Our large (24” x 14”) slates have arrived – Ellon Timber delivered our crate of 400+ reclaimed welsh grey slates, they were as good as the sample suggested: Even thickness; good condition, good match for our existing slates. They are indeed as wide as one & a half of our slates, so will serve their purpose perfectly.
Monthly Archives: June 2019
First fascia panel powder coated
Having got a scrap of aluminium coated with primer, a couple of weeks ago, we took several leaps forwards, using one of the fascia panels for the courtyard side of the east wing. The approach is fairly low-risk: Once nailed into place, it will be a good 3m above ground level, so any minor imperfections would be hard to spot.
Preparation
I drilled 3mm holes 1cm in from the top edge to let us wire the panel to our supporting frame. We got a bowl of water with washing up liquid and used a scouring pad to get loose crud off the panel. This gave it a scrubbed look in places and we got quite a bit of oxide off. We did notice a bit of pitting, otherwise a good smooth surface. Once dry, we scrubbed it down with acetone using a J-cloth. We moved the oven from our bothy/shed onto the floor immediately opposite the spray booth, so it was straightforward to gingerly lift the whole assemblage round and lower it in.
Trial & error
I experimented with the compressor and spray gun set up. I set the outlet air pressure to less than one bar and used an adjuster screw on the gun to fine tune the powder flow. After a couple of fits and starts where I got clumps of powder blowing out, I managed an even flow. The electrical side of the sprayer was easy, I fixed the grounding wire via a crocodile clip to the very top of the panel, which will be out of sight. I powered up the high voltage until and used the foot control to switch it on/off. I practice it was easier and more comfortable to use the foot control in one hand than on the floor by foot.
Coating the primer
So, I got going, covering the panel, 30cm x 250cm, with what I hoped was an even coat of primer. If I could see hints of aluminium below the powder coating, I re-coated it until it was an even, dull finish. I took care to get the back lip covered, that fits over the bottom of the fascia board.
Curing the primer
A niggle is that the oven is barely wider than the panels, it was a challenge not to tap/scrape the bottom corners of the panel as it went in. Then it was lid on, lid closed down (with six small woodworking clamps), then switch the power on. The electronics on the oven are smart and remember the target temperature between runs, so there was nothing else to do but watch the temperature climb to 180c, around 20 minutes. The controller does seem to learn as it is used, it manged the last few degrees more quickly that the first few times and never went over-temperature by more than 0.4c. As the oven got to 180c, I started my phone timer and, after 10 minutes turned the power off, then left the oven to cool down to 80c or so before we took the lid off. As an aside, I noticed the extension lead and kettle leads got distinctly warm and I make a mental note to fully unwind the extension lead for future runs.
The result was really quite impressively good, with a couple of small patches of over-thick coating. I smoothed these down with 180 sandpaper under a small piece of wood, the recleaned it with acetone. There were a few pits that had not quite filled. I had also used slightly too-long piece of wire at one end, which meant one corner was just touching the bottom of the oven, it came out with the aluminium showing.
Prepping the top coat
We broke open our 25kg back of RAL 6004 blue-green powder and put an inch or two in our second powder bottle. I used our test scrap of aluminium to practice on and was a bit disappointed at the uneven coating I got, but I went ahead and cooked it. The result was OK, the powder had melted to cover most of the imperfections. I suppose given the rough surface, I should not really have expected better.
The top coat
So I got going on the primed panel. This coated better than the test piece, I put what seemed like a quite heavy coat on, until all signs of primer were obliterated and the panel had a dull but very even appearance. I put it as carefully as I could into the oven, but brushed both bottom corners on the insulation, partly wiping it off. This is clearly going to be an ongoing challenge.
So we cooked the panel and waited with some trepidation for the oven to cool down, then lifted the panel out. And lo & behold, it was good! It had a beautiful even matt-ish (slight sheen) finish,with just three imperfections: The two bottom corners were showing primer, as expected and there was a 3cm scratch on the front surface that had gone down to the aluminium. The pits all appear to have filled.
I ordered a small bottle of touch-up paint and will see if that is good enough. Otherwise we were very pleased with the finish and we both like the colour. The next steps will be to see if we can process two panels or more at a time and to finish folding the remaining panels.
Working hours
We are in a bit of a pattern of work now. We are up and about shortly after 8am and out by 9am. We work through the day taking lunch between 2 & 3 pm, then an afternoon shift until 6-8pm. Now it is light until 11pm, we have done a few evening shifts as well until 10-11pm. Saturday mornings Jill usually does Parkrun in Ellon, I do the weekly shop and we get back about 11am. Sundays we take turns with Jills parents and her sister/brother-in-law, cooking an evening meal. We borrow a kitchen when it is our turn, the caravan is not really equipped for such things. Of course we do sometimes venture out into the wider world, to collect building materials, to visit garden open days or to go to garden centres. The latter two usually with Jill’s parents.
Tanking and studwork in the North Wing
Ric finished rendering the bottom metre of the north wing before he headed home and as soon as it dried out, Jil painted on the primer and by the end of the following day we had got the whole lot tanked. We did prep on the foundation between north and west wings so we can get some on the studwork up and temporarily clad it with OSB to keep rain and wind out. Jill peeled back the DPM, we trowelled on a bed of mortar, then DPC on top, then taped the DPM back up over it. The following day we tanked it, for good measure.
We carried on with the studwork in the north wing, finishing the north wall in a day and building the studwork across the foundation the day after. We arranged the studs either side of rooflights so that the studs were the other sides of the trusses from the rooflight.
We have yet to go back and rework the three rooflights we added in to earlier studwork, where one stud is nailed up in the way of what will be the rooflight reveal. We will join a timber to the truss side and run it u to the truss, then cut out the original at the right height to be below the reveal.
The only other real peculiarity was immediately to the left of the front door, where we unwisely placed our incoming water supply and a foul drain right where we need to build studwork. We carved lumps out of the timber to work round it, but will have to work out how to prevent them showing once we have boarded up. This leaves about 1 days-worth of work on the south wall to get that out of the way, on our next rainy day.
Planning ahead – Slating & Floor Screed
The next big job is building up the gable ends of the east wing, it will take several weeks, but we have everything we need for that. We need to raise the stonework to reflect the raised wallheads and rebuild the coping stones into parapets. We also need to powder coat the fascia cladding and fit that. After that, Ric will return and we will look at slating and floor screed.
Slating
We have 430 large reclaimed slates, 24” x 14”, heading our way via Ellon Timber, from The Slate Centre in Haverfordwest. These will become our slate & halfs. It took a bit longer than expected because some of my emails did not get to them, however the phone saved the day. We have our soakers to run slates up the parapets, the lead flashing and copper nails and the slate guillotine. So this should all be ready to roll.
Screeding the floors
As with laying the floor slab, this is a job of many layers.
- The 100mm PIR foam panels are stacked in out east wing, with the aluminium tape to seal them together. We have the 25mm insulation that will be the upstands round the edges and the 6mm plywood that will hold the upstands in place against the studwork against the weight of the screed mix.
- We need to plan running heating and hot & cold water distribution pipes through the insulation (using 25mm insulation below and above) and buy it in. We will probably use copper pipe for our potable water, but WRAS-approved plastic pipe for everything else.
- We need to order two 10-port underfloor heating kits, each with 1000m of pipe, which will be fixed at 100mm spacing: We will have a heat pump that delivers water at 35c-40c, so need the closer spaced piping. Each kit will serve up to 100 square metres of floor. The packs include manifolds, valves & pumps, but not the thermostats, wiring centres and actuators which we will source separately when we are doing first and second fits.
- We will wire the heating pipes to mesh, to even out the heat distribution. We found out about D45 wrapping mesh, which is 3mm welded wire at 100mm spacings, ideal for our purposes. We will rest it on shallow upstands and use the wire ties we used to tie the floor slab mesh together. The mesh is on order. We will order the cement and sharp sand for the screed nearer the time. We will also get a load of the quarry dust we used to blind the hardcore in the floor slabs, we will mix it 50:50 with the sand to increase the grittiness of the screed. The screeding will be a bit of a grim job, we need a bit over 11 cubic metres and will mix it by hand.
Breather membrane II
We plugged on for several days working across the roof of the north wing. Firstly the south side facing the courtyard, then the north side. It was fairly simple stuff, slowed down by the 11 rooflights which we had to hop over on the three courses up each side and a piece along the ridge. Each involved dragging the roof ladders to an angle above the rooflight to get them close enough to climb across and getting Jill to lift the bottom end of the long ladder over. A top tip, we have a hammer tacker and a staple gun, I used the latter because it made a cleaner, more consistent job. I used the tacker on the east wing roof and in my inexpert hands I damaged the fabric too often and left too many at odd angles, which eventually either pulled out or further tore the fabric.
We had plenty of rain and as we got the fabric on, we began to see specific points where the rain was dripping in, over the tops of a few of the rooflights, plus at least one higher up the roof. We can investigate these when the floor has dried out enough to show how much water is coming through. It could be that the water is ponding up on the fabric lapped up onto the top frames of the rooflights and finding its way through holes in the fabric – they seem to keep dripping longer than the rain lasts, also the water wat dripping from the sarking board immediately above the frame, down onto the frame, rather than leaking directly down from between the frame and the fabric. Jill shovelled up the standing water on the concrete slab and it is all drying out nicely despite the drips.
We ran the membrane right up to the open end of the north wing, that will get tied into the west wing roof when we have one. It was a bit of a bodge because the incomplete sarking meant we could not get the roof ladders up to the edge. We stapled the overhang onto the end of the last truss and ran batten down each rafter. We also just managed to screw the ends of the roof battens holding the joins down into the rafter, where I could not get two hands to drive nails in. This just leaves the valley troughs to install, a separate job once the aches and pains from scrambling over roof for days at a time have gone.
The Powder Coating Oven works!
As Jill was folding the first batch of fascia cladding, Ric built a booth to house the equipment we will use to spray the powder on to the aluminium. It was wider than 2.5m, so it could take full-length sections of cladding. He had a shelf underneath to hold the compressor and the electronics for the spray gun. He got it set up to his satisfaction, then we broke into one of our 25kg bags of powder. This happened to be the grey epoxy primer. We put a couple of cm into one of our two spray canisters, he set the pressure at 1 bar, pressed the foot pedal to get the static charge and tested it out on a manky, rough piece of waste aluminium. He got us along to spray the other side. My first pass was too light, with aluminium still showing through, the next pass finished the job.
At this point we decided we may as well fire up the oven and see if it really worked. We had acquired an oven thermometer that we stuck through the lid and into the top of the oven, to measure oven temperature rather than thermocouple temperature i.e. the temperature of the air being blown out from the fan. We hung the aluminium on a piece of wire, clamped the lid on and turned the power on. It was still set at 200c from our last trial run, Ric got it back to 180c and we watched it as it heated up. The oven thermometer reacted surprisingly (to me) quickly to the increasing temperature indicated by the thermocouple, but soon started to diverge by a few degrees. The question was, was this because there was thermal lag i.e. it was taking a long time for the heat to raise the temperature in the oven, or was it because the thermometer was rubbish? The difference increased right up to 22c at 180c, with the thermometer indicating 158c, at which point it stopped rising. It stayed like this for the 10 minutes we ran it at temperature.
We turned the whole thing off and after another 10 minutes lifted the lid off. The powder had fused and had left a not-bad finish, except that Ric had not cleaned the aluminium, so there were corrosion pits and bits of sawdust faithfully trapped in the primer. It answered the question about the thermometer – it is rubbish and the oven does in fact work as advertised! The heating cycle was about 40 minutes total.
When we have an area dry enough to have the oven on the floor next to the spray booth, we will get going on the cladding panels. At present we plan to scrub the outer surfaces down with scouring pads and soapy water, clean them with acetone and hang the panels in the spray booth on a rack one at a time for spraying the primer on, then lift the rack en-masse into the oven for 10 minutes at 180c. Then back on the rack in the spray booth for the final coat and back into the oven for another 10 minutes at 180c.
Fascia cladding
Whilst I was scrambling around on our east wing roof, Ric got Jill working with the aluminium folder. She was quickly producing excellent quality cladding for our fascia boards. She marked up a sheet of 0.7mm aluminium and cut three lengths per sheet. Each of those got two folds at right angles to make a bottom lip that goes under the underside of the fascia board and up the back out of sight. She made a 45 degree fold along the top edge that will lap onto the top edge of the sarking board and will, when complete, be nailed into place below the eaves protectors and membrane. She had to measure up each panel to fit, because in a couple of places we had put packers above the boards. After two days we had enough panels to cover the fascia boards facing the courtyard. We will space them apart with a 10mm gap and will cover that with 50mm x 3mm aluminium flat bar folded to the same profile. Another leap forwards in a short space of time. The next milestone – demonstrate that the powder coating oven works!
Slate & Halfs
We reclaimed the slates off our old roof, but want to use slate & halfs (375mm wide rather than 250mm) rather than half slates, to make it easier to get a watertight roof, particularly up the valleys. I found a really good match last year with new Chinese Blue Grey Fesco slates from a store in Scarborough. So I phoned them up to ask about ordering 400 slate & halfs and was surprised that they were rude and grumpy and said no. I phoned several other places and one of them explained the problem – slates are shipped in consignments with lots of slates and not many slate & halfs, so if they were to sell me 400 of them, they would leave customers for their slates short. I see their problem, but they were still abominably rude. And it opened my eyes to the fact that selling slates requires no knowledge, understanding about, or even control over, what they are selling.
Ric had the bright idea of looking for large reclaimed slates. The largest common size is 24” x 14”, which is not much narrower than the slate & halfs that we need. We found several places, mostly in Wales. The first did not have any, despite their website saying they had 10,000 of them. The second did, but refused to send me a sample. They said the slate would not survive posting, I said in that case send me a broken piece, they still would not. The third place did not answer the phone. The fourth said they might have a few hundred and did agree to send a sample out. After a week I phoned back and got a different person, who said they would send a sample out. A week later I phoned back and the original chap was there. He again said he would post a sample out and a few days later got emails saying a) he would, then b) he had, but the packaging looked suspect and he was worried it might fall apart in the post. A week later I was about to ring again when lo & behold, it arrived. It was in a Jiffy bag and somehow, they had got the sample pushed into the lining layer between the outside & inside of the bag.
What mattered was that it was an excellent match and when I said I wanted 400 of them, he went off to count them. He phoned to say they had 900 of them. Furthermore he thought he might get 400-450 of them onto a single crate, to reduce the delivery cost. If it all pans out, this overcomes the biggest obstacle to medium-term progress. It would have been great if it had happened a month ago, but better now than another month down the line. I expect it will put the squeeze on us in late summer to get the steading slated up. We recently acquired a large slate guillotine which will allow us to trim these slates down to the height of ours, as well as to cut the angles needed for the valleys and to fit the ends of runs of slate.
Breather membrane
With the rooflights all in, we could – and did – get going with the breather membrane. We used DuPont Tyvek Supro, which is rated for the weather in this area, is suitable for sarked roofs and comes in 1.5m wide rolls. In theory this would mean three courses to fill a roof, in practice it needed a capping piece over the ridge. Ric chose the east side of the east wing roof to start because it does not have valleys. He ran the first two courses, cutting the membrane around each of the two rooflights, lapping it up the bottom and top edges of the frames respectively. He fitted separate pieces to the sides, always ensuring that higher pieces of membrane lapped over lower pieces. We used a hammer tacker to knock stainless steel staples into the sarking to hold the membrane against the roof, every 50cm or so at four heights per course. At each end he folded back a length to run up the parapets, then we fitted batten up the sides and along the bottoms of all the courses, to hold it all in place. The bottom course we did from ladders, for the others we put the two roof ladders up and hopped between them to move across the roof. We rigged up a length of tube up the middle of the roll of membrane and attached it in various ways to the roof ladder.
Ric left me to do the easy bit, to run the third course which is above all the rooflights. Except I really struggled. I tried to follow a line with the top of the membrane along the sarking and discovered a bit late that the course below dipped down in the middle and I was not getting the 150mm overlap. So I did a couple of changes of direction, which left big wrinkles in the membrane. About halfway along, I got it aligned and I comparatively raced along, but had to get Ric to finish the edge as I had no stomach to be moving roof ladders down the roof right at the edge.
I have a very poor head for heights and always found it uncomfortable hopping around without scaffolding. I particularly I was never happy getting from the ladder onto the roof ladder and down again, where the roof ladder did not stretch down to the bottom of the roof.
Anyway I got it done and over the next week worked on with the other side. This sounds (and is) not very impressive, but my working time was really disrupted: We had several planned days out; I needed to divert to other things that had to be done whilst Ric was around and we had the digger & dumper, as in spreading hardcore on the track; we had some terrible weather, losing whole days to heavy rain and wind. Once we got back to decent weather, I finished the last fiddly bit of the east wing and got ready to head off down the north wing roof. The membrane we have put up has done the job, with very little water getting into the east wing. Instead it is falling onto the bare soil of our courtyard and turning it into a muddy lake! I expect it will be like this until we can get the roof slated and get gutters up. There is some water getting in around the rooflight frames, we may need to install enough of the flashing kits to deflect it down the membrane.
East Byreleask Steading 