Building a chimney

[MattPope]

We have a chimney to be built as part of an extension and I'm a little surprised to see simple thermalite blocks being used without any internal flue. I was under the impression the chimney needed to be built with a proper masonry flue. I don't believe you can just stick in a flue liner as these are designed for existing chimneys with a flue.

Am I missing something?

Cheers,

Matt

 

[theoldun]

Insufficient information.
Is flue for open fire, closed solid fuel appliance, multi stove or gas fire?
Regards pldun

 

[^woody^]

It can be lined afterwards

 

[MattPope]

Sorry for lack of detail Oldun - valid point!

The plan will be to have a woodburning stove. At present the builders have just constructed a blockwork 'box'. What sort of liner would be fitted afterwards? I had thought there would be some sort of masonry tubing going in there as the chimney is built up but it seems not to be the case.

Hopefully this is all normal and nothing for the building inspectors to raise any concerns over.

Thanks.

Matt

 

[theoldun]

It can be lined afterwards

With respect woody, suggest you read Approved Document J. Items 1.27, 1.29, 1.4 and Table 2 Size of linings in chimneys.
OP, suggest you read materials for flues in 1.27.
Regards oldun

 

[^woody^]

With respect oldun, I suggest you look around the country to see all the chimneys which are relined and not rebuilt

 

[MattPope]

So I guess the question is what is going to be used to line the chimney now that the void has been built. It can't be a regular liner as these are only for relining existing flues.

Part J was quite interesting but if I get it right I need a masonry or clay type flue....Have the builders got it wrong?

Thanks for info.

Matt

 

[theoldun]

Woody,
As we are all being so polite, we will continue to carry on doing so

With respect oldun, I suggest you look around the country to see all the chimneys which are relined and not rebuilt

If you had read the post correctly you will note that the OP is not relining a flue, but building a new, repeat new masonry flue and stack.
Approved Document J item 1.27 clearly states that new masonry chimneys should be constructed with flue liners and masonry suitable for the intended appliance. Suitable masonry is also listed.
Item 1.28 and 1.29 give the lining requirements to achieve a class 1 flue and recess. Table 2 gives sizes of flues
If you build a class 1 flue then you can fit any appliance that you wish, although you may have to decrease the flues diameter with flexible flue lining for certain appliances.
Hope this meets with your approval woody. If not please feel free to come back when you have your funny hat on.
Regards oldun .

 

[theoldun]

.Have the builders got it wrong?

Matt

In a nutshell. Yes. Would also question what blocks have been used We always use brick.
Regards oldun

 

[^woody^]

Hope this meets with your approval woody.

It certainly does not

1.27 says nothing about needing to building in liners as the chimney is built. It just says that it should be lined.
The intention of 1.28 is to state that liners are required, and not just a flue formed in brickwork as per days of yore

1:28 gives the all important "liners to be installed in accordance with the manufacturers instructions". So if the manufacturer says put the flue in afterwards, then you do that

It's perfectly reasonable to build the chimney and then line it

 

[MattPope]

I seem to have caused a stir here. Thanks for the comments though. I guess I should call our BCO to discuss what the requirements are as another matter in the construction so far has caused some issues.

I must admit that I had expected the chimney to have been fitted with some sort of flue as it was being built and I did expect that it might have been built of brick rather than thermalite block.

What products are typically fitted after construction if teh flue is not built in at the time?

Thanks in advance as always.

Matt

 

[theoldun]

Hope this meets with your approval woody.

It certainly does not

Sounds like you are getting umpty with us woody. Put your purple hat on with the goose feather, may make you feel better.
QUOTE. 1.27 says nothing about needing to building in liners as the chimney is built. It just says that it should be lined.
Not correct, read on and it states, with acceptable mortar joints for the masonry and suitably supported and caulked liners.
QUOTE The intention of 1.28 is to state that liners are required, and not just a flue formed in brickwork as per days of yore
We started building in 225mm clay liners in the mid 60s. Prior to that we used to parge them and a fine job we used to make.
QUOTE 1:28 gives the all important "liners to be installed in accordance with the manufacturers instructions". So if the manufacturer says put the flue in afterwards, then you do that
We all know that installations should be carried out in accordance with manufacturers instructions, so the important part is all ways but loose
QUOTE It's perfectly reasonable to build the chimney and then line it
Its also perfectly reasonable to give someone a playful slap if they deserve it, but you try and explain that to Mr Plod.
We fully understand the designated T400 N2 3 G factory made twin wall 200mmdiameter rigid flue liners that go up the side of a fish and chip shop, and believe you me it is not possible to thread them up or down a brick flue, especially if there is a bend.
Just to throw one more fly in read section AD J item 1.41. Flexible flue linings should be used only to reline a flue and should not be used as the primary liner on a new chimney.
Matt, would suggest you consult with your building inspector as he is the lad to sign it of, or pay for a consultation with Hetas engineer..
Regards oldun

 

[^woody^]

There is no logical reason why flue liners need to be built in as works proceed, when other options are available

Above all, you are making the schoolboy error and forgetting the major fact that the Approved Documents are not the building regulations. The regulations require a separate flue from the chimney, that's all. How this is achieved can vary

 

[Nige F]

Interesting " debate"- as a Non Hetas/gas safe /building surveyor/no more than C+G qualified person I would think that IF the flue is for a multifuel stove then a twinwall stainless liner " might " be better than sectional ( pumice ) flue liners built in - because a fire in a flue from tar deposits might be less damaging if a b`ggered liner can be removed and replaced - than the damage that`s caused by a fire in a lined chimney - Just my 2d worth

 

[theoldun]

There is no logical reason why flue liners need to be built in as works proceed, when other options are available

Fair enough woody, then please educate us and list the other options.

Above all, you are making the schoolboy error and forgetting the major fact that the Approved Documents are not the building regulations. The regulations require a separate flue from the chimney, that's all. How this is achieved can vary

How does this grab yer for a schoolboy error

What Are Building Regulations?

The Building Regulations are minimum standards for design, construction and alterations to virtually every building. They are developed by the Government and approved by Parliament.

The Building Regulations also contain a list of requirements (referred to as Schedule 1) that are designed to ensure minimum standards for health, safety, welfare, convenience, energy efficiency, sustainability and to prevent misuse, abuse or contamination of water supplies.

These regulations set national standards for building work, whether it be on a major new development or an extension or alterations to your home. They cover all aspects of construction, including foundations, damp-proofing, the overall stability of the building, insulation, ventilation, heating, fire protection and means of escape in case of fire. They also ensure that adequate facilities for people with disabilities are provided in certain types of building.

Building Regulations are regularly being updated, and consist of parts A-P.

woody Note Part A-P which are the14 Approved documents

Leave you with two thoughts of Abe Lincoln
“You may fool all the people some of the time, you can even fool some of the people all of the time, but you cannot fool all of the people all the time.”
And
“I am not bound to win, but I am bound to be true. I am not bound to succeed, but I am bound to live by the light that I have. I must stand with anybody that stands right, and stand with him while he is right, and part with him when he goes wrong.”
Regards oldun