Wooden door

Christine Smith <consartpap [at] earthlink__net> writes

>This query is posted on behalf of someone who does not read the
>List.  He owns a home in a small, very old town in Abruzzo, Italy.
>The entrance to the house is a two-leaf paneled wood door, which
>townspeople believe to be about 300 years old.  The identity of the
>unfinished wood is unknown, but believed to be hardwood.  The door
>leaves swing on old iron hinges, and there is no other hardware
>(i.e. no lock or handles).  Although the door is very weathered and
>some stiles and rails have eroded as people gripped them like
>handles, the wood appears to be sound.
>
>What recommendations do readers of the DistList have for cleaning
>the door of dirt? What kind of finish would be appropriate in an
>area that receives considerable amounts of snow?  The town and owner
>do not want a painted finish.  All tools and materials must be
>readily available in Italy or safe to transport in checked airplane
>luggage. It seems highly preferable to do all work without removing
>the door leaves from the very old hinges.

This query poses a common problem in architectural conservation:
what to do with weathered wood and the film it glazes over the
beholders eye with called patina.

The "dirt" described that needs washing off is probably the remains
of cellulose left behind as UV light destroys the lignin in the wood
that binds the whole lot together. The constant erosion by wind and
water normally takes care of the loose wood fiber thus leaving the
weathered wood look one wishes to save. In most cases trying to wash
away this "dirt" only will expose more fresh wood grain for the
sun's rays to deteriorate. Depending on the species of wood and its
exposure to UV and the weather a wood surface can easily weather
away 5 mm in a century. This is the primary reason we paint wood so
as to provide an opaque film resistant to the sun's UV rays and as a
barrier to moisture. "Cosmetic" is the popular reason for painting.
In this particular case, a simple soap and water scrub might loosen
any mud on the door's bottom followed with a simple water rinse if
it is truly soils "dirt" which I doubt it is.

As to protecting the bottom of the door where the most moisture and
mechanical damage may occur, I would suggest making sure that the
wear in the hinges does not allow the door to sag to the point where
it then drags on the threshold or stone landing. Metal rubbing on
metal over the ages will wear hand forged metal away and if this is
the case, one might consider bronze bushing washers/spacers that
make up for the wearing away inserted between the hinge leafs might
be necessary if one can open the hinge parts. This will help to keep
the doors from dragging and damaging their bottoms.

The bottom wood in the door [the side stiles and the bottom rail]
are where fungal attack is likely to take place as water
[rain/snow/ice] is wicked into the end grain of the stiles and also
the pockets in mortise-and-tenon joints where the rail and stiles
are jointed. A low tech solution that will not change the appearance
of the door is to pepper the bottom [underside] edge of the door
with solid copper tacks or nails. These will leach copper to the
surrounding surface and act as an effective fungicide. Small slips
of copper sheeting can be cut and fitted into any joint crack
between the rail and stiles and if carefully done they should not
show. One might also consider drilling small drain holes at the
appropriate places into the mortise-and-tenon joints so that
moisture entering them is drained out. These holes can receive small
sleeves of copper screen that act as a fungicide and also keep
insects out. Considering the doors have remained useable for 300
years, I doubt the joints have suffered much rot. However, the above
are minimal interventions one could do at low cost that will keep
the doors useful and at the same time maintain their sense of age.

Richard O. Byrne
Consultant Architectural Conservator


                                  ***
                  Conservation DistList Instance 21:48
                  Distributed: Monday, March 10, 2008
                       Message Id: cdl-21-48-004
                                  ***