Moss Removal

 

CARE OF THATCH      Useful contacts at the end of this page

Good thatch will not require frequent maintenance.

Establish early on what condition the thatch is in - then appropriate work (if necessary) can be programmed.

Do not assume that because materials are slipping or that the roof looks a mess that it needs rethatching.

Do not assume that because the roof looks neat (with a well executed ridge pattern) that it is in prime condition.

A thatch which looks thick is not necessarily a good thatch.

A thatch which looks thin is not necessarily a bad thatch.

The life of a thatch can be extended significantly by a timely and appropriate repair.

Do not move around on your thatch unnecessarily. Do not allow others to do so.

Do not let non-thatchers fit netting, flashings etc. without advice from an experienced thatcher.

TV aerial erectors etc. should be required to keep off the thatch as much as possible.

DO NOT allow standing on the ridges or the use of ridges as working platforms.

Ridging

A patterned ridge is not more durable than a ridge finished flush with the main coat.

A ridge should be fitted in pitch with or greater than the main roof elevation.

A thick cut ridge does not make it necessarily a good ridge.

The pattern may disappear prematurely from a thin cut ridge.

Falling or fallen pattern liggers does not on its own mean a ridge needs  repair

The condition of the rafters may appear alarming to house owners or surveyors not familiar with thatch, pole rafters of various hard woods but mainly Ash are common and the occasional broken or rotten rafter is not unusual, these can often be replaced from within the roof space with minimal disruption. Major timber faults (Ridge trees "A" frames and trusses) require specialist advice and possibly advice  from the local council conservation department.

The performance of thatch depends on many factors, such as roof shape and design, pitch of roof, position - geographically and topographically - the quality of material and the expertise of the thatcher.

Determining how all of these interact is complex. Therefore, an understanding of likely performance is beyond all but the most experienced. Even then unusual eventualities can make roofs under perform or perform beyond the expected lifespan.

Average figures quoted from statistics are of little use as the permutations for averaging the above criteria would lead to a very untypical roof type. As stated judgements on performance and likely performance should be made in individual circumstances. For instance depending on circumstances it is possible for Long Straw to out last Water Reed.

Alterations:

See Conservation and Fire Precautions.

Consult with the thatcher who is to undertake the thatching work, or with some person who has the appropriate thatching experience, knowledge of other building and roofing forms.

Life of thatch can be extended significantly by appropriate repair.

Water penetration into thatch is limited.

Thatch does not (when working properly) absorb large amounts of water, (hence there should be no large increase to roof weight due to water retention).

Any water striking the apex of the roof is transferred down the roof surface from stem to stem until it drops from the eave. Water penetration, when it occurs is minimal and is usually due to capillary action.

Thatch is not by its nature prone to wind damage. Experience gained in the1987 winds in the South East showed thatch in a good light compared to some other roofing materials.

In the Netherlands the large pan tiled barns often have the hip extremities thatched In reeds to ensure limited wind damage.

Experience of hurricane force wind tests up to 100 mph in California again has shown thatch when applied correctly has good wind resistance. However, older and some existing thatches particularly in prone areas can benefit from a well fitted netting.

Long Straw thatching should always be securely netted to avoid bird penetration as is sometimes the case with Combed Wheat and some Water Reeds. Take advice from your thatcher.

The presence of moss is not necessarily detrimental to the thatch. It can in some circumstances appear unsightly. If required it is always desirable for a thatcher to remove the moss by the best means he considers.

Northamptonshire has some thatching techniques peculiar to this area but not exclusively so. The roof was held in place by cob (clay and dung) In some cases the first layer of thatch is the same date as the timbers and even the building date of the property, smoke staining, unusual materials and the mud itself may well be of huge historical importance  and requires the expertise of a crafts man used to these methods, the removal of such materials will contravene conservation regulations.

FIRE PRECAUTIONS

The incidence of Fire in thatch is often overstated. When fire in thatched properties occurs it is often started by means associated with fires starting in all kinds of housing. Therefore, all the normal and sensible precautions to avoid household fires should be taken.

Take advice from your local Fire Authority.

Fire precautions for thatch are given in " The Care & Repair of Thatched Roofs " published by The SPAB* and the COUNTRYSIDE AGENCY. It is recommended you purchase this leaflet, available from either of the publishing bodies.

Do not build, rebuild or design chimneys which pass close to or through thatch without appropriate expert advice.

Do not pass metal and other heat conducting flues through thatch.

Keep chimneys in good condition. Repoint or line as necessary.

Do not hold barbecues, bonfires or firework parties close to the house. Try to influence neighbours to be sensible with garden fires.

Keep an appropriate length of non kink hose at hand and if possible attached to a tap.

Ensure any person working in or on the house is aware of the dangers which unthinking use of naked flame can bring.

Do not allow use of blow lamps in the roof space.

Do not allow flame stripping of paint around eaves on thatched windows.

Plumbing joints can be made with compression fittings.

Run electric wire in conduit.

Television/radio aerials should be mounted if possible, so that they do not overhang the roof. The cable kept clear of the roof surface and not taken through the roof space/attic.

Any rethatch or major ridge job should have all material taken from around the chimney so that it can be checked and repaired if needed.

As the temperature changes in a thatch roof space do not vary as much as other roof coverings despite makers recommendations smoke alarms should be considered, low voltage mains powered linked alarms are available. Most thatch fires start in the roof space and due to the thickness may not be apparent for many hours.

CONSERVATION GRANTS VAT

Conservation.

You must have listed building consent by law before you attempt changes to any listed building, this includes the thatch. Speak to the conservation department of your Local Authority especially about any features you consider unusual. This is particularly important if you are about to re thatch or repair a thatched roof. Delays can be caused and work disrupted if you are not careful on this matter. Work can be stopped and reinstatement of existing features Insisted upon. Dialogue at an early stage between the owner, architect, builder, thatcher and Local Authority can avoid this and other difficulties which may occur. Also much useful advice can be gained from your Local Authority Conservation Department.

Grants

These are often available for rethatching and sometimes for repairing thatch. Grants usually fail Into two basic categories:

[1] An Historic Buildings Grant [2] An Environmental Health Grant

For [1] contact the Conservation/Planning Department of your Local Authority

For [2] contact the Environmental Health Department of your Local Authority where a grant is sometimes made depending on the rateable value.

A few thatched buildings are listed by the Department of the Environment as grade two star. In this case grant aid is sometimes available direct from English Heritage* Again contact through the conservation Department of your Local Authority.

VAT

Never assume zero rating on thatch.

Occasions for zero rating are rare and may include:-

Putting thatch on a new building

Rethatching a listed building where listed building consent has been give for a change in roof shape or design

Extensions to existing building.

Change from one thatch type to another even including the complete removal of thatch and replacement of rafters, does not mean zero rating.

Always have written agreement with the Customs and Excise on zero rating before you commence work.

Always have written agreement and consent with local Planning and Conservation department.

BUILDING FOR NEW THATCH AND EXTENSIONS TO EXISTING THATCHED PROPERTY

Consult with a good, experienced thatcher at the early design stages on roof construction, pitch, shape and overall design. Inform him of all alterations to the design.

Decide on the material to be used at the outset. There may be design, planning/conservation or material constraints.

Decisions of an informed nature will need to be taken on where any intended joins to existing thatch can be made. Existing material type and condition will need to be assessed.

Present thatch levels, thickness and related elevations will be due to the existing number of coats of thatch. It is possible the existing thatch cannot be matched with the application of a new single coat. This must be considered in the design or costed to allow the build up of new thatch to existing thickness.

Discuss with your thatcher at a very early stage to discover the options and their cost.

Make sure any person (even in a profession) has true expertise before accepting any comments related to the use and performance of thatch.

"The Thatchers Craft " published by the Rural Development Commission (Now The COUNTRYSIDE AGENCY) Known as the thatchers bible, sadly out of print but:-

 Now available for free download in PDF format at -:
http://www.hct.ac.uk/Downloads/cp_thatch.html

"The Care and Repair of Thatched Roofs" published by the Society for the Protection of Ancient Buildings (SPAB) and the contents of this file will be invaluable to the Builder/Architect.

This information was produced by The National Council of Master Thatchers Associations  with additions by Leo Wood

Full Specifications for thatch

COUNTRYSIDE AGENCY. John Dower House, Crescent Place, Cheltenham, GL50 3RA

Society for the Protection of Ancient Buildings. 37 Spital Square, London, E1 6DY. London Tel 01718368591

Royal Institute of British Architects 66 Portland Place London WIN 4AD Tel 0l71 5805533

 2 Marsham Street London SWIP 3EB Tel: 01712763000

Historic Buildings Division, English Heritage, Fortress House, 23 Saville Row, London, W1X 2HE Tel 01 973 3000

1999-2005  All Rights Reserved - see legal.

 

 

                                                        

 
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