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There are a few on that bottom row that are not sitting nicely. That is quite a kick up.

Indeed!!

It's an Insulated Raft Foundation. The Insulation is structural, 100% of the building's loads are passed through it and spread on to the ground beneath.

Thanks all for your support/advice. Agreed, we will make them up ourselves. Have had to upgrade the xps400 to a 500 version as appears the 400 is elusive. We shall prevail!

That’s a ‘him’ problem, but he cannot start interfering with your property to jerry rig a solution as a means to an end. Go knock the door and start the ball rolling by showing the pics.

It’s 5 o’clock somewhere Make these up on site and chillax. 3 bits of EPS won’t ruin the week. Just shutter them well externally, belt & braces, and put some extra pins in to keep bits from floating up / away durning the pour. Using a quality expanding foam to bond these together will make them act as 1 solid piece btw; apply pressure for 1hr until cured, and then you’ll have to break the EPS to get these apart again. Rock solid once foamed together and as bombproof as you’ll ever need.

But only the steelwork and concrete are structural - the insulation is just that, insulation. It does provide support to the wet concrete while it cures so is just form work that remains in place. It an insulated slab at the end of the day.

Up to you . DIY has less rules / repercussions that I face, working on 3rd party / clients homes etc.

Cross-ventilation may be your issue. One air-brick in that space won't do much. You need 'ins' and 'outs' and ideally diagonally-opposite air-bricks to ensure as much 'scavenging' of warm moist air as possible. Given how shallow that void is a solid floor might be sensible. It may even need digging out further to accommodate sufficient support and insulation.

That wasn't my experience in 2016/17. The Engineers doing optimised rafts, like AFT, ie. 100mm thick in the main, with a deeper ring beam and single layer mesh, were all packaging up their calcs with EPS Supply. Some were also packaging concrete, steel and labour for installation. If there are now Engineers that will sign off an optimised raft from sheet EPS and only charge for the calcs then that is a benefit. Can anyone share some names?

The formwork is really just a short cut/timesaver. It's the engineering that really matters. I had thought that some raft suppliers give you the choice of just using them for the engineering or for both that and the formwork. Where rafts are more common I believe that using the precut XPS formwork is still not the norm with most making it from 100mm sheet.

Interesting... Are you doing the calcs, or a 3rd party SE, and does their insurance cover you for the DIY approach? I couldn't find a way of avoiding being "locked in" to a specific supplier and being charged a premium for the EPS - although I was happy in the end (after a long search and negotiation) the premium wasn't too high.

AFT used to use Springvale EPS, in the UK for their UK orders. I hadn't realised they'd changed to their Swedish Supplier for the UK orders. I did get extras from Springvale, but needed Olaf to "OK" the order. I assume the AFT <-> Springvale relationship turned sour??? Have you got Olaf's details? He still has the AFT domain, so his email is likely still operating. I believe I have his UK mobile, but he did use it in when in Sweden - have you got that? If you are not in a rush, I'd try Olaf to supply the correct sections - no question on insurance cover then. If not then I'd make them up myself, but you need to use the EPS200 or EPS300 spec that L Formers were specified in.

I can’t remember to be honest, I don’t recall it being particularly damp but I may be guessing! can’t rip out, it’s all new flooring. no air brick which I think is an issue- the wall the joist butts up to in one of those pics is the adjoining house (semi detached) so it feels like the only place for an air brick is outside the bifold but as you can see here there’s very little room

If you put up a drawing showing the cross section and location, then we can maybe advise on the method.

I'm hoping to make my insulated slab entirely myself using sheet materials so I would say No 3 and bash on.

Make your own as needed, technically not right, but hey, we've all gone over the speed limit more then once and not an issue And yes it's 12pm somewhere in this world - pour away, but make mine Gin and Lemonade

Is the earth under the joists damp? It needs to be completely dry. Is there any ventilation to outside? Ideally there should be airbricks either side and a crossflow of fresh air. Can you rip out the timber floor, insulation and screed, or is that too disruptive?

Agreed make your own. The priority is strength as insulation can be sorted after.

Another vote for make your own.

If you are at the Airport, then no otherwise standards must be maintained. As above, great advice to make your own and move on.

I would look to make your own bits. As mentioned above once you get your head clear of the initial panic, suitable grades is eps and xps and some bracing and away you go.

First, don't panic! I think this is an easy option. The AFT forms are just a way to make the concrete laying easy, producing the same shape with standard (correct spec) XPS should be fine. Maybe reinforce with wooden forms on the outside if not sure of the glue strength. If you look at people in Sweden laying these types of foundations they don't necessarily use preformed XPS anyway, just build up from sheet.

Oh lord, I could cry. Sorry its long but please read! So, having thought we'd have no issues with AFT (insulated raft supplier) going out of business we have, according to the law of sod, now got a rather large issue. We've, for various reasons (some self influcted, others not) been quite delayed starting laying our insulated raft so, it has been safely stored away in one of our barns for the past (eek!) year. After carefully completing the ground works/drainage over the past few months, with what felt like a ship load of pea gravel! all has been fine, levels all spot on and finally, this week we started laying it all out. So now we are at the issue. We carefully installed the perimeter L Elements around 3 sides before we realised, oh bu##er, we don't have enough, we are 3 short! I initially thought it was our fault for not counting them all on delivery (stupid, things were a bit chaotic on the day unloading a huge lorry) but, after cross checking paperwork it looks like AFT didn't actually order enough from Benders! On the original quote from AFT we have 45 detailed but, after double checking the order directly with Benders, there's only 42! I hadn't expected to need to check AFT had actually ordered enough, assuming it's their mistake and not Benders as, obviously, I can't see what AFT sent to them! So, here we are up the proverbial creek without a paddle. Falling at the first hurdle, not a great start! So, please, opinions/advice on how to get us moving again. As we see it options are: 1. Contact AFT for help? I have a contact number (that works) for Greg, but not sure how far we'll get. Left a voicemail & text yesterday (after speaking to him earlier in the day about a minor corner detail, before we found the big issue!) but no reply yet (not a great sign) 2. Try to source from someone else, Benders are Sweden based and don't supply direct but, maybe someone in the UK is getting a delivery from them we could piggy back on. Buildlite/Greenraft i think use similar elements but time likely a big issue here. 3. Manufacture our own L shape elements - doesn't look too tricky (am i being naive here?!) Xps base glued to eps upstand then render the exterior. Then, shutter like mad before concrete pour to ensure they don't fail. Hubby keen on this option as likely much quicker. 4. No idea what else, all suggestions gratefully received! P.S is it too early for Gin?!

Would I need a backdraught shutter given both are on the input side of the inline fan? Air could only pass between the two rooms when the fan is off and that air transfer wouldn't be an issue anyway would it?