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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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.

Tidying the north-east gable-end

The gable-ends on the east wing are generally intact. The northern one has been neglected and had lost both retaining stones (to support the coping stones on the parapet) and four or five quoin stones on each side. Ric had fixed one side back in April/May, I did the other side as a training exercise.

The first job after measuring up and working out how many quoin stones I needed, was to create a stable shelf to support the lowest one. I chiselled out loose mortar and the grass and weeds and was able to insert a small stone to create a quoin-sized platform. Given our healthy collection of quoins, we found a set that required little splitting, cutting or chiselling to match the courses of rubble up the wall. I used a spirit level to get the quoins stacked vertically and lined up to form a sharp corner, filling the space behind the quoins with mortar and broken concrete. Part of the thickness of the wall will be hidden behind roofing, I used concrete blocks here in place of granite. Having got the four courses of quoins in place and filled out back to original wall with rubble, I left it a day to go off.

It was fairly straightforward, the following day, to lift the rather massive retaining stone into place. I hoisted it onto the scaffolding, rolled it across the boards, moved the hoist to just above the quoins and we were able to lift it into place really quite precisely.

The parapet is to be around 250mm thick and 100mm above the finished roof, we will leave rebuilding it until the trusses are in place and we are definite about final roof level. The remaining 200+mm on the inside edge of the gable will be covered by sarking boards extending from the last truss, with the slates flashed into the parapet. I ran concrete blocks up the inside edge of the gable, a little below expected truss top chord level.

It was a relief to get the retaining stone back in place and it makes the gable end look a whole lot better.

July visit

I was at the steading for a full week in early July, with Ric. The aim was to prepare for our September visit, where we want to get roof trusses up on the east wing and, if practical, part of the north wing.
To summarise where we are with the east wing…

• West wall (facing the courtyard): We rebuilt the doorway and installed lintels over the door and small window in April, then built rubble wall above the lintels to old wallhead height. We still need to lay blockwork to raise the roof to the design height.
• South gable-end: The parapet and retaining stones will need raising to the new roof height but can be done after the trusses go on. At the same time, we need to remove the stub of a concrete lintel that was embedded into the courtyard corner.
• East wall: The pre-existing doorway has been blocked out as a window and we completed the stonework up to sill height back in April. Last Christmas we opened out a section of wall to install two windows. The backing blockwork for one window is complete, the other is not blocked out because we plan to install quoins for a splayed window and do not really know how that will play out. We need to do the stonework (sills, quoins, lintels) for all three windows, complete the backing blockwork, lay the rubble walling, then raise the wallhead to the design height with the four courses of blockwork.
• North gable-end: This needs one side tidying up, replacing missing quoins and the retaining stone (for the coping). The parapet will need raising to the new roof height, but can be done after the trusses go on.

So most of the work on this block translates into:

1. Getting possession of the 41 granite lintels we ordered in March from Lantoom Quarry, Liskeard, Cornwall.
2. Converting three of the lintels into window sills for the three window openings down the east wall of the east wing.
3. Installing the sills, building quoins up the sides of the window openings and placing concrete (structural) and granite (decorative) lintels.
4. Completing the inner skin of concrete blocks up to old wallhead height, where we had demolished original wall.
5. Re-building granite rubble walling in front of the concrete blocks, around and over the window openings, up to old wallhead height.
6. Lay the four courses of concrete blocks above the walling, to raise the roof to the designed height.

Ric was confident we could do it, I was prepared to give it a shot. Being mid-year in northern latitudes, I could allow myself as long working days as I could stand – it gets light at 4am and dark after 10pm!

I brought the strimmer up with me to tame the grass, nettles, docks & thistles, but quickly realised that it was a bit late. The hot, dry weather meant that the perennial weeds had seeded and gone over already and had woody stems – strimming them would be dissatisfying and not very useful.

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.

Quoin stones, cills and lintels

With the blockwork for our new walls heading sky-wards, we must turn our minds to the decorative lintels & cills for our 5 doors and 18 windows and to the quoin stones we need for them and for the four wall corners that need to be re-built (both the gable-ends that we demolished). We have until March next year to get what we need, so that Ric can get going in April.

Terminology
I was brought up on ‘lintels’ and ‘sills’ and have found that ‘lintols’ and ‘cills’ are in common use in the area. I may not be consistent in my usage!

Structural lintels
We are sorted for these. We have already bought more than half the (concrete) window/door lintels. We will order the rest as 3.6m lengths and cut them to size. We will get a couple of steel lintels for the garage door.

Decorative lintels: The existing ones are a mix of concrete, granite and wood (which are still in very good condition). Many of the granite ones had cracked, I believe we have six which can be re-used. Our 3m x 3m big window in the east wing will keep the current concrete lintel, so we need to source 17 new ones, typically 1.2 – 1.8m wide, 200mm tall and 100mm deep. The new garage door will have a steel lintel with a shelf to support a decorative lintel, this would need to be 2.7m, although I did hear of someone using two shorter ones and covering the gap with an ornamental crest.

Our building warrant assumes granite lintels. We may have some big-enough loose pieces of stone on site. Otherwise we need to look around – a problem when we are down south. For example, I contacted someone on Gumtree who has a pile of granite from a demolished building in Aberdeen, he did not have much of an idea whether it would be suitable, we need to go and look. We also found someone with lintels they wanted to sell for hundreds of £ each. We will do what we can.

If we run out of time, we will look at cast granite i.e. granite that has been ground up and reconstituted with a cement binder. Inverurie Precast Ltd, for example, make a full range of products, we may need to go and see them. My concern is that most cast stone products are highly and precisely shaped and finished, where we would want something rather rougher.

Cills
Our warrant calls for concrete cills, this does not appeal. In fact we have had a look around, they do weather in quickly and once lichen starts spreading, it is not obvious that they are concrete. But we are still not keen. Ric wants to use granite and to saw and finish our own, again we are short of suitable pieces. We have none in the few remaining windows, there may be a few on site. As with lintels, if we can find stone locally, we will do so, otherwise we will look at cast stone.

Quoin stones
At one time we were short of quoin stones. We saved all the ones from the walls we demolished, but we have eight windows, one door and the garage door to form.

We bought a pile of granite from our neighbour, Mr Aitken, two years ago, without worrying too much what was in it. We had nagged George to move them onto our property, to no effect, so we got Ric to do so back in August. It took him a day-and-a-half and was a bit of a revelation. The pile was mostly quoin stones, probably over 100 of them. They are better finished than most of ours and quite a few are Peterhead granite, so we do need to do our best to blend them in with our rather rougher ones. There were several longer pieces of stone which will probably not be long enough for lintels, but may make good cills.

The main pile is just about cleared, a second pile is behind the logs

Some of the quoin stones from our neighbour