A Recap & some odds and ends

We were in Aberdeen over the Christmas and New Year period, mostly for social reasons, but with the intention of opening up two more windows in one of the steading walls.

Ric & Geoff had  stayed on for some time after we finished our September stint. We missed the last pour of concrete, in the east wing, and whilst they had made good progress on blockwork before we left, there had been plenty left to do. So our first visit was a chance to catch up on progress and check the state of the site.

Floor slab

We now have all our sub-floors in place. They had done as good a job of the east wing as they had on the rest. All are within a cm or so relative to each other and across each slab, apart from the garage floor which is 15cm higher and is the finished surface. We had not cut the expansion joints that the warrant requires us to do, for any continuous area over 30 square metres. Technically they are needed to provide a line of weakness in the event of contraction, to avoid random cracks across the slabs. However it had been raining whilst the slabs were laid and they were all under a cm or two of water when we arrived, so I expect there had been little scope in between for expansion/contraction. There were certainly no signs of any cracking, although the top few mm was starting to spall off in place, assisted by freeze & thaw. I expect we will cut the slots when we re-start work in April 2018.

Floor slabs

Blockwork
All our replacement walling has to have an inner course of standard concrete blocks laid on their sides i.e. 212mm wide. In the time they had available, Ric & Geoff got every opening that needed blockwork built up, mostly to lintel or sill height.

Having had misgivings about the whole issue of demolishing walling and rebuilding it, I was heartened with how well the blockwork tied in to the existing walling. For example Ric had started to sort out a particularly tricky piece of blockwork where the east wing joins the north wing on the courtyard side. We had removed a lot of granite because it was in poor condition and the adjacent door opening was a fairly shapeless 3-dimensional gap. He had cunningly tied in a column of blocks to form a neat internal corner that we can key quoin stones into, to form one edge of the door opening.

They had got two concrete structural lintels in place over the main bathroom window and had the padstones ready in several others.

They had embedded strips of stainless steel mesh into the blockwork at intervals, to tie into the new stonework. This means that when Ric is next up we can paint on the liquid DPM and get started on stonework, assuming we have our replacement sills and lintels. I am hoping that, once we can get the structural lintels on top of new granite, we can block out the wallheads ready for roof trusses separately from getting the outer, decorative granite lintels in place – if we need to. I expect that, if we want to go for getting roof trusses on by the end of the year, we will concentrate on building up the load-bearing walls at the expense of the gable-ends. Again, if we need to.

New/rebuilt walling

Wind

We had worried a little about the gales in November and the cold snap in December. The good news was that the only wind damage was to our builder’s fence panels, that were mostly horizontal, and to our electricity meter cupboard, where the door had completely blown off. The latter unsurprisingly had damaged hinges but I sort-of put it back together and leaned a solid lump of wood against it until we can do something more permanent – possibly some sort of strap that we can use to hold the door in place. As for the fence panels, we stood them up and used a couple of stout timber props tied into the panels to stop them blowing over again. I hope. We were particularly pleased that our shrub-guards netting survived the gales, having blown away twice over the least year!

All our shrub guards passed with flying colours! They survived the gales.

Drainage

It has rained quite a bit in the area over the last few months and we noted that…

1. Our flooding problem in the track and driveway area is completely fixed!
2. The short section of hedge on our north boundary right next to our track is still under water and we will want to run a short French drain to connect to the one Ric installed last year across the driveway.
3. The east boundary that had flooded around the time we put our fencing and hedging in, was not too bad, mainly because water is no longer running off the fields the other side of the fencing.
4. We will need the planned linear drain in front of our garage door, because water was coming of the track and ponding up. Not much, but it will make a big difference.
5. The mystery excavation under the boundary fence between ourselves and the holiday let had filled with water to 40cm below ground level. I expect that simply reflects the water table in the winter and explains why…
6. The bottom of the plot around out soakaway has some flooding, including a section of boundary hedging. We do need to look to a) do a bit of landscaping to make sure it does not pond up and b) see if we can help get surface water off site a bit quicker.
7. The concrete sump that our septic tank temporarily drains into had water up to 40cm below ground level.
8. A small point, but the drain cover is now in place over our concrete surface water tank, there is one less thing to fall into now. We did not get round to clearing the sludge out from the tank, I need to hire a bilge pump at some point.

So we are clearly not quite there yet, We need to do some minor drainage engineering. Given the high water table, we will be very interested in how our raised drainage mound performs as and when we get it in place.

Caravan and stove
The caravan was in good shape and did not look wind-damaged, but is starting to look green from algae. The drain cocks Ric has installed in the water supply meant the water heater was completely emptied and should be good to go next time we are in residence. The stove was installed in the caravan and Ric had had a test firing of it. The stove does look tiny, but we have high hopes for it.

It looks tiny, but is was highly recommended.

The stove pipe should be a good radiator.

The double-layer section o fpipe should preserve teh roof where it goes through!

Rodents
We have a bit of an issue with small furry mammals. They had got in to the caravan again and must have been desperately hungry. They had found the gauntlets that came with the stove, made of some sort of leather, and had consumed quite a large chunk of one of them. They had even come across a pair of ear defenders in the bothy that were not out of chewing range; They had eaten their way through much of the soft plastic – the foam soundproofing and the vinyl over the earpieces!

The bothy doors
When we built the bothy doors, two years ago, I made them a bit of a tight fit. By the time we got up this time around, the wet weather had made them expand a bit too much and we could no longer close them. I borrowed an electric plane from brother-in-law Bryan and took several mm off one door and painted the edge with preservative. It mostly sorted the problem, there is one point where it catches a little, I will see if it still a problem in the spring.

The tools for the job.

A satisfactory conclusion…

The weather
Having been up in the area off & on over 30-odd years, I got in the habit of expecting one or two falls of snow over Christmas/New Year. For whatever reason though (and yes, I do believe in man-made climate change), the last decent fall was way back in 2010.

• In 2013, when we first discovered the steading, the weather was chilly and variably windy and damp, but not cold enough to snow.
• In 2014, when we were putting up our fencing, it was well below zero, but still, dry and sunny, apart from one day of wind and sleet.
• In 2015, when we put the new doors on the bothy, it was chilly and damp.
• In 2016 when I dug out an inspection chamber do re-route some pipework, it was again chilly and damp.
• In 2017 we had the first significant fall of snow over the period, in seven years. We only got an inch or two, but it stayed for days, iced over and became quite a hazard. The combination of uneven ground, a capping of ice, melt-water and poor grip on my work boots meant that I landed on my bum several times a day and got quite adept at collapsing gracefully. Driving on the local back roads was exciting and the floor slabs became like skating rinks.
• I had left the dog’s water bowl outside and it had a good crust of ice on top. I lifted it out and observed an impressive array of ice crystals that had grown at angles down into the water.

Not much depth of snow, but it iced over and was lethal.

This layer of ice was on teh dogs drinking water bowl. These amazing ice crystals had grown down into the water!

Creating the floor slab – II

The Plan
We had booked our concrete over three consecutive mornings. I went with the volumetric mixing trucks because they have up to 6m of reach from the back of the truck and because they can hold 9+ cubic m of materials, however the trucks are 8m long, much bigger than barrel mixers, so we had to do some rearranging on site to give them access. The first day we would fill the garage and master bedroom areas in the west wing, with one load, estimated 7.6 cu m. The following day we would use two loads to fill the north wing, estimated 14 cu m. Then on the third day, do the east wing, estimated 7.6 cu m.

The Reality
We used more concrete that I expected: My estimates were bad, I had assumed a dead-level blinded surface and exactly 125mm depth of concrete. There was a few cm variation within each discrete area (master bedroom & garage in the east wing, the north wing and the east wing) and some variation between them. So the garage area base was not exactly 15cm higher than any of the other areas. These differences were significant. If the north wing, for example, was just 1cm lower than it should be relative to the other areas, we would need almost one extra cubic metre of concrete. My other mistake was to assume that the extra volume to fill the troughs (along the sides of the east & west wings, to support structural timber) were to be spread evenly across all the floor area.They were not. So I particularly underestimated the amount of concrete for the east and west wings.

Both my brothers told me, after the event, that I should have added 10% to my estimate and ordered 33 cubic metres.

Day 1
Anyway, the truck turned up on the first day. We got him to pull up in next-door’s driveway and back up to the master bedroom area. We had parted our fence, so the truck could get as close as possible: We will patch it up once the job is done. It went very smoothly. The concrete was set up for a C35 mix and was fairly runny and well-mixed, so flowed easily. By adjusting the number of chutes on the end of the mixing auger and the direction of the auger, we really did not have much raking to do. My youngest brother, Geoff, did the skilled work. He had a laser level that stood at one end of the area and a receiver that he fixed at the right height on his tamping tool. If the tool was low, it made rapid beeps, when too high, it made slow beeps. When it was at the required level it made a continuous tone. So with a minimum of fuss we got the master-bedroom area filled.

It had used at least a cubic m more that I had estimated and the driver thought he did not have enough materials to fill the garage area, so we rescheduled for a separate job over a fourth day. This was annoying, but not disastrous. Geoff used his concrete roller to push the aggregate down, then his float at intervals to smooth out the surface. It rained, but we still got a good surface.

Floor slabs

We cut our fence to let the truck back right up to the steading building

The chute went right to the middle of the master bedroom area

Geoff used the roller to push the aggregate down out of site, then this float to polish the surface

It rained, so the wet concrete is partly underwater

But the water does not seem to damage the finish

Our dog, Misty, escaped at one point and left her mark…

Day 2
The following day a different driver turned up with a smaller truck. he backed up to what will be our garage door and filled the garage area. We opted for a stiffer mix, which was bit more work, but should allow a better finish, since it is the final surface (no insulation or screed on top).

Annoyingly it rained more heavily than the previous day, but again Geoff got a good smooth finish. Ric spent part of the day clearing lintels and granite out of the way so the truck could back up next day to the north wing through two openings.

Ric built up the access to the garage area with hardcore to allow twh truck to get as close as possible

This is a itlle truck compared to yesterday

Raking the concrete to the edges

Another excellent finish from Geoff

Day 3
We got the first truck load in the west half of the north wing and got the full 9 cubic m. We were a bit concerned about whether we had got the area more or less that half-filled. We also had to get the concrete spread over a longer distance. Ric constructed a separate chute from a sheet of galvanised steel on a wooden frame and, when the truck reappeared an hour and a half after leaving, it worked perfectly. As it happened, we used 6 cubic m from the second load – I think the floor must have been, on average, a bit higher here.

The galvanised sheet on the chute came out looking polished and shiny – just like new. Was this the abrasive action of the flowing concrete, or a chemical thing?

At one point the driver did say he would had enough concrete on the first day to finish the garage area, after all. Hey ho!

Geoff spreading the concrete delivered down Ric’s home-made concrete chute!

The chute in all it’s glory

Geoff polishing the surface!

The end-result

90 square metres of concrete…

Our water supply pipe finally fixed in place by 125mm of C35 concrete!

Day 4
On the final day, the driver loaded a full 10 cubic m of material on the truck, got it backed up to the bathroom window area and, with Ric’s chute, got the whole area filled with one load. Just. There was about a bucket of mix left over. It rained again and Geoff worked a smooth surface under water.

Geoff working his magic on the west wing floor

We used 33 cubic m of concrete in total – my estimate of 30 illustrated exactly why I needed to have used the ‘add 10%’ convention. Laying concrete is stressful because of what can go wrong and the difficulties with correcting mistakes. Aberdeen Concrete ltd made it much easier than it could have been. They were helpful and we only paid for the concrete we needed. But we were all relieved once the last load went in. We did have to clear quite a lot of space to allow their trucks to get backed into the opening we wanted to use.

Having spent the last three years climbing about inside the steading, it is quite strange walking on a flat, hard, continuous surface. The drain pipes look much more professionally installed now they poke vertically out of the concrete and it is blessing not to be tripping over the external electrical cables and water supply. We know from the puddles on the concrete that the surface varies by less than 1cm over each area. It will be a good base for the insulation panels and screed.

Creating the floor slab – I

We pushed on with our main priority – getting a concrete floor slab in place. A job of many layers…

First, clean up the excavation
We squared up the excavation, clearing bits by hand that the digger could not get to – this was quick, a few hours and barrow-loads for the whole floor area. I spread the trimmings across some of the low areas. We temporarily removed most of the drain pipe we had placed the year before, to make access easier and avoid damaging the pipes. We left the drain for the cloakroom area in the north wing, because it only stuck out by a metre or so, and the deep drain in the bathroom area in the west wing, because it was still (just) buried in the subsoil.

1 – Hardcore
Next up was the 200mm layer of hardcore. We started in the garage area because it was easy access and small. It would also let us access the master bedroom area beyond. Ric used the digger to load the dumper and drop the hardcore in the area we were working. I spread and levelled the hardcore, working from the back of the area towards the entrance. The hardcore is brutal stuff and was a pain to work with. It includes hefty lumps of broken concrete/stone up to 15cm long and the matrix looked like a mix of smaller broken concrete/stone and quarry dust. The big stones seemed to ‘float’ to the surface when dropped from the dumper, I spent a disproportionate amount of time and energy shovelling or throwing them by hand into the un-filled areas. I spread it by eye, trying to get it 5cm or so above the compacted level we needed. It got easier with a bit of practice, eventually I had no problem getting a decent regular surface with no more that 3-4 cm difference in height over the area. We filled the area then used the wacker plate to compact it. That worked a treat. After four runs – along, across, along and across – it compacted down the expected 50mm and had all locked solid.

We built a ramp of hardcore to get the dumper truck in and out – 6 dumper loads. We left the long sides clear of hardcore to form troughs along the edges, about 50cm wide at the top and 20cm at the bottom. These will fill with concrete, to thicken the slab as per the architects design – to support the structural timberwork that will hold our floor joists up. We did not bother in the places we had already laid foundations, these will support the slab directly. We cleared the hardcore ramp into a space we had left, compacted the whole lot and that was job done. We put the pipes back in and had to use pickaxes to break up the compacted hardcore, a couple of hours of hard labour. Lesson learnt – we will put the pipes back in place before compacting!

The following day, Ric built hardcore ramps to get access to the long north wing and the east wing. Then it was a lot more of the same – empty a dumper-load, pick out the big stones on the surface and drop them out of harms way, level with a shovel and, when the area was filled, compact it.

In the north wing we needed to complete the pipe that will feed air to our woodburner – I had run the pipe under the wall from the outside but could not finish it because there was a pile of spoil inside. Ric had uncovered the end of it when he excavated the subsoil out, it projected about 50mm into the floor space so that it will be easy to get at, to finish off. I waited until we got the run of hardcore right up to the pipework, connected a pipe to halfway across the floor and put an upright on the end of that. We dumped the next loads of hardcore right on top of the pipe, then carried on as normal.

In the east wing, we left the long edges clear of hardcore, to form the troughs for thickening the floor slab, just as we did at the west end.

After three days work, we had all 230 square metres covered in hardcore and compacted. We had used 110 of our 180 tonnes of hardcore, more that I estimated, but we are not short of the stuff. I guess we had over-dug some areas e.g. because of obstructions.

Floor slabs

We did the garage area first, it is a bit rough because of the large stones on the top.

We ran this ramp from the garage area to the master bedroom area.

We used a broken scaffold board for the run up

Adn another load makes its way.

We levelled out the ramp at the end.

We got a flatter surface this time around.

We used a pick-axe to re-lay the drain pipes – slow work

We are making inroads into our hardcore piles!

In the long run in the north wing, the cloakroom drain pipe is currently above the base level and will just be covered by the hardcore

The drain is safely under hardcore

We put pea gravel around the drain pipes

We got teh best finish so far…

And this is the wacker, amazingly effective.

The last area to do, the east wing.

Annoyingly, this pipe is partyl above hardcore level.

And the last of the wacker-work!

2 – Running services through the floor slab
We had already laid two armoured electrical cables, originating in the plant room area, near the future front door. They both run through the master bedroom area and into the south run of drain trenches. One is for the bothy and diverts off and (temporarily) above ground under the caravan. The second carries on all the way beyond the septic tank, where it will power the pump for our raised drainage mound. We have also laid a 20mm blue water pipe alongside the cable that runs to the bothy. It too starts its journey in the plant room, where the rising main will appear above concrete. This pipe is in use as our temporary water supply to the caravan, we will run the pipe and cable into the bothy once the caravan is finished with.

We want to lay a third electrical cable, for our polytunnel. It will run from the plant room, along the full length of the north wing and across the west wing to our family bathroom area, where it needs to exit the building on the east side through the foundation opening.  We are burying all the cables and the pipe in the blinding layer, above the hardcore and  below the damp proof membrane.

We did one other job at this point, testing the reinstated drains for leaks. We bunged up one end of each pipe at the inspection chamber, filled the pipe  with water and left it for ages to see if the level dropped. They did not, they all passed with flying colours.

The electric cable for the polytunnel is laid on the hardcore before the blinding.

The water supply and the three power cables all in place in what will be the power room.

3 – Blinding
The 50mm of blinding helps level the surface and protects the damp proof membrane from being punctured by stones in the hardcore. On advice from our builders merchants, we got 20 tonnes of quarry dust delivered. This is more gritty than the sand I was expecting to use and compacts well. Plus it is half the cost. We divided the floor area up into equal-sized segments and put a dumper-load – a tonne or so – in each segment. We raked it out roughly level then used a home-made screeding rake to level it out and compact it. This was one of our short, fat, kwikstage scaffold boards on its side, with a handle attached. We even put a spirit level on it to work out when the blinding was levelled. The tool was surprisingly solid and heavy and using it was hard and slow work, but after enough runs across at different angles, it produced a very flat, compact, smooth finish. We finished off with a single run of the wacker plate for good measure. We used a couple of extra dumper loads to line the edges and bases of the troughs we had left in the east and west wings. The three electricity cables and one water pipe were duly buried. They all come up together out of the blinding, cable-tied together, in a corner of the plant room area.

We spread the piles of quarry dust evenly over the hardcore

We got a pretty good level surface.

We did a single run with the wacker.

It was a comparatively quick and easy job.

The east wing was slower to sort out because of the foundation blockwork and the drain pipes.

We lined the troughs at teh sides of the east and west wings (to thicken the floor slabs).

This is our screed rake, made from a scaffold board. Note the spirit level!

The most troublesome area…

4 – Expansion joint
We are required to put an isolation joint round the perimeters of all the slabs, to accommodate expansion of the slab. I used 13mm bitumen board, which is a soft fibreboard that I could cut with a Stanley knife, but which went quite floppy in the rain. I cut the boards into strips – 17cm wide (7 per board) for most of the perimeter and 40cm  (3 per board) in the troughs. It was my least-favourite job to date – slow and too much bending, standing & kneeling. We ran the board into our doorways and the various nooks & crannies in our walls. The positive in all this is that the damp proof membrane will be protected from sharp edges in our walls.

The strips of expansion board in teh troughs were 40cm deep.

Elsewhere they were 17-18cm.

5 – Damp Proof Membrane (DPM)
We used 1200 gauge (300 micron) polythene DPM in standard 4m x 25m rolls. We always worked across the floor area between outside walls, using PVC single-sided tape to seal the 400mm overlaps. We did not bother with the double-sided tape we had planned to use. The open areas were easy. Where we had a pipe coming up, we cut a slit, dropped the membrane over the pipe, then cut a small square of membrane that we cut accurately to the diameter of the pipe, slid down and securely taped to both pipe and membrane. It was a lot more tricky sorting out the various door recesses and the troughs. We had to cut and patch it a lot – a sort of giant craft activity. The tape was very effective, even on damp membrane, but was not so good when rain puddled up. I also found by experience that DPM is not the thing to do on a breezy day – at one point I had to give up and wait until the wind died away.

A slow start!

We used a couple of sheets of mesh to stop the DPM being blown around. We overlapps the lengths of DPM by c. 40cm.

We cut out sqaures of membrane to push down over drain uprights, then taped then securely in place.

Most of the garage area was covered in one length of membrane!

We ran the DPM up onto the foundation blocks and taped them down.

6 – Reinforcing mesh
The last job before we got the concrete mixers in was to lay the reinforcing mesh. We used 8mm A252 panels 3.6m x 2m on 70mm supports. This in theory gives us at least the required 25mm of cover over the mesh, even where the mesh panels overlap. We made slow and steady progress, working through a handful of 9” angle-grinder disks cutting the panels to allow for pipes and recesses. Moving the panels into place was definitely a two-person job, it was too easy to catch the membrane and make holes in it. We overlapped the panels by 30cm and wired them together – using a twizzler device to wind the wires and tighten them. It was all solid enough to walk on. The most awkward bit was where one of our pipes gradually sloped up above the blinding and up to mesh height. I cut out a couple of small panels of mesh and used a sledge hammer to form them into curved up-stands that went over the pipe and were tied to the mesh either side. Hopefully there will be enough depth of concrete that they will be covered!

The mesh is in place in the west wing…

We used teh angle grinder to cut the mesh and wired the sheets together with a 30cm overlap.

The long run in the north wing, ready for concrete.

The west end ready as well.

I used a sledge hammer to bend this sheet of mesh over the raised drain pipe.

We hung mesh down into the troughs to further reinforce them.

Concrete & Lime

Concrete

I have discovered the complicated world of ready-mix concrete. We need around 30 ‘cubes’ and want delivery trucks with elevators at the back end, so we can get the stuff within the steading walls before barrowing it i.e. no more than 10m to push each barrow load.

I looked around, there are loads of companies in and around Peterhead and Fraserburgh. I checked out a reasonable sample, none do trucks with elevators. By chance I looked nearer Aberdeen and spotted one that did on-site mixing, which I knew nothing about. I glanced at their website and Lo! They had a piccie of a truck with an elevator and a chute, that would reach up to 6m from the back end of the truck. I phoned them, they can deliver when we want it, it will take 3 loads of one of their trucks, we can have one or two trucks relaying the materials to our site. Perfect. The price, £115 inc vat per cu m, is also not bad.

It turns out the company uses ‘volumetric mixing’ trucks. They have hoppers for sand, gravel & cement plus a tank for water. They mix on site by metering materials onto a conveyor belt and into an auger screw, add the water, then the screw mixes the concrete and pushes it out into the chute. Fine by me. I texted my two builder brothers and got suspicious replies. One said he tried it years ago and did not like it because it did not mix as well as a normal barrel truck. The other asked dubiously whether they would certify their mix.

I did some due diligence on Google and discovered that the industry is ‘somewhat’ divided about volumetric mixing. In the pro camp, they all say that you only get and pay for exactly what you need, there is no transport time for it to go off, it is cheaper because the trucks can do several drops in one round trip, they can alter the mix at any time. Nothing about the quality of mixing, though. The anti camp say that it is lower quality, but also that it is unfair because the volumetric trucks are classed as ‘engineering’ vehicles not HGVs, so they pay less road tax, do not need operators licences and do not need to meet upper weight limits for their vehicles. A fully loaded volumetric truck can mix 10 cu m in one load and weighs in at around 40 tonnes. Some-one suggested that if the trucks had to meet HGV weight limits, they could carry enough materials for about 4 cu m, so they would not be economic. And so on. The debate is heated.

I checked with our architect, he said we did not need a certificate for the concrete.

A question for another day, “how hands-off can you be and still get decent quality housing stock?”

I found some US technical documents about the relative qualities of volumetric v weight batched concrete. If the equipment is set up correctly and the operative knows what they are doing, they found that volumetric concrete was marginally stronger than barrel or drum mixed. So, what to do? Actually, it was an easy decision, the plusses greatly outweigh the minuses. The mix they quoted for, C35, is so massively over the top for a floor slab that it would have to be wildly variable to cause us future problems. So I will phone them and give them the opportunity to show their expertise and customer service. At a not-bad price.

Lime

We have found a source of lime that we will go with. In principle we want to match our mortar to what was used when the steading was built, but that may well have been produced from local materials that we do not have access to. Possibly sea shells. Or that rare outcrop of limestone up the coast towards Boddam. Who knows? We also observe that the walls in east and west wings are substantially tougher than those in the north wing, but is that because the builders used more mortar or a different composition?

So, to be practical, we looked for a commercial medium-strength naturally-hydraulic lime (NHL 3.5) that we knew we would be able to get hold of in large enough quantities, over several years. There are several candidates, so we looked at a) availability in Aberdeenshire and b) cost. Our local builders merchant sells a brand of lime, but it is over £17 per 25kg bag ex vat. Looking at on-line suppliers, their per-bag costs are lower, but by the time you add in transport, it is up to that sort of level. We kept looking until we found Singleton-Birch. They are based in the Lincolnshire wolds near Louth – close to where I was brought up – but have a stockist in Linlithgow, a stone-throw from the Forth bridges. I will drop in on our way up to Aberdeen and get 8 bags or so, at £11 + Vat a bag. If it is what we want, they will deliver tonne pallets to the steading for around £13.75 inc VAT per bag.

Lime goes off quite quickly, in the way cement does. I will take a whole load of heavy-gauge plastic bags (that we get out dog food delivered in) to wrap them up. We will see if that extends their life enough to work through a tonne batch.

Our next challenge is finding a consistent sharp sand to go with the lime, that resembles the original mix. We will start with the local stuff, which comes from a local quarry the far side of Ellon – recommended by the architect.

Getting ready for the floor slab & walls

We are getting going on organising our August/September session at the steading, just two weeks, unfortunately. Ric will go up the week before and stay on for a week afterwards.

New/rebuilt walling

Floor slabs

We will have a fairly demanding timeline to get our big job done, getting the floor slab laid:

1. Dig out the remaining steading floors- all the long northern stretch and much of the west wing. We need to screen the soil and find somewhere to deposit it all. I expect this will fill the week before we arrive.
2. Clean up the floors round the edges where the digger had trouble, level it all out to 53cm or so below finished floor. We will be doing this for a day or two, as soon as we get up there.
3. Spread 200mm hardcore, probably in two layers, using a wacker plate to get it compacted. At the edges where the slab needs to bear structural timber, we do not place hardcore, so we can thicken the slab downwards. I expect we need a bit less than a week.
4. Spread 5cm soft sand to blind the hardcore, a couple of days work.
5. Lay Damp Proof Membrane (polythene), double-taped where the sheets join. A days work.
6. Use supports to get sheets of A252 rebar mesh in place. I expect we will do this just ahead of the concrete so we keep reasonable access.
7. Get the concrete mixer trucks in with 30 cubic metres of concrete, have a fun few days getting it placed, levelled and presentable. This will be much better if we can get mixers with concrete elevators on the back – not sure yet. As far as we know, my youngest brother Geoff is still coming up to do the skilful bits. Three days work I reckon.

Obviously we do not want a lot of rain over the period, I expect showers will not stop us but heavy rain will. I foresee some long old days.

We have various sections of drain, for the bathroom, cloakroom and en-suites, that will be under the slab. We will do leakage tests on them before we cover them permanently. We stick a bung at the end of the section of pipe e.g. where it goes into an inspection chamber. We create a 1500mm head of water and check that no more than 50ml per 1-metre run of pipe leaks over two hours. We also want to run an electrical cable through the sand blinding towards where we want our polytunnel – 6mm2, 3-core.

Whilst this is going on, we will get everything needed to start building walls. We have to build a leaf of blockwork 220mm wide on the inside by laying standard blocks on their sides. We will tie them in to the existing walls. We paint liquid DPM on the outside face of blockwork and use our steel expanded mesh to tie the outer leaf of granite in to the blockwork. We will get 8 or so bags of NHL 3.5 (medium strength) lime and experiment using local sharp sand to make lime mortar. All being well, we can use any time not doing floor slab on getting some experience of actually building upwards – essential if we hope to get our roof on by the end of next year.

The shopping list is looking like this:

• 1.7 tonne digger, hire 3 weeks
• Mini dumper, hire 3 weeks
• Wacker plate, hire 1 week
• Soft sand, 18 tonnes
• 1200 gauge DPM, 25m x 4m x 3 packs
• Single-sided tape, 100m
• Double-sided tape, 100m
• A252 Rebar mesh, 240 sq m
• Mesh supports, as many as we need
• 6 sq mm armoured cable, 50m
• NHL 3.5 Lime, 25kg x 8
• Sharp sand, 2 tonnes
• Stainless steel wall ties, 200
• Expamet 20m x 65mm, 3
• Synthaprufe liquid DPM, 25 l
• Hessian 40m x 1.4m (to protect the lime mortar while it goes off), 2