epsilonGreedy

I cannot think of a less offensive collective phrase for the people on this forum. Every boat floating in a British marina provides an example of such a low loss supply and probably every caravan too. Live-aboard boaters count their daily amp hours and struggle to match PV amps generated with consumption, there is nothing exotic to matching battery volts output with the consumption needs aboard. Larger american yachts tend to favour 24 volts which is just two commodity batteries in series. All of which illustrates a low cost commodity solution exists for a very low tech problem. The worlds of boating and RVs have proven cheap solutions for this whole challenge. It therefore seems strange to me that the forum is predisposed to focus on a few high margin fringe suppliers who target their products as price insensitive self builders.

I am about to start the construction of my footing blockwork and I want to ensure blown beads remain an option for cavity insulation later in the build. Do I need to build in a tray to prevent beads settling at the bottom of the cavity below ground ground level? I am in rainfall zone 1 / 2.

If the AECB wants to be effective why do they undermine their cause with puerile rabble rousing leftie language? The problem is not profit. Domestic gas boilers are built for profit and so are cars. Both have delivered steady advances in energy efficiency under the dark cloud of capitalist incentive. There is a problem with British house building but it is not capitalism.

With respect I think this is just a British blind spot, a bit Googling reveals a healthy market for DC led lightning overseas. A humble DC switch on my old boat could comfortably handle 20 watts at 12v volts DC. People on this forum seem happy to shell out £5k to £20k on bleeding edge home technology yet go belly up at the first hint of DC trouble in a £10 light switch.

We will claim it is onsite workers accommodation for a few months but eventually it will become our primary residence so I am prepared for a Band-A council tax bill at some point.

Indeed. Some economists have observed there was a remarkably close correlation between the introduction of the Government new build incentive and an equivalent pop in new build asking prices.

We are looking at £350 transport costs for a 30 mile delivery, one of the benefits of building in a poor area of the country where statics are a primary residence for many.

Is it time to debate whole-house DC lighting again? I got some negative feedback here 4 months ago for exploring this subject but now the maths has changed. With all those PV watts stored locally in a battery does it make sense to loose 10% stepping up the electricity feed to 240 volts AC and then loose possibly 50% again converting that back to DC within some cheap circuitry embedded within each LED light.

While on this subject would I be correcting in thinking that corridor width is critical on the approach to an m-spec door? There is one smaller minimum for a head-on approach to a door but if there is a turn the corridor must be wider.

I was in a similar position to you 6 months ago and the Self Builder's Bible was the most effective book I purchased to demystify the whole challenge. Even if you contract the whole house build it pays to understand as much as possible since you will then be able to call a swift halt on any rogue tradesmen doing the wrong thing. After reading the books and watching the YouTube videos there will still be a myriad of details to learn as you go, take for example my current thread on block footing design.

Probably 120mm + 75mm with UFH pipes embedded.

Soapbar blocks = a top tip. Thankyou. I think I will build up an extra wall section for the adjacent wall supporting the beams to save confusion. I could go all the way and include a demo beam offcut of say 500mm if I could pick up an offcut somewhere. I had been thinking that the dpc shown on my original BC diagram could not prevent damp raising into the floor infill blocks.

I must be overlooking something here, would 120mm of insulation + 75mm of screed make the FFL up perfectly?

In the photo the two courses of inner wall bricks are supporting the edge block of the horizontal floor. The beams would be running parallel with the portion of the footing wall shown, the diagram I posted with the opening thread post show the position and height of the first beam in from the wall. (Edit: My building advisor who is a trad solid floor man did wonder if beam/floor flex might move this first edge block and thus cause it to leverage the block wall above.). The block heights of the adjacent wall supporting the beam ends is more interesting. If a beam protrudes 55mm below into the void then instead of two regular 65mm coursing raising 150mm to the first horizontal floor block there is now a 95mm gap to the bottom of the beam, I guess this is where those 40mm coursing slips are used.

Because I had assumed that the worst option for a wet site would be such a ground bearing slab. I can see the attraction of a passiv sab house sitting on 300mm of rigid foam and well clear of whatever swampiness lays below. Surely the next best thing is beam & block & void where techniques to combat rising damp are focused in the footing walls. It is there regardless of what you want, nature, rainfall and the watertable control that. The only thing we control is what layers of building strata exist between our toastie UF heated bear feet and winter reality below. I am not sure why you instinctively questioned the viability of 200mm to 300mm of air to combat rising damp and instead recommend stones, concrete and a slither of plastic ? p.s. I am hoping to learn through this debate.

Henry Ford had a similar idea and the automobile industry never looked back. There are two approaches to selfbuild, the methodical and cautious approach involves ground surveys, core samples, structural engineers and specialist slab contractors.And while you are at it best bring in a CDM 2015 consultant, its only 1.5% of build costs. Before you know it £30k to £40k has gone just to get up to dpc with a floor. By going mainstream block & beam I have avoided all that. Total costs to date are £650 for the house and garage foundation dig and about £2700 for concrete plus around £300 of hired in labour/advice. I have not costed out the next month to a working floor in detail but it looks like 850 blocks for the floor, about 1000 blocks for the footings, some coursing bricks and engineering bricks and about £800 of labour. On a separate issue I am genuinely interested to know why you think a passive slab wallowing in a puddle is preferable to a trad block & beam house straddling over a puddle with a nice air void below.

And @dpmiller& @Declan52 I have dry assembled the following footing block build up that is the best equivalent of my building control diagram shown in the first post. Is my 3-block substitution for the trench block similar to what you are intending/have done? The buff/red brick boundary represents the average external ground level around the perimeter of the house.

I know, I was responding indirectly to @PeterW's intervention. In 6 months our weather has swung from so dire it put the building industry into temporary economic contraction which then dented national GDP and now we have the driest spell since the drought of 1976.

I think this would be true of half the building sites in the country but it is a massive extrapolation to conclude beam & block & void is a suspect building practice unsuitable for these sites. The notion of a drainable void sump is something that interests me and another BuildHub member described such a feature recently as part of his foundation design.

We are talking about a 1 in 30 or 1 in 100 year flash flood risk, not Noah's biblical flood ascending to my foundations. I mentioned the extra 150mm in dpc height in order to illustrate the amount of material that would be needed to create a solid floor base. At present all I have is 600mm x 600mm of poured concrete and a remaining trench depth of between 550mm and 650mm, so I can make a tactical change if convinced, happy to keep discussing. Not sure why a passive slab floating on a swamp would be inherently better to a trad foundation standing proud of the swamp with a drying air current wafting through its floor void? Anyhow the site is not a swamp, a fully laden 8 cube concrete wagon drove right up to within inches of my open trenches last week. Not a dribble of water at the bottom of my trenches.

It is the done thing in these parts. My veteran building control inspector's normal inclination to towards simplification and ignoring modern building frivolities but even he gave a reassuring wink re. Beam & Block. A minor surface flash flood risk means my DPC is 150mm higher than standard.

Oh, is it just an NHBC thing? Though it is tempting not to design in a floor void air chilling mechanism I know my plot is drainage challenged hence encouraging airflow feels like the right thing to do.

I thought they are mandatory for ventilation of a beam & block floor void? Not yet looked into the radon risk, I thought it was a Cornish thing and so this is not yet in my top-10 ToDo list. My plot is located where the Lincolnshire Fens rise up in elevation and become the hilly Lincolnshire Wolds.

We started shopping for a static site caravan over the weekend and I soon realized I had wandered into a strange new world. She liked the generous room proportions of a one bedroom example but I was concerned about resale potential as the market is largely comprised of 2 and 3 bedders. I liked a 20 year old lightly used example but a GasSafe friend warned the gas heated/ducted warm air central heating would be problematic to service as the gas fitter needs an extra certification for this. The owner of Statics4Less pointed us towards a PVC clad example which is a deluxe feature apparently. We only looked at double glazed examples as we face a winter in the static. I have the connection of services all sorted in my head and in addition we will push ahead with getting a roof on some part of the build to accommodate a washing machine and tumble dryer. Any static caravan buying tips will be appreciated.

I am having trouble interpreting the regulations for the height of weak mix cavity fill with relation to DPC and ground level. One interpretation would mean the lower end of my telescopic air vents would be encased by the infill. Would it be ok to partially encase the ducts?