Questions and answers for architects,
builders and prospective owners of thatched properties
What is thatch?
Thatching in the UK means to cover a roof with material of a vegetable origin such as straw, reed, heather, bamboo leaves, grasses etc. The type of material chosen used to depend on its local availability. This is less the case today.
How does thatch keep weather out?
How does a super tanker made of iron and steel with a flat bottom stay afloat? The question how does thatch keep the weather out is seen by Thatchers in a similar way. A combination of its compactness and the steep pitch of a thatched roof mean water runs off the roof by dropping from one end of a stem of reed to another. A new thatch will only ever get wet about 1" down from the surface.
Why don't most thatch roofs have gutters?
Generally because of the thickness of the thatch the bottom projects far enough away from the walls of the property to shed the water away from the walls.
What therefore happens to the water run-off?
Some new properties have a soak-away trench - filled with small stones, but with a lot of properties the water just finds its own way of soaking into the ground or drying on the surface of the ground.
Can I have gutters?
Yes they lay on metal brackets and are generally made of timber and are V-shaped. Some people have them over doorways.
How thick is thatch?
In the UK new water reed or straw is generally 12" - 15" thick.
Why are some roofs a lot thicker than this?
With straw roofs layers are added to existing layers, sometimes these roofs can be 3' or 4' thick.
Is it the case the thicker the thatch the better?
No, it is not the thickness of the thatch, but the pitch of the reed on the roof that is the crucial element in shedding water. Often a thick coat of thatch will have a slacker pitch. The length of the reed or straw also has a role to play.
How long does a thatch roof stay new looking?
About 2 years. Most then turn a charcoal grey colour.
Can I spray my roof with anything to make it stay new looking?
Irish thatchers use a solution of copper sulphate, but this needs to be done regularly.
How long does a thatch roof last?
It depends on the material, it depends on the pitch, it depends on the aspect of the roof, and it depends on the workmanship. Generally water reed is thought to last the longest around 40 - 50 years.
Will a roof require any maintenance?
A new ridge will need to be fitted every 10-15 years and at this time the whole roof can be dressed and cleaned and any moss removed.
Why do some roofs have wire netting on them?
Netting is added for two reasons - first with new roofs it is to protect straw roofs from birds; it is also fitted to ridges for the same reason. Second with older roofs it adds protection from strong winds etc especially in exposed sites. Some Thatchers also put wire netting onto new water reed roofs.
Does a thatch roof attract mice, vermin, and spiders?
Any roof space will have spiders - thatched or not. Often if mice are in a thatched roof they too would be found in a non-thatched roof, especially in rural areas.
What is the ridge made of?
In the UK ridges are made from straw or sedge because this is easier to bend over and form a watertight bond at the apex.
Does it catch fire easily?
Not easily. Shut the thickest book you can find and try lighting its closed pages on the opposite side to its spine! Lack of air and compactness is the key as with water shedding.
Can the materials be fire-retarded?
Yes but not fire proofed! The material can either be sprayed on completion or the material dipped in a fire retardant before being applied to the roof. The Thatcher will carry out both of these tasks.
What about incorporating fire retardant measures in my roof?
A fire boarding, a fire foil or felt barrier, or thatchbatts that fit between the rafters can all be used.
Can I have real fires?
Yes no problem. Chimney heights should be well above the highest point of the thatch. Chimneys should have a lining and be well cleaned. Heat sensors that are specifically for chimneys on thatch roofs can also be installed.
Are thatched roofs expensive to insure?
Premiums are the lowest they've ever been; incorporating fire preventative measures makes insuring a thatched roof in the UK not much more than a slate or tiled roof.
Where can I get cheap insurance?
Speak to me.
How is thatch fixed to a roof?
Nailed, tied or stitched/screwed and with a recoating job pegged to a base coat.
Can any roof be thatched?
Yes so long as it is steep enough - 45 degrees or more is ideal.
I have an existing roof that I want to strip of tile and have thatched. What special construction features should I be looking at?
Thatch is very flexible. Most roofs require very little alteration. Please contact us for details.
I have a roof that is not quite 45 degrees, how long will it last if it was thatched?
Difficult to say. Even on many steep thatched roofs of 50 degrees + there are areas which have a slacker pitch, such as tops of dormer windows. One would not expect these to last as long as the body of the roof.
What about lead work?
With the exception of box gutters and gullies, all lead work is dressed down on to the surface of thatch i.e. around chimneys. We can do this for you.
How much does thatch weigh?
7lbs per square foot.
Do I need to put felt under my thatch?
No - But most roofs incorporate this for two reasons. It keeps the property dry whilst thatching work is taking place and obviates the need for tarpaulins. Second it prevents dust and loose bits of reed/straw falling into the roof space after thatching has been completed
How does a thatch roof compare to the cost of other roofs?
One must look at this over the lifetime of any roof and take into consideration all insurance costs, heating costs, down pipes and gutter costs and maintenance etc. Certainly more expensive than most other roofs.
Where will my thatch come from?
Ask your Thatcher. Most reed used in the UK is imported. Most countries have their own reed beds whether thatching has a tradition or not i.e. the United States.
Does the Thatcher work off scaffolding?
Yes apart from small maintenance and repair jobs. Law in the UK requires scaffolding.
How long will it take?
Ask your Thatcher. It depends on the size of his team, the size of the roof and how complicated it is.
Is there much mess?
On a re-thatch yes; also ceilings that abut the underside of rafters may gain hairline cracks in them. On a new thatch there is less dust and rubbish can be disposed of on a daily basis.
I live in a very exposed place; I want to have a thatched roof but am concerned about damage that strong winds will do?
Thatch will 'give' a little especially around the edges as it is not a solid construction like a tile or slate roof. Strong winds are therefore not a problem. As an additional item you could ask the Thatcher to apply wire netting to all elevations.
Is thatch a good insulator?
Yes, the adage cool in summer, warm in winter holds true.
I want to look into thatching but I don't know any architects who have ever come across thatch?
Don't worry this is generally the case even in the UK. Give us a call or better still get your architect to call us.
How much will cost to employ a thatcher to work on my roof?
Thatch is priced by area or "square"; 1 square equals 100 square feet. Patching work is priced by how long the work will take and materials, overheads, etc. Ridging work is priced by the linear foot or metre.
Checklist for you when you receive a quote and compare prices:
Does the quote include scaffolding, the disposal of waste, travelling and accommodation?
Can I compare quote items like for like within the quote (i.e. is my ridge going to have the same cut pattern - one may involve more work)?
How long will my thatcher be on site? A one man band may be cheaper but may be on your roof for 6 months, where as a larger team may do the same work in 4 weeks but charge you more!
Ask to see his guarantee in writing. Ask the Thatcher what happens to his guarantee if he should suddenly die or cease trading? Does he guarantee materials and/or his workmanship and for how long? Most importantly what does his guarantee exclude!
Why is thatch a craft?
Every load of materials is different; every Thatcher applies himself in a different way.
Do Thatchers need to gain qualifications?
To date no. There are courses that a very small number of trainee Thatchers go on and in the UK moves are being made to incorporate thatching under the National Vocational Qualification system.
How long does it take to learn to be a Thatcher?
I have been thatching since 1980 and I am still learning and hopefully improving. Maintaining quality whilst working at speed sets a very good Thatcher apart from others. Thatching is not rocket science but it is a hands on practical activity; ultimately much depends on the teacher as well as the pupil.
What do Thatchers do in the winter?
Carry on thatching. It's a job like any other - 12 months of the year.
What is the strangest true story you can tell me about thatch?
When I started thatching in East Anglia in 1980 a local paper carried the story of an elderly couple living in a thatched cottage that was being worked on by a Thatcher. The Thatcher found a Second World War bomb in the thatch!
