MortarThePoint

Is this what you mean?

I'd like to lower the level of the patio in the design as there is a gentle gradient along the length of the house that makes the patio quite high at one end. The design has two courses of bricks between the patio level and finished floor level (FFL), so that's 150mm. There will be a door frame which will add a bit more height I expect. The factors that come to mind are: Is there a building reg that limits the height change without the use of a step? Staircases have a 220mm limit and the door threshold is in some way equivalent to a step, but if there is a frame that adds extra height What would feel weird, 350mm doesn't feel viable but is 225mm? How low can the door frame be before it adds expense or looks rubbish. I'd expect the door frame to sit on the two courses of bricks and so have its bottom at FFL. I'd like to have 200mm between patio level and FFL I think, but that is only on paper not based on experience of traversing such a doorway.

It's a fair point Vijay. I'm not trying to be difficult It's just that I don't have years worth of experience to rely on to be able to spot a good job when I see it and there are various things that need to line up. They were out by 150mm with a section of foundation and my very nearly preordered (I bottled placing the order when I saw the foundation misplacement) floor slabs have a tolerance of 10mm + 0.1%. I hadn't given them a spec for the foundation presuming that the drawings and accepted best practice gave sufficient guidance. I think I should have asked them what specification I should expect from their blockwork and that's what I'll do with the brickie. I can then evaluate what they come back with.

You're right, I had some sour faces over that. They were OK with reaching the other tolerances, but not the plumb / cavity ones due to exactly what you said. When it's above ground it will be the face that needs to be accurately plumb. Unfortunately, they were generally put out by it all. I'm used to having my work specified and am uncomfortable doing work for people without a clear specification. Trades seem to take it as a lack of faith thing which is unfortunate as it isn't personal. We are using precast floor slabs that set a tolerance on the wall.

Well I have sent the text below to the guys doing the below ground blockwork. It's tighter than the figures discussed above but then I can accept mild exceedance. Saying I specified +/-5mm, knowing I actually needed +/-10mm, and got +/-15mm makes the discussion clearer. I think all of the things are reasonable. I'll let you know how I get on ? "Dimensions: Lateral construction drawing dimensions +/-5mm (i.e. brick or block lateral placement +/-5mm) Brickwork or blockwork flat +/-3mm over 10m (after 450mm of blockwork from foundation concrete) Brickwork or blockwork level +/-5mm (after 450mm of blockwork from foundation concrete) Cavity gap +/-3mm Plumbness +/-1mm over 1m Mortar: Check the Structural Engineer's Construction Drawings but I think it specifies class (ii) / M6 below FFL. "Site mixed mortar should be batched consistently and accurately using batching boxes or buckets. The use of shovels for proportioning should not be used." Full joints (no tipping and tailing or deep furrowing). Other: The concrete fill in a cavity wall should stop at least 225mm below the base dpc Any drawings, building regulations and accepted best practice (including NHBC guidance) that sets tighter tolerances or additional requirements apply."

Looks good and certainly got your money's worth on the connection ?

I've just received the default answer: "all new build domestic services/meters do now have to be external, either on an external wall in a meter cabinet or an external kiosk." I'll have to decide if I want it inside and if so how important it is to me.

I've added a couple of other options: E - ProDave's suggestion F - On front elevation of utility near where house consumer unit likely to be I've also added drain routes. I'm hoping it's not an issue to pass under a surface or foul water drain. If not only A, B and options.

OK so it sounds like A & B are back on the cards then. I have emailed UKPN to ask if they allow new connections inside a new house.

I was mindful of the routing clashes but not the 3m requirement. The 3m requirement rules out A & B. ProDave: does that mean you have the CU in your kiosk? In terms of clashes, can the electricity be routed under drainage pipes?

I'll pass it by them. Did they insist it had to be visible from the front elevation then?

Interesting thought. I don't have a problem with supply during the build, but this does have its benefits. Is a kiosk not expensive?

I need to decide where to put the hockey stick for the electricity meter as the sub floor blockwork plan is being finalised. The diagram below shows where the electricity enters site and the DNO would make the connection. I can see three main options A - On the house elevation nearest pole and most visible from the drive B - On the rear elevation nearest the pole and visible from gthe back garden C - On the utility wall (rear or side) where the plant is located, but not the ASHP D - On the garage which is where the ASHP is to be located The Air Source Heat Pump is planned to be on the back of the garage so as to hide it visually and acoustically. I have asked ASHP suppliers and they say that run of pipe to the house is fine. What do people think? I am tempted to go with 3 phase as well as the pole supports that (site previously had it).

I am tempted as it is out of the way then. It may be more possible now given the lockdown being eased slightly.

Well the demolition guys did a pretty good job of lifting all that 100mm Celotex. Most of the foil has come off and many are a bit curvy. I think its GA4100. It's going a bit brown in the sun and rain, but I guess that's only on the surface. The garage plan uses 100mm mineral wool insulation in a 100mm cavity. I am wondering about the merit of ripping this down to 450mm wide slabs and widening the cavity to 150mm to include this. It would save about £1000 and make use of about half of this pile. I think if I had to add the foil back on it would end up being more hassle than it's worth.

We're going for hot water sink and a loo. I don't fancy being repeatedly told off for traipsing filth in to the new house ? A shallow pit is a good call. Combined with a low lift and you've got most of the win of full lift. There might be a call to the Structural Engineer coming up. That said, I think I remember reading somewhere that pits aren't allowed any more due to fume buildup. Is that beyond a certain depth or something?

We're going to be pouring the raft for our garage/workshop in a couple of weeks. It's a real treat for me to have this space and part of the reason why we are doing the whole selfbuild thing. It's my last chance to think of some of the details to add and I thought I would ask people to fantasise a bit. They can be simple details (e.g. I am thinking of asking them to cast in anchors near the door pillars for pulley winches) to that 'if only I could' thing (e.g. I'd love a car lift but that's not on the list unfortunately).

I'm a fan tolerances like +something/-0 (e.g. +50/-0 mm) as it conveys which way pain lies.

Don't trades worry what the next one in line is going to think of their work? I couldn't work in a way that has contempt for the next guy when it's relatively easy to take some pride.

Lead Acid batteries are about to be in massive demand as people wander out to their cars and find the batteries are stuffed. RAC has had a special offer of free replacements which I think they will regret. A friend got a text message from their car dealer to say their car needed charging. Makes you wonder how much they know these days.

Thanks, I'm sure you're right. One of those things you churn on in the middle of the night having been woken up by a 4yo.

No holidays for a while at this rate. (more thinking Covid-19)

Well I had lots of time to think of some ideas overnight: 1) It can be off foundation centre and that's fine to a limit which I'll find out from the Structural Engineer. 2) The exterior wall at the rear (top of frame) could be pushed back a bit. Currently the wall to foundation is centred on the cavity. Below DPC, the inner leaf is 190mm blockwork and the outer is 100mm blockwork. If that wall had its overall footprint centred then that is a 45mm shift. Due to the walls higher up being of thinner blockwork, the cavity side of the 190mm blockwork will be more highly loaded, but I'd hope that over the two courses below DPC that effect would disappear(?) 3) The inner leaf of a cavity wall carries most of the load. I know that the wider you go with the cavity the less structural the outer leaf becomes, but I don't have any load sharing proportions to back that up. My cavities are to be 100mm. *IF* the outer leaf is only supporting its own weight and the inner leaf is supporting its own weight plus all the floors and roof then you could arguably centre the load on that basis and it yields 95mm. If the outer leaf takes 1/3 and the inner leaf 2/3 then its about 45mm. Arguably double those shifts would yield the same moment on the foundations as was originally designed in, just in the outward rather than inward direction. 4) Use thinner stronger blocks. The spine wall running the mid-length of the house is designed as 215mm/10.4N blockwork below DPC and 190mm/10.4N above DPC (a). If that 190mm/10.4N was thinned to 100mm/21N, but still centred on the lower blockwork, it would yield half the change in block width, so 45mm (b). They would be special order blocks and the wall would be more vulnerable to lateral loads, but there may be something there. Even 140mm/15N blocks offcentre from the lower blockwork could give 40mm or more. Thinner blockwork doesn't help the first floor as that's already 100mm, but could help on the ground floor. Could go as far as 100mm/21N shifted over 100mm (c) but that feels iffy. 5) Get the groundworks guys to dig and fill next to the misplaced section of foundation, or at least some piers at right angles. I can only imagine their reaction but it is their mistake. I'll see how they navigate it when they measure up for the below DPC blockwork as they are doing that too. I haven't discussed the misplaced foundation section with them yet and want them to kind of work it out for themselves rather than have me point it out. Hopefully some mixture of the first 4 will get things back on track.

That's worth knowing, thanks.

Thanks, I'm a bit of a nerd. That and buying QCAD which was the best £30 I've ever spent.