STANDARDS AND SPECIFICATIONS OF WORK FOR THE THATCHING OF
BUILDINGS IN EAST ANGLIA
Part 1- Long Straw
Part 2- Water Reed
Part 3- Combed Wheat Reed
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Little is generally known about thatch, its renewal or
maintenance. There are often articles in newspapers and magazines and
sometimes in professional journals but most of them are uninformed and
technically inaccurate. Some are so poor as to be unintelligible, even to
the thatcher. Only two authentic works or reference exist and even these
are guidelines rather than technical manuals.
The general ignorance extends into the building industry
and into relevant professional and official circles. There are no British
Standards for the materials used in thatching or for the specifications of
finished work. Even if they did exist it is doubtful if many would
recognize the quality of materials being used or the specifications to which
they were being employed. Building Inspectors stay away from thatching in
progress, architects make incredibly basic mistakes in designing for thatch,
surveyors reporting upon thatched property find themselves out of their depth
and local authority officials in environmental health or planning departments,
entrusted with the allocation of public monies in grant aid, are only now
beginning to feel their way out of paying good money for bad work, which, has to
be done again. It does not help that often the work has been done by
thatchers the department has itself listed and, therefore, whatever the legal
niceties might be, de facto recommended to the general public.
General public generally means the thatch owner and here,
situated as he or she is at the end of the consumer chain, is the ultimate cause
for concern. Experience has shown that the owner is by no means better
informed than the rest. Many do not even know what kind of thatch is on
their roof. The thatch owner is exposed and vulnerable. He can be
approached with offers of ‘technical advice’, be persuaded to join
meaningless and expensive ‘schemes’ which trade on his ignorance, be
deceived by memberships of ‘master craft’ organisations whose credentials in
thatching cannot be verified or established, consult or employ ‘thatchers’
who have not served proper apprenticeships or do not have the best interests of
the client at heart or can start next day by adding one more job to the two or
three already in train.
The fact is that thatching is entirely self-regulating and
central to this process is the quality and integrity of the thatcher himself.
There is no legal restraint upon the person who chooses to set up in business
and describe himself as a thatcher, or even a master thatcher.
Furthermore, there are a number of fringe areas, notably the insurance of
thatched property, where there are considerable financial gains to be made.
These provide incentives to become involved with thatching for the wrong
reasons. To the entrepreneur motivated by turnover and little else, the
training and expense necessary to become a competent thatcher represents a
commercial barrier that has to be overcome in the fastest possible time.
The same argument is applied to the time and care necessary to do good work.
Methods of training are traditional and protracted and not all are prepared to
travel that road. An apprenticeship means sober induction into the habits
of craftsmanship. Properly carried through with a recognised master man it
requires two to four years. Combined with the very personal desire to
achieve high standards of workmanship and business integrity, a genuine
apprenticeship will produce a sound craftsman who can only grow with experience.
The EAMTA exists to advance this concept in Suffolk, Essex, Norfolk and Herts
and is recognised by the Countryside Agency as the effective voice representing
the craft in East Anglia.
There are some who do not share this concept. In an age
of mass production and unit construction they see the term ‘master thatcher’
as commercially exploitable and they are immeasurably helped in this by the lack
of any legal definition for the term. For some years now the Association
has become increasingly concerned at the threat to well-established values and
the quality of work or conduct brought to its attention and in which it has been
asked to intervene.
The Association has, therefore, sought to educate the
thatch-owner and all interested parties by advertising its presence, increasing
its contacts and generally building upon the reputation it now enjoys as one of
the most reputable and progressive thatching bodies in the country. We
believe the East Anglia Master Thatcher’s Association’s efforts have met
with some success and certainly there has been a very considerable increase in
the volume of correspondence with those seeking professional help or advice.
But there have also been problems and the largest single problem has been the
lack of any yardstick by which local authority officials could gauge or control
the quality of thatching work being done under the grant assisted programmes for
environmental health and listed buildings. Help was given to individual
authorities and in one or two instances basic specifications were drafted.
It became increasingly apparent that there was an urgent and general need for
concise but authoritative standards and specifications of work for the three
basic thatching materials in the region to be compiled and circulated to every
local authority.
It is long established that good craftsmanship is closely
allied to good standards of covering. Two standards are central to all
specifications: the depth of material over the fixings and the depth of material
overall. If to these are added solid casework of even pitch and density
then quality work is almost assured. Almost, because there remains the
quality of materials employed. Here the specifications can only give
guidelines and it has to be said that where there is doubt then professional
advice should be sought. The secondary effect of insisting upon sound
specifications of work is to screen out those operators who either cannot or
will not work to them.
The standards and specifications that follow were originally
produced in 1986 as a schedule to the constitution of the Suffolk Association,
to serve as the agreed basis for the integrity of work and they continue to
discharge that function. They have since been revised and republished by the
Standards Sub-committee of the East Anglia Master Thatchers Association. The
EAMTA is the regional body, consisting of the Suffolk MTA, the Essex & Herts
MTA and the Norfolk MTA. The EAMTA is a member of the National Council of
MTAs.
For the specification of roof frames, the user should consult ‘The
Thatcher’s Craft’ published by The Countryside Agency and the Technical
Pamphlet 10 ‘The Care and Repair of Thatched Roofs’ published by the Society
for The Protection of Ancient Buildings
STANDARDS AND SPECIFICATIONS OF WORK FOR THE THATCHING OF
BUILDINGS IN EAST ANGLIA
Revised and republished by The Standards Sub-committee of
The East Anglia Master Thatcher’s Association
October 1998, April 2005, June 2009
Quality of the material
The
Association recognises only good quality long straw grown especially for the
purpose of thatching. The
guidelines for assessing quality are as follows:
1 Specification of materials
Long straw should be preferably hollow
stemmed, winter grown wheat, although rye straw and its rye/wheat derivatives,
such as Triticale are recognised. Rye straw should be noted as a less durable
material, to some degree, due to the cell structure of its species.
There is no wheat variety, suitable for thatching, on the current NIAB seed
list. Old seed must be retained and currently the main varieties in use are
Maris Widgeon, Maris Huntsman, Aquilla, Square Heads Master and Masterpiece.
Where artificial fertiliser is employed,
the Nitrogen level should be kept as low as possible, normally in the region of
50 units/acre for the modern approved varieties of wheat. For the older
varieties of wheat that predate artificial fertilisers introduction, it is
strongly advisable to keep the nitrogen levels down to below 30 units/acre, best
applied as a balanced grassland fertiliser of NPK.
Crops are cut, traditionally, with a
binder, when the nodes are still green and the grain is of a cheesy texture,
this ensures that the straw is frozen in its prime, thus preserving it’s
strength. The grain moisture content at this point is about 30%. The sheaves are
then stood up, ‘stooked’, in the field to slowly dry and condition the straw
in it’s prime condition, and to ripen the grain in the heads. This normally takes 2 – 3 weeks.
The straw should have an average cut length of at least 30 inches.
Whichever method of threshing is
employed, it should leave the straw stems only slightly bruised, and not unduly
damaged or crushed, avoiding the breaking of stems, with a certain amount of flag (dried leaf) mixed in with
the stems. The straw should not be discoloured to any degree. It should be
strong and supple and able to resist or even defy efforts to break it by
twisting a handful continuously.
2 Traditional preparation
Long straw type material is composed
from uncombed material, which is dampened and shaken onto a bed system.
It would be normal for a traditionally
prepared bed to be thoroughly mixed, with no lumps of straw aligned the same
way, in order to ensure that a reasonable mix of heads and butts can be pulled
from the bed, when yealming.
A bed of straw should be of a reasonable
size, or weighted, to help with a clean pull. Good double handfuls are then
pulled out and laid side by side, to form a line of straw. Once a line has been
made, bunches are worked tightly together, cleaned of waste and straightened to
form yealms.
Yealms resemble straw tiles,
approximately 18” to 24” wide and normally 4-5 inches in depth, but can be
increased up to 7-8 inches. Yealms can be made tapered with a pronounced bigger
end, for big end down thatching, or a more parallel yealm, suitable for big end
up thatching.
3 Traditional
application/ thatching to the roof
It would be normal to place the yealms
into position, with a certain amount of sliding before fixing, without dressing
into position. The ‘softened’ nature of this material, due to it’s
preparation process, is important in allowing the material to ‘lie’ on the
roof, without the need for dressing.
The long straw thatch when nearing
completion should be raked through. Clipping should, normally, only be reserved
for the eaves/gable edges and tidying up around the surface liggers. Shaving of
the long straw thatch would be considered un-traditional and unnecessary.
It would be normal to expect to aim for
an even mix of heads and butts showing on the surface of a freshly thatched
roof, with an allowance of 10-15% dominance, of either heads or butts showing,
being accepted as normal.
The three sections above define
traditional Long Straw thatching. Where a different technique/style/method is
employed, such as dressed/butt-ended/shaved straw, this should be made apparent
to the consumer. It would be normal practice that the re-thatching of Listed
Buildings be in the traditional Long Straw thatching craft technique.
Application for membership to the Association shall only be by the traditional
Long Straw thatching technique.
New Work
Preparatory
-
All old thatch and wire is to be removed where present.
-
The roof frame shall comply with specifications for
thatch.
Fixings
-
The normal method of fixing will be by hazel, other wood
sway or mild steel rod, sufficiently strong to avoid bowing between rafters.
-
Sways will be either tied to the roof frame or secured
using conventional thatching hooks of appropriate length.
-
Every double course will be secured to every rafter.
-
Sewing is recognised as a traditional method to be
employed where circumstances demand it.
-
Hazelwood brotches are recognised as appropriate to brow
and half courses
The criteria to be employed at all times are that the
material is to be fixed under tension and that it shall not slip.
Casework
-
The material shall be tightly thatched and of an even
density.
-
The surface shall conform to the pitch of the roof and
will not normally be less than 45 degrees.
-
Eyebrow windows may exceptionally be reduced to a pitch
of 40 degrees.
-
The minimum thickness of the face work, measured above
the face of the batten, at right angles to the rafter, shall not be less
than 16 inches.
-
Lining or backfill courses shall be employed as necessary
to avoid the courses lying too flat.
-
Face work thickness will be maintained through all
features. Valleys will be rounded out to give a minimum depth of 20
inches over the valley centre.
-
The minimum depth of material over the fixings will be 6
inches but 6-8 inches will be normal.
-
Flues may be cut, banded or rolled according to local
style and custom. The criteria shall be that there is an adequate
overhang to protect the gable end, minimum 3 inches overhang at the board
and 7 inches overall.
Recoating work
Preparatory
The removal of old thatch will vary according to region, for
example the cut flue and the banded flue require different treatment. The
criteria is that surplus material will be removed down to a sound base coat of
about 12 inches and that the basecoat be additionally secured e.g. by hooks and
sways if necessary. It will also be normal but not invariable to strip out
old eaves and flues.
Renewal of Casework
-
The material shall be tightly thatched and of an even
density.
-
The surface shall conform to the pitch of the roof and
hollow areas thatched out.
-
The minimum thickness of the new coating shall be 10
inches and this shall be regarded as the standard specification for
recoating work.
-
Face work thickness will be maintained through all
features. Valleys will be rounded out to give a minimum depth of 13
inches over the valley centre.
-
Where for economic, technical or vernacular reasons the
standard specification is reduced to 8 inches this should be made clear to
the consumer.
-
The minimum depth of material over the fixings for a
standard coat will be 6 inches but 6-8 inches will be normal.
-
The treatment of flues shall be in accordance with
paragraph 8 above.
Fixings
-
Where eaves and flues are renewed, the new bottles will
normally be secured using hooks and sways.
-
Elsewhere it will be normal to use hazelwood brotches of
adequate length to secure the new coat to the old, with or without the use
of straw scuds.
-
Every course and half course shall be adequately secured.
The criteria to be employed at all times are that the
material is to be fixed under tension and that it shall not slip.
Ridgework
-
Ridges may be block or flush pattern, according to the
local requirement. All block ridges will be laid additional to the
casework.
-
Both types will be in pitch with the casework and
adequately secured with long-rods, cross-rods and brotches.
-
The final substrate, be it roll or twisted tops, shall be
covered with a tightly packed turnover not less than 4 inches thick at the
apex.
-
Where a block pattern ridge is employed, the depth of
cut, including ornamental pattern-work, shall be a minimum of 3 inches
thick.
-
Joints at chimneys etc, projecting from the ridge shall
be weathered by adequate flashings.
The Association does not recognise the practice of cutting a
block pattern out of casework thickness.
Netting
All areas of the roof will be securely protected by 20 gauge
19mm (maximum) mesh galvanised wire netting or polythene equivalent.
Netting shall conform closely to the roof shape and be fixed
in such a way that it can be easily removed in the event of fire.
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Part 1 - Long Straw
Part 2 - Water Reed
Part 3 - Combed Wheat Reed
Quality of the material
The Association requires that the Reed used shall be suitable
for the task, mature and dense.
Further information on quality can be found on the Materials
- Water Reed page.
New Work
The Association does not recognise the practice of ‘coating
over’ with Water Reed.
Preparatory work
-
All old wire and thatch to be removed.
-
The roof frame shall comply with the specification for
thatch.
Fixings
-
The reed is to be secured by adequate fixings to ensure
that there is no slippage.
-
Every course of reed should be fixed to every rafter.
-
The dimensions of the sway should be sufficient to ensure
that there is no ‘bowing’ between rafters.
-
The depth of material over the fixings will be a minimum
of 5 inches.
Casework
-
The Water Reed shall have a compact finish and even
density.
-
The surface of the reed will conform to the pitch of the
rafter that will not normally be less than 45 degrees.
-
The minimum depth over batten or substrate from the
surface of the thatch will not be less than 12 inches.
-
Face work thickness will be maintained through all
features. Valleys will be rounded out to ensure a minimum depth of
reed over the valley rafter of 16 inches.
-
Eaves and flues will be applied in the angular East
Anglian style and not ‘rounded off’.
-
All junctions of ridges with reed casework e.g. gable
windows, shall be adequately weathered by the use of a reed saddle piece.
-
Soil pipes etc, piercing the casework shall be weathered
by adequate flashings, sufficiently long to reach the sway.
-
Box gutters to chimneys will be sufficiently large to
prevent the accumulation of debris.
Ridgework
Material- good quality Long Straw or Marsh Sedge.
-
All ridges will be of the block pattern, minimum
thickness 3 inches, cut to shape if required and secured by liggers and
cross-spars.
-
A reed roll should be fixed to the apex and covered with
a dense turnover of 4 inches minimum thickness.
-
The ridge shall be in pitch with the rafters.
-
Joints at chimneys etc, projecting from the ridge shall
be weathered by adequate flashings.
Netting
The ridge will be protected by 20 gauge 19mm (maximum)
galvanised wire netting or polythene equivalent.
If wire netting is fixed to reed casework, it should conform
closely to roof shape and be fixed in order to ensure its easy removal in the
event of fire.
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Part 1 - Long Straw
Part 2 - Water Reed
Part 3 - Combed Wheat Reed
Quality of material
The quality of straw required is the same as that recommended
in PART 1 – LONG STRAW. Providing
the length of the straw does not fall below 27 inches it is still suitable for
combing, although the ideal length is 36 inches.
The straw shall be suitable if on passing through the reed
comber, situated on top of an ordinary threshing drum, it comes out undamaged,
with grain and leaves removed and with all the butts laid in one direction.
No straw shall travel through the drum.
Groundwork and reed preparation
Stacks on site shall be covered with a tarpaulin as a
protection against adverse weather conditions.
Wheat reed bundles shall be butted and then trimmed to clean
the exposed ends. The bundles shall then be lightly damped and allowed to
steep prior to use. This damping practice is not so essential when hooking
on new work.
New work
The specifications for preparatory work, fixings and casework
shall be the same as for PART 2 – WATER REED
with the following amendments: -
Fixings
-
The depth of material over the fixings will be a minimum
of 6 inches.
Casework
-
The wheat reed shall have a compact finish and even
density.
Recoating work
Preparatory work
All old wire netting shall be removed.
Old thatch shall be stripped off down to a sound basecoat of
about 12 inches and that basecoat secured by hooks and sways if necessary.
It will also be normal to strip out old eaves and gables but this is not
invariable.
Fixings
-
The reed is to be secured by adequate fixings to ensure
that there is no slippage.
-
Every course of reed shall be fixed to the basecoat
underneath.
-
The depth of material over the fixings will be a minimum
of 5 inches.
Renewal of casework
The specifications for casework shall be the same as for PART
2 – WATER REED with the following amendments to paragraphs 1,3 and 4: -
-
The wheat reed shall have a compact finish and even
density.
-
The minimum depth over basecoat from the surface of
the thatch will not be less than 10 inches.
-
Face work thickness will be maintained through all
features. Valleys will be rounded out to ensure a minimum depth of
reed over the valley base-coat of 13 inches.
Eaves and Gables
The Association recognises the practice of setting the cut
portions of eaves and gables with good quality long straw.
Gables shall be cut with the top edge overhanging the bottom
edge by about 3 inches.
Ridgework
The Association does not recognise the practice of butt-up
ridges. The material forming the thickness of the ridge shall be of wheat
reed, good quality long straw, or sedge.
The material forming the in-fill and wrap-over shall be of
good quality long straw or sedge.
-
All ridges will be of the block, patterned type, laid
additional to the casework, minimum thickness- 3 inches, cut to shape if
required and secured by liggers and cross-spars.
-
A reed roll should be fixed to the apex and covered with
a dense wrap-over of 4 inches minimum thickness.
-
The ridge shall be in pitch with the rafters.
-
Joints at chimneys etc, projecting from the ridge shall
be weathered by adequate flashings.
Netting
The ridge will be protected by 20 gauge 19mm (maximum)
galvanised wire netting or polythene equivalent.
When wire netting is fixed to reed casework it should conform
closely to roof shape and be fixed in order to ensure its easy removal in the
event of fire.
NOTICE
These standards and specifications are current at the time of publication.
However, the Association reserves the absolute right to modify or amend them,
without notice, in the light of research and development in materials and
techniques.
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Part 1 - Long Straw
Part 2 - Water Reed
Part 3 - Combed Wheat Reed
