epsilonGreedy

Not yet. I will have that conversation prior to placing an order, for the moment I am waiting on the other main supplier in my area to produce the initial quote. If the larger size chords do not perform to the 8mm deflection criteria I am not sure there are further improvement options available having upped the joists chords one or two sizes at 400mm centres. My plot is subject to a ridge height limit so going up one joist height would lead to a problematic ceiling design on the first floor.

Update: I got a revised quote back this morning for increasing the chord size in 35 joists. The cost increase is about 10% or £200. 10 joists were upped from 97mm to 122mm. Another 10 4m span joists upped from 72mm chords to 122mm and the remainder 3.6m span joists from 72mm chords to 97mm.

No, which begs the question why did you associate a 400amp fused DNO cable with any notion of householder electrical safety? RCDs are significant and this is the point, crossing cables where one is not RCD protected. As has been mentioned here before DNO supply cables are not armoured so one forceful plunge into soil with a sharp spade or over eager grab with a digger bucket and... Surely you can comprehend the common sense in his concern even if there is no matching chapter in the regs. My electrician was over 50 and during the job he complained about the £20k he had spent on a paddock for the family horses, so we can infer some some commercial success and competence as an electrician. How wide is a digger bucket? Perhaps my guy was applying real world experience and knows building sites can be chaotic and dangerous places hence he did not want any chance of a live 400amp feed getting through to the static caravan post an accident elsewhere onsite. I find it odd that you feel motivated to deride the safety advice of a time served professional electrician because you cannot find a matching paragraph in the regs and yet you have spent an excess of £300 on your double pole RCBO consumer unit to obtain a small incremental increase in safety that is not required in the regs.

When I got my static caravan connected the electrician was not happy that I had the DNO feed and RCD protected caravan cable crossed and touching in a service trench. In retrospect I can see his point. A 400amp fuse is of no benefit to a living creature. In the absence of any safety standard I will fit the conduits 400mm apart.

I need to be careful about pampering Swmbo, if she is too precious for raw screedflow concrete floors what next? Flowers on St. Valentines day! Seriously though we found some delux reconstituted stone tiles at the Bicester self build show that create a French limestone floor effect. The salesman was offended when I referred to them as ceramic tiles. We are both prepared to live for a year with a few rugs on concrete if this gets us to an ideal long term fitout.

I am planning to install two hockey stick conduits in the same area of a cavity wall. One conduit will take the unprotected 100 amp DNO feed from underground up through the wall which will terminate in the cavity wall mounted meter box. All as per regs. The second conduit will take a protected SWA high amp cable from the consumer unit out down the conduit and underground to the garage. The relatively close proximity of the meter box and CU mounted in the same wall could result in the two conduits being very close inside the cavity wall and also by implication in the ground below. Would I be correct in thinking there is a minimum safe distance between the live DNO feed and other protected circuits originating from the CU?

Is this what they call a "high integrity" CU with 3 rails? I like the idea of say the lights, freezer and security on RCBOs and the rest of the circuits controlled by communal master RCDs plus cheaper MCBs. This is a useful link for beginners trying to get their head around CU options. https://www.consumerunitworld.co.uk/choosing-a-consumer-unit-343-c.asp Edit: Another link with extra detail on high integrity CUs aimed at beginners. https://www.checkatrade.com/blog/2018/08/03/what-is-a-high-integrity-consumer-unit-and-when-should-it-be-used/

Ok a week later and a bit more knowledgeable on this subject I have been looking at the price of these options. There seems to be a £20 difference between a single pole MCB and single pole RCBO. For a half decent design with 15 protected circuit outlets I make that an extra £320 for an all RCBO design. Are my sums correct? My last rental house had dicky electrics and the whole house often tripped out leaving us groping around for a torch so I can see the benefit of a dual RCD design with the lights split across each RCD/Rail.

My plot was granted planning permission with some permitted development rights removed e.g. no greenhouse or garden structures.

Actually my move-in level of finish is close to your thinking. I have emphasised more plasterboarded walls because living with exposed inner block walls in the first habitable rooms is less appealing than your interim timber frame OSB panels. I will spend a day coating the inner block walls with a cement/sand thin render once the roof is on to help reduce air leakage but left like this represents a dust health hazard I suspect. Temp stairs handrails. Yup a good idea and would help save the final balustrade from knocks during the remainder of the build. I feel it is psychologically important to have one room 100% finished and think this will be the master bedroom with its bamboo floor. After that I will try to finish the large sitting room with the feature brick fireplace and wood burner, because then we can have guests around. I like the idea of recycling temporary kitchen worktops into the utility room. I hope the disposal of the posh static caravan will pay for the longterm kitchen fitout. Following that I will just buy the remaining materials in bulk and bang in the VAT reclaim because I do not want to get into a dispute about multi year occupancy prior to a final VAT reclaim.

Many here prefer a thicker screed with UFH because: The floor can absorb more heat during the cheap overnight tarif. Such a thin screed will exhibit hot spots with UFH piping at a regular spacing. What is your opinion on these points?

My first stab at a budget. I am punting ball-park figures at this stage. The lefthand numeric column is for materials and the righthand is for professional labour. Any feedback is welcome. Forgot to say this is for a 1500 sq ft L-shaped house. In this budget I have excluded 150 sq ft in the single story rear entrance lobby utility area.

On a wet Sunday afternoon I have been musing over how many £'s it will take to get from a weather tight shell to a minimal viable home for two people.The reason for this project planning is that Swmbo has decreed a third winter in the static caravan is a winter too many. The definition of a minimal viable home I am budgeting for is: One fully decorated bedroom 4m x 3.8m Plaster boarded living room 5.4m x 5.2m Family bathroom finished to an average standard (the fancy wall hung Geberits will be in the ensuite to be completed later). Very basic kitchen or we could use the static caravan kitchen for a while as we transition to the house. Electric fittings to habitable rooms. UFH working. HW tank plumbed in. Stairs fitted with balustrade around the landing. What have I overlooked? I will post my budget spreadsheet in the next post and update that based on any feedback.

Yes though there are limits. Avoiding floor bounce is high up my list of priorities based on the experience of my previous mass builder house of 15 years. The master bedroom floor (14' x 12') was manifestly under specified with its solid timber joists (thanks Bryant Homes). The adjacent trance of houses built by McClean to a similar price point had wooden I- beam joists and felt a lot more solid. Conversely this week I ordered 100m2 of R37 cavity batts rather than higher performing R32, this equates to a whole house build cost saving of £600. After running the numbers through the@Jeremy Harrisspread sheet I found the annual heating cost difference was £27 using £0.15 per kWH. Edit: Also I purchased a pack of the R32 and R37 batts and trial fitted them into the cavity with the lead brickie, he was a bit concerned the denser R32 batts would push out against the freshly laid brick or block courses.

The number one news story in the United Kingdom on Friday/Saturday.

I discovered this during a recent holiday in a highly insulated new build holiday cottage, it was too hot at night and I spent the whole week trying to find the optimum time to turn off the central heating in the evening. 7:30pm was about right. That experience has prompted me to revised my ideas about how to heat my new build. My latest thinking is to run the UFH with the thermostat set to 17 degrees and then use a few wet radiators to raise the temp to 20 degrees to create a nice healthy diurnal temperature graph.

Thanks I might stir this into the conversation with the floor designer on Monday. Presumably deflection numbers are calculated with an industry standard reference load?

This is informative and encouraging. I only have one 5.4m joist span specified with a 122 chord, this is the joist that runs past an internal chimney breast and which also takes the load of shorter joists that fill in around the chimney. The remainder (x 10) of the 5.4m span joists have 97mm chords. The 4m span joists that form the floor of the master bedroom have 72mm chords. Collating all the advice and experience in this thread I will phone the floor designer on Monday and ask him how much 122mm chords on all > 3.5m spans will add to the floor cost.

Well done, I have just been doing what-if tests using the @Jeremy Harrisheat loss spreadsheet. For my house reducing the target internal temp by 10% from 20 to 18 degrees lowers annual heating KWs by 20%. I believe humans evolved with an expectation of diurnal thermal duress and a bit of shivering = a healthy body. There is an analogy with the prevalence of diabetes and modern day snacking lifestyles where the body is continually supplied with an excess of easy access carbohydrates.

Same here, not being on the official database has not proven to be an impediment for commercial delivery outfits prospering in the 21st century. If the Royal Mail wants to sow the seeds of its own demise by trying to sell an incomplete PAF database then good riddance.

The front pages of today's news papers illustrate it did not take Marxism to restrain personal freedom in the UK. The Orwellian thought police are active and threaten your freedom today, so decreed a senior judge yesterday.

This is worrying. I first got a design and quote 2 years ago while buying the plot. At that time the longest clear span was 4.0m. That design used the PosiJoist size where the joists are 22.5cm high. Since then we removed the classic central entrance hall and created a max clear span of 5.4m, so when the new design came through I though good that has bumped the floor into the next 25cm joist height category. Loosing 2" of ceiling height would be an issue if I requested 30cm high joists. Could you confirm your joist centres? Mine are specified at 400mm throughout. Also I assume your joists are open metal web joists?

The floor designer explained the new European standard is max permanent deflection under load including an extra allowance for material creep over a period of time. My understanding is that reduced bounce, which we householders use to assess how solid a floor is, comes as a by product of reducing static load deflection.

How confident are you @Gem77there will only be 6 months remaining to a finished house from August onwards? I ask because finding, transporting and getting a static caravan up and running as a home on your self build plot involves time and expense. I suspect for a short period up to 6 months a conventional house rental makes more sense. To get a static caravan properly set up on site for a winter requires: Searching for the caravan which is more demanding than say shopping for a second hand car. Checking that road transport is a viable option through the final roads to your site and any tight bend onto site. Overhanging trees were the main headache for my delivery. You will want to prepare a base with some hardcore so that the van does not develop a tilt over the winter. While doing this also think about daily car parking and paths across site. Can you find a position onsite for the van that still allows a minimum 3 meter working perimeter around the house in build? Will the van sit in a position that will obstruct digging of drainage or service trenches to the main house? Will you be able to find a position onsite with enough elevation to route a sewerage pipe from the van into pipes in place for the main house? Once you have the van on site budget for: Many hours to get the van levelled up on freshly prepared ground. I think I have 30+ heavy blocks shoring mine up A day to connect up the drainage pipes under the van or more if extra trenches need to be dug. Multiple days to add skirting all round to stop freezing winds getting under the van. Buy or make steps for access. A visit from a gas safe fitter to get central heating up and running. Outside lighting is very useful. Offsite storage for everything else needed later for the main house. An extra £40 on your site insurance to cover the van. Our quality of life onsite improved once the washing machine and tumble drier were up and running in a shed but even the shed was a mini DIY project. The shed required its own hardcore platform and extra trenches for electricity, mains water and another short drainage pipe branch. When I thought I had finished this the washing machine then danced around the shed floor which meant I then had to build a raised platform with timbers much thicker than the shed floor. Having said all that we have been happy onsite for 18 months. In our case we are just two in an extra wide static caravan hence we have the same floor space as a small flat (480 sq ft).

I have got a quote and design for the first floor with metal open web joists (Wolf) and wonder if these deflection criteria equate to a good solid floor with little bounce? The longest clear span is 5.45 meters. Without prompting from me the designer spec'ed 400mm centres and 256 deep joists. The wood chord width is 97mm on the longest joists. The reason for this post is that previously a forum member suggested specifying a design deflection limit more demanding than the industry standard. However in the past few years the UK floor design industry has switch to a European technical standard so I do not know how to specify a better floor when requesting a quote. The designer of the first quote has responded by saying "We can increase the thickness of the timber on the longest spans where you might feel the most bounce. Although this would increase the cost it would not be significant".