the_r_sole

I backed the wrong horse and went for celotex.... what a melon when everyone else went for kingspan! (it's always funny to see what people take from the posts, seems you cannot be explicit enough)

Be aware that if you change anything you will have to provide an update SAP calc and amendment to warrant before you get your completion certificate, so you should run any changes to the specifications past your architect asap - you'd be amazed how many times builders "rules of thumb" which get rid of the "expensive, over-specced architects insulation", mean that you no longer comply with the regs!

spec a system with BBA approval - they will all have their preferences but using a system without a BBA is your issue here not the actual construction method - all they want is a paper trial so if something goes wrong they can say it had BBA so not their responsibilty

yeah, but that's a bit like saying, you don't need any PV as long as you bang in loads of insulation and take out all the cold bridging! Everything has a cost and a practical consideration to go along with it so it's all about balancing what can be done vs what's a good way to solve the issue

SAP is a pretty blunt tool but you need to pass it before you can start building in Scotland, so it becomes a critical part of the process

If you go this route, make sure you've done a detailed condensation risk analysis - there's something I always worry about by insulating between and then outside studs, you've got the structure surrounded in insulation and not giving moisture anywhere to go, it's just the same as a hybrid roof construction where you risk condensation forming on the critical bits of structure...

is Glasswool 35 the same as frametherm 35? I had real difficulty getting uvalues worse than about 0.17/0.18 on the walls through a sap calc recently so it really comes down to what else the op has to pass that

It's a bit o a strange layout for me - I don't really get a feeling for what you are trying to achieve, there's a huge distance from the front door to the kitchen which seems a bit problematic, why have you changed the position of the kitchen away from everything, is there different light or something in there? I'd almost be tempted to put the kitchen where the snug is shown and have kitchen/dining/sitting across the rear (and access the utlity from the kitchen) then have the snug as it's own room where the kitchen is, potentially accessed through the hallway cupboard. A snug for me can't be in the busy corner of the main space with a rooflight over it, you're getting no peace at all there!

where are you building @davejura? You really need to work through a SAP calc for the build to figure out what you need where. I've done a couple of sprayfoam kits (client choice, not mine!) but they do give good air tightness, the uvalues I've seen aren't actually much better than your rigid insulation boards and the costs aren't hugely different, no matter what the reps tell you

Get a professional involved... There's all kinds of implications with a house over 4 floors, and planning considerations with roof terraces. On the plans themselves there's no much to comment on, it's a series of boxes. If it was me doing a tall house I'd be looking for opportunities to open up double height spaces or have overlapping spaces and create a bit of interest and connection

Yeah, maybe not adopted everywhere, I just noticed a while back they stopped asking for that note to be removed or changed on our applications, or if they did be resistant to removing it! I'm at the absolute end of my tether with planning departments at the moment so maybe they've stopped poking me ?

Not any more, they've changed their validation requirements on having that note on (although some local authorities need an argument to accept it!)

What's an "Architectural Engineer"? New one on me that. Anyway - in the good old days, would you have asked your professional for their paper, pencil and drawing board? The pdf/paper drawings are the output of the design process and should have all the information needed for their stated purpose, if you need setting out drawings or more dimensions, ask the professional to give you them. When I draw details for example, they will be slightly out from the dimensions marked on the drawings so that membranes etc can be properly read on the drawing and the drawing is clear to communicate how to put the detail together rather than be dimensionally accurate - hence the notes "do not scale from this drawing"

Hmmm... wouldn't d&b my own house. A contractor will be doing the day to day project management no matter what procurement route you are heading down. I've never seen a house where changes haven't been made made after the contractor is on site and that's difficult in d and b. The advantage of d and b is being able to start early and with some cost certainty (as long as your requirements are clear enough), the thing where it always fails is quality, look at any public project where they've found major defects and generally they'll be procured through d and b. If you are leaving the contractor to detailed design make sure they do post completion testing and assume all responsibility for regs/completion. I'd also want someone doing independent inspections very regularly. For one off houses I'd always want a traditional contract with either the architect or a qs doing the contract administration (nothing to do with project management) with a very detailed set of drawings and specifications forming the agreed contract...

I dont have a problem with large hallways per se but having a hallway wider than the main living spaces in the house is a bit counter intuitive when it costs so much to build... I think there are other places I'd look to create a feature that doesn't need a quarter of the most expensive bit to build, but if you've got money to burn why not make the house more interesting? For me the justification of keeping a simple form to ease the buildability then have so much floor area not working hard on a small footprint is pretty flawed logic.

A 3m long x 700mm wide cupboard for coats will be absolutely useless, I think there's way too much hall way on the ground floor, it must be over 25% of your floor area. Your ground floor has zero future adaptability. First floor the only bedroom which isn't dual aspect is the master!? The office doesn't seem like it's a useful proportion, put some furniture into that layout and you'll start to see the issues

I really don't understand how a lot of the English architects being talked about on this site do things, seems like they are only doing (or being asked to do) a small part of the overall process? We would always tender the structural engineer and the client appoints them directly, but it seems like the communication of who's doing what is weak in this one?

It's not like you've got a full arrangement that's perfectly symmetrical and then one thing out of place, the whole thing isn't symmetrical! It's not an issue

Planning usually prefer a traditional or modern approach, smashing the two together doesn't always go down that well! What way is the building orientated, do you have a site plan?

Unrealistic budget, inexperienced designer, family friend.... what could go wrong ? In all seriousness if you want to do something relatively complex in your build like passivhaus and do it as cheaply as possible - you want the most experienced designer possible to work with, not someone learning on the tools in my opinion

There's the current house arrangement which has it's own access from the main road, and then your proposal which takes that one step further introducing a shared access from the main road and new development where you have to pass one property to get to the one behind - so if you're looking for examples then that's what to look for. The other thing to consider is that if that relationship with the oast house (can't help singing the alan partridge podcast theme here!) is common i.e. further from the road and behind other houses, it might make your case weaker to develop the area behind/around it as the oast house is no longer a stand alone unit. If ever there was a job for a planning consultant....

Hah, yeah, sorry - my post is probably quite negative, I've just had a lot of arguments with planners!!

immediate reaction is that the development looks completely at odds with the existing settlement pattern, although the current house also is, you could say the proposed would appear as back land development which many local authorities are opposed to. Speak to a planning consultant as early as possible to understand if this is even slightly a go-er! The ones that we use will tell us that if they don't think there's a chance before needing paid!! infill needs to be in between two things to be infilling something, so that's a massive stretch!

If you're submitting a new application anyway, definitely include it in the plans. If you don't have a completed house then there's no permitted development rights, usually anything you change or add during the construction phase would be approved using a non material variation to your planning approval

It looks like the condensation is on the inside face of the window? that's a ventilation issue rather than a window failure, you're creating a huge amount of stream in a bathroom and if it's not getting drawn out it will condense somewhere