Thatching styles and materials

[Bayliss]

I'm fortunate (I think) to live in a cottage that is thatched, the material is long straw and laid/applied? in a loose lay traditional method. So the roof looks wibbley wobbley with dips and bumps, rather nice looking in my opinion. Now compared to the other style of straw thatch that is laid in a tighter and much flatter smoother tradition, what are the differences in respect of wear and tear, if any?

 

[middi]

A picture would help.

Thatched rooves consist ( more or less ) of two types of thatch -long straw or reeds-

Straw is not as long lasting as reeds and needs regular " topping up", this involves removing a surface layer ( or the decayed layer) and replaced by a new layer of thatch. Eventually the whole lot needs to be replaced, it will not last for ever.

Your thatch may look very nice by the fact that it is all over the place, just make sure ( or have it checked) that it is not the decaying process that gives it that " higgledy piggledy" look. A good thatched roof, be it long straw or reeds, should be uniform, neat and straight ( apart from any natural sagging of the roof rafters, which can be quite normal)

Middi

 

[tobydog]

The following is a good read on long straw. I'm sure they are rare but it's fascinating that there are still very old houses out there that have their original base coat. We're reed. 30 years in and hopefully at least 20 to go (I hope)!!

http://www.buildingconservation.com/articles/longstraw/longstraw.htm

 

[Bayliss]

Thanks for replies and link which I shall click on shortly. Our roof has only just been re-thatched, well three years back now. The Thatcher that we employed is a craftsman and he is the third or fourth generation to continue the business. I was sure that I had read somewhere, years ago, that two types of thatching styles existed with long straw. The more straight and uniform as mentioned by Middi and the type on my roof which has a 'poured' on type look. Maybe I am getting mixed up in which case I may have a problem with my cottage's hat.
I shall take some pictures tomorrow but as to getting them up on this forum!! techi dimwit here.

 

[Jellyfire]

Hi Baylis, I think that it's the phrases 'wibbly wobbly bumps and dips' that got middi concerned, it makes it sound very much on its last legs, 'poured on' is a much less worrying description!

The poured on look is typical of long straw, ours is much the same. I presume it comes as a result of the depth of thatch, reed is removed and replaced when a roof is rethatched and typically is much more angular looking. With long straw is can be stripped of the top layers as Tobydog describes, eventually making a pretty deep layer of thatch. Our bottom layers seem to be original, about 500 years old, and the whole thatch is about 5ft deep, and you can see the different layers almost like tree rings.

Long straw is generally softer looking than reed anyway, and the extra depth is presumably what gives the look you are referring to as all the edges get softened and rounded

 

[Penners]

reed is removed and replaced when a roof is rethatched

That's right. You can add extra layers to a straw thatch, but not to a reed one. This has to be completely stripped and replaced.

But the ridge of a reed thatch will be straw - possibly with the addition of sedge.

 

[tobydog]

Jellyfire - with 5ft of straw I hope your chimney and any liner you might have are in excellent order. The contact point between the thatch and chimney is the flash point for most thatch fires when there is a leak of hot gases or general build up of heat. Do you use a woodburner, particularly one of the efficient modern and hot ones? You can get chimney heat sensors but they aren't cheap. Don't mean to scare you. We don't have the same issue with comparatively thin reed 12 - 14". Build up of heat is not normally a problem in our house at this time of year

 

[Jellyfire]

Tobydog, we've got two flues, the one which had a wood burner and was lined when we moved in has now been condemned (the stove and liner), was a bit of a miracle it never set the roof ablaze judging by the face of the chimney man when he saw it!Suffice to say we don't use that one now until we eventually get it replaced.

We've just had a new burner put in the other flue, with a rigid liner with an outer insulation layer, very reputable company that were recommended for thatch that installed it so is hopefully all safe now, touch wood!

 

[robgil]

If you look closely at some thatched roofs you might notice more and more thatchers using sawn and planed, treated timber instead of split hazel. :shock:

 

[Jellyfire]

Have you passed by our house on way to Tesco by any chance Robgil?

Is it bad form to have sawn timber rather than hazel then? Does
It have any problems associated with it or is it just aesthetic?

 

[88v8]

Another reason for straw/wheat rooves looking wibbly is that the ears/seeds on the ends of the stalks get incorporated into the roof, pretty much in a straight line at the end of the each raise. Rats like to eat the ears, and tunnel through the roof under the surface, munching the ears as they go. Eventually the surface above the tunnel starts to sag.
There is no way to repair this damage short of stripping the area, so look to your top-wiring :shock:

Not a problem with reed, as there's nothing to eat.

Ivor

 

[robgil]

Have you passed by our house on way to Tesco by any chance Robgil?

Is it bad form to have sawn timber rather than hazel then? Does
It have any problems associated with it or is it just aesthetic?

I cant make up my mind which house is yours, I've seen two very similar cottages out your way and I think one of them might be yours.
Perhaps not bad form to use sawn timber but it was a point put across to me by the thatcher who will be doing my roof, he grows his own straw and hazel and guaranteed the best traditional materials would be used. I doubt it would cause any problems, for me it would be purely aesthetic but I do like to see attention to detail when forking out huge amounts of hard earned on a straw roof.
I was told to choose a thatcher very carefully and not be misguided by deciding by price alone, which is what I was doing at the time.

 

[Jellyfire]

Cant really see ours from the main road, its near the tennis courts if youve ever turned off to go into Diss from the other side.

Our roof was only done a few years ago and seems to be in pretty good nick, so fingers crossed it won't need rethatching in the forseeable future, so the sawn timber will be staying on ours for a while yet, though now you've drawn my attention to it it's probably going to start annoying me!

I guess its tricky to choose a good thatcher, as you wouldn't know how good they were until 20 years down the line.

 

[robgil]

Cant really see ours from the main road, its near the tennis courts if youve ever turned off to go into Diss from the other side.

Our roof was only done a few years ago and seems to be in pretty good nick, so fingers crossed it won't need rethatching in the forseeable future, so the sawn timber will be staying on ours for a while yet, though now you've drawn my attention to it it's probably going to start annoying me!

I guess its tricky to choose a good thatcher, as you wouldn't know how good they were until 20 years down the line.

Sorry.
You can always have the timber replaced later if it niggles you enough.
I think the trick to thatch longevity is good maintenance, especially on mossy north facing roofs.

 

[biffvernon]

Is it bad form to have sawn timber rather than hazel then? Does
It have any problems associated with it or is it just aesthetic?

Hazel, the traditional material, has many advantages. When fresh, it can be split, twisted and bent to form the staple-like hoops that are used to hold straw thatch down. (You don't actually see these so aesthetics is not an issue. They are now sometimes replaced by steel or plastic version but these do not grow on trees, have to be bought rather than cut from a nearby coppice, promote the growth of factories rather than woodland, have a large carbon-footprint, do not last as long and are basically a crap substitute for the natural and traditional material. Where split hazels are seen, holding down the ridge thatch for instance, sawn timber is similarly a poorer material. It is probably imported from abroad and has to be treated with poison to make it as durable as untreated hazel. Sawing a piece of wood breaks the fibres at the surface allowing water to get in and promote decay, whilst split hardwoods are pretty much waterproof and will resist decay.

Short-cuts with traditional building methods are to be avoided.

 

[Bayliss]

As an aside to the main topic, we paid 1k for each 'Thatchers Square' of roof area to be thatched. That is a 10' x 10' thatched area and I understand that this is the pricing method always used by the profession. The ridge is included within the price but we paid a little extra for new flashing to chimney stack.