GUIDANCE ON THE DESIGN
AND SPECIFICATION OF WORKS
when restoring, extending or building new traditional cottages in North
Wales.
Scope and purpose
This simple guidance is intended for anyone considering building work on
a traditional cottage, of the sort commonly found throughout Wales, but perhaps
especially in North Wales. It will explain what to look for, what to avoid,
and will show how the charm and character of a cottage can be sympathetically
conserved, largely using the same traditional techniques that were used
originally to build it. It will be found that the advice given here will
cost a great deal less than other unsuitable methods, many of which could
do much harm to the building in the long term. Further information on any
matter can be obtained from John Nicholson at the address given at the end
of this article. A free consultancy service is also available to anyone intending
to restore or conserve a traditional house or cottage.
Why conserve?
Traditional buildings are important for their simplicity, economy and reserve.
They do not stand out of the landscape, but blend into it. Traditional buildings
do not create an ‘eyesore’ in the countryside, but should enhance it. This
is achieved subconsciously, through a number of factors, but the form, quality
of proportion, and texture of natural local materials are all important,
together with a simplicity of design and construction methodology that seems
to emerge from the very landscape itself, as if these buildings were not
made by man, but are derived from the earth itself.
This guidance should help those intending to extend, restore or build a new traditional building, so as to avoid commonly made mistakes. Hopefully it may also inspire a greater appreciation of our local vernacular and encourage the care and preservation of surviving traditional buildings.
Observe the local vernacular
Study other remaining buildings, from different periods within the local
area. Take notes of commonly features, many of which will be referred to
below. Record carefully all parts of any building that you intend to alter,
with photographs and drawings. Avoid mixing styles that may originate from
widely different periods, no matter how attractive they may be. Do not copy
features from other attractive buildings that are not of the same type or
position, for example a porch or bay window design found in a town house
could be inappropriate in a country setting. Seek a copy of the local "Design
Guide" available from the local planning authority. Discuss your ideas with
the conservation officer.
Position
Notice how other buildings relate to the landscape and to the contours.
In most parts of Wales the axis of cottages are placed parallel to contour
lines, so that the ridge is parallel to a contour. This way, cottages in
elevated positions appear to shine out over the view, and blend with the
topography as if they were always there. Notice how cottage look best if
they appear to be attached to the landscape through the relationship with
surrounding out buildings, or by walls trees and hedges. This not only provides
additional shelter and privacy, but helps the buildings to blend into and
compliment the landscape. Therefore, avoid scouring the areas surrounding
traditional buildings, avoid removing existing outbuildings, and convert
them if at all possible. If wall have to be removed to provide access, then
keep the stone to hand so they can be re-used to repair or rebuild structures
later.
Scale
Traditional buildings seem to be smaller and more ‘reserved’ than modern
ones. This is partly because they may be surrounded by other buildings, walls
and trees. It is important to keep external wall heights as low and
‘cottage’ like as possible. If necessary use lower ground floor ceiling heights
than normal modern practice, (2.2 M to 2.4 M is ideal), and extend first
floor ceilings into roof voids with .3 M to .5 M of angled ceilings under
the roof up to the first purlin. A lower external profile can also be achieved
with raised flower beds or banks immediately in front of the building to
raise the apparent ground level.
Features
The basic ground plan of vernacular building throughout Wales is surprisingly
consistent over a wide period. The standard cottage has two main rooms, a
larger one to the left with a large inglenook, and the smaller to the right,
called the parlour. The cottage has a central doorway, with a window at each
side, giving the cottage the external appearance of a face. The main gable
walls have central chimneys, giving the cottage the external appearance of
‘ears’. The staircase should be in the middle of the house, normally rising
from the front door, but spiral stairs can also be found rising at the corner
of a cottage or at the side of the inglenook. Stairs placed at one end of
a cottage will not provide access to all first floor rooms without a corridor.
A central stairway is therefore better for reasons of access, ventilation
and heat distribution. Traditional cottages had purlins (generally two per
pitch) to support thin rafters. Slated or thatched roofs were under torched
with lime. Additions to the basic plan, were nearly always by attachment
at each end creating bays. Small low roofed out-shuts were common. Despite
their small size by modern standards, these features can still be attractively
incorporated as snugs in renovation work. This basic form of cottage plan
should be kept in mind at all times.
Proportion
Keep to the traditional proportion of window and door sizes to the wall
area. Windows should always be taller than they are wide. Wide
‘picture’ or ‘landscape’ windows should be avoided. If extra lighting is
needed (for example over a kitchen or utility room sink), then place two
windows together with a central mullion, thereby retaining the traditional
proportion. First floor windows should not be as tall as those on the ground
floor. First floor windows should always be placed exactly above the ground
floor windows and at the same width. Most traditional cottages have a ground
floor window each side of the central front door, with three corresponding
windows on the first floor. The front door need not be placed exactly in
the middle but slightly to the right, giving the left hand room a larger
fireplace reveal. The left hand chimney over the main inglenook, should also
be thicker than the right hand chimney that only served the parlour. This
slight displacement of the formal pattern creates an important visual rhythm,
and has particular value if picked up several times within a group of buildings.
Extensions
Any extensions to the main house form should be made firstly to at least
one side before extending to the rear. Extensions to the side (as a long
house), should stand back from the front of the house by at least 200 mm,
to maintain the visual dominance of the house.
Preparation
Before staring any construction work, drawings and a working specification
should be prepared. It is not always necessary to have an architect do this,
and many architects have no understanding of the value or care of traditional
and vernacular buildings. Some of the worst possible work is done to
specifications prepared by engineers and architects. Before contacting any
architect, ask to see examples of their work and make sure that they do
understand that old buildings need special care and treatment.
Regulations
It may be necessary to discuss proposals with the Building Regulations
Officer of the local authority if new buildings, extensions or new services
are proposed. Internal alterations, maintenance, and the replacement of
perishable elements within an existing building is not subject to scrutiny
of the Buildings Inspector, and does not require planning permission, so
long as there is no extension, change of use or other development as defined
by Section 55 of the Town & Country Planning Act. It should therefore
be borne in mind that the re-use and repair of the existing elements within
a building avoids the need for compliance with many new regulations that
come into force as soon as these elements are removed prior to replacement
with new. This can be very important in the case of replacement floors and
stairs, which if removed may have to be replaced at different heights to
provide regulation headroom. If proposed work is likely to fall subject of
approval from the Building Inspector then is can be helpful to seek advice
from the local authority Conservation Officer, who may be able to argue for
the need to relax or waive regulations.
Planning permission
The construction of any new building or the extension of an existing
one, (including extensions in height) will require prior planning approval
from the local planning authority. The demolition of unlisted buildings does
not normally require planning permission, but replacement does. The use of
any existing out-buildings within the curtilage of a dwellinghouse for any
purpose incidental to the enjoyment of the dwelling house also does not require
planning permission. However, any form of alteration to a listed building
does require planning permission, but in this case it is a free service.
Restoration work that will help to improve or conserve a listed building
may also be eligible to grant aid. In Wales, this is obtained from Cadw.
Damp prevention
DPC or injected treatments to prevent rising damp should never be used
on traditional stonework, new or old. The only way to prevent rising dampness
is to provide a well drained and vented French ditch. This is a drained ditch
dug around the perimeter of a building into which is set a graded perforated
land drain, which is ducted away from the building to a suitable soakaway.
The ditch is then filled with clean rubble (minimum size of 100 mm dia.),
to within 200 mm of the surface, and is then blinded off with old slates
or slate waste, and covered with earth or turf. When digging trenches for
new foundations it is worth allowing additional width for a French ditch.
Site preparation
Drainage Footings and drainage channels for new buildings can be dug
and strip foundations laid. A Building Inspector will need to inspect both
the dug trenches, and the filled strip foundations, and will issue a certificate.
At this stage it is worth adding an air vent pipe to allow outside air under
the floor to a position as close as possible to the main fireplace to prevent
unnecessary draughts. This channel can also be used as an internal drain
from the floor space to the French ditch. Topsoil removed from the plot during
excavations should be stored separately for further use.
Ground Floors
Suspended timber floors are not necessary unless there is a particular
reason to do so. They are more typical of 19th century urban buildings. Ground
floors are best finished with a natural surface, like slate or ceramic
‘quarry’ tiles. These can be obtained through salvage or can be purchased
new. Beware of imitation ‘traditional’ tiles that are mounted on a cement
or ceramic base, as although they look very attractive at first, they will
not last as long as the real thing. A concrete platform will have to be laid
to support any laid floor, and it is wise to give this ample insulation.
The normal procedure is to dig out the floor void to 300 mm below the proposed
level of the finished floor. This is then filled with 100 mm compacted clean
rubble to provide drainage, blinded with pea or slate waste, then the plastic
DPM, which must be folded up the internal walls to 50 mm above the floor
level. Over this 50 mm polystyrene insulation sheets should be laid as tightly
as possible and if necessary secured with a layer of corrugated cardboard
to prevent the insulation ‘floating’ through the concrete.. Finally lay on
top of this 100 mm concrete, leaving 50 mm for the screed and the laying
of slates or tiles.
Stonework
Existing stone work should be retained when ever possible. Most stonework
can be simply repaired by removing any loose or unsuitable (hard Portland)
cement, and re-mortaring with lime mortar. Smaller sneck stones should be
inserted into joints to secure stonework, and reduce the width of exposed
mortar. Before starting any new build work, it is worth spending some time
laying out the available stones for a whole building and grading them according
to shape and size. Any matching stone pairs (made by splitting one stone
in half) can be especially useful. Bold quoin stones should be used at the
external corners, and around all door and window openings. Large stones should
be selected for the bottom, reducing in size evenly to the top, therefore
the largest four stones will be placed at the four corners of a new building..
External walls should be made as thick as possible, at least 500 mm, and
should have a ‘batter’. This means that stone walls should taper towards
the top, starting at say 500 mm to 600 mm, and reducing to about 350 mm to
400 mm. for a two story cottage. An external stone facing can also be achieved
using a normal modern cavity wall made from 100 mm concrete blocks with a
50 mm cavity, and then an extra cavity with 50 mm polystyrene insulation,
and then 200 mm of stone work and rubble fill. The so called ‘rubble fill’
between the locking ‘quoins’ needs to be laid carefully. Notice how traditional
stone work has been coursed, so that the longest axis of every stone is
horizontal, and each stone covers two stone below it, (two over one, one
over two). Lime mortar should always be used on stonework, without raised
pointing. It is important to ensure that it is the stonework that
‘reads’ visually, not the mortar.
Cob walls
North Wales is one of very few areas in the British isles where cob
(compacted subsoil) was traditionally used as a building material, and it
is tragic that so many of these buildings have now been lost. The method
is better preserved in Devon, and it is worth preserving as cob walls provide
the best thermal and hydraulic interior protection, and are very cheap to
make. Cob walls have a high natural insulation and thermal capacity, so rooms
are warm in winter and also cool in summer. Cob is good because it
‘breathes’, preventing internal dampness, and reducing over dryness. Cob
walls should not be repaired using hard Portland cements. New cob walls can
easily be made, as a cheap and energy efficient way of building.
Window and door openings
Internal window reveals should be angled to reflect light into the room.
The internal edges of the reveals should be rounded, without sharp arises.
Lintels can be made from slate or stone, despite what the building regulation
officer may say. A simple and effective way to make a regulation proof lintel
is to select a wide enough slab of slate at least 30 mm thick with one straight
edge which used as the lower edge. This is positioned to form the external
lintel. Inside, a board of oak can be provided to form the internal lintel.
Between the two can be placed any number of pre-stressed concrete lintels
to meet the necessary structural conditions, and these can be cemented together,
with sufficient mortar to ensure that the slate facing is stuck to the inner
core. Nails or screws can be attached to the inside surface of the oak board
to bind it into the mortar. It is useful to make to oak board much wider
than is required as a lintel, so that any curtain fittings can easily be
attached directly into timber without any need to drill into or damage the
wall.
Internal walls can be made from concrete block, especially if they are structurally required to support purlins. However, there are examples of internal walls made from vertical dressed slates, some even extending through two floors! Many cottages have wooden boarded internal walls, which are easier to alter later. Resist any inclination to harden or straighten new masonry walls. It is important to keep the traditional atmosphere consistent throughout the building. Try and keep the impression of wall thickness, even though internal walls need not be thick, by using extended reveals at openings and doorways.
First Floors are often supported on undersized joists, that probably have been further cut into by plumbers and electricians so that floors are now sagging and springy. This should not be regarded as a fault unless they structure is clearly critical. Broken or damaged joists can be strengthened by gluing and screwing supporting bearers down each side. These can be moulded with a plain chamfer or a bead to provide additional interest if exposed. This method should not be used if the original joists are infested with woodworm. Instead, a new joist should be fitted.
Original old floorboards can generally be recognised by their width, and absence of tongue and grooved edges. Try and use second-hand or reclaimed wide boards where ever possible, and select the widest boards available when constructing a new floor. It is worth buying floorboards well in advance, and storing them in a dry place prior to fitting to prevent shrinkage. Nail floorboards with traditional cut nails, or forged nails. It is good to pre-drill the boards with a pilot hole to help guide the nails. Old joists may need to be levelled, and also it is often necessary to pack the upper surface of joists to ensure a level floor surface. A plain wax surface is adequate for softwood floors, there is no need to provide a high gloss varnished floor.
Ceilings were made using cleft laths through which plaster was pushed from below. The inner surface then given a finishing coat, and whitewashed. This was normally the only means of heat insulation. There is no need to use this time consuming method today, except for localised repair of an otherwise undamaged ceiling.
If it is found that the plaster of a ceiling has parted from the lath work, the a simple repair can generally be made if accesses is available from above. Thoroughly clean the ceiling from above with a vacuum cleaner to remove any particles of broken plaster. Then prop the ceiling from below, taking care to spread the support with a flat board. Check the pressure is sufficient to bring the old plaster into contact with the remaining laths. Repair any missing or broken laths, then flood the whole area with a new plaster of Paris mix to which a proportion of fine sand can be added. Continue to support the ceiling from below for two days until the plaster is well set. It is also possible to secure a sagging ceiling with wood screws and large washers from below attached from below.
Roofs
Roof angles should be the same for the main roof and all extensions.
Purlin construction should always be used. Avoid the use of modern timber
sawn to standard 3" thickness. Second hand or new rough sawn fresh timber
purlins of 4" by 5" will span 10 feet easily. Place the purlins so the surface
of the narrow edge is parallel to the rafters. The purlin is therefore in
its strongest position having its diagonal nearly vertical. Care should be
taken to ‘read’ the grain of purlins to ensure that they are placed with
as much hanging sag as possible, and not to bow upwards.
Old rafters were very thin by modern standards, and this prohibits the insertion of sufficient insulation within the roof thickness. If a roof must be stripped and re-laid, then it may be advantageous to replace the old rafters with thicker ones to meet regulations, because this will also allow ample space for new insulation between the rafters. However, the same effect can be achieved, (without having to comply with the minutiae of regulation) by simply adding extra battens to each rafter. These should be screwed and not nailed to the existing rafters, to prevent impact damage. Rafters can be laid to give the appearance of sag, so characteristic of traditional buildings. This can be achieved by lifting the last three rafters at verges very slightly, and by lifting the ridge board.
Underfelt
The underside of traditional roofs were almost always sealed with a layer
of lime plaster, called torching. This helped to secure the slates, which
were otherwise held in place only by riven wooden pegs. The torching also
reduced the draft that could lift the slates and in severe winds remove slates
or blow water up under the slates causing leaks in the roof. This provided
no additional insulation to a roof, and an unreliable water protection. To-day
a bituminous underfelt should always be laid over the rafters and secured
by the slating battens. It is important to lay the roofing felt with sufficient
sag to allow any water to run into a slight valley between the rafters so
as to reduce any dampening of the slating battens. It is important to allow
a ventilated gap of at least 25 mm between the underside of the roofing felt
and any internal insulation. This is necessary to prevent damage by condensation
within the insulation, that could rot the rafters.
Alternatively, a new form of microporus ‘breathing’ membrane can be used, which is more expensive but has a great advantage over the use of a bituminous or plastic membrane because it allows insulation to be brought up to its under surface.
Traditional torching can be repaired if there are only small areas that are faulty. Also, it is now possible to increase the insulation value of a traditional roof, using an ultra light weight torching mix, made from lime putty, with vermiculite and pearlite filler. This can be supported with short nails partly driven into the inside surfaces of the rafters, and also with a wire netting reinforcement. The insulation layer can be built up in layers of 15 mm to 30 mm at a time according to the stickiness of the mix, and finished 5 mm from the inner surface of the rafters.
Slating
The form and style of original slating should be carefully observed and
copied wherever possible Original slated roofs are very different to modern
ones. Either small narrow slates were used, or very large slates, and very
often, slates were laid in random widths and with reducing courses, the largest
slates at the bottom reducing to the smallest slates at the ridge. This gives
the roof perspective, and prevents the appearance of diagonal lines. For
replacement or repair work, generally use rough cut ‘extra heavies’. These
are often the cheapest type of slate obtainable from the quarry, and are
the best for traditional buildings. Avoid modern thin cut slates in regular
sizes that look like plastic. Slates can be nailed in place, but consider
using short hardened plated screws driven with an electric screwdriver if
there is any risk that hammering may damage the structure of dislodge other
slate work. Verges should not overhang, but should finish no more than 15
mm beyond the plane of the external wall. New barge boards should be avoided,
and should be of a simple form when they must be used. Gutter boards should
be of minimum width, and can be beaded. Lead flashings and soakers should
not be exposed, and should be cut as simply as possible and then covered
in mortar.
Windows
The sills of first floor windows will be lower in the rooms than those
on the ground floor. Sliding sash windows should be used, if possible with
12 or 16 panes. Never use Velux type roof lights. Instead, use proper dormers,
or conservation type roof lights. Dormers should be designed in the form
of a gable by extending the exterior wall up above the gutter line in the
form of a gable, with a window reveal.
Windows should be fitted deeply into the reveal by at least 100 mm, preferably 150 mm, both to provide the greatest protection from weathering, and also because deep set windows look better. Avoid the use of crass ‘look alike’ wooden windows form manufacturers that are said to be indistinguishable from authentic sash windows. They immediately make a traditional buildings look fake. The sills of traditional windows can easily be replaced without the need to remove the windows from the aperture. A new hardwood sill can be fitted to extend the life of an original window for many years. Wooden sills should not project beyond the front of the surrounding frame, as happens in modern windows. Take great care to retain original blown glass. This material is now very rare, and is quite different from modern flat plate glass. Old glass should be carefully preserved, and if it is ever removed from the frame then mark the top with a sticky label, to ensure that it is always replaced the same way up. This is because glass is still liquid, and it very slowly flows downhill. It will be found that old glass is thicker at the bottom than at the top.
Internal details can greatly improve the attractiveness of a window. Explore the shape of the window reveals with curves and double angles. Consider fitting double level interior sills, or shutters to improve thermal insulation, and sound protection. Avoid the trend of putting a radiator under every window, on the basis that this is the area with the greatest heat loss. Instead, place radiators near to or within the thickest internal wall.
Insulation
Traditional buildings had little if any thermal insulation, and yet there
was ample material available, in the form of wool, moss, shavings, shells
and husks. There is no explanation why so little effort seems to have been
made to conserve internal heat. To-day the trend has in many ways gone too
far the other way, with central heating, plastic double glazed windows and
draught proofing becoming a cause of much ill health. An over heated stuffy
room with unchanged moisture laden air is a breeding place for germs and
bacteria. There is a need to circulate air, changing the entire air within
a house at least twice a day. Ventilation is therefore very important. For
this reason a duct should always be fitted to introduce outside air near
to a fireplace or boiler, to prevent draughts. Also, windows should be made
to open easily, especially in bedrooms. Signs of inadequate ventilation are
mildew and mould forming in the corner of rooms, and on any colder wall surface.
The use of double glazed windows is not so important in the small windows of traditional cottages as in modern buildings with large ‘picture’ windows. No only does the smaller size of window lose less heat, but also their fitting within deep reveals, behind curtains and shutters, will reduce heat loss. However, it is not impossible to make new ‘Georgian’ wooden windows with double glazing, and an advantage is to make first floor sash windows revolve so the outsides can be cleaned from indoors.
The greatest single improvement to the quality of accommodation in most traditional cottages is the insulation of the roof or ceilings. This can be done by modern materials like rock wool or polystyrene insulation blocks, but fibre glass is not desirable because it tends to collapse if ever it gets wet. Alternatively Warmcell paper fill insulation can be used, or treated sheep fleece. Fleece is potentially the most effective and long lasting domestic insulation material, available from local sources. Fleeces can be dipped into a special solution that prevents deterioration and moth infestation, and also fireproofing. The fleece then ‘sets’ into whatever form it is placed.
Other potential insulation materials include, feathers, saw dust and shavings, the husks from nuts and grain crops, pearlite, vermiculite, and polystyrene. Most have fir risk implications. Many are vulnerable to vermin attack. It is therefore important to be able to inspect lofts and attics periodically for any problems.
Internal Doors
Any old board doors should be collected and re-used where ever possible.
Look out for wide boards, occasionally a single board 24 or more inches wide
may be found. Old forged hinges are also well worth using, with thin straps
ending in a droplet. If new doors have to be made then it is easy to make
up new three board ledged doors using 10" (250 mm) pine boards, beaded along
one edge, tongued together and nailed to the braces with old style cut nails.
The nails are drive through and folded over like a claw on the back, and
then hammered into the surface of the braces. Traditional latches can be
found second-hand, and can be purchased new. But it is also easy to make
new wooden latches from oak, which make a more pleasant noise.
Plasterwork
Avoid commercial gypsum plaster, except as a cover for plasterboard,
and then only as a last resort. Learn how to make traditional lime plaster
by blending lime putty with sharp sand, and some goats hair. Lime plaster
is easy to make and to apply, but needs to be kept damp for a while using
wet rags or occasional mist spraying. Lime plaster gives a much better surface,
and helps the walls to breathe. Do not plaster walls to a uniform flat surface.
Notice how traditional plaster walls have slight bulges in them, and generally
are slightly concave, stepping out into the room at floor level, and being
slightly hollow at eye height, and then sometimes flaring out again towards
the ceiling. This gives each room a special feeling of space, and also enhances
illumination. Do not use hard edged corners, but curve each arris appropriately
to the situation often using the natural curve between the thumb and index
finger.
Painting
Lime plaster over painted with lime wash gives the best possible internal
illumination, and prevents the formation of mold. Lime plasters and lime
paints are very much cheaper to make and use than any other interior paint.
Woodwork is best painted with traditional lead based oil paint. This can be obtained from specialist suppliers. When properly applied, good quality oil paint will out last any plastic. Other paints for internal use can be made from casein (milk powder) and a good emulsion paint can be made from glue size.
Interior fittings
It is a pity to take a great deal of trouble to restore the fabric of
a traditional building and then fill the inside with out of character kitchen
and bathroom fittings. Modern kitchen ‘units’ supplied in kit form are invariably
made from chipboard or MDF (medium density fibreboard) with a hard melamine
decorative coating imitating wood grain, granite or marble. How much better
to use genuine natural building materials. For a kitchen in North Wales this
should include slate work surfaces, perhaps with some marble from an old
wash stand. Simple pine doors can be made in exactly the same way as interior
doors, and the main structure of kitchen fittings can be made from timber
or better as brick or concrete block supports, skimmed with lime plaster
and whitewashed. Doors to cupboards can also be made from a large piece of
slate, if necessary pierced with a pattern of vent holes, and hung on strap
hinges. Internal shelves can also be made from large roofing slates, supported
on iron pegs set into the brickwork. Before plastic and stainless steel sinks,
ceramic sinks were common, and many are still to be found as troughs in fields
or salvage merchants. New ceramic ‘Belfast’ sinks can also be purchased.
It is also possible to make wooden sinks from teak boards, secured by long
studding clamps at each end. This will provide a thoroughly long lasting
kitchen stronger than any fitted units, and at a fraction of the cost.