Our Fireplace

We have been working, off and on, on our fireplace. We plan to install a woodburner boiler halfway along the north wing, in the lounge/dining room and backing on to the kitchen/family room. This is to supplement/complement the air-sourced heat pump (underfloor heating) and the PV panels (hot water). The boiler should be capable of heating both hot water and the underfloor heating. In the grand scheme of things we would expect to use only the heat pump and PV panels over the summer months and to use the woodburner occasionally over the spring and autumn and heavily over the winter months, with the heat pump filling in the gaps e.g. overnight. For the first year or two, we have a large supply of old roof timbers to feed it.

We installed an air supply under the floor slab using 110mm soil pipe, this will feed at least a 14KW stove. We have our eyes on an Arada stove that puts most heat into water and much less into the room, in which case we should be able to get up to 12KW into hot water, the same output as the heat pump.

We planned to build the fireplace from granite, using the large lintel we retrieved from the west wall of the west wing, over the large opening that we have blocked in. It was 2.6m long and needed George’s big digger to lift off and transport. We just managed to lever it into the north wing using the mini digger and used rollers and levers to get it roughly where we needed it. It has been increasingly in our way ever since and now that we want to insulate the east and north wing floors, we need to at least create the fireplace foundation and do something about the lintel.

Agreeing the general size, shape and appearance of the fireplace was not easy. We looked at what other people had done in similar circumstances and we did not like most of them. We want to make a statement, but not to oppress. We want to use as much of the lintel as possible, but need good open access along the north wing. Using the full 2.6m of lintel would leave us only 1.5m of spare width. So we decided on the fireplace being no more than 1.9m wide, giving a 1.2m passageway one side, in line with the openings between the east and west wings, and room for storage the other side. The fireplace will be off-centre, by around 30cm, which should not be a problem. We want to see granite at the front and inside the fireplace, but not above the lintel or around the sides and back. So we will back the granite with mortar/concrete that will allow us to dot & dab plasterboard right up to the edges of the stonework. Above lintel height we will use concrete blockwork then just a timber framework above that to ceiling height. That will give us a good thermal mass around the stove, but let us run double-walled stovepipe up through the roof.

With a eye to the building standards, we settled on the hearth being 1300mm wide and 900mm deep, allowing the side walls to be 300mm thick and the back to be 280mm. The hearth will project forwards 230mm, so that the stove can be at the front of the fireplace.

We used sarking board to make the formwork and cast 150mm of concrete. This will be 15mm below the screed and will allow us a choice over the height of the hearth, either flush with the finished floor, or raised above. I built ducting from concrete block and slate, at the bottom, to allow the air supply to be used from whichever side of the fireplace we wanted.

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We let the concrete harden for a week before building upwards. We used some of our best Peterhead (red) granite quoin stones at the front, with the good faces at the front and inside of the fireplace. We built three courses, to get around 1050mm above the foundation. We used shuttering to back the quoins with concrete, to stiffen it enough to support the lintel. For the rest of the fireplace we picked over our granite rubble to find particularly flat faced boulders that were skinny enough to keep within our designed thicknesses. We did not complete the back of the fireplace at this point, because the pressure was on getting the lintel cut to size and hoisted up onto the quoins.

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We trimmed the lintel to length by drilling seven 18mm holes across the width at each end and using the feathers and tare set to split the ends off. Then it was using the angle grinder to cut the ends square and the bush hammer to soften the edges and roughen the surface.

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Thus we were left with a 2m length of granite that was around 350mm tall and 280mm wide. This worked out to around 500kg and our chain hoist was only rated to 500kg – it seemed a close-run thing whether it would survive the lift. We built a bay of scaffolding over the fireplace, with three scaffold boards on edge above the lifting point to support the hoist. We manoeuvred the lintel using our stone trolley and rollers half onto the foundation, the idea being that we could lift the lintel and, once at height, simply rotate it round to rest on the quoins. We could then shuffle it precisely into place. And this is exactly what happened. The chain hoist survived, although we built columns on concrete blocks underneath the ends of the lintel as it went up, just in case. We got the lintel lined up with the quoins, horizontal across the opening and with a vertical face. Then we removed the concrete blocks and scaffolding and were able to press on with floor insulation. We will not be tripping over the lintel any longer!

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Building up the front door

The front door area had concrete blockwork on the left side tied onto existing rubble wall. The right hand side had been completely demolished, so was just concrete blockwork up until it met the north-west gable wall, which had also been demolished but had the concrete blockwork up to the height of the upstairs window sill. The gable wall is set 20cm forwards of the front door wall.

Stonework
We worked courses along both sections of wall, one per day. We used our best red Peterhead granite quoin stones rescued from the former (now demolished) farm house on the next-door plot. We kept the stones symmetrical either side of the front door, but generally used bigger stones on the gable wall, so it got higher more quickly that the front door. We put five courses up and had reached lintel height for the garage door, but added another course to the front door to get it to the same height.

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Front door lintels
The front door lintels were the same as our other windows, but longer – a third concrete structural lintel in front of the two over the concrete blocks, then the decorative granite lintel. We filled the gap with concrete. So we are now able to build the concrete block raised wallhead above the front door and put the remaining roof trusses on.

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Christmas 2018

We had a couple of jobs in mind over Christmas/New Year. Firstly, to get a load of our possessions up and stored in our immediate neighbour’s large shed/garage. Secondly, we want to temporarily board up windows and doors in the north and east wings, so that as the roof goes on we can start to dry them out and create a reasonably protected working area. 

As it happened the weather was unseasonably warm, still & sunny, so we got a small stretch of wallhead blockwork finished and the missing sarking board over the east wing trusses. So it did turn out to be a quite productive visit. It has knocked a week off our schedule for when we move up permanently in April 2019. 

We got a Christmas bonus – our replacement big lintel, for the garage door, was waiting for us nine months after we ordered the original! 

North wing windows & doors

The north wing has two doors and three windows on the south wall. The doors are missing their decorative granite lintels, but are otherwise good to go. The three windows have sills, one already has quoin stones  and I got another window partly built up, before we headed south. All three are missing granite lintels. The north wall has two windows and what will be the front door. Both windows have sills, one has quoin stones, both are missing the decorative granite lintel. The front door is still only blockwork with a pair of concrete structural lintels in place, otherwise it needs the full works – sill, quoin stones, stonework to either side of the quoins, an extra concrete lintel and the granite lintel.

These all need sorting before we can finish the raised wallheads and get the rest of the north wing trusses on. Having got so far with the sarking on the east wing roof, Ric set out to do as much of this as he could before he finishes in the second half of October.

South wall: He completed the quoins in the window I started and in the remaining window on the south side. He finished them both up to lintel height, added the extra concrete lintels, then put granite lintels over all five openings. Three of the openings already had the raised wallhead blockwork above them, these left 50mm of headspace to lower the lintels down into their sockets. Ric used the eletric hoist and the cradle for lifting blocks. He rested the granite lintel at the end of the cradle and lifted it up as delicately as possible. He found he was able to get the lintel to height, then lift it up a small enough amount to slot it back into place. Neat. For most of them, he was even able to fill the gap between concrete and granite lintels with concrete, from above. The door at the east end was more of a problem because it had trusses over it and Ric had fixed the fascia board in place. He ended up squirting foam up into the gap. Once this had all gone off enough, he filled in the gaps in the raised wallhead, meaning that side is ready for the rest of the north wing trusses!

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Moving trusses: We had no real choice at the time but to rest our north wing roof trusses against the north wall of the north wing. The only place with enough space was right in front of one our incomplete window openings, meaning Ric could not work on it without moving the trusses. He did the manful thing. He cut the birds-mouthes (the cut-outs on the rafters that rest on the wallplates) on every single raised tie and trimmed the end of the rafters to approximate length and shape. He lifted the trimmed trusses over the wall and stacked them inside. He got them as vertical as possible and left them in three groups down the length of the north wing, securely strapped to the wall. Given the amount of ladder-climbing and the fact that the scaffold tower is a complete pig to manouver, this could not have been a fun job. However, we did then have the north wall clear to finish doors and windows!

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North wall: This left Ric a couple of days to do what he could with the windows and doors in the north wall. He got the granite lintel over one window, then installed the granite threshold for the front door and laid the first quoin stones. The front door is close to our newly constructed blockwork for the gable end we demolished last year and we will have to do the stonework for both areas together. The gable end projects 220mm out from the line of the north wing, so he fitted the first quoin stone at the junction of the walls. Hopefully, Ric will get the remaining window up to lintel height, so that next spring we will only have to get the front door stonework completed, then fill in the gaps in the raised wallhead. I expect we will run the stonework at the same time onto the gable end as far as the garage door.

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At which point, we can get the rest of the trusses up! This should be comparatively quick and easy since all trusses are at 600mm centres, the wallheads are parallel and they are the right distance apart. We do need to trim the concrete blocks to make room for the bottoms of the rafters and let the birds-mouths rest on the wallplate. Putting sarking on should also be a little quicker than on the east wing, because the 600mm centres will mean less cutting boards to size.

More windows, blockwork and rubble walling

Alongside building the bathroom window opening, we worked on the remainder of the east wall of the east wing,. We had decided that the southern-most of the three windows in the wall would use our complete set of splayed quoins stones i.e. where the window opening widens out towards the back of the wall. This will be in the room with the gallery and the large (3m x 3m) south-facing window.

We did not know exactly what space the quoins needed, so had not laid the backing course of concrete blockwork at that end of the wall. They have a lip at the outside face, with the window being fitted at the back of the lip. Because the stones were rather roughly finished, it was not clear what the angle of splay would be, until we installed them. So we laid sills in the second and third window openings, then laid the first pair of splayed quoins. I guessed the angle of splay and laid concrete blocks back to the inside edge of the wall. The following day, we laid the next pair above, I had not been not too far out – I laid a fillet of block on one side, to line up with the second quoin, the other side needed no adjustments. As the third and fourth quoins went on, it all became much more clear and I was able to lay the concrete blocks up to the height of the lintels and paint on the synthaprufe. Ric worked on the middle window to keep pace. We laid the remaining concrete structural lintels and the outer granite lintels on both openings, I then finished the concrete blockwork right up to original wall, painted on the synthaprufe and filled the gaps behind the granite lintels with concrete.

And that was my time used up, I had to head south again. Ric stayed on for another two weeks to finish of the east wing wall and then do what he could on the north wing.

Our first home-grown window opening!

Having got our bathroom window sill in place, I got going on forming the window opening. We had decided a while ago that all three windows on this length of wall would use red Peterhead granite quoins. I levelled up the granite walling to just above sill height, picked my first two quoin stones to match the coursing of the rubble wall and trimmed the corners so that they overlapped the sill by 30mm each side and lined up with the concrete blockwork at the back of the wall. I laid them in lime mortar and pinned them in place. It was quite straightforward to build the quoins up, alternating the direction they lay (along wall, across wall, along wall etc.), four courses each side. The door frame will be set back from the outer wall face by 215mm, less the length of projection of sill over wall face, less the length of overlap of frame onto the back of the sill. This is around 150mm and any gaps behind that we could fill out with concrete block, to save stone. I built back from the quoins to original wall as I went, to stabilise the whole thing.

I left the quoins a day for the mortar to go off enough, then Ric cut the third concrete structural lintel (the other two were already in place supporting the concrete blockwork) and the outer granite lintel and lifted them into place, with a gap between them. I made a wooden framework to fit under the window, wedged it in place then filled the gap with a dryish concrete mix. I tied a luggage strap around the two lintels and wedged a stone in the top between the lintels, to hold everything in place until the concrete set. Which it did by the following morning. And that was our first self-constructed window opening. There are already 5 pre-existing window openings, but it was still a great feeling to do our own!

Our first home-grown window sill!

Getting our granite lintels delivered was quite a turning point for us: We cannot get our roof trusses installed until we rebuild our walls; we cannot rebuild walls without getting windows and doors formed; we cannot form windows and doors without sills; we could not make sills until the lintels arrived. Our building warrant had specified concrete sills – this did not appeal to us at all. Ric convinced us that we could convert lintels into sills without too much effort & cost. So as soon as we got the lintels, Ric got to work. He used the bathroom window, in the east wall of the east wing, to test out his ideas…

1.  He cut a 1.6mx212mmx100mm lintel to the width of the window + 50mm.
2.  The sill has to slope forwards to shed rainwater, Ric used the angle grinder to trim the front face to be vertical once the sill is in place. He used the bush hammer on the sawn front and ends to get a suitably rustic roughened finish.
3. He used a simple wooden jig to guide him using the angle grinder to score irregular lumps on  the base to a level and used the medium breaker with a chisel tip to clean it up.
4. He trimmed the front of the underside to be horizontal once the sill is in place, then cut a groove along the length, as a drip-line.
5. I installed tanking membrane over the base of the window opening. This was laid on a single coat of primer and run down the inside of the wall by a few cm. We need to tank the lower metre of the wall (and 1.5m of floor) before we build the timberwork to hold the wall insulation, we will run the tanking up and overlap onto the window tanking, to make a continuous barrier to water.
6. I used a 6mm double-sticky-sided foam strip to create a cushioned base to lay the sill on. We laid five strips down the sill area, doubled up to 12mm.
7. We placed the sill over the adhesive strips and adjusted it to be horizontal along the length. It had a sensible slope downwards.
8. I cut three lengths of 25mm x 1mm galvanised steel strapping, drilled holes in the back of the sill and into the top of the concrete behind the sill, then screwed the straps in, to stop the sill being able to slide forwards.

And that was it. When we get round to it, we will squirt foam under the sill to seal it and spread the loading on the sticky foam seals – although I was rather surprised that it really did not compress a great deal under the load. The window frame will lap over the back of the sill by a few cm, we have plenty of space behind to run insulation and the window ledge under the rest of the window frame.

Lintels – good news and bad news

I had badgered Lantoom Quarry about making sure the 41 granite lintels would arrive at our local builders merchants, Ellon Timber, the day I arrived. They had been vague, saying they would tell me if there was a problem, but not confirming they had despatched them. So the morning after I arrived at the steading, I nagged Ellon Timber and again got vague suggestions that granite lintels may have been dropped off. In the end I got fed up with vagueness and drove across to look.

There were indeed granite lintels – 18 lintels on two pallets, making up one consignment. I got on the phone to Lantoom and invited them to find and deliver the remaining 23.

Meanwhile I got Ellon Timber to deliver what they had, as soon as possible. They got on site the following day. I checked what was delivered with what we ordered and was heartened that all the odd-sized ones had been delivered, except for the 2.7mx300mmx150mm garage door lintel. So what was missing was that one and 22 of the 1.6mx212mmx100mm lintels.

Lantoom got someone on the case, they sent me a list of what they thought was missing. It was nothing like my list, which I sent back. The following day then emailed me to say that the missing granite was in Liverpool, would be sent up and that they hoped it matched what I was expecting! It arrived at Ellon Timber after I had headed south again. I expect it to arrive at the steading imminently.

What mattered, though, was that there were enough lintels of the right sizes to crack on with the east wing.

The new granite was sold as ‘silver’ in colour and it is noticeable paler than the grey Aberdeen granite. It is rather harder and is good quality, with a definite ‘ring’ to it. Even thin offcuts are remarkably tough. We do not forsee any problems bearing the weight of rubble wall above them. In the case of the big garage lintel, we will lay our second steel Catnic above the granite lintel anyway, so that it does not bear the weight of the wall directly. We expect the new granite to weather and blend in with the old – we already have quite a bit of red Peterhead granite that will be mixed in with the majority grey Aberdeen granite – when dry it is not strikingly and obviously different. When wet we might get a more distinct effect with the three colours of granite, I sort of look forwards to finding out!

The lintels were delivered in their natural split state with unfinished, irregular surfaces. They were accurately correct in length and height but not necessarily a regular thickness. The 100mm lintels were consistent to a cm or so, but the 150mm ones varied between 140mm and 180mm. The latter are mostly for door thresholds, we can accommodate the different thicknesses because they will be bedded onto concrete. We are going for a rustic effect and will not level out the irregularities.

First door and window reconstructed!

We bought lintels and sills on the assumption that there were none on site – we were not there at the time we ordered, and were not sure about the state of the few that were still in place.

It turned out:

• There are doors at opposite ends of the courtyard, one has a sound lintel in place, the other we had taken down and preserved. The latter has an adjacent small window, that had a rough sill (not projecting out at all) already in place and another suitable lintel in storage.
• The one remaining upper-storey window, in the north-east gable-end, has a sound lintel. We replaced the rotting timber internal lintel with concrete ones whilst we were tidying up that gable-end.
• We think there are two other lintels that we removed, that can be re-used.

We chose to use the courtyard door + window as the first openings to re-construct. One door pillar, immediately out from the corner where the north and east wings connect, had been demolished, for safety. The other door pillar is sound and forms one side of the window surround. The other side of the window and the sill were also sound. The backing blockwork was all in place, we painted on the three coats of bitumen-based DPC and let it dry out. Ric then built up the missing door pillar cutting quoins to fit into the existing stonework and tying it in with the strips of expanded stainless steel mesh previously set into the concrete blockwork. He stopped about halfway-up on the first day, to let the mortar go off a bit, and restarted next day.

We left it a couple of days further, then used the chain hoist to lift the window lintel up first, then the door lintel. There was a gap between the granite lintels and the two concrete structural lintels set into the concrete block work. We shuttered the gap underneath and poured in medium strength concrete.

And that was it, apart from completing the stonework above the lintels to the old wallhead height – we did that as a training exercise. Beyond that we can then block above that to new wallhead height, ready for the roof.

Fireplace

Our building warrant allows us to install a wood-burning stove in the steading, halfway down the north wing. We have even laid in an air pipe, under the slab. The idea is to use it as a second source of heat for the under-floor heating (to supplement the heat pump) and hot water (to supplement the PV panels), as well as to heat the room it is installed in. Given the high levels of insulation in the building, we need much more heat going in to water than out into the room. We have abandoned the original idea of a double-facing stove to heat both the dining/living room and kitchen/family room – there is only one model that also heats water and it gets bad reviews. There is at least one model of well-rated single-faced stove that will put 12kW into heating water and around 3kW into the room – probably about right for us.

The plans show a rather modest stove surround and chimney breast.

Serendipitously, we are in a position to go for something much more impressive. We rescued a 2m lintel from over the large original opening in our garage area. We toyed with using it over our front door, however it is really too high and deep and is rather rustic, with two good faces and two rough faces. Ric suggested instead that we use it for our fireplace. The idea has taken hold. We spent several days umming and ahhing about designs and will probably do the following: 1) use the lintel over the fireplace, with the wide good face forming the front, 2) we have the option of using the good narrow face as a mantel shelf, in which case the stonework above would be stepped back appropriately – this is controversial so probably will not happen, 3) we will support the ends of the lintels on stone blocks selected from our quoin stones – either around 30cm wide or 35cm wide. The lintel is grey granite, most of the quoin stones are red. From this point on we have not worked out what we want. We will make the chimney breast some 900mm deep, between 1800 – 2000m wide. We will need to decide how high we want the lintel and how much stonework is exposed. Ric suggested exposed stone to the ceiling, we are not so keen: we found a steading on the ASPC website that had exactly this and it was too overpowering- our ceiling, for example, will be over 3.5m above floor level.

We will build the stonework directly on the floor slab, with concrete blocks to bring it up to final floor level. We probably need to start building it all before the roof goes on, because we will need scaffolding in the upper reaches. We moved it in through a door opening with the digger, onto wooden rollers on the concrete slab. We then rolled it more-or-less into position…

While we think this all over, I started to clean up what would be the lower surface of the lintel – it is quite uneven and rough. We used the angle grinder to cut notches every 10-15mm and used the medium breaker to chip the leftovers out. This has left a stripy surface. I tried a hand tool with a carbide tip and club hammer, to even out the surface, but it was hard work. I will buy some narrow chisels to see if we can level up the surface better than with the wide one. We also have a bush hammer on order, that may help finish the surface.