Średniowieczna więźba dachowa nad nawą środkową katedry w Kamieniu Pomorskim w świetle badań architektoniczno-dendrochronologicznych

Ulrich Schaaf, Maciej Prarat, Tomasz Ważny

doi:10.37190/arc220401

Streszczenie

Średniowieczna więźba dachowa nad nawą środkową katedry w Kamieniu Pomorskim w świetle badań architektoniczno-dendrochronologicznych. Tematem artykułu jest konstrukcja dachowa nad nawą środkową katedry w Kamieniu Pomorskim. Istnieją wprawdzie liczne opracowania odnoszące się do dziejów budowy tej świątyni lub do rozwoju historycznych więźb dachowych ogólnie, ale w żadnym z nich nie uwzględniono omawianych w tej pracy więźb dachowych. Sytuacja ta oraz konieczność naprawy konstrukcji uzasadniły wykonanie badań architektonicznych celem rozpoznania jej historii budowlanej oraz techniki ciesielskiej. Badania zastanej substancji materialnej przeprowadzono we wschodnich wiązarach, uwzględniając następujące aspekty: strukturę nośną, strony odwiązywania, złącza ciesielskie, system ciesielskich znaków montażowych, budulec i jego obróbkę. Rezultaty tych analiz uzupełniono i skonfrontowano z wynikami badań dendrochronologicznych oraz przedstawionymi w literaturze przedmiotu. W wyniku tych badań udało się ustalić, że nawę środkową katedry kamieńskiej zwieńczyła pierwotnie więźba wolna ze ściągami, która pochodzi z początku lat 60. XIV w. Została ona wzmocniona w końcu lat 60. XIX w. przez dodatkowe belkowanie powyżej strzałki sklepienia, konstrukcję stolca leżącego oraz konstrukcję wieszarową. Kolejne wzmocnienia nastąpiły fragmentarycznie już w ramach trwającej od końca drugiego dziesięciolecia XXI w. naprawy. Mimo wiekowości i napraw pierwotna konstrukcja przetrwała w dużym stopniu. Zastosowany w Kamieniu Pomorskim typ konstrukcji dachowej – więźba wolna ze ściągami – służył w okresie średniowiecznym do konkretnego zadania budowlanego – wykonania dachu nad sklepieniem wchodzącym w jego obręb. Wstępny przegląd literatury przedmiotu wykazał, że przykłady takich rozwiązań przetrwały w różnych częściach Europy do dziś, ale tylko w małej liczbie. Z terenu Polski jest to póki co jedyny znany taki przykład z XIV w. Badaniami architektonicznymi objęto obecnie pozostałe więźby wolne ze ściągami katedry, nad oboma ramionami transeptu i prezbiterium. Warto pokusić się o przygotowanie szerszego studium na temat tego typu więźb średniowiecznych oraz próbę zestawienia więźb katedry kamieńskiej z więźbami z innych miejsc.

Podgląd pełnego artykułu jest możliwy wyłącznie na większych ekranach.

2022

4(72)

Ulrich Schaaf*, Maciej Prarat**, Tomasz Ważny***

The mediaeval roof structure over the nave

of the cathedral in Kamień Pomorski

in the light of architectural and dendrochronological research

Introduction

The subject of this article is the roof structure over the

nave of the cathedral of St. John the Baptist in Kamień

Pomorski.

Numerous scientic and popular studies have been

written on the history of the construction of the cathedral

in Kamień, but none of them discusses roof structures, ei-

ther in the context of their construction history, or in the

context of the applied carpentry art [1]–[6]. Only the build-

ing survey drawing included in Ohle’s works shows the roof

structures in the following sections: longitudinal through

the transept facing east, longitudinal through the transept

facing west, transverse through the nave, and longitudinal

through the entire cathedral facing north [5, Figs. VII, X,

XI, XVI]. The roof structures of the cathedral in Kamień

have not been included in the literature relating directly to

the history of mediaeval and modern roof structures

This research gap and the need to repair the roof struc-

ture over the nave body of the cathedral became the rea-

son for the carrying out of architectural history investiga-

tion in order to learn thoroughly its history of construction

and the construction techniques used in various periods.

Owing to the advancement of repairs that had been going

on for several years and the related replacement of many

* ORCID: 0000-0003-3055-1009. Faculty of Fine Arts, Nico-

laus Copernicus University in Toruń, Poland, e-mail: u.schaaf@umk.pl

** ORCID: 0000-0001-7076-2009. Faculty of Fine Arts, Nico-

laus Copernicus University in Toruń, Poland.

*** ORCID: 0000-0001-6641-0131. Faculty of Fine Arts, Nico-

laus Copernicus University in Toruń, Poland.

The roof structures of the Kamień Pomorski Cathedral are not

mentioned in works dealing with the history of roof structures in Poland,

e.g. in studies by Raczyński [7], Ganowicz [8], or in works relating to

a wider area, e.g. in the publications by Ostendorf [9] or Binding [10].

structural elements, the architectural research focused pri-

marily on the last ten eastern trusses not yet covered by

conservation works (19–28).

The substantive extent of the research included: rstly,

the analysis of the carpentry technique used to build and

repair the roof structure (the following were taken into

account: the arrangement of structural elements, timber

framing sides, carpentry joints, a system of carpentry as-

sembly marks, and building material and its processing),

secondly – chronological stratication on the basis of ma-

terial analysis of the substance and literature, as well as

dendrochronological research, and thirdly – an attempt to

determine the signicance of the mediaeval roof structure.

The test results are presented below in the same order.

Analysis

The nave of the cathedral is crowned with a cross-braced

collar beam roof structure. It consists of 28 trusses with

a span of approximately 13 m, a height of approximately

10 m, and an inclination angle of approximately 58°. The

axial distance between the trusses varies from 0.93 m to

1.23 m. The trusses with tie beams (two each time) are locat-

ed above the inter-span buttresses of the cross-ribbed vault.

The remaining trusses between them (from six to seven)

are devoid of tie beams, i.e. they are free trusses because

the vault apexes reach above the level of the tie beams.

Architectural studies have shown that three additional

construction units were added to the cross-braced collar

beam roof structure: rst, the entablature slightly above the

rise of the vault, second, the inclined standing queen post

structure, and third, the king post structure. The entabla-

ture is carried by short studs based on the original internal

wall plates. Two frames with inclined roof strengthening

structures rest on this entablature and support the lower

DOI: 10.37190/arc220401

Published in open access. CC BY NC ND license

4 Ulrich Schaaf, Maciej Prarat, Tomasz Ważny

collar at their connection to the rafters. Together with

posts and passing braces, some of these beams constitute

the trusses of the king post structure. The entablature is

suspended from its central longitudinal frame of the king

post structure. Neither the position of the secondary en-

tablature nor of the king- and queen-posts coincides with

the location of the primary roof trusses of the cross-braced

collar beam roof structure, as they are always located next

to it.

The results of the detailed analysis of the eastern truss-

es (19–28) were discussed separately for the cross-braced

collar beam roof structure and separately for the second-

ary entablature with frames the inclined standing queen

post structure and the king post structure.

Cross-braced collar beam roof structure

1. Primary characteristics of cross-braced collar beams

• Structural layout

In the principal rafter trusses (19, 20, 27 – Fig. 1),

the tie beams rest at both ends, each time on two wall

plates lying on mural crown of the outer walls of the nave.

These tie beams are connected with rafters with a length

of about 12.50 m, which are supported by two rows of

collar beams. The almost vertical down braces connect the

tie beams with the rafters roughly in the axis of the inner

wall plates and stien the trusses in the lower zones. Long

intersecting passing braces form additional stiening and

at the same time support the rafters. They connect to the

rafters just above the tie beams, intersect with the pass-

ing braces, the lower collar beam, and with each other,

and end at the opposite rafters approximately halfway be-

tween the lower and upper collar beams. Paired common

rafters (Fig. 2) dier from the principal rafter trusses only

in that instead of the continuous tie beam there are two

sole pieces.

The layouts of the structural elements are repeatable

both within principal rafter trusses and paired common

rafters. However, some dierences have been observed in

the angle of inclination of the intersecting passing braces

and at the level at which they connect with the rafters.

This fact suggests that the carpenters did not use the 1:1

scale pattern when connecting the passing braces with the

rafters on the carpentry platform.

The longitudinal stiening of the roof structure was

provided by oblique wind braces attached to the rafters

at the bottom.

• Truss framing side

Architectural research has shown that the examined

trusses (19–28) were set/mounted in such a way that the

side on which the trusses were framed is now the eastern

side

. On this side, in each truss, the structural elements

are in one plane, and the dierences in cross-section are

noticeable only on the rear side. The lap joints are also

visible from the framing side; from this side wooden pegs

were driven into the joints and the elements were provided

with carpentry assembly marks (Fig. 3a).

• Carpentry joints

Three types of carpentry joints were used to connect the

individual elements of the roof structure to each other: cogged

joints, lap joints in various variants, and bridle joints.

Also in the case of trusses 8–18 not included in the survey the

eastern side is the timber framing side, while in the case of trusses 1–7

it is the western side.

Fig. 1. Kamień Pomorski,

cathedral, roof structure

above the aisle,

principal rafter truss, No. 27,

analysis and stratification

(elaborated by U. Schaaf,

M. Prarat)

Il. 1. Kamień Pomorski, katedra,

więźba dachowa nad nawą,

wiązar pełny, nr 27,

analiza i rozwarstwienie

(oprac. U. Schaaf, M. Prarat)

ThemediaevalroofstructureoverthenaveofthecathedralinKamieńPomorski 5

The tie beams and sole pieces are connected with the

wall plates by a single cogged joint.

The rafters are connected with the tie beams and sole

pieces only by a straight lap joint secured with two wood-

en pegs, while the tie beams and sole pieces have no pro-

trusions. A scarf joint bridled was used to connect the raft-

ers in the ridge.

Both the lower and the upper collars connect to the raft-

ers by a notched pegged lap joint. It is a stopped lap joint,

but its front side ends in a slightly arched cut in front of the

rafter’s edge. This shape does not full a structural function,

but a decorative one, showing the skills of the carpenter.

Down braces were connected at the lower end to the

tie beams and sole pieces by single or double dovetail lap

joint. The joint itself is secured with a wooden peg, and

the sole pieces have short protrusions. At the upper end,

the down braces reach the rafters with which they are con-

nected with a notched pegged lap joint. As with collars,

the lap joint is stopped. Moreover, the upper edge of the

lap joint is slightly bevelled with respect to the angle of

inclination of the down brace.

The intersecting long down braces are connected at their

lower end with the rafters in the same way as the down brac-

es are, i.e. with the notched stopped lap joint. The front side

of the lap joint of the overlay is either curved or straight-end-

ed. Passing braces intersect with down braces using straight

pegged lap joints, with the lower collar using a cross lap

(which additionally strengthened the transverse stiening).

The long intersecting passing braces and the lower collar

intersect also with each other again using a straight lap

joint or a notched joint. At the upper end, the passing brac-

es are connected with the rafters using stopped lap joints

of various shapes. There are, inter alia, the following forms

of lap joint: dovetail, half dovetail, half dovetail with a notch.

The auxiliary lines during the creation of carpentry

joints on the carpentry platform were made with a stylus,

with traces preserved in places.

• System of carpentry assembly marks

All the examined trusses were marked in one direction,

from the west to the east. Marks making it possible to dis-

tinguish elements on both sides of the axis of symmetry

were also consistently used. Nevertheless, the marking

system is varied.

In the rst of the tested trusses from the west, in truss

19, the elements on the southern side are marked with

a “V”, and on the northern side with a “V” with a by-mark

placed in the middle of the “V”.

In the following trusses, from 20 to 27, the elements

on the southern side were marked with line marks made

with an axe or a hand adze (Fig. 3a), and on the northern

side, with rectangular marks made with a chisel (Fig. 3b).

Theoretically, the marks could grow from three to ten.

However, during the assembly, there was probably con-

fusion of the trusses, because the actual numbering in the

trusses 20–27 is as follows, from the west to the east: 3, 4,

5, 6, 8, 9, 10, 7. However, this mistake did not create any

problems, because all the common rafters, unlike princi-

ple rafters, have the same arrangement

In truss no. 28, the carpentry marks were not recog-

nized, because it adjoins the brick gable between the nave

and the aisle crossing with its timber framing side.

Also in the trusses not included in the analysis, simple numerical

marks were used, distinguishing their left side from the right side. They

have dierent shapes and are not always arranged in a logical numerical

sequence.

Fig. 2. Kamień Pomorski,

cathedral, roof structure

above the nave,

paired common rafter, no. 26,

analysis and stratification

(elaborated by U. Schaaf,

M. Prarat)

Il. 2. Kamień Pomorski, katedra,

więźba dachowa nad nawą,

wiązar niepełny, nr 26,

analiza i rozwarstwienie

(oprac. U. Schaaf, M. Prarat)

6 Ulrich Schaaf, Maciej Prarat, Tomasz Ważny

• Building material and its processing

The preliminary dendrochronological research shows

that two types of wood were used for the construction of

the truss: pine and oak. Pinewood predominates, while

oak was used, among other things, in the case of both raft-

ers in the extreme eastern truss adjacent to the brick gable

between the nave and the aisle crossing (truss 28), and in

the case of some passing braces [11].

An axe was used for the pre-treatment of the build-

ing material, with some traces in the form of “V” shaped

cross-sections transverse to the direction of the bres

(Fig. 4a). Then the building material was smoothed with

a carpenter’s adze, which left on the surface typical long

and slightly rounded cuts running almost parallel to the

bres (Fig. 4b). Some of the elements processed in this

way, called whole trees, were divided into smaller ones by

dividing them with a hand saw. This process is evidenced

by slightly oblique notches running unevenly across the

wooden elements (cf. Fig. 3a). In this way, half-trees or

trees with a cross-section of 1/3 or 2/3 of the thickness

were obtained. In some cases, hand saw processing from

two parallel sides and a cross-sectional ratio close to the

ratio of 1:3 prove that 1/3 of the tree was used

. In many

cases, however, it was impossible to distinguish accurate-

ly between half-trees, 1/3, or 2/3 of the tree. This applies

to elements that show traces of a hand saw on only one

side. Only in one case was the use of a quarter-tree found,

which was processed with an axe and an adze on both

sides, and a handsaw on both sides.

The tie beams and short tie beams were made exclu-

sively of the whole tree. Their cross-section ranges from

20–25 × 18–30 cm. Whole trees and half-trees or 1/3 or

This is the case, among other things, with the down brace and the

passing brace on the northern side of truss no. 19.

Fig. 3. Kamień Pomorski, cathedral, roof structure above the nave: a) assembly mark in the form of straight lines made with a hand axe,

b) assembly mark in the form of rectangular cuts made with a chisel, building material processed from the side of timber framing with a hand saw

(photo by U. Schaaf, M. Prarat)

Il. 3. Kamień Pomorski, katedra, więźba dachowa nad nawą: a) znak montażowy w postaci prostych kresek wykonanych toporem ręcznym,

b) znak montażowy w postaci prostokątnych nacięć wykonanych dłutem, budulec obrobiony od strony odwiązywania piłą ręczną

(fot. U. Schaaf, M. Prarat)

Fig. 4. Kamień Pomorski, cathedral, roof structure above the nave: a) initial processing of wooden building material made with an axe,

b) smoothing of pre-processed wooden building material made with an adze (photo by U. Schaaf, M. Prarat)

Il. 4. Kamień Pomorski, katedra, więźba dachowa nad nawą: a) wstępna obróbka budulca drewnianego wykonana siekierą,

b) wygładzanie wstępnie obrobionego budulca drewnianego wykonane toporem (fot. U. Schaaf, M. Prarat)

ThemediaevalroofstructureoverthenaveofthecathedralinKamieńPomorski 7

2/3 trees with a cross-section of 17–24 × 22–26 cm were

used for the rafters. Also, down braces were made from

both the whole tree and the half-tree, or 1/3 or 2/3 of the

tree; their cross-section is 9–22 × 20–28 cm. The inter-

secting passing braces are only half-trees or 1/3 or 2/3 of

trees with a cross-section of 7–13 × 22–24 cm.

• Building material transport

In some structural elements, two round holes, about

3 cm in diameter, with remnants of withes and wedges

have been observed (Fig. 5). This proves that at least some

of the structural elements were transported by rafts from

the felling site in or around the forest to the site near the

construction site. These rafts must have been built each

time from several branch-stripped logs, connected to each

other by a pole placed over them in a transverse direction,

and attached to each log with a withe and secured with

two wedges. The greater number of holes with remnants

of withes and wedges suggest that the raft was repaired or

rebuilt during transport. These traces also prove that the

logs were oated rst, and then the building material was

made of them.

Booms with ropes were used for the vertical transport

of structural elements from the ground level to the level of

the roof structure. Special cuts were made at the corners

of the given element to prevent slippage of the rope with

which it was wound up and then pulled upwards. Such

cuts were found on various elements of the roof structure.

2. Characteristics of changes introduced to

cross-braced collar beams

The analysis of the construction has shown that the

original structural elements have been preserved in the

vast majority of the thoroughly examined trusses. Only in

trusses 19–20 and 22, has the replacement of some wood-

en elements in full or their fragments, or the addition of

wooden elements been found.

In truss 22 (Fig. 6) on the southern side, the down brace

zone was re-strengthened by introducing an additional

sole piece placed on the primary sole piece and an addi-

tional down brace adjacent to the primary brace. These

elements are connected with each other and with the orig-

inal structure using pegged lap joints of various shapes.

These are traditionally processed with an axe, adze, and

handsaw in the case of a brace, but have no carpentry as-

sembly marks.

Fig. 5. Kamień Pomorski, cathedral, roof truss over the nave,

building material with traces of float in the form of round holes

with the remains of wedges and withes

(elaborated by U. Schaaf, M. Prarat)

Il. 5. Kamień Pomorski, katedra, więźba dachowa nad nawą,

budulec ze śladami spławu w postaci okrągłych otworów

z resztkami klinów i śrykówek

(oprac. U. Schaaf, M. Prarat)

Fig. 6. Kamień Pomorski,

cathedral, roof structure above

the nave, paired common rafter,

no. 22, analysis and stratification

(elaborated by U. Schaaf,

M. Prarat)

Il. 6. Kamień Pomorski, katedra,

więźba dachowa nad nawą,

wiązar niepełny,

nr 22, analiza i rozwarstwienie

(oprac. U. Schaaf, M. Prarat)

8 Ulrich Schaaf, Maciej Prarat, Tomasz Ważny

The secondary origin of the lower collar beam and in-

tersecting passing braces (except for their lower ends) in

truss 19 (Fig. 7) is evidenced, inter alia, by their treatment

with a power saw on two sides, the lack of carpentry as-

sembly marks on them and straight lap joints as carpen-

try joints. The passing braces were also connected to the

rafters not from the timber framing side, but from the rear

side. The tie beam in truss 20 (Fig. 8) consists of two parts

connected to each other by a straight lap joint, secured

with a screw vertically, and iron at bars attached to the

side and also connected with screws. The short part on

the north side was machined with a power saw, which al-

lows its classication as secondary. In many fragments,

the wall plates are also of a secondary nature. This is evi-

Fig. 8. Kamień Pomorski,

cathedral, roof structure above

the aisle, paired common rafter,

no. 20, analysis and stratification

(elaborated by U. Schaaf,

M. Prarat)

Il. 8. Kamień Pomorski,

katedra, więźba dachowa nad

nawą, wiązar niepełny, nr 20,

analiza i rozwarstwienie

(oprac. U. Schaaf, M. Prarat)

Fig. 7. Kamień Pomorski,

cathedral, roof structure above

the nave, paired common rafter,

no. 19, analysis and stratification

(elaborated by U. Schaaf,

M. Prarat)

Il. 7. Kamień Pomorski,

katedra, więźba dachowa

nad nawą, wiązar niepełny, nr 19,

analiza i rozwarstwienie

(oprac. U. Schaaf, M. Prarat)

ThemediaevalroofstructureoverthenaveofthecathedralinKamieńPomorski 9

Fig. 9. Kamień Pomorski, cathedral, roof structure above the nave:

a) reinforcement of the connection of two parts of the tie beam (principal rafter truss 20) with a flat bar,

securing the principal rafter trusses with tensile-resistant anchors (19–20) above the principal rafter truss beam,

b) connecting the sole piece with the rafter using two flat bars, joining the (secondary) upper plate

with the passing brace and rafter using a flat bar (photo by U. Schaaf, M. Prarat)

Il. 9. Kamień Pomorski, katedra, więźba dachowa nad nawą,

a) wzmocnienie połączenia dwóch części belki wiązarowej (wiązar pełny 20) płaskownikiem,

zabezpieczenie ankrami wytrzymałymi na rozciąganie wiązarów pełnych (19–20) powyżej belki wiązarowych pełnych,

b) spięcie stopki z krokwią dwoma płaskownikami, spięcie belki (wtórnej) z zastrzałem i krokwią płaskownikiem (fot. U. Schaaf, M. Prarat)

a b

denced, inter alia, by their connection edge-to-edge with

the tie beams and sole pieces, and by their processing with

a power saw. In addition to the reinforcement of the down

brace zone on the northern side in truss 22 (cf. Fig. 6),

replacement of individual elements or their fragments in

trusses 19–20 (cf. Figs. 7, 8), and with a partial replace-

ment of the wall plates, iron elements were introduced

into the entire roof structure (Figs. 9a, b), now a bit rusty,

both to protect the wooden structure against parting and to

strengthen wooden connections. The treatment and joints

used suggest that the changes described here occurred lat-

er, after the strengthening of the foot zone in truss 22.

In one of the passing braces in truss 19 (cf. Fig. 7) the

upper end was replaced, as evidenced by its processing

with a modern power saw on all sides and a scarf joint,

which connects both parts of the brace. The same treat-

ment is applied to the upper collar in truss 19, the lower

part of the northern rafter and one of the intersecting pass-

ing braces in truss 20. Among other things, this treatment

and the lack of assembly marks and signs of weathering

make it possible to combine the assembly of these ele-

ments with the repair that has been ongoing since the end

of the last decade.

Secondary entablature with a frame

inclined roof strengthening

andaking-andstandingqueen-poststructure

A secondary entablature was inserted into the exist-

ing cross-braced collar structure slightly above the vault

apex, thus creating a working platform (cf. Fig. 7). The

entablature rests sideways on the upper plates, which are

in turn supported by short posts standing on the inner wall

plates next to the original down braces. Secondary posts

are attached to the braces with nails. They connect with

the upper plates with a mortise and tenon joint without

a peg or with a butt joint (Fig. 10). The beams are, in turn,

connected to the upper plates by cogged joints of various

shapes. The auxiliary lines needed to make the joints were

made with a pencil. All the beams were additionally con-

nected with the original passing braces and rafters with

at bars fastened with screws with square heads and nuts.

The studs were mostly made of half-tree, less often of

quarter-tree, rst processed with an axe and an adze, and

then divided with a power saw. Their average cross-sec-

tion is about 11/18 cm. A whole tree processed with an axe

and an adze with an average diameter of about 18/20 cm

or 20/22 cm was used for the upper plates and beams.

Secondary framesoftheinclinedqueenpoststructure

stand on the entablature and support the lower collars of

the original roof structure at the connection to the rafters.

Each frame consists of posts, oblique, but not parallel to

the rafters, an upper plate, and up braces, which stien

the frame in the longitudinal direction at every other post.

The roof strengthening is devoid of a straining beam in the

transverse direction, and therefore, the upper plates and

the primary rafters were fastened with screws with square

heads and nuts. The posts are joined at the lower end with

beams using a straight lap joint without a mortise, and at

the upper end with wall plates using pegged tenon joints.

The straight lap joint was also used to connect the braces

with the posts and upper plates. The lap joint on both ends

10 Ulrich Schaaf, Maciej Prarat, Tomasz Ważny

Fig. 10. Kamień Pomorski, cathedral, roof structure above the nave, eastern part, secondary entablature with a frame of the inclined queen post structure, analysis and stratification (elaborated by U. Schaaf, M. Prarat)

Il. 10. Kamień Pomorski, katedra, więźba dachowa nad nawą, część wschodnia, wtórne belkowanie z ramą o stolcu leżącym, analiza i rozwarstwienie (oprac. U. Schaaf, M. Prarat)

ThemediaevalroofstructureoverthenaveofthecathedralinKamieńPomorski 11

rst

processed with an axe and an adze, and then divid-

ed with a power saw. In the longitudinal frame, a whole

tree was used for the upstand beam (binder) (26 × 26 cm),

a half-tree for the passing braces (approx. 10 × 20 cm), and

a quarter tree (approx. 15 × 19 cm) for the spandrel beam.

Chronological stratification

As a result of the analysis of the existing material sub-

stance, literature review, and dendrochronological research,

it was possible to distinguish three construction phases:

the period of construction of the roof structure and the

period of two repairs, as described below. Not all items

could be dated; they are listed at the end of the stra ti-

cation (Fig. 12).

PhaseI

– building the cross-braced collar

beam roof structure (1361/1362 – d)

The architectural research has enabled the reconstruc-

tion of the original cross-braced collar beam roof structure

over the nave. Researchers, as already mentioned above,

have not included the roof structure above the nave in their

analyses, and the completion of the nave body construc-

tion was dated dierently, from the beginning to the mid-

1360s [1]–[4]. The dendrochronological research shows

that the trees were felled during the vegetation break of

1360/1361

, which has made it possible to date the build-

ing of the roof structure to the years 1361–1362 [11]. This

roof structure is, therefore, a primary structure formed im-

mediately after the completion of the masonry body.

The vast majority of the structural elements have sur-

vived from that period. The original structure in trusses

21–28 has been fully preserved.

PhaseII

–repairoftheroofstructure

at the end of the 1860s

The second phase involves the incorporation into the

existing roof structure of the entablature with frames of in-

clined queen post and a king post structure. All these units

are integrally linked and have survived in their entirety

to this day. The upper plates of both roof strengthening

frames bear the date 1869, which makes it possible to date

the repair of the roof structure to the end of the 1860s

The type and the processing of the building material

as well as the carpentry joints used lead to the conclusion

that the replacement of the end of the tie beam in truss

20 on the northern side and the replacement of the lower

Nine samples were taken from the structural elements of the roof

structure over the central nave, of which eight could be dendrochrono-

logically dated. Four were taken from oak elements and four from pine

elements. The latter originated from the hills of the forests along the

Oder River in the Uckermark region [11].

This repair is probably a continuation of the restoration of the

cathedral begun in the late 1840s under the supervision of the then Royal

Conservator of Monuments in Prussia, Ferdinand von Quasta [3, p. 10].

of the brace goes into the mortise, but is not in one plane

with the posts or the upper plate. Each time it is only se-

cured with a screw. Also, in the case of frames with an

inclined queen post structure, auxiliary lines were drawn

with a pencil for making the joints. The studs and upper

plate were made of building materials with a cross-sec-

tion of about 20/22 cm. They were treated on one or both

sides with an axe and an adze, and on the other sides with

a power saw. The entire southern frame of the queen post

structure is marked from west to east with carpentry as-

sembly marks in the form of Roman numerals. The posts

within the examined eastern fragment have marks from

VII to XI, while the braces from VII to X. This means that

the posts and braces were counted separately. The north-

ern frame of the queen post structure is marked essential-

ly in the same way. Marking was made rst with a pencil

using Arabic numerals, and then with a chisel using Ro-

man numerals. This marking is a logical continuation of

the system of assembly marks used in the western parts

of the roof structure and proves the homogeneous nature

of both secondary roof strengthening frames.

The secondary kingpoststructure (Fig. 11) consists of

three trusses and a longitudinal frame. Two full trusses

(A-B) each consist of a king post and two long braces sup-

porting it, a tie beam acting as a tension tie and two short

braces connecting the king post with long braces. The third

truss (C) is not a king-post truss, as it consists of only a tie

beam and a stud standing on it. The longitudinal frame

consists of king posts, an upstand binder from which an

entablature is suspended above the vault, a spandrel beam,

and stiening braces. The upstand binder is situated next

to the king post on the northern side. The spandrel beam

on the southern side enters only 2–4 cm into the mortise

made in the king post. In trusses A and B, the long braces

connect to the beam and the king post by a pegged tenon

with a notch. A pegged tenon joint was used to connect the

braces with the king post. The beams were suspended from

the king post by means of a at bar (stirrup) fastened with

screws. Moreover, this at bar is bent at both ends and addi-

tionally fastened with small cramps. The same straight lap

joints are used in the longitudinal frame as in the case of the

queen post structure. They are secured with either screws

or nails. The individual parts of the spandrel beams are

connected to each other by a scarf joint. This connection

was additionally reinforced with a nailed at bar, and with

bent ends secured with small cramps. The auxiliary lines

needed to make the joints were made with a pencil. The

system of carpentry assembly marks basically consists in

marking structural elements in the trusses from east to west

with triangular marks adjacent to thin lines – one triangle in

truss B, two triangles in truss A. Both sides of the symme-

try axis are additionally distinguished by line marks – one

on the southern side, two on the northern side. This system

of marking the king post structure is continued further on

the west side and proves the simultaneous introduction of

this structure in the entire roof structure above the nave. In

the trusses, king and queen posts (only king posts) (about

23 × 22 cm) and braces (about 21 × 19 cm) were made from

the whole tree processed with an axe and an adze, and pass-

ing braces (about 20 × 22 cm) were made of a quarter tree,

12 Ulrich Schaaf, Maciej Prarat, Tomasz Ważny

Fig. 11. Kamień Pomorski, cathedral, roof structure above the nave, eastern part, secondary entablature with a king post structure, analysis and stratification (elaborated by U. Schaaf, M. Prarat)

Il. 11. Kamień Pomorski, katedra, więźba dachowa nad nawą, część wschodnia, wtórne belkowanie z konstrukcją wieszarową, analiza i rozwarstwienie (oprac. U. Schaaf, M. Prarat)

ThemediaevalroofstructureoverthenaveofthecathedralinKamieńPomorski 13

Fig. 12. Kamień Pomorski,

cathedral, roof structure above

the nave, trusses 19–28,

stratification

(elaborated by U. Schaaf,

M. Prarat, drawing by

M. Kumorowicz-Brzeska)

Il. 12. Kamień Pomorski,

katedra, więźba dachowa

nad nawą, wiązary 19–28,

rozwarstwienie

(oprac. U. Schaaf, M. Prarat,

rys. M. Kumorowicz-Brzeska)

collar and inter secting down braces in truss 19 took place

in the same period.

The period of repair should also be related to the intro-

duction of iron elements both to protect the cross-braced

collar beam roof structure against parting and to strengthen

its wooden connections. This is indicated by the use of iden-

tical iron elements and the method of their fastening as in

the case of entablature, the queen and king post structure.

PhaseIII

–repairoftheroofstructure(2020s)

The processing of the building material with a power

saw and the use of wooden dowels and screws made it pos-

sible to combine the replacement of the upper collar and

the upper part of one of the passing braces in truss 19 and

one passing brace and the lower part of one rafter in truss

20 with the last repair of the roof structure

Undated secondary items

The architectural research has shown that in truss 22,

an ad ditional sole piece and an additional down brace

were built into the northern side. These elements have not

yet been dated.

An attempt to define the meaning

of the primary roof structure

The architectural research has made it possible to re-

construct the original roof structure over the nave of the

cathedral in Kamień (Fig. 13). The reconstruction shows

Identical solutions were used in the already fully repaired western

trusses (1–18).

that the structure is a collar beam one with two collars

and intersecting long passing braces stretched in each

truss between the rafters, and with tie beams only above

the inter-span reinforcing arches (19–20, 27–28). In the

remaining trusses there are only sole pieces, because

the rise of the vault apex reaches into the roof structure.

The angle of inclination of the rafters is 58°. The only

stiening in the longitudinal direction is wind braces

running diagonally under the rafters. In the connection

of individual structural elements of the roof structure

lap joints of various forms dominate; cogged joints were

used only in the case of connecting the tie beams and the

sole pieces with the wall plates. According to the dendro-

chronological research, this roof structure was created in

the 1360s.

This type of roof structures is a development of simple

collar beam structures with identical trusses over churches

with a at ceiling or with a vault located lower than the

roof structure. This development consists in introducing

the vault caps into the roof structure and, consequently, the

use of principal rafter trusses (with tie beams within the

inter-span reinforcing arches) and paired common rafters

(with sole pieces within the vaulted caps). The use of such

a solution also means that only the principal rafter trusses

ensure the transverse brace and anchoring of the masonry

eaves walls. On the other hand, for the purpose of bracing

the foot zone of the construc tion in the paired common

rafters, it was necessary to introduce the sole pieces and

vertical down

braces, which together with the rafters form

rigid

. The advantage of introducing intersecting pass-

ing braces is in additional non-movable triangles, which

The development of cross-braced collar beam structures from

simple collar beam structures is discussed by, among other authors,

Binding [10, pp. 49, 50].

14 Ulrich Schaaf, Maciej Prarat, Tomasz Ważny

Acknowledgements

The authors of the article would like to thank the West Pomeranian

ConservatorofMonuments inSzczecin, Mr. TomaszWolender,forthe

commissioning of architectural research on the roof structure over the

navebody,DeanProvostFatherDariuszŻarkowskiforunlimitedaccess

to the church, and also Krystyna Drozd, the author of the measurement

anddrawinginventory,oftheconstructiondesignfortherepairofthe

roof structure, and the creator of the inventory drawings, which were the

basis for the architectural research.

References

[1] Kasten F.K.A., Beiträge zur Geschichte des Camminer Doms,

Prüfer, Berlin 1883.

[2] Lüpke F.W., Der Dom zu Cammin, “Baltische Studien” 1876, fasc. 2,

1–57.

[3] Spuhrmann R., Der Camminer Dom, Formazin & Knau, Cammin

in Pommern 1915.

[4] Eggert H., Der Dom zu Cammin, Ohlenroth, Erfurt 1935.

[5] Ohle W., DodziejówkatedrywKamieniuPomorskim.Analizabu-

dowlanawschodnichczęściromańskich, “Materiały Zachodnio po -

morskie” 1959, t. 5, 331–360.

[6]

Skibiński S., KatedrawKamieniuPomorskim, Księgarnia św. Woj -

ciecha, Poznań 2002.

[7] Raczyński J., Przyczynki do historji ciesielskich konstrukcyj da-

chowychwPolsce, Zakład Architektury Polskiej Politechniki War-

szawskiej, Warszawa 1930.

[8] Ganowicz R., Historyczne więźby dachowe polskich kościołów,

Akademia Rolnicza im. Augusta Cieszkowskiego, Poznań 2000.

[9]

Ostendorf F., DieGeschichtedesDachwerkserläutertaneinergroßen

AnzahlmustergültigeralterKonstruktionen, Teubner, Leipzig 1908.

[10] Binding G., DasDachwerkaufKirchenimdeutschenSprachraum

vom Mittelalter bis zum 18. Jahrhundert, Deutscher Kunstverlag,

München 1991.

[11] Ważny T., Analizadendrochronologicznakatedryśw.JanaChrzci-

cielawKamieniuPomorskim, Toruń 2021 [manuscript in author’s

archive].

[12] Eißing T., KirchendächerinThüringenunddemsüdlichenSachsen-

Anhalt. Dendrochronologie – Flößerei – Konstruktion, Bd. 1–2,

Reinhold, Altenburg 2009.

[13] Heyn F., DieDanzigerDachkonstruktionen.Ihrekonstruktiveund

historischeEntwicklung, Schwital & Rohrbeck, Danzig 1913.

provide better transverse bracing, and additional support

of the rafters without loading the tie beams.

A preliminary literature review shows that this solu-

tion was applied throughout Northern Europe during

the Middle Ages. There are a few known examples from

France from the 12

century and from England from the

century. In German-speaking countries, such roof

structures were common in the 2

half of the 13

and

throughout the 14

centuries [10, pp. 63–82], [12, pp. 103–

105]. In the territory of present-day Poland, the solution

of using the cross-braced collar beam roof structure from

before the 15

century is known only from Kamień Pomor-

ski

, which makes it possible to assign to it exception-

al signicance both in the historical aspect and from the

point of view of the craft of carpentry.

Translated by

EdwardMaliszewski

Neither in the above-mentioned works concerning historical roof

structures in Poland [7], [8], nor in works covering only certain regions/

areas of Poland, or individual cities of Poland, is there any mention of

cross-braced collar beam structures [13]–[19]. Only Bronner describes

similar solutions over St. Adalbert’s Church and St. Catherine’s Church

in Wrocław, but he dates them not until the 15

century [20, pp. 6–8].

Fig. 13. Kamień Pomorski,

cathedral, roof truss of the nave,

trusses 19–28, reconstruction

of the original cross-braced

collar beam

(elaborated by U. Schaaf,

M. Prarat, drawing by

M. Kumorowicz-Brzeska)

Il. 13. Kamień Pomorski,

katedra, więźba dachowa nad

nawą, wiązary 19–28,

rekonstrukcja pierwotnej więźby

wolnej ze ściągami

(oprac. U. Schaaf, M. Prarat,

rys. M. Kumorowicz-Brzeska)

ThemediaevalroofstructureoverthenaveofthecathedralinKamieńPomorski 15

[14] Bronner J., Zur konstruktiven Entwicklung der Dachstühle auf

Breslauer Kirchen und Monumentalbauten, Korn, Breslau 1931.

[15] Bożejewicz E., Drewnianekonstrukcjedachoweśredniowiecznych

kościołówchełmińskich, MA thesis, Department of Conservation at

Nicolaus Copernicus University, Toruń 2006.

[16] Konieczny A., MittelalterlicheDachkonstruktionenderDanziger

KircheninderGeschichtedesDachwerksimDeutschordensland

Preußen, [in:] G.H. Gorning (Hrsg.), Achtedeutsch-polnischeBe-

gegnung zur Wissenschaft und Kultur im zusammenwachsenden

Europa, Danziger Naturforschende Gesellschaft, Lübeck 2007.

[17] Gogolin M., Więźbydachowekościołów Pomorza odkońcaXIII

do połowy XIX wieku. Przekształcenia typów i rozwiązań kon-

strukcyjnych, Wydawnictwo Uniwersytetu Kazimierza Wielkie go,

Byd goszcz 2008.

[18] Warchoł M., HistorycznewięźbydachowekościołówwWarszawie,

Miasto Stołeczne Warszawa, Warszawa 2015.

[19] Wawrykiewicz L., Skarzyńska-Wawrykiewicz M., Katalog śred-

niowiecznychkonstrukcjidachowychnatereniehistorycznejWar-

mii, Olsztyn 2019 [manuscript in author’s archive].

[20] Bronner J., ZurkonstruktivenEntwicklungderDachstühleaufBre-

slauer Kirchen und Monumentalbauten. Ein Beitrag zur Zimmer-

mannskunstinSchlesien, Korn, Breslau 1931.

Abstract

The mediaeval roof structure over the nave of the cathedral in Kamień Pomorski

in the light of architectural and dendrochronological research

The subject of the article is the roof structure over the central nave of the cathedral in Kamień Pomorski. Although there are numerous studies

relating to the history of the construction of this cathedral or to the development of historic roof structures in general, none of them has yet included

the roof structures discussed in this work. This situation and the need to repair the construction have justied the carrying out of the architectural

research to learn its construction history and carpentry technique.

The research on the existing material substance in the eastern trusses, taking into account the following aspects: load-bearing structure, sides of

timber framing, carpentry joints, a system of carpentry assembly marks, building material, and its processing. The results of these analyses were

supplemented and compared with the results of dendrochronological research and that presented in the literature on the subject.

As a result of this research, it has been possible to establish that the chancel of the Kamień Pomorski cathedral is crowned with a cross-braced

collar beam roof structure, which dates back to the early 1360s. It was strengthened in the late 1860s by additional entablature above the vault rise,

and an inclined queen post structure and a king post structure. The next strengthening took place fragmentarily as part of the repair that has been

underway since the end of the late 2010s. Despite its age and repairs, the original structure has survived to a great extent.

The type of the roof structure used above the nave in Kamień Pomorski – a cross-braced collar beam roof structure – served a specic construction

function in the Middle Ages – the construction of a roof over a vault within the boundaries of the roof. A preliminary literature review has shown that

examples of such solutions have survived in various parts of Europe to the present day, but only in a small number. In the territory of Poland, so far

it is the only known example of this kind from the 14

century.

Currently, the remaining cross-braced collar beam roof structures over both arms of the transept and chancel of the cathedral in Kamień Pomorski

are included in the architectural research. A wider study on this type of mediaeval roof structures, and attempts to compare the roof structures of the

Kamień Pomorski cathedral against a broader background are desirable in the future.

Key words: Kamień Pomorski, cathedral, roof structure, Middle Ages, architectural research, dendrochronological research

Streszczenie

Średniowieczna więźba dachowa nad nawą środkową katedry w Kamieniu Pomorskim

w świetle badań architektoniczno-dendrochronologicznych

Tematem artykułu jest konstrukcja dachowa nad nawą środkową katedry w Kamieniu Pomorskim. Istnieją wprawdzie liczne opracowania od-

noszące się do dziejów budowy tej świątyni lub do rozwoju historycznych więźb dachowych ogólnie, ale w żadnym z nich nie uwzględniono oma-

wianych w tej pracy więźb dachowych. Sytuacja ta oraz konieczność naprawy konstrukcji uzasadniły wykonanie badań architektonicznych celem

rozpoznania jej historii budowlanej oraz techniki ciesielskiej.

Badania zastanej substancji materialnej przeprowadzono we wschodnich wiązarach, uwzględniając następujące aspekty: strukturę nośną, strony

odwiązywania, złącza ciesielskie, system ciesielskich znaków montażowych, budulec i jego obróbkę. Rezultaty tych analiz uzupełniono i skonfron-

towano z wynikami badań dendrochronologicznych oraz przedstawionymi w literaturze przedmiotu.

W wyniku tych badań udało się ustalić, że nawę środkową katedry kamieńskiej zwieńczyła pierwotnie więźba wolna ze ściągami, która pochodzi

z początku lat 60. XIV w. Została ona wzmocniona w końcu lat 60. XIX w. przez dodatkowe belkowanie powyżej strzałki sklepienia, konstrukcję

stolca leżącego oraz konstrukcję wieszarową. Kolejne wzmocnienia nastąpiły fragmentarycznie już w ramach trwającej od końca drugiego dziesię-

ciolecia XXI w. naprawy. Mimo wiekowości i napraw pierwotna konstrukcja przetrwała w dużym stopniu.

Zastosowany w Kamieniu Pomorskim typ konstrukcji dachowej – więźba wolna ze ściągami – służył w okresie średniowiecznym do konkret-

nego zadania budowlanego – wykonania dachu nad sklepieniem wchodzącym w jego obręb. Wstępny przegląd literatury przedmiotu wykazał, że

przykłady takich rozwiązań przetrwały w różnych częściach Europy do dziś, ale tylko w małej liczbie. Z terenu Polski jest to póki co jedyny znany

taki przykład z XIV w.

Badaniami architektonicznymi objęto obecnie pozostałe więźby wolne ze ściągami katedry, nad oboma ramionami transeptu i prezbiterium.

Warto pokusić się o przygotowanie szerszego studium na temat tego typu więźb średniowiecznych oraz próbę zestawienia więźb katedry kamieńskiej

z więźbami z innych miejsc.

Słowa kluczowe: Kamień Pomorski, katedra, więźba dachowa, średniowiecze, badania architektoniczne, badania dendrochronologiczne