood the situation. It may have helped that our architect is local (lives a couple of blocks from us) and has a history of success with very contemporary designs in the area. It's possible the planners had become a little tired of losing to him at appeal! It's all a load of gamemanship and there are many ways to play the game. Start with something bigger than what you want, and trim down to make it look like you're giving something up, or start small and make amendments to enlarge towards what you really wanted. Submit a highly professional, polished job making it clear that you know what you're talking about and are willing to fight, or submit something drawn with crayons and play the naive, honest homeowner. So much fun, I almost regret that we got permission first time around!

Interesting. Can't remember the last time I actually bought bleach, but certainly many (perhaps many, many!) years ago you used to be able to buy the plain watery stuff. I thought it worked better in toilets because it dissolved easily rather than just sitting on the bottom like the thick stuff. No point even considering bleach though, if the pure stuff is available easily and cheaply.

By "ordinary", I meant unscented and unthickened. I wasn't aware of any additives in cheap bleach of this type - I'm sure I've read in more than one place of its usefulness for sanitising drinking water in small amounts. Whether I'd want to rely on a household bleach for more than emergency/apocalyptic use is perhaps another question.

Ordinary bleach!

Have you read @Bitpipe's posts on this topic? Very useful info.

Gawd dad, you're so embarrassing. I'll be in my room.

You're putting words in my mouth now You said In essence, the concrete burns the foil and renders the board much less effective. I read that as you saying that the loss of the aluminium had a significant impact on the insulation effectiveness of the board. I was simply making the point that the foil contributes nothing to the insulation of the board in an application where there is no air gap (as with Durisol). That's a fact, hence me saying To the extent that my answer addressed that statement, I believe it's correct. If you were saying that damaging the aluminium layer allows subsequent meaningful damage to the underlying board rendering it much less effective, then that isn't something I'm qualified to address. I also don't know exactly what the manufacturers say, nor why they say it. My question was about how much hydrogen is generated and how deeply it potentially penetrates the concrete in a Durisol application. The reactions alone don't provide an answer to that. You also need to look into things like foil thickness (ie, how much hydrogen is generated per unit area) and what the dynamics are of hydrogen gas in this structural arrangement. Again, I'm unqualified to comment, although I have a gut feeling that the damage isn't going to be as bad as you're suggesting. I have pieces of treated softwood left over from the start of our build that have been out in the elements for over two and a half years and they're perfectly fine other than some surface bleaching from the sun. I imagine they'd be in even better condition had they been positioned within an envelope that largely protects them from the vagueries of the British weather. I also have a several hundred year old house just around the corner from that that's still on its original wooden frame. Not softwood, admittedly, but it does illustrate that not all organic material is the same. Durisol says they "mineralise" the wood before they encapsulate it. Anyone know what that means?

Taken to its end point I suppose that means you must object to all forms of wooden construction. I'm not sure it's fair to lump all forms of organic material in with untreated and/or poorly encapsulated sheepswool! You said "In essence, the concrete burns the foil and renders the board much less effective"), To the extent that my answer addressed that statement, I believe it's correct. I'd be interested to know how much hydrogen is generated and how deeply it potentially penetrates the concrete in a Durisol application. I suspect the risk is much higher in a flooring application, where the bubbles are formed underneath a layer of concrete, and could rise into it through buoyancy. In the Durisol application, the hydrogen bubbles would need to move horizontally into the concrete to cause trouble, based on their relative positions in a Durisol wall. Seems less likely than the flooring case. Interesting to hear this though - I'd never really thought about the advice not to allow concrete into contact with foil-faced insulation.

What about putting strips of something over the webs (or maybe every third of fourth web) that will be detectable with a stud-finder? Would aluminium tape work?

Indeed, modern smartphones have several (perhaps 3-5) orders of magnitude more processing power than those probes. From a brief search it looks like they used a 2.3 MHz processor with 18k of memory for the Viking lander.

Just had a thought in the car: When i made the comment above I was thinking about the concrete and cement/wood components and neglecting the rigid insulation in each cavity. So yes, there is cold-bridging. The question is whether it's problematic cold-bridging, and to that I don't know the answer.

We did CAT 6 throughout. Wish I'd done more! Remember that for low-rate applications, you can always add a small switch to multiply out the number of connections you have. Also, as mentioned above, go crazy where there's going to be a TV or the like. Pretty-well everything seems to be internet-connected now. You can have a TV, Sky box, set-top box (eg, Now TV and the like), HD recorder, games console or two, music-streaming device, etc. Longer term, HDMI over CAT 5e/6 for 4k requires more than one CAT cable. Realistically, I'd be putting in at least 4 and ideally 6 runs to your main TV-viewing area now and leaving a duct for future-proofing. I ran the 20-odd cables in our house myself. Piece of the proverbial, as long as you have some help. Termination is pretty easy as long as you're methodical with colours and keeping the wires tightly twisted in pairs all the way to the punch-down points. Take care not to bend the cable too much, especially for CAT 6. I believe this can affect the screening.

Interesting stuff, thanks @najem-icf To be fair, I don't think cement-impregnated wood is anywhere near as attractive to vermin as the sheepswool in that article. What's the U-value of the block material itself? It looks like there's quite a bit of air captured in the shredded wood, which I imagine means it has a U-value that's quite a bit lower than concrete. If that's true, then it's less a case of cold-bridging, and more a case of warm-bridging! Not sure whether that makes any difference to the assessment, but it feels like it'd be less likely to cause a problem than true cold bridging. Thoughts? As you referring to the internal PIR/PUR or a separate later added afterwards? If the former, as I understand it, if there's no gap between the foil and the next surface, the foil contributes nothing to the insulation value anyway, since it can no longer reflect radiated heat. Heat will instead move by conduction due to contact. In that case, it's irrelevant whether the foil is intact.

I had a book about space when I was a kid, bought through one of those school book clubs. There was a large section on the Viking and Voyager probes. I can still remember the pictures, although it must be 30+ years since I last saw them!

Yes, those values were achieved, but not with SIPs. @JSHarris was one of the first in the UK to use MBC Timberframe, an Irish company, which a number of us have since used to build our frames. They do a cellulose-filled twin-stud on insulated raft construction, which achieves the U-values above while avoiding thermal bridging. There's a lot (and I mean a LOT!) of detail about Jeremy's build in his blog.

What a load of cack. Welcome them onto your property, explain the situation, and see what they say. If they talk about enforcement, tell them to have at it but they're wasting their time and money given it's on the way out anyway.

Hi Naj Let me second that. Looking forward to your contributions - always good to have people with knowledge and experience aboard!

And there's the problem. The decision should be the result of the objection, not the other way around. It annoys me that people will take on an important role yet happily remain ignorant of their responsibilities. We know this stuff and we're mostly amateurs!

It really annoys me that planning committees think that their subjective idea of what's attractive in a building is important (incidentally, I believe not liking the "appearance" is not a valid basis for rejecting a planning application - I assume they couched in other terms, like "not in keeping"). Our planning committee is a bunch of elderly, deeply conservative men who want all new houses to look exactly like houses built between 1900 and 1935. It's fine if it's an ugly box as long as it has hung tile and a pitched roof!