Tony L

I don't think it has to be the front door. I think it can be the "back door" (on the side of the house in my design) so long as your WC can be easily accessed, in a wheel chair, from the back door.

Thanks, everybody, especially @SteamyTea for putting the spreadsheet together. I've not started playing with this yet, but I have learned about Bin Method.

Thanks, Nick. I've been completely into the airtight + MVHR way of thinking since I first read about it here 18 months or so ago. I've just been improving my knowledge over the past few days to help keep my partner on board with these ideas after she was fed some mis-information by somebody who we were considering using to deal with our building reg.s & construction drawings. I'll have a look at that link when I get a chance, just to improve my understanding. I will likely be paying an expert from Wales to deal with my MVHR when the time comes. My design will leave spaces in all the right places.

Surely you need an evidence-based conversation and come to a joint decision. Several evidence-based conversations have already happened. I will keep going with more of these & eventually I may bring her around to our way of thinking, (“our”, referring to you & me, rather than her & me). The design already has much less glass than she wants & no wood burner. I’m making her sound like an idiot, so I must point out, she does have some excellent & rare qualities. If she doesn’t get it then I may just go ahead & do what you & I think should be done anyway, or more likely, we’ll endure a hot summer then fork out for some a/c or fan coils (with no VAT reclaim). I’ve got to bear in mind that her trade-off between how the house looks & how comfortable/economic it might be is different from mine. & it’s difficult to influence some people’s beliefs by presenting evidence to them. Within the build hub community, almost all of us like evidence, science, logic, & we’re open to having our views corrected by others who present persuasive evidence to us. A lot of people aren’t like that. There are millions of people in this country who believe in all sorts of strange ideas that aren’t supported by real evidence. I could go on & on, but I’ll stop there, just in case I land myself in a load of trouble for upsetting one or more of the strange belief people who may stumble across our forum. Thanks for your post – I’ll be quoting your, “8-10 the U Value”, when we next discuss the windows - that’s if I can persuade her to believe in U values.

Don't say that - I had to work really had to get her to agree to the chimney being deleted from the early design.

Not even a little bit? What am I not understanding here: I'd have thought that if the air outside is cooler than the air inside & my MVHR system is taking warm air from inside, bypassing the heat exchanger in summer mode, & replacing the exhaust air with cool air from outside, this will help keep the inside temperature lower. Of course, MVHR won't be the entire answer to the summer overheating problem, but I think it must be having some effect.

Thank you very much for your post, @Nick Laslett. I am persuaded I should spend time on Jeremy's spreadsheet as soon as the time can be found. At the very least, I will read the thread about how it all works. I have considered a plan for summer hot air purge, involving a small as possible window at the highest point on my east gable, which is shaded from the afternoon/evening sun (& can have the glass fully covered anyway). The window will connect to a vent duct, with a super efficient fan inside, that will suck air from near the apex of the vaulted ceiling above the landing & dump it outside. I'll open a downstairs window. I can see this being more effective than just opening a few windows, & it could be left to run when the house is unoccupied. Good idea/bad idea? I haven't fully thought this through yet.

That's good. I've got those in the right order then. I'm planning external motorised blinds on the two small Fakros in the two south facing bedrooms. I'll make provision for (ie a long hole where the eaves overhang) external Venetian blinds for the French windows to the patio. I don't think my budget will allow for PV. I'd really rather just plan to work a few more months before I retire & have some PV, but my partner doesn't like that plan, so I'll give her that one & I won't feel so bad about overruling her wishes when something really important comes up.

I've just put one of these fans in my rental property. There's a PIV in there too. V good. It was part of my strategy to deal with a black mould problem.

That's an excellent explanation. Thank you, @IanR. Yes, I didn't think it did - the way I explained my understanding of how the test works could have been better.

I know the PH airtightness target (ie max allowed) is 0.6 ACH @ 50Pa. My understanding of this is: if one of the external doors is opened then sealed up with an airtight membrane with a fan in it that sucks air out of the house to create a pressure difference of 50 Pascals between the inside of the house & the air pressure outside, & we keep the fan going & the pressure difference stable for an hour, if the house is going to score 0.6 this means that, in crude terms, 60% of the air inside the house at the start of the hour will have been sucked out of the house by the and of an hour & replaced with air from outside that will have found its way in through gaps and air-permeable surfaces. I also understand, that even a score at twice the value of the PH minimum, ie 1.2 ACH is still good, & if I can get a score this low, MVHR (or similar) will be required. If somebody wanted to rely on trickle vents & other holes in the house, rather than MVHR to provide ventilation, then they would have to ensure their house scored 3.0 ACH or greater, otherwise they’d be falling foul of building reg.s – in England – I suspect there are different rules for other areas. So, if I haven’t already gone wrong, my question is: what does this sentence following mean & how does this relate to the 0.6/1.2/3.0 ACH figures from my examples above? I can't make sense of it. Obviously, "that" is supposed to be "than", & presumably "p.a." is another way of writing "Pa". What is "h."? Hours? Perhaps this is a different way of measuring the leakage/permeability of the building in terms of the length of the building's perimeter. The sentence is from an example Building Construction Notes document that I’ve received from an arch tec, I’m considering using to complete my house design & provide drawings:

Thanks for Jeremy’s spreadsheet, @Adrian Walker. It certainly looks more straight forward than the PHPP spreadsheet I looked at, but I would have to ask a lot of questions if I were to use it to help evaluate my design, in which I am not too concerned about what’s going on downstairs, but am keen to understand what’s going on further up, where I have 3 dormers, 4 flat roofs, both north & south facing windows in the sloping roof, no heating &, if things work out well, no electric cooling either. I think I’d still rather outsource heat loss/solar gain calcs to somebody who can do it far more quickly than me. For now, I’m focusing on trying to find a competent person to take on my building regulation & construction drawings, including finalising some elements of the design. @Nickfromwales has recommended somebody, & I’m hoping this problem will soon be solved.

Good info - thanks, Nick. I was thinking it might be because the U values may not be good enough. I have been mindful of solar gain. Our summers aren't getting any cooler. All the glass you can see on the facade in the Sketchup drawing above is on the north elevation, so the low sun will just about shine through these windows for a short time in the morning as it heads around to the east elevation, & there's shading on the west side, so there will be negligible solar gain before the sun sets in the evening. The glass area on the other three elevations adds up to less than you can see on the north elevation & there's a 1m overhang on the roof at the back of the house to give shade to the ground floor windows.

No - the design isn't yet sufficiently developed to start anything like that. PHPP modelling sounded like a good idea (even though I will not reach PH standard), but then I had a quick look at PHPP modelling a while back & decided I don't have the time I'd need to learn how to do this myself, & paying somebody else to do it will likely cost more than I'm prepared to pay. If anybody wants to tell me, I've got this wrong (or perhaps tell me I've made a reasonable decision) please do so.

The building regs may force you to have less glazing. Thanks for the warning; that hadn't occurred to me.

Yes: if I can afford it, I'll be having one of these when my house is done. I've seen quite a few in my area. Pale orange seems popular, but it shows tyre marks. I think grey, as pictured, looks best.

I’d prefer less glass. The purpose of the glass is, to please my partner, who wants lots of glass, especially on the façade. It’s half her money, so I’m compromising. I’ve deleted a lot of the glass from our original approved plan, having learnt so much here on BH over the past year. Windows have been deleted from the sides & the south facing rear elevation. I also persuaded her that her log burner was a daft idea for this kind of house, & the chimney has been deleted as well. I’m more concerned about unwelcome solar gain in the summer months, on the east & south elevations, than I am about having to turn the heating up. The glass in the sloping roof above the hall/landing could be reduced, but this is helping to create space in front of the landing, because windows are a lot thinner than the roof so, yes, we could easily improve the thermal efficiency, but this would detract from the feeling of space in the hall/landing area - it’s a galleried landing & there’s only just enough space in front of the landing to make it work as a galleried landing, so the window reveals are really helping to create much needed space. The views aren’t “stunning”, but they do give us great pleasure. The views mostly comprise lots of different kinds of trees. There are one or two edges of other buildings visible, but we can’t see any of the other buildings’ windows, so the neighbours won’t be able to see in. There’s a small newbuild bungalow right next door on one side, but there’s a holly hedge between us (we trim it down to around 2.3m tall when it needs it). The house opposite, over the other side of the road, is in several acres, so all we see is the trees along their boundary with the road, & we have to look very hard to glimpse their house in the distance. The road is a B-road & there are no pavements, so there’s very little pedestrian activity. The view at the back will be our 2m high garden fence (just over 9m from the back of the house) + above this there’s a long view of trees to either side, & lots of sky, so very pleasant. On the west side, there’s big plot again. There’s a monster hedge on this neighbour’s side of the boundary (well maintained by the neighbour's gardeners) & all we can see of their house is the top of the roof.

Well done, & thanks for sharing - this is inspiring.

That's a good question. I ask myself often, & I keep getting different answers. I did the designs (several of them) & drawings to achieve planning permission; somebody else helped me out by adding a few notes. I'd not have bothered hiring them if I'd realised how easy this would have been, but this happened before I'd discovered Build Hub. I think I could (with lots of help from BH) have a go at doing the building reg.s /construction drawings & heat loss calcs, if I had fewer commitments & I wasn't in so much of a hurry, but I'm keen to pay to get this done well & done quickly. This is the next task. Then QS. Then we'll likely have to make some revisions to the drawings (for budgetary reasons) before they go in for approval. I reckon I can make a garage base (I've done this twice before) & stick build a garage (not done before) & deal with the roof. I want the garage to go up before we start ordering the insulation, so we can store it out of the weather. Due to other commitments/ time constraints & my ineptitude, others will be doing most of the building work. I expect I will decide my partner & I will PM this between us, to save money. I'd love to PM if it wasn't for my other commitments, but as things are, I know I won't love the experience. I'm not yet sure whether we'll hire every individual trade, or whether we'll employ a building firm to do the next stage (superstructure without roofing finishes) then the standing seam roof (if we can afford it) & flat roof finishes, then windows, & so on. Of course, PMing myself may not save anything at all - it depends on how many serious mistakes I make. In my day job (90% desk based), I'm good with attention to detail & completing tedious tasks, then checking my own work, so I expect these are transferable skills that can be usefully deployed on my building site. I envisage doing jobs such as preparing my B&B base, laying membrane then PIR, the next membrane, UFH pipes & getting ready for the screed, perhaps installing MVHR ducting into the metal web joists, soundproofing between floors, soundproofing & boarding stud walls, constantly reminding everybody about my precious air tight envelope, reprimanding anyone who damages the air tight envelope, sacking repeat offenders, making a DIY air suction rig & finding some leaks. The task I'm most looking forward to taking on is the exterior cladding on the three dormers.

All ours will be built in as well. I think I read that to reclaim the VAT you’ve got to be able to see the wall finish in the back of the built in wardrobe (I don’t have a problem with that) & you’re only allowed one shelf – is that right? Is this shelf rule enforced? I can’t see how it would be.

This is all very reassuring. Thank you, & good luck with your recently announced next project. I'm looking forward to reading about it.

Thanks. I'll have a look for this (& come back to you, if I can't find it). I was thinking to put a stripe of purple paint or flexible (lime?) parge onto the walls, then fix a ledger board with bolts into resin in the blocks. This seems more straight forward than Tony trays to me (although I could easily be wrong about this). Also, the ledger board approach means my joist ends won't be inside my (only 150mm) cavity, sucking heat out from the house. I could be persuaded on the Tony trays - I should think this would give a saving on materials.

Thanks @SteamyTea. I don't have plans in a suitable format to upload here yet. I have my original PP drawings, with lots of annotations hand written onto them. I don't have U-values - I'm hoping to find a competent person to decide on the build up of the various external surfaces & work out all this for me. Once I have drawings worthy of BH's attention, I'll upload them & invite criticism. Thanks again for your offer.

Thanks @LiamJones. That's impressive work you've done there. If I get to build a second house, I'd like to try to do what you've done. I did the PP negotiation/drawings myself, but I just don't have the time to fill the gaps in my knowledge then set about dealing with all this myself. I have a business to run, an elderly mother to look after (still in her own home) & other commitments (I'll spare you the details), so I just want to pay a competent person to deal with the drawings so we can get the full plans approval & start building the superstructure. We've already built up to our B&B floor under building notice. & we need the drawings to get a QS estimate as well - then we may need to change the spec' to fit our budget.

I didn't actually sack him - he's waiting for me to annotate his drawings & point out all the errors (this is a lot of work as there are so many errors). I'd rather start again with somebody new, who is competent & will make all the difficult decisions for me - such as wall/roof build up, insulation types, membrane types, what happens at all the surface junctions, etc. Each time I start a conversation with somebody new, it costs me a lot of time - only to find out they can't do what they said they'd do. I'm under a lot of pressure from my partner, who is angry & impatient. She's at the stage where she just wants a house that looks really good & can be built within our budget; she doesn't really care if it costs a fortune to heat in winter & overheats in the summer.