2. Timberwork Case Studies
MSc. Building Conservation
22 February 2013

3. Paul Price
Woodwrights
Oak frame
carpentry
and timber
conservation

4. An overview of historic
carpentry and timber repair
Topics:
1.Recognising historic carpentry
2.Repairs: surveys and methods
3.Case histories

5. Historic timberwork
Part of our built heritage – in Ireland: especially roofs.
A valuable record of historic craftwork - timber conversion
and scribe carpentry.
Christchurch
Cathedral,
Dublin.
17th C.
oakwork

6. Ilustrations from:
McCracken, E. (1971) The Irish Woods Since Tudor Times

7. Holy Trinity Church,
Fethard, Co. Tipperary
Medieval oak roof frame,
discovered 2010

10. See-sawing (swivel or trestle sawn)

11. Timber Conservation Aims
Conserve the overall aesthetic form of the structural frame
while repairing the structure.
Preserve original timber as much as possible.
Timber surfaces, which preserve marks recording the
original timber conversion and framing methods.
Dunsoghley Castle, Co. Dublin.
High quality scribe carpentry;
Double collar;
Arch-braces with locking tenons;
Scribe numbers visible.

12. Timber Conservation Process
Survey: historical value, condition, and structure.
Repairs: minimal, unobtrusive, reversible.
Outlook: maintenance check-list
Norway - Loft repair.
Timber replacement:
New timber selected,
cleft and hand hewn
to match original
decayed element.

13. Recognising historic carpentry
Conversion: logs into timber
Carpentry: scribing, jointing and raising frames

14. Oak - tough and durable.
Baltic pine – imported.
Two forms of historic
timberwork:
Treewrighting
axe-hewn, boxed heart,
often smaller ‘stuff’,
cottage roofs;
Frame carpentry
hewn plus rip-sawn,
mortice and tenon,
large range of scantlings,
use of grown “bends”,
larger, more durable
buildings.

15. Hewing: Turning logs into timber.
Marking and notching

16. Juggling
Hewing
Notching
Finishing with broadaxe

17. Hewing:
Finishing- A broadaxe was used to give a flat finish

18. Close up of
hewn surface
Axe nick marks
Stop mark
Note mutual
angle of marks

19. Pit-sawn
surface with
framers’ level
mark

20. Scribing: Timber placed over full scale layout so that
joints can be scribed to allow accurate fit of irregular timbers

21. Reference
line
Plumb bob

22. Scribed
shoulder

23. Scribe carpentry workshop

24. Numbering: Usually Roman -
chiselled or race-knifed

26. Recognising historic timberwork
Hewn or pit-sawn surfaces
Carpenters layout marks - scribe lines and references
Mortice and tenon joints
Chiselled numbers at joints
Scribed joints - shoulders scribed to match irregularities

27. Repairs:
surveys and methods

28. Surveys
Record Drawings
Basic survey - Schematic timber drawings and photographs.
Full Survey: Archeological level recording.
Estimating
Annotate basic survey schematics with current condition and
possible repairs

29. Bishops Palace, Salisbury,
Wiltshire, England
Roof by Francis Price 1726
Our repairs 1998

30. Cathedral Church,
Cashel
Nave roof 1780
Large span 46ft
=14m
Transition carpentry
Diagnosing a
structural problem.
– Is it really a
problem?

31. Cashel Cathedral Church Roof:
• Queen post roof with king strut
• Ceiling load has deformed roof

32. Joint separation
100mm+

33. Cashel:
Structural Original
schematic
Current
Movement appears locked but should be monitored

34. Repair Methods

35. Repair Methods for Historic Timberwork
•Steelwork: straps, flitch plates, cables,
brackets, bolts, screws to secure joints and
framing.
•Carpentry: replacement timbers, patch and
end repairs.
•Resin: consolidation, packing, patch and end
repairs.
Beware the “honest” repair
Making repairs look distinctive from original work
is often an excuse for unsightly repairs.

36. METAL REPAIRS:
•Often cheapest and best if hidden or subtle- no disassembly needed
•Reversible and easier. Unsightly if visible and poorly designed.
•Use galvanised or stainless steel for repairs.

37. CARPENTRY REPAIRS
•Potentially damaging
disassembly required for
replacement or end
repairs.
•Requires high quality
repair carpentry for good
results.
•Decide whether to match
conversion methods.
•Use oak with oak etc.

38. End repairs
• require careful
fitting and
assembly
• use dry timber
where possible.
• may have to use
green -allow for
shrinkage and
later tightening

39. New tenon repair - only possible if frame
elements disassembled

40. Multiple scarf repairs to softwood wall

41. Rafter notch joint
reformed in resin
RESIN REPAIRS:
•Good for consolidating valuable decayed timber and for packing
out steel repairs.
•Bad for large end repairs. Can be very ugly.
•Always use resin designed specifically for structural timber work.

42. Timber durability:
Excellent if kept dry.
Good if sheltered.
Bad if continually damp.
Exposed to weather for 600 years
Leaking weathervane
- king post decayed

43. Case Histories

44. Barn, Co. Wicklow An exceptional and
18th Century unusual barn frame

45. Barn in Wicklow
Shipping marks on Baltic Pine on hewn surfaces.
Race knifed symbols denoting timber baulk
quality and quantity.

46. Unusual framed cantilevered roof overhang

47. Bridled scarf with
sallied abutments in a
10 cm by 6.5 cm
timber !!

48. Dragon tie hip assembly: Note numbering

49. Purlins scribed over hip bevel

50. Curved End New tie and
reassembly numbers

52. Historic pine: Left side has been sandblasted.
Note serious loss of fragile but intact surface.

53. Winchester Cathedral,
South Transcept
Dendro date 1313
Difficult working conditions
Laminated in-situ repairs

54. Disassembly: can see inside joints
•Soulace brace with locking tenon
•Axed tenon faces
•Drawbored tenon
•Centre lines

55. Southwick Barn.
Hampshire, England
Collapsing barn- uprighted, mostly in-situ steel repairs

56. Gusset bracket and flitch repairs

57. Wooton Bassett,
Wiltshire, England
Decay of 19th century
oak repairs due to
impermeable black
paint

58. Repaired frame prior to stripping impermeable paint
Frame and replastered panels then limewashed

59. House at Laxfield, Suffolk
working with Traditional
Oak Carpentry Co

61. Structural frame repairs - support carefully!

62. Cill plate decay - due to constant wetting,
impermable paint, and cement mortar/render.

63. Exterior new timber
conserving interior -
Coach screwed together
with resin packing

64. Installing new cill with
new and repaired timber

65. Frame reassembled with new plinth built up.
Exterior frame aesthetic conserved.

66. Decay treatment

67. Interior timber
entirely saved.
Poor quality of
framing timber
-hedgerow stuff

68. Charlton Court Barn, West Sussex, England
Dendro-dated
to 1404
Major repairs
•Roof stone removed, frame realigned, joints reassembled
•Very costly - steel building over, detailed repairs throughout.
Use for special buildings.

69. Patch repair: coach End repairs:
screwed and plugged Tabled stop splay scarf

70. New timbers where missing
•Re-make in new timber on
pattern of existing.
•Better than unsightly
exposed steel.
•Can make decision to
match existing conversion
to similar pieces.
New aisle sway
brace

71. Purlin span decreased using in-line steel angles - no plywood

72. Completed frame repair
•Aesthetic conserved
•Structure repaired

76. An overview of historic
carpentry and timber repair
Topics:
•Recognising historic carpentry
•Repair surveys and methods
•Case histories

77. Thank-you
Paul Price
woodwrights.ie