Screeding the north wing

We got the eastern end of the north wing ready for screeding whilst we worked on the east wing. We laid three loops of heating pipe for the kitchen area and one for the pantry. We did not lay pipe under the stairs or along the part of the north wall where we might put cupboard units. We put the second manifold between the kitchen and dining areas, between the fireplace and the north wall – this will be cupboard space. We pressure tested the four loops, with blanking pipes in the other 6 pairs of ports and had two of the compression fittings leak at 6 bars. We fixed this by using PTFE tape.

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The rest of the north wing has been our workshop and has been quite cluttered with large and heavy items. We ended up clearing it out, finishing laying the insulation and mesh, installing and pressurising the underfloor heating pipe and screeding it as one (long) exercise, to be completed whist Ric is there.

Clearing the north wing
We cleared the small, loose stuff littering the floor easily enough and were left with the bigger items. We could not move stuff over the screed so everything had to go outside, across the courtyard and in through the big window. Each item was a challenge. The tables we carried between us. The aluminium folder we wheeled one end on our little trolley over scaffold board, The freezer housing we wheeled on the sack trolley at one end on scaffold planks. The washing machine and freezer fitted on the small trolley on scaffold boards. The woodworking machine was the challenge – we got it over the doorstep and across our pallet boardwalk on OSB laid on scaffold boards, then across the to window just on OSB. The run into the big window was too steep for us to push/pull, so we used our big orange ratchet straps wrapped around out external wall studwork and pulled it the last metre up and over the window sill. It was a miserable couple of hours, so we were more than glad to get it done.

Laying the last of the insulation
We laid the remaining full panels quite quickly and were left with a metre or so at the end and the area between the plant room and front door, which is where our pipes run. They all needed to surface in the plant room and it was quite complicated. We soldered the remaining lengths of 28mm copper pipe to the runs from the stove, ran them straight to the middle of the plant room, too a sharp left and brought them up against what will be the south wall, against the bottom of the stairs. We put a short length of 110mm brown pipe over the copper pipes to protect them from the screed. The cold water we ran over to the north wall, close to the rising main and both ends of the hot water loop next to the cold. The two pairs of feed/return pipes for the underfloor heating we pulled round to the east wall, mainly because they were a bit on the short side. They were a bit of a struggle to get anywhere near upright, so we left them at about 45 degrees. We filled in around the pipes with left-over chunks of board.

The services for the west wing we will run up the wall, through the joists to the upstairs en-suite then straight across the joists to the master bedroom en-suite. So we did not need to bury any additional pipes in the insulation, it was a case of taping all the joints and on with the next step.

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Laying the mesh and heating pipe.
The mesh was easy, two sheets cover the width of the north wing with a bit of overlap and we covered the remaining floor with just over 4 sheets, including outside doorways. We cut the mesh for expansions joints in all internal doorways, at the west end of the dining area and the east end of the kitchen (to keep to the 8 linear metres/40 square metres limits).

We did the remaining heating pipework as 6 loops. Three for the dining room area, one for the entrance lobby and adjacent cloakroom, one for the utility room and one for the hallway between north and west wings. These joined the four existing loops at the manifold halfway down the north wing.

Pressure testing was trouble-free, although filling 10 loops with air to 6 bars was a bit of a struggle for our little 6-litre compressor.

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Screeding
We split the screeding into four blocks. Timing was down to a) the availability of the hire bull float, b) us all being around all day and c) the weather being dry enough to mix screed.

Session one was small – the section between the east wing and the kitchen area, around 8 square metres.

Session two was the kitchen area down to the fireplace, 40 square metres.

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Session three was the dining room area from the fireplace down to the utility room/cloakroom, 40 square metres.

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Session four was the rest of the north wing up to the junction of the west wing.

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We were nominally laying 65mm  of screed, in practice the depth was often nearer 80-90mm, so we used quite a bit more screed. However, we ended up at the from door only mm out from the planned level, so we were right – it was the slab that was wonky, not our laying. We were knackered by the end and it will take a while to sink in that we can get going building the inside of the steading as soon as we get the slating finished. The inside already sounds rather more like empty rooms than a building site – a bit echoey.

Screeding the east wing

With the floor insulated and with the under floor heating pipes installed on mesh and pressure-tested, we were ready to screed the floor. We used a sand cement screed in the proportions of 1 part cement, 2 parts sharp sand and 2 parts quarry dust. We mixed it to a consistency where it would ball in the hand and break cleanly when pulled apart – not too sticky and not too dry. It was nonetheless quite dry and it really clagged up the mixer. We ended up scraping the barrel (literally) after a couple of mixes and giving it a good wash down every load. It took quite a few mixes to get the right consistency, when we did we speeded up significantly. An over-dry mix would not level properly and had a rough finish. An over-wet mix stuck to the float and was hard to get level. 

We barrowed the mix up and over the big window sill on scaffold planks, supported inside on small blocks of wood to keep the boards clear of the pipes. 

We did not use boards to mark out tramlines and use a board across the top to level the screed, the most popular technique on YouTube. Instead, Ric created small heaps, or spots, up to a metre apart. He used a float to flatten them down and a spirit level to get them all on the same level. These quickly became solid enough to use to work screed around them, using the spirit level to scrape out the high points. I was sceptical that i would be able to work accurately enough to help out, to my surprise it worked, and very well. It was accurate enough to be able to triangulate reliably enough between points to keep the surface level across the length and breath of the area. We dumped barrow loads of screed at a time between the spots, used a rake to spread it and either used an offcut of timber or our feet to tamp it down between and under the pipes. Then it was down to using a float and spirit level to smooth it out. Once we had a big enough area done, we used a hire bull float to smooth out the surface. It did a reasonable job, but we could have done with something rather heavier. 

The floor area is around 50 square metres, so we needed to worry about cracking due to expansion. This is a particular concern in tiled areas like the bathroom and kitchen. The guidance is to put expansion strips every 8 linear metres and every 40 square metres. So we ran a strip across the width of the east wing, between the second bedroom and the lounge at the south end. We cut a 65mm strip of 25mm insulation and sawed it down the middle. Where it crossed pipes, we cut notches on the strip and put a sleeving of polythene pipe insulation on the pipes either side of the foam strip. For good measure we also put expansion strips across all the doorways. 

Day 1
On day one we got the north bedroom, understair cupboard, bathroom and the connecting corridor done as far as the outside door. There was a lot of fiddling around and it was relatively slow. Ric did an excellent job around the pipes coming out of the floor to the manifold, including the 22mm pipes for hot and cold water and the flow & return for the heating. 

The trickiest area was the bathroom. This is to be a wet room, so we needed a surface that would drain water off the floor into the shower area. We had already cut out the insulation in the shower area, trimmed 25mm of the bottom and fixed it back. Ric worked it so that the door was level with the corridor but dropped slightly into the room. The floor was raised more at the edges in the corners and had very gentle slopes down to the middle of the room, then to the shower drain. The finish was a little rough because it was slow work and started to go off, however we are tiling it. It was a big relief to get a tricky job behind us.

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Day 2
Day 2 left us more than half the area to cover, but it was open so was faster going. We had interruptions because of heavy showers and a required visit to Peterhead, so we worked until 10:40pm to finish it.
We used the car headlights to light up the mixer and had bought two worklights for where we were screeding. We need the latter more generally as we race towards autumn and have the prospect of a waterproof roof. 

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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.

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