Due to lack of time three structural items were not completed :
Addition of Struts:These are the pieces which brace the King Posts back to the main ties. They occur only on the two internal frames. They should be rebated into the posts and ties as shown on drawings DH01(A) & DH02(A) Sections B-B & D-D .
Addition of Skew rafters:These are the pieces which run diagonally from beneath the main ties outwards to the wall plates. For purely structural reasons they are not necessary. However, they were included because, firstly, they occur in the Bedesworld example, and, secondly, because they give a very graphic illustration of the structural function of the frames in tying the wallplates back to the main ties. However, they will be difficult to build. Peter and Axel will have to weigh up the pros and cons in order to finally decide whether or not to include them.
Protection of post bases:Unfortunately none of the timber buried in the ground was soaked in pine tar. It is nonetheless vital that these parts are protected because they are buried in ground which is heavy and not free draining. Unless it is treated the timber will rot and this will happen most quickly at the junction between the ground and the air. Various means of protection were discussed.
Pine, or birch, tar, is not a possibility because the wood needs to steep in it.
One possibility is to excavate to about 15cm below finished floor level and then singe the bases of the posts using a blow lamp to form a collar of carbonised wood. After that the excavated earth would be backfilled taking care to reinstate the layer of stones which separates the bottom of the wattle and daub walls from the ground. Another possibility is to excavate as above but to pack the post bases right round with lumps of charcoal from the local factory. This would serve the same purpose as singing, so the charcoal would have to be tightly packed.
Excavation to finished floor level:Loose top soil will have to be removed down to a level where the ground can be compacted to form a dense floor. Danish experience indicates that this will require the removal of up to 10cm . Floor finish:Various possibilities exist for floor finish. Compacted earth is one; stones driven into the earth to form a reasonably smooth stone pavement is another.
Completion of wattle and daub walls:When we left most of the wattle weaving on the external walls had been completed. Depending on the weather it may now have been finished by the students. Still to do is all the wattle weaving on the two gable ends and on the internal partition; plus, 100% of the daub.
Windows & Vents:It was agreed that the two window openings on the near gable, i.e., those serving the larger compartment in the house which would have been occupied by people, should have timber shutters with a clear central vertical emphasis continuing the line of the king post above and the central wall post below. These shutters can be top hinged so as to swing up and in by means of ropes, or let down when the building is closed. At the far gable, above the smaller compartment occupied by the animals, it was agreed that the window openings would be filled with woven wattle but without daub. It may be possible to make the shutters in Ribe over the winter.
Doors( two required) : Again, it may be that these can be made at Ribe. If not, then I can ask the Galgaels if they’d be prepared to make them.
Fixing of rafters:With the exception of four edge rafters all the rafters remain to be fixed. They should be located at not more than 80cm centres , and preferably less - and notched over the purlins and the wall plates and fixed with one oak nail at each purlin and each wall plate. Nails should be as large as possible in diametre without splitting the wood. Probably The rafters should extend beyond the finished surface of the walls to give a minimum overhang of 40cm. Also important is to ensure the use of tilting fillets at the rafter ends.
Removal and replacement of Wind Bracing:The wind bracing which is currently on the building is temporary. It should removed before the rafters are fixed and should be replaced below the rafters using timber sections of about 10cm diameter as shown on the drawing.
Fixing of battens:As shown on the drawings it is anticipated that the battens will be tied to the rafters using strips of cow hide about 7mm wide. These strips will have to be cut from the hides already there and Anders’ experience is that the only way this can be done is using a cutting machine. It cannot be done by hand.
Overhangs:The minimum permissible overhang of the thatch forward of the finished wall surface below is 35cm. This applies to both gables and walls. Because the wall plates are not long enough at the gables the overhang of the edge rafters is only about 18cm. This will be increased to 22.5cm by the addition of the barge boards, but the thatch itself should project a further, say, 15cm to achieve an overall overhang of 37cm. This is very important in order to protect the vertical gable or wall surfaces from water damage.
Thatching:Professional thatchers will have to be employed for this. Apparently Ribe has some. Libby also knows of two working in Perthshire. Once the thatchers are known, it will be necessary to go over the techniques employed for fixing the battens, tilting fillets etc. with them, in order to ensure that they will be compatible with the techniques used by the thatchers.
The most important conclusion is that Parabow has access to resources and expertise which can build buildings from scratch. There are a number of other conclusions which Parabow may wish to consider with a view to future ventures:
Having got this far, it is vital that the Saxon building is completed. All the collaborators should maintain pressure in order to ensure this.
On the basis of this project, and the earlier one in Iceland, the projects should last more than ten days, if possible. An optimum length of time would seem to be 17 days, or a week longer than what we’ve been used to.
When I originally sized the timber sections used at Authausen, I feared that I may have oversized them. This is not the impression I got from the drawings however, and having now seen them “insitu” my feeling is that, if anything, they should in some cases have been larger. I think this applies particularly to the wall plates.
In saying this it is important to realise that part of the problem lies in the irregularity of the timber, which may be the section size as specified for a small part of its length, but actually be less, sometimes considerably less, than its specified size for most of its length.
This in turn comes back to the quality of the timber, which , as used at Authausen, was not particularly good.
The conclusion would seem to be therefore that specified timber sizes should generally be on the large side, and that the poorer the quality of timber is likely to be, the larger the specified timber sizes should be in order to compensate for irregularities in section sizes.
Graham Wylie. Architect. 23rd November 1999.Glasgow, Scotland.