Chris and Shona Scatchard from Caithness have spent the last few years experimenting with building roundhouses inspired by Iron Age examples, using the materials available locally. Chris has kindly put together this inspiring piece about his experiences!
There have been many attempts to reconstruct Iron age roundhouses by archaeology groups and other enthusiasts, but because so little of the original structures remain (usually just post holes, fire pit and rain gully), the reconstructions are based on best guess and expert speculation. I do however, believe that we can be sure of one thing, the roundhouses of the period would have been built out of the most abundant, workable local resources, be it stone, trees, reeds, turf, wattle and daub etc., and therefore subtly different from area to area across the country.
A few years ago, on the cusp of my retirement I purchased a rundown Croft in Caithness. Facing out over the Moray Firth and North Sea, just a few hundred meters back from a 65-meter cliff, it is exposed to say the least! But, with a miniscule budget, a desire to be environmentally friendly and to do it all by hand, I turned to a book by Tony Wrench “Building A Low Impact Roundhouse”, in which he built a sustainable off-grid roundhouse in Wales in 1997.
It must be said, the book is not a blueprint for roundhouse design, rather a story of experiences, ideas, pitfalls and successes on his journey which, if you have an interest, should inspire and set your creative juices flowing!
Local materials for me to build with are STONE, Caithness provided many cities of the world with flagstone in the 18th century, in fact, many of the older farms in the area still have flagstone fences and rooves, and for every spade full of soil you dig here you’ll have moved 3 of stone! LOGS, from Dunnet Forestry Trust just 15 miles away, all windblown plantation pines (Sitka, Lodgepole and Corsican Pine), cut by volunteers. FIELD RUSHES, hand cut and baled from our own fields. TURF, again from our own fields.
I decided to build one henge of logs (most reconstructions have two based on a double ring of post holes in many excavations) and erect atop it a reciprocal framed log roof structure, this was so I didn’t require a centre pole allowing maximum span within, and for a turf roof the pitch is lower benefiting growth of the grass. I also decided to build a full ring of dry stone wall between and around the henge for strength.
Having cleared an area of ground and marked it out with an internal area of 3.5-meters, I proceeded to de-bark the 2 meter henge uprights (all about the thickness of a large thigh) and bitumen paint the lower quarter which would come in to contact with the soil. Of course, in excavations from the iron age there is evidence to show that they quite often burn the surface of wood to charcoal because it not only resists rotting but is also waterproof, but for me, building alone, modern techniques saved time! And in time, I will know which method worked better.
The 9 henge uprights were set about a foot in to the ground and supported with large foundation stones for the dry-stone wall. If one builds on the surface, temporary braces are required to keep the structure stable until the henge tops go on. The uprights were about a meter apart (slightly more for the doorway), but I found it very difficult to be more precise due to the uneven thicknesses of the logs, but this, as I have come to appreciate, is part of the beauty of working with natural timber in the round, each log has its own story in its rings and shape, each feels and acts differently when worked with saw, chisel or drill.
Next I cut logs of slightly smaller thickness for henge tops, jointed to overlap atop each upright and then secured in place, together and in to the upright by drilling a hole right through and inserting a 6-inch nail. It is most likely that iron age builders would have used thinner timbers of more flexible tree types (probably deciduous) and tied, secured them with hide, willow wands or woven vegetation like stinging nettle rope. For me, again it was about what I know based on my experiences, and the resources available. I didn’t want 2 tons of logs and turf coming down on me whilst building (or after for that matter) this somewhat experimental structure.
I had put aside a few interestingly curved timbers, one of which I used over the doorway, the jointing was challenging and enjoyable, so much so I went on to build an elaborate porch!
A word about reciprocal framed roof structures – An internet search will tell you that “the reciprocal frame has been used since the 12th century in Chinese and Japanese architecture”, however, Tony Wrench explains that, an architectural firm called “Out of Nowhere” made them popular in this country in the 1980’s.
For me, an explanation of how the reciprocal frame works is impossible, so again I rely on the internet. “A reciprocal roof is assembled by first installing a temporary support (commonly known as a Charlie Stick) that holds the first rafter at the correct height. The first rafter is fitted between the wall and the temporary off centre support, and then further rafters are added, each resting on the previous rafter and the wall. The final rafter fits on top of the previous rafter and under the very first rafter. The rafters are then tied with rope or wire, and the Carlie Stick removed, allowing the whole structure to find its level and settle”.
I used the longest logs I could transport, 4-meters, which were sized, de-barked and groove cut so that they would safely “slot on” across the preceding log. Because I desired a large roof overhang on the roundhouse, I could use the henge as a fulcrum and manoeuvre the roof logs by myself and tie them in place with bale twine (well, what else would a crofter use?). The wall end of the roof logs was placed directly over the uprights allowing for the full weight of the roof to project down in to the ground. Removal of the Charlie Stick was a scary moment, with lots of weird noises and creaking as the structure settled on the henge. At the wall end, I again drilled right through the roof log, through the henge top and in to the upright, then hammered home a 12-inch piece of rebar. At the upper end where the roof logs cross I wrapped strip metal banding and nailed it in place, ensuring no movement whatsoever.
At this stage one is left with a beautiful ¾ meter circle in the centre of the roof made by the crossing of the roof logs. Note, the larger the hole in the middle the lower the pitch of the roof.
Next came the intermediate roof logs, placed 1/3rd of the way down the main roof logs and across the wall in the centre of a gap, secured in a similar way. After this was the outer ring. A ring of logs cut and jointed like the henge tops but going around the outside ends of the main roof logs. This becomes a retaining log to stop insulation and turf from sliding off the roof. Using every scrap of old fencing wood I could find, I cut purlins and nailed them like a ladder all the way to the top of the roof. I cut the excess tops of roof logs off and planked the hole at the top. Tony Wrench made a skylight out of an old coach windscreen for his roundhouse! Remember, self-building with natural materials allows for imagination and innovation.
The field rushes which grow abundantly on our waterlogged fields were cut and baled by hand (1ft x 1ft x 2ft bales) and covered the roof as insulation. More overkill! I have found that a thin layer of rushes is enough to protect the waterproof membrane and the turf is a great insulator on its own, however, we’re I to build an off-grid home for myself I would add full bales and more! This was followed by the said waterproof membrane and the turf cut from our fields.
Whilst all this roof building was going on, I was also collecting stone and building up the walls, but time was passing from Autumn to Winter and I quickly noticed that the dry-stone walls we’re in no way weatherproof! The wind blew like a gale through them and wind-blown rain penetrated very quickly. With most dry-stone structures like Brochs, Atlantic Wheelhouses and Blackhouses, the walls are several meters thick and stones angled downwards towards the exterior block the ingress of water. I therefore decided to finish the wall as is then fill with cement mortar, not the most environmental way but given the cold and wet of winter I didn’t think lime mortar would be viable.
After I had finished, some 8 months after starting! My Pygmy goats entered their new home called “Buffy’s Bothy”.
In hindsight: A fantastic experience but I’d recommend a group of 4 or more people build together, the risk of serious injury building with heavy logs and stone is not to be ignored! The mature grass on the roof proved to be a weed problem (Dock seeds blowing in the wind!) so a ramp to the roof allows the goats to pop up on pleasant days and keep it trimmed, much to the amusement of passing motorists and holidaymakers!
A form of shelter or lean-to had to be added to stop the vicious Easterly winds we get blowing directly in to the roundhouse, but all in all I am happy with the results.
I have gone on to build a further 3 roundhouses, each one different but all using the same reciprocal roof design, and more simplified joints. The largest 5.5 and 6 meters across are lambing sheds come hay stores and are built across field fences so with 2 gates they can be used from either field. I have clad these roundhouses with waney edged boards to speed up the building process.
In the future, I’d like to pick the brains of a thatcher and try to roof a roundhouse with the field rushes. In this case I would want a greater pitch and would be able to try a double henge where the centre roof supporting pole is cut off after the roof is finished. But for now, as a new crofter, there is much else to do!
Thanks to Chris and Shona Scatchard for this fascinating feature about their experiences constructing Iron Age roundhouses in modern day Caithness.