epsilonGreedy

Have you seen the BBC's annual taxi bill? Even your BBC licence fee has an energy component. Now consider your morning bowl of shredded wheat: the nitrogen fertilizer required energy to produce, the sowing and cropping of the wheat, manufacturing and transport to Tesco plus the lighting and heating at the Tesco store. A slice of all that energy has your name on it.

Does she have a recipe for caramel coloured mortar?

Yes fair point though it would be interesting to compare Kw miles traveled for Nuclear, Coal, Wind and PV. I suspect that at its height nuclear did not have the north/south imbalance of wind today though 3 Mile Island illustrates why placing nuclear plants next to population centers is to be avoided. Anyhow 0.86 of a gigawatt is not be be sniffed at, that one wind farm could halve our draw from France on a windy day.

The TedX talks are one of the few highpoints of YouTube intellectual discourse, 663k views for the David MacKay talk or about 1/1000th the interest in an Adele pop video. Can the planet be saved?

Right now there is a 37 mile long scar across the Lincolnshire countryside that looks like the construction of a Roman road, it has been dug to deliver the 860 MW output from the Triton Knoll offshore wind farm into the national grid. The necessity for this 2-year onshore construction project illustrates the cost of getting renewables from source to point of consumption. This fascinating TedX presentation illustrates with unemotional science and maths how overstated projections are for the role of renewables particularly in the UK. The graphs presented at 4 minutes 10 secs show how UK citizens drew the short straw in the quest for renewables. A reality check on renewables https://www.youtube.com/watch?v=E0W1ZZYIV8o

Oh. My local concrete suppliers offer metal or poly fibres. Glass fibres (GFRC) seems to be used in specialist concrete panel products manufactured offsite in a factory. If metal or poly are the mainstream options for wagon delivered concrete and if metal is out for a slab floor then there does not appear to be a realistic fibre substitute for rebar.

How many weeks of tuition did you receive to get to level-2? I read through a masonry wall tolerances document because I am building a brick and block house. Most of the stated tolerances relate to creating a straight, true and structurally sound finished wall and I would not want internal walls that did not meet those criteria. Imagine fitting a prebuilt stairs to an internal wall with a 20mm bow over 4 meters. Rubber brickie gloves enhance the grip power of your fingers. The mortar needs to be stiffer than normal otherwise the blocks collapse through a 10mm mortar bed after a few leveling taps. How heavy are these blocks? I ask because I thought health & safety standards have imposed a 20kg weight limit per block.

Ok that makes sense. A few months ago when you suggested fibres as an alternative to rebar in a garage floor were you thinking of a specialist non metal fibre like carbon fibre?

The link above is suspect, it does not work and in that post cut & paste is also disabled.

Since starting this thread I now question whether steel fibres are suitable for a garage slab floor if there is a tendency for some to migrate to the surface. If plastic fibres do not contribute to longterm tensile strength should they be considered a substitute for rebar? Think I am coming around to my original hunch of 2 months ago that rebar is right for me after all.

Having read some turgid scientific reports on fibre reinforced concrete this evening I think you are correct. I cannot find the original BuildHub thread, @PeterWmust have been referring to steel fibres when he mentioned fibres were an alternative to rebar.

18% looks high. An average house built to 2013 thermal standards looses about 14% of it heat through the walls. 0.2 dived by 0.17 = 1.18 18% of 14% = 2.5% increase on overall house heating cost.

There are two paths to take: Federated, delegated division of responsibility. Single point of trust to organize, do and deliver. The more you spend on advisers and experts, the less money is left over in the pot for the doers. A gaggle of part time advisers might provide reassurance in the early stages but who will be on your side for the whole journey?

In another thread a couple of Buildhub veterans indicated that for a garage floor fibres were a reasonable substitute for rebar.

How big is the house and is it a rectangular 2-story box or a u-shaped single story villa.

My local go-to concrete outfit could not deliver on my preferred day and so I phoned a brandname concrete supplier. The pro sales team expended 10 times the veribiage just to agree with my suggestion of the nearest outlet. Then we got onto what mix I needed: Me "how much extra for fibres in the mix". Supplier "Oh no you won't need fibres for a garage floor because its not structural". Me "well how much anyway" Supplier "Will you want ordinary fibres or structural fibres?" At this point I started wondering if the cheaper ordinary fibres are not structural what purpose do they serve?

The other week a 13 ton digger was working close by and was idle waiting for others to catch up. Seeing an opportunity to avoid manually barrowing 5+ tons of hardcore from the drive into the garage foundations for the slab I agreed a price with the driver and stood back. The beast trundled over shaking the ground and then effortlessly munched through the pile of hardcore in 20 minutes, the pile to garage distance was within a single swing of the digger arm which helped. The driver then took another 10 minutes to spread it out within the footings. Good days like that a few and far between.

Since starting this thread I have spread 1/2 m3 of blinding sand over the surface which should equate to a 20mm layer on top of the hardcore. Running the compactor over the blinding sand was a far smoother ride than the hardcore, most of it wriggled between the hardcore as I don't have a 20mm layer left on top. The local building pro advised me not to lay the membrane until a few hours before the concrete delivery to avoid puddles or tears due to foot traffic.

I have 100 blocks to hand should I underestimate, never thought of throwing things in to raise the finish concrete level. My self build neighbour has offered to help though think I will play safe and find an extra 3rd team member.

I ordered a roll of DPM yesterday and emphasized it needs to be regulation 1200 gauge. The BM lorry just dropped off a roll of Capital Valley 300mu 4m x 35m. Just thought I should check that 300 MUs = 1200 gauge?

Yes. I was thinking the thickened edge would help if the slab is subject to heave from the subsoil below. I have been out re measuring the hardcore level and found the edges were generally lower by up to 20mm which equates to 6" deep in the centre of the main slab 5m x 4m and upto nearly 7" around the outer 400mm boundary. I need to recalc my order because at this stage of body fatigue an extra £50 of concrete is a bargain compared to shifting more hardcore into the garage footings.

I had a similar thought this morning i.e. create a slight hint of a peripheral ring beam in the poured shape though I am finding it difficult to compact the outer edges because I don't want the compactor to collide with the containing blocks.

I will have some side projects ready to take any surplus if I have a few barrow loads left over. Experience of earlier concrete delivery has refinforce the point there is no time to say to the wagon operator "hang on while I have a think".

I am getting ready for my garage floor concrete pour and have done many circuits with a compactor. Think I am ready for the sand blinding layer but I can still see a few shallows under a 4m staight edge. The concrete will be 150mm deep and I assume will flow to mask out any undulations in the compacted hardcore finish. How level is level enough? +/- 5mm or +/- 10mm?

Is this a newbuild or a renovation?